Unexplained Neutropenia Research Articles

Atezolizumab plus chemotherapy versus placebo plus chemotherapy in untreated locally advanced or metastatic urothelial carcinoma (IMvigor130): final overall survival analysis results from a randomised, controlled, phase 3 study

IMvigor130 demonstrated statistically significant investigator-assessed progression-free survival benefit with first-line atezolizumab plus platinum-based chemotherapy (group A) versus placebo plus platinum-based chemotherapy (group C) in patients with locally advanced or metastatic urothelial carcinoma. Overall survival was not improved in interim analyses. Here we report the final overall analysis for group A versus group C. In this global, partially blinded, randomised, controlled, phase 3 study, patients (aged ≥18 years) with previously untreated locally advanced or metastatic urothelial cancer and who had an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled at 221 hospitals and oncology centres in 35 countries. Patients were randomly assigned (1:1:1), with a permuted block method (block size of six) and an interactive voice and web response system, stratified by PD-L1 status, Bajorin risk factor score, and investigator's choice of platinum-based chemotherapy, to receive atezolizumab plus platinum-based chemotherapy (group A), atezolizumab monotherapy (group B), or placebo plus platinum-based chemotherapy (group C). Sponsors, investigators, and patients were masked to assignment to atezolizumab or placebo (ie, group A and group C) and atezolizumab monotherapy (group B) was open label. For groups A and C, all patients received gemcitabine (1000 mg/m2 intravenously; day 1 and day 8 of each 21-day cycle), plus investigator's choice of carboplatin (area under curve 4·5 mg/mL per min or 5 mg/mL per min; intravenously) or cisplatin (70 mg/m2 intravenously), plus either atezolizumab (1200 mg intravenously) or placebo on day 1 of each cycle. Co-primary endpoints of the study were investigator-assessed progression-free survival and overall survival for group A versus group C in the intention-to-treat (ITT) population (ie, all randomised patients), and overall survival for group B versus group C, tested hierarchically. Final overall survival and updated safety outcomes (safety population; all patients who received any amount of any study treatment component) for group A versus group C are reported here. The final prespecified boundary for significance of the overall survival analysis was one-sided p=0·021. The trial is registered with ClinicalTrials.gov, NCT02807636, and is active but no longer recruiting. Between July 15, 2016, and July 20, 2018, 1213 patients were enrolled and randomly assigned to treatment, of whom 851 were assigned to group A (n=451) and group C (n=400). 338 (75%) patients in group A and 298 (75%) in group C were male, 113 (25%) in group A and 102 (25%) in group C were female, and 346 (77%) in group A and 304 (76%) in group C were White. At data cutoff (Aug 31, 2022), after a median follow up of 13·4 months (IQR 6·2-30·8), median overall survival was 16·1 months (95% CI 14·2-18·8; 336 deaths) in group A versus 13·4 months (12·0-15·3; 310 deaths) in group C (stratified hazard ratio 0·85 [95% CI 0·73-1·00]; one-sided p=0·023). The most common grade 3-4 treatment-related adverse events were anaemia (168 [37%] of 454 patients who received atezolizumab plus chemotherapy vs 133 [34%] of 389 who received placebo plus chemotherapy), neutropenia (167 [37%] vs 115 [30%]), decreased neutrophil count (98 [22%] vs 95 [24%]), thrombocytopenia (95 [21%] vs 70 [18%]), and decreased platelet count (92 [20%] vs 92 [24%]). Serious adverse events occurred in 243 (54%) patients who received atezolizumab plus chemotherapy and 196 (50%) patients who received placebo plus chemotherapy. Treatment-related deaths occurred in nine (2%; acute kidney injury, dyspnoea, hepatic failure, hepatitis, neutropenia, pneumonitis, respiratory failure, sepsis, and thrombocytopenia [n=1 each]) patients who received atezolizumab plus chemotherapy and four (1%; unexplained death, diarrhoea, febrile neutropenia, and toxic hepatitis [n=1 each]) who received placebo plus chemotherapy. Progression-free survival benefit with first-line combination of atezolizumab plus platinum-based chemotherapy did not translate into a significant improvement in overall survival in the ITT population of IMvigor130. Further research is needed to understand which patients might benefit from first-line combination treatment. No new safety signals were observed. F Hoffmann-La Roche.

Heterogeneous Genetic Landscape of Chronic Idiopathic Neutropenia Revealed By Whole Exome Sequencing

Background: Adultpatients with persistent, unexplained neutropenia who do not fulfill the diagnostic criteria of any underlying disease are characterized as chronic idiopathic neutropenia (CIN) cases.It is an exclusion diagnosis that can be established after a thorough clinical/laboratory investigation for any underlying causes, including negative anti-neutrophil antibody testing, inconclusive bone marrow (BM) aspiration/biopsy and normal cytogenetics. CIN patients regardless of their absolute neutrophil counts (ANC) usually display a benign and uncomplicated clinical course. Although the pathogenesis of CIN remains largely unknown, we hypothesize that a constitutional/congenital background might exist, at least in some cases, that have potentially escaped diagnosis during childhood. Aim of the study: To investigate the genetic landscape of neutropenia in CIN by conducting whole exome sequencing (WES) analysis in a number of adult CIN patients. Methods: We have performed WES in 16 adult (median age 59 years, range 30-72 years) patients (11 females and 5 males) with CIN according to previously published criteria (Fioredda F, et al Hemasphere. 2023). The patients had median ANC 1.2 x 10 9/L (range 0.4-1.6 x 10 9/L) for prolonged period and unknown neutropenia onset in most cases. Genomic DNA was extracted from peripheral blood samples, coding fragment libraries were prepared, sequencing performed on Illumina NovaSeq 6000 System, and data subjected to an in-house pipeline for bioinformatic analysis for variant calling and annotations. Singleton analyses were performed focusing on genes associated with congenital defects of phagocytes, BM failure (BMF) and immune deficiency and dysregulation. Mean depth of coverage was 70x and the mean number of variants/sample was 22553. Results: WES analysis identified 10 pathogenic/likely pathogenic (P/LP) variants in 10 patients. The variants consisted of 4 frameshift mutations, 3 nonsense mutations, 1 missense mutation, 1 splice-site mutation and 1 splice-region mutation. Pathogenic variants in congenital neutropenia (CN)-related genes included only a heterozygous mutation in G6PC3:c.511C>T,p.Gln171Ter (previously detected in one of our CN patients; Nikolouzakis TK et al, Ann Hematol. 2022). Pathogenic variants in genes associated with BMF were detected in two genes, namely FANCM:c.1492C>T, p.Gln498Ter and CTC1:c.3058C>T,p.Gln1020Ter, respectively. The majority of the pathogenic variants were found in genes associated with immune deficiency and dysregulation. These involved: (i) a heterozygous mutation in DCLRE1C:c.1784dup,p.Ile596fs (associated with immunodeficiencies affecting cellular and humoral immunity); (ii) a LP mutation in ORAI1:c.132_133del,p. Arg45fs and a pathogenic variant in SPINK5:c.1302+4A>T (related to combined immunodeficiencies with associated or syndromic features); (iii) a pathogenic variant in MEFV:c.2080A>G, p.Met694Val and a LP variant in PSMG2:c.703-2A>T (both genes associated with autoinflammatory disorders); (iv) a LP variant in IRF7:c.1089dup,p.Pro364Alafs (associated with defects in intrinsic and innate immunity); and (v) a LP variant in PEPD:c.738_739insGT,p.Ser247fs (associated with immune dysregulation). Regarding variants of undetermined significance (VUS) an average of 4.5 VUS variants per patient were detected in genes related to CN ( HAX1, VPS13B, LYST), BMF ( GATA2, SAMD9, CXCR4) or immunodeficiency ( TCF3). However, none of these patients display clinical symptoms typical of these conditions. Specifically, the majority of the patients presented with mild/moderate neutropenia and rarely with severe neutropenia, they have relatively normal BM biopsies and do not display major symptoms or signs related to severe immunodeficiency or immune dysregulation syndromes. Conclusions: This study is the first attempt of WES analysis in adult CIN patients and shows that there is a heterogeneous genetic landscape underlying the disease. More studies are required so that the detected P/LP variants and VUS can be associated with the clinical phenotypes to more accurately interpret their potential contribution to the neutropenia phenotype.

Clinical Characteristics, Management, and Allogeneic Hematopoietic Cell Transplantation of Patients with Toll-like Receptor 8 Gain-of-Function Mutations

Toll-like receptor 8 gain-of-function (TLR8 GOF) is a recently described inborn error of immunity due to germline or somatic mutations in the TLR8 gene and characterized by severe neutropenia, infections, lymphoproliferation, humoral immune defects, and in some cases, bone marrow failure. Treatment of TLR8 GOF has been challenging to date, and guidance for optimal therapy is lacking. We describe the clinical characteristics and management of 10 patients with TLR8 GOF variants, including the first female patient and further clinical outcome on the 6 patients initially reported with this disease with a focus on the role of allogeneic hematopoietic cell transplantation (HCT). All but one patient were male ranging from 0.5 months to 28 years at age of symptom onset. Eight patients had somatic mutations with variant allele frequencies of 7-26%; two patients had germline mutations. The 9 male patients all had severe neutropenia and varying degrees of anemia and/or thrombocytopenia. Oral ulcers, recurrent infections, hepatosplenomegaly, and hypogammaglobulinemia were common. Immune phenotype was variable, ranging from severe lymphopenia to marked T cell lymphoproliferation. Several patients had an inverted CD4:CD8 T cell ratio and skewing of T cell subsets to the terminal effector memory phenotype. Increased double-negative T cells were also observed. All patients had low class switched memory B cells. Bone marrows were hypo- to hypercellular with marked myeloid hypoplasia, and in most cases, with increased T cells, large granular lymphocytes, and/or lymphoid aggregates. Neutropenia was initially responsive to granulocyte colony stimulating factor (GCSF) +/- steroids in several patients but ultimately become refractory to therapy. Immunomodulatory agents and chemotherapy were unsuccessful. Six patients underwent allogeneic HCT; two patients died at 8 and 18 years without definitive therapy; and one patient was lost to follow-up. The female patient had germline disease and presented with pure red blood cell aplasia at 2 weeks of life and is scheduled to undergo HCT. Transplant data were available for 5 of 6 patients who underwent HCT. Age at transplant was 3 to 21 years. One patient who received a graft from a 7/8 HLA-matched unrelated donor developed severe veno-occlusive disease and secondary graft failure. The patient underwent a second transplant and ultimately died. Another patient received a matched sibling donor HCT while critically ill from Candida lusitaniae and mucormycosis infection with associated multisystem organ failure. The patient engrafted with 100% donor chimerism but died on day +15 post-HCT. The remaining 3 patients are alive and well 8 months to 2 years post-HCT. Two patients received grafts from HLA-matched donors (1 sibling and 1 unrelated) with reduced intensity conditioning and cyclophosphamide, mycophenolate mofetil and vorinostat for graft-versus-host disease (GVHD) prophylaxis. The third patient underwent a haploidentical HCT with myeloablative conditioning and post-transplant cyclophosphamide. Post-HCT complications included acute skin and/or gastrointestinal GVHD that was responsive to therapy in all patients, and severe lung GVHD in one patient. There were no major infectious complications. All three patients had full donor chimerism in myeloid and T cells with complete resolution of disease phenotype at last follow-up. The patient for whom detailed transplant data is not available received a haploidentical HCT. He developed mixed myeloid chimerism for which he received multiple donor lymphocyte infusions and was alive at last contact >3 years post-HCT. TLR8 GOF should be considered in male and female patients with severe, unexplained neutropenia refractory to GCSF, and particular care should be taken when investigating for mutations given the disease-causing variant allele frequencies as low as 7%. Neutropenia and immune dysregulation were refractory to all therapies in our cohort, and TLR8 GOF was fatal in two patients who did not receive definitive therapy. Allogeneic HCT is curative and should be considered without delay for medically suitable patients.

A Pragmatic Approach for Managing Unexplained Neutropenia in a Brain Tumor Patient

Cancer patients experience a decrease in blood counts either due to the myelosuppressive effect of oncological treatment or bone marrow infiltration due to distant metastases. Oncological interventions, such as chemotherapy, immunotherapy or large-field irradiation, are common causes of neutropenia, thrombocytopenia, or pancytopenia in cancer patients. Non-oncological reasons for the decrease in blood counts can be attributed to drug-induced, autoimmune diseases, or viral infections. Recently, case reports have been published for neutropenia/thrombocytopenia due to the Coronavirus disease (Covid-19) pandemic too. Here, we discuss a case of phenytoin-induced neutropenia in a brain tumor patient and a pragmatic approach for managing unexplained neutropenia, that is, neutropenia unrelated to cancer or oncological intervention. Timely recognition and timely intervention can prevent fatal outcomes.

Absolute Monocyte Count as Early and Safe Marker for Antibiotic Cessation in Febrile Neutropenia Without Etiology in Pediatric Oncology Patients.

There is no practice standard regarding antibiotic duration in children with cancer and unexplained febrile neutropenia (FN). We hypothesized that absolute monocyte count (AMC) and absolute phagocyte count (APC= ANC + AMC + bands) are more sensitive, earlier, and safe markers of antibiotic cessation compared with absolute neutrophil count (ANC). A retrospective review of FN episodes (FNEs) in pediatric oncology patients was conducted between 2009 and 2016. Included patients were afebrile for 24 hours and without an identified infectious source at antibiotic cessation. Primary endpoints, including recurrent fever, readmission, bloodstream infection, microbiologically documented infection, and adverse outcomes, were assessed 10 days after antibiotic cessation and compared among different bone marrow recovery parameters (ANC, AMC, APC). Secondary endpoints included length of FN stay, antibiotic-free days, and cost. Three hundred ninety-one FNEs in 235 patients were included. Three groups were compared based on ANC (cells/μL) at the time of antibiotic cessation: < 200 in 102 (26%), 200 to 500 in 111 (28%), and >500 in 178 (46%). No statistically significant differences in primary endpoints were identified among the 3 ANC groups; however, a trend toward unfavorable outcomes in the ANC ≤200 cells/μL group compared with the ANC >200 cells/μL was observed. Primary endpoints based on AMC >100 cells/μL at the time of antibiotic cessation showed statistically significant favorable outcomes compared AMC ≤100 cells/μL (80%, 88%, 90%, 89%, and 93% risk reduction in recurrent fever, readmission, new bloodstream infection, new microbiologically documented infection, and adverse events, respectively). Similar favorable results were seen when APC >300 cells/μL was used as a threshold for antibiotic cessation. The median length of stay for FN if discharged when AMC >100 cells/μL was 3 days shorter and associated with fewer unfavorable outcomes, thus resulting in fewer hospital days, fewer antibiotic days, and decreased cost. Our results suggest that AMC >100 cells/μL (regardless of ANC) or APC >300 cells/μL may be safe thresholds for empiric antibiotic cessation and result in reduced unfavorable clinical outcomes within 10 days postdischarge, reduced antibiotic days of therapy and reduced health care costs. Further prospective studies are needed to validate AMC as an accurate surrogate marker for antibiotic cessation in FNEs in children with cancer.

Severe congenital neutropenia due to G6PC3 deficiency: early and delayed phenotype of a patient

BackgroundSevere Congenital Neutropenia type 4 (SCN4), is a rare autosomal recessive condition, due to mutations in the G6PC3 gene. The phenotype comprises neutropenia of variable severity and accompanying anomalies.Case presentationWe report a male patient with confirmed G6PC3 deficiency presented with recurrent bacterial infections and multi-systemic complications. Our case was the first with a novel homozygous frameshift mutation in G6PC3. The patient demonstrated large platelets on his peripheral blood smear which is a rare presentation of this disease.ConclusionAs SCN4 patients could be easily missed, it is recommended to consider G6PC3 mutation for any case of congenital, unexplained neutropenia.

Prevalence of STAT3 mutations in patients with rheumatoid arthritis-associated T-cell large granular lymphocytic leukaemia and Felty syndrome.

Neutropenia is a key presentation of Felty syndrome (FS) and rheumatoid arthritis (RA)-associated T-cell large granular lymphocytic (T-LGL) leukaemia. Clonal rearrangement of T-cell receptor (TCR) gene supports the diagnosis of T-LGL leukaemia but not FS. Mutations in the signal transducer and activator of transcription 3 (STAT3) gene are highly specific for T-LGL leukaemia, but their prevalence in FS remains poorly clarified. The study included 100 patients with RA and unexplained neutropenia. TCR rearrangements were examined in blood (100 cases), bone marrow (47 cases), and spleen (12 cases) using the BIOMED-2 protocol. Patients were stratified into RA-associated T-LGL leukaemia cohort if a clonal TCR rearrangement was identified in any of the tested patient samples, and into FS cohort in other cases. Mutations in the STAT3 were examined using next-generation sequencing (NGS) technology in blood (100 cases), bone marrow (37 cases), and spleen (7 cases). STAT3 mutations were identified in 71% (49/69) patients with RA-associated T-LGL leukaemia and in 10% (3/31) patients with FS (p=4.7×10-8). Three samples from the RA-associated T-LGL leukaemia cohort and 5 samples from the FS cohort had STAT3 mutations in the absence of clonal TCR rearrangement. The results suggest that STAT3 mutations are significantly less common in FS than in RA-associated T-LGL leukaemia. Moreover, NGS can detect clones undetectable by fragment analysis. We speculate that in patients with RA and neutropenia, the detection of STAT3 mutations can point to T-LGL leukaemia even in the absence of clonal TCR rearrangement.

The Morphologic Spectrum of Myelokathexis in WHIM Syndrome and Germline CXCR4 Variants: New Insights into Cellular Changes in the Bone Marrow and Peripheral Blood

Introduction WHIM syndrome (WHIMs) is a rare disorder caused by germline CXCR4 mutations, classically characterized by warts, hypogammaglobulinemia, infection, and neutrophil retention in the bone marrow (BM), with distinctive morphology termed myelokathexis. Demonstration of myelokathexis by BM evaluation plays a key role in disease recognition and diagnosis. However, the spectrum of BM morphologic features and correlation with specific CXCR4 mutations are not well described. Moreover, diagnostically useful peripheral blood (PB) smear findings and morphologic changes after CXCR4 antagonist therapy are largely unknown. Methods We conducted a multinational, retrospective review of clinicopathologic features of patients with established WHIMs (n=20) or germline CXCR4 variants considered likely pathogenic or of uncertain significance (n=3), including 14 BM specimens and 10 PB smears. Assessments to date were performed by 2 observers in 6 cases and a single observer in the remainder. BM morphology was compared to other neutropenia disorders (Shwachman-Diamond syndrome, n=5; GATA2 deficiency, n=5; severe congenital neutropenia with ELANE variants, n=4) and patients without hematologic disorders (n=10), together "controls." Correlations and contingency analysis (2-tailed Fisher exact test) were performed using Prism v.9.4.0 (GraphPad Software). Results Median age at WHIMs diagnosis was 18.5 years (range, 0.1-53 years), with female:male ratio of 1.1:1. Recurrent infections, warts, and hypogammaglobulinemia were present in 100%, 53%, and 40% of cases, respectively. BM aspirate smears contained neutrophils with long intranuclear chromatin strands and hypermature condensed chromatin ("myelokathectic neutrophils") in all WHIMs cases, making up 32% to 80% (median 66%) of total neutrophils (Table). In comparison, neutrophils with myelokathectic changes were seen in 0% to 4% of control BMs. Myeloid hyperplasia (myeloid:erythroid ratio >4:1) was present in 50% of WHIMs and 4% of controls (P=.0028); vacuolated neutrophils in 92% of WHIMs (≤29% of total neutrophils) and 17% of controls (P<.0001); apoptotic neutrophils in 58% of WHIMs (1%-4% of total neutrophils) and 8% of controls (P=.0025); and nonparatrabecular neutrophil clusters on core biopsy in 3/3 WHIMs and 5% of controls (P=.0017). Vacuolated eosinophils and myeloid shift toward hypermaturity were present in WHIMs. There was no correlation between percentage of BM myelokathectic neutrophils and degree of CXCR4 truncation. BM in 2 patients with CXCR4 p.S341Y showed myeloid hyperplasia, increased neutrophil apoptosis, and infrequent myelokathectic neutrophils (5%-10%). Neutropenia was present in all untreated WHIMs. Myelokathectic neutrophils were present in PB of all patients with known WHIMs and accounted for 8% to 30% (median, 18%) of total neutrophils. Percentage of PB myelokathectic neutrophils showed an inverse correlation with absolute neutrophil count (ANC) (r=-0.783; P=.0074). Neutrophil apoptosis, neutrophil vacuolization, dysmorphic (hypogranular, hyperlobated, vacuolated, or apoptotic) eosinophils, and/or dysmorphic basophils were present in 80%, 30%, 70%, and 60% of WHIMs cases, respectively (Figure). PB in 1 patient with CXCR4p.D84H showed neutrophil hypolobation without myelokathectic morphology. CXCR4 antagonist therapy with plerixafor (n=4) [Dale et al. Blood. 2011] or mavorixafor (n=1) (interval, 4-12 h) resulted in increased white blood cell (WBC) count and ANC, with a similar proportion of myelokathectic neutrophils as before therapy. Conclusions In WHIMs BM specimens, the proportion of myelokathectic neutrophils is variable and may not be prominent; the classic finding of myeloid hyperplasia is only present in a subset of cases, which may result in underrecognition of the disease and delayed diagnosis. Neutrophil vacuolization and apoptosis, eosinophil vacuolization, and prominent neutrophil clusters may also prompt disease recognition. We establish characteristic PB morphologic features which, in a patient with unexplained neutropenia, may suggest a diagnosis of WHIMs, including myelokathectic neutrophils, neutrophil vacuolization or apoptosis, and dysmorphic eosinophils and basophils. CXCR4 antagonist therapy led to an increase of WBC/ANC, while pretreatment morphologic changes persisted after a short interval. Analysis of additional cases is ongoing. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Shwachman Diamond Syndrome with Arrhythmia as the First Manifestation a Case Report and Literature Review

ObjectiveAnalyze the different clinical manifestations and genetic characteristics of Shwachman diamond syndrome (SDS).MethodsThe clinical data of a case of neonatal onset Shwachman diamond syndrome with arrhythmia as the first manifestation were retrospectively analyzed, and the relevant literature was reviewed to summarize the clinical manifestations, genetic characteristics and treatment of Shwachman diamond syndrome.ResultsThe patient, female, age 1 month 24 days, with ventricular arrhythmia as the first manifestation, accompanied by growth retardation, liver damage, and persistent decrease in peripheral blood neutrophil count (< 1.5 × 109/l), no pancreatic exocrine gland dysfunction at the initial stage of the disease. Gene detection showed that the SBDS gene chr7:66,459,197, c.258+2T > C homozygous variation.ConclusionAlthough the classic manifestations of Shwachman diamond syndrome are pancreatic exocrine insufficiency, pancreatic adiposis and unexplained neutropenia, its clinical manifestations are complex and diverse, involving multiple systems. For suspected children, early genetic examination is helpful for subsequent diagnosis and treatment.

Toxicological Diagnosis of Severe Neutropenia Due to Levamisole

Introduction: Levamisole toxic syndrome may include several effects, such as bone marrow suppression, severe agranulocytosis, neurological symptoms, or cutaneous vasculitis. Methodology: This report emphasizes the importance of differential diagnosis in young patients with severe neutropenia by hair toxicological analyses. These analyses can reveal the presence of cocaine and his metabolites but also sometime levamisole, a synthetic drug, originally approved by the US Food and Drug Administration as an anthelmintic agent that is still encountered as one of the main contaminants of cocaine. Many physicians are not aware of this contaminant and do not take it into account when diagnosing cases of sudden severe neutropenia. Results: In cases of sudden otherwise unexplained neutropenia, the detection of levamisole in hair may represent the most efficient method for demonstrating the toxic effect of chronic levamisole exposure, because urine conventional drug testing often fails to identify the compound due to its rapid elimination (2-3 days).

Gene Heterogenicity Diagnosis on Children with Complicated Immunological and Hematological Abnormalities

Some abnormalities in peripheral blood of children coexist with abnormal immunological function,such as autoantibodies, humoral and /or cellular immunity disorders.It is difficult to diagnose in the past,especially in children suspected withImmune Thrombocytopenia and Evans syndrome.To explore accurate diagnostic method in children with complicated immunological and hematological abnormalities, 9 complicated cases with positive findings under 14 years old were studied. Gene mutations were screened with high-throughput sequencing, genetic data were analyzed using bioinformatics and clinical information analysis technology and the suspected pathogenic mutation were verified using Sanger sequencing technology. Interpretation of pathogenic mutation included biological significance, genetic significance and coincidence degree of clinical characteristics. In suspected cases , proband , parents and germline cells were examined as well.The initial diagnosis were: 3 cases of Immune Thrombocytopenia (the third was thalassemia with secondary ITP after hematopoietic stem cell transplantation), 4 cases of Evans syndrome, 1 EB virus-related Hemophagocytic syndrome , 1 case of unexplained hemolytic anemia and neutropenia. The main abnormal genes found were as follows respectively: WAS, MYH9, GP1BA,NF1+CBL, ITGA2,VWF, ABCG8, ERCC4,RPS19+LRBA.In the end ,they were diagnosed sequentially as Wiskott-Aldrich syndrome, Epstein syndrome/Fechtner syndrome/ Hemorrhagic disease platelet type 6, Von Willebrand disease/ Hemorrhagic disease platelet type 3, Juvenile Myelomonocytic Leukemia, Glycoprotein Ia deficiency / Hemorrhagic disease platelet type 6, II type Von Willebrand disease, Sitosterolemia, Fanconi anemia complementation group Q, Diamond-Blackfan anemia/Common variant immunodeficiency disease type 8.With multi-factor comprehensive analysis including the effect of mutation, mode of inheritance and clinical characteristics, mutations can be verified as causative agents.If gene sequencing of only hematological system diseases can not explain, it is suggested to do the whole exon mutation analysis of single gene genetic disease or CNVseq, mtDNAseq if necessary. Complex genetic defects exist in some complicated immunological and hematological abnormalities DisclosuresNo relevant conflicts of interest to declare.

Therapy Related Acute Myeloid Leukemia in Solid Tumors: Two Pediatric Case Reports and Review of the Literature

Introduction: Therapy-related acute myeloid leukemia is devastating late effects in solid tumors. The most frequent and lethal secondary malignancy is secondary acute myeloid leukemia t-AML. t-AML is a sequel of specific chemotherapeutic agents, specifically alkylating agents, and topoisomerase II inhibitors, commonly used in treating solid tumors. t-AML is relatively rare with a poor prognosis. Case reports: We are reporting two cases of t-AML. Case 1: A 13-year-old girl presented with left hand swelling in 2014. Biopsy confirmed the diagnosis as Ewing sarcoma. She started a chemotherapy regimen that contained alkylating agents and epipodophyllotoxins. In 2017, local recurrence occurred, and she received salvage chemotherapy (ifosfamide, carboplatin, and etoposide) followed by amputation of the left 4th finger. In 2020, she had a second local recurrence with unexplained prolonged neutropenia. Diagnosis of t-AML was confirmed by bone marrow aspiration. Case 2: A 5-years-old boy presented with an abdominal mass in July 2006. It was diagnosed as rhabdomyosarcoma and treated with alkylating agents. He showed a good response to the treatment initially. In September 2007, prolonged pancytopenia, neutropenia, and thrombocytopenia occurred. Diagnosis of t-AML was confirmed by bone marrow aspiration as it showed mild dysplastic, moderate marrow fibrosis. Conclusion: t-AML is of growing interest to the pediatric oncologist and requires further studies to develop pathways for leukemogenesis. We discussed two cases to highlight the importance of designing treatment regimens for solid tumors associated with t-AML.

Large Granular Lymphocytosis With Cytopenias After Allogeneic Blood or Marrow Transplantation: Clinical Characteristics and Response to Immunosuppressive Therapy

Large granular lymphocytosis (LGL)-or LGL leukemia-is a T- or NK-cell lymphoproliferative disorder that often results in cytopenias and autoimmune phenomena. Several studies have described LGL in a subset of patients after allogeneic blood or marrow transplantation (alloBMT), almost exclusively in the setting of asymptomatic lymphocytosis. Some have suggested an association with improved transplant-related outcomes. In contrast, clinically significant LGL after alloBMT is only described in small case reports. This study sought to assess the characteristics, significance, and response to treatment of LGL associated with unexplained anemia, thrombocytopenia, or neutropenia after alloBMT. We performed a retrospective analysis of 150 patients who were evaluated for LGL by peripheral blood flow cytometry (LGL flow) for unexplained cytopenias following initial engraftment after alloBMT from January 1 2012 to July 1, 2019. We identified patients with abnormally increased populations of LGL cells (LGL+) as assessed by Johns Hopkins Hematopathology. We collected demographic, transplantation, and LGL treatment information from electronic medical records. We compared LGL+ patients to patients with unexplained cytopenias with negative flow cytometry for LGL (LGL-) in this cohort. We also assessed change in blood counts after 4 weeks of immunosuppressive therapy in LGL+ patients. Cytopenias occurred at a median of 5.7 months (range 1-81) after alloBMT. The majority of the transplants were nonmyeloablative from haploidentical donors, and all patients received post-transplantation cyclophosphamide for graft-versus-host disease prophylaxis, consistent with the overall alloBMT characteristics at our center. We identified 70 patients with LGL and cytopenias, representing 47% of those evaluated by flow cytometry. There were no significant demographic or transplant-related differences between LGL+ patients and LGL- patients. The median age was 59, and 63% were male. LGL+ patients were more likely to have had cytomegalovirus (CMV) viremia (73% versus 28%, P < .0001), but not acute or chronic graft-versus-host disease. LGL+ patients had higher absolute lymphocyte counts (1500 versus 485/ mm3, P < .0001), a trend toward lower absolute neutrophil count (660 versus 965/mm3, P=.17), and lower neutrophil to lymphocyte ratio (0.39 versus 1.71, P < .001). There were no differences in overall survival or relapse-free survival. Of those with T-cell LGL, 45 were assessed for T-cell receptor clonality. In all, 22% were clonal, 53% oligoclonal, 4% polyclonal, and 20% indeterminate. Thirty (43%) LGL+ patients received immunosuppressive therapy (IST) for cytopenias. First-line treatment was corticosteroids for 25 (83%). Among those treated, there was an increase in median absolute neutrophil count from 720 before treatment to 1990/mm3 after 4 weeks (P=.0017). Thrombocytopenia and anemia showed at most a mild improvement with IST. LGL was a common association with otherwise unexplained cytopenias after alloBMT, almost always after prior CMV infection. LGL in the setting of cytopenias did not predict improved transplantation outcomes compared to those with cytopenias without presence of LGL. IST was effective at improving neutropenia associated with LGL after alloBMT.

Analysis of a single-institution cohort of patients with Felty's syndrome and T-cell large granular lymphocytic leukemia in the setting of rheumatoid arthritis

T-cell large granular lymphocytic leukemia (T-LGLL) is a lymphoproliferative disorder characterized by a persistent increase in the number of large granular lymphocytes (LGLs), neutropenia, and splenomegaly. Clinical manifestations of T-LGLL in the setting of rheumatoid arthritis (RA) are often identical to those in which one would suspect Felty's syndrome (FS). These disorders are distinguished by the presence of T-cell clonality, which is present in T-LGLL but not in FS. Mutations in the signal transducer and activator of transcription 3 (STAT3) and 5b (STAT5b) genes can be used as molecular markers of T-LGLL, but their prevalence in FS is unknown.Eighty-one patients with RA and unexplained neutropenia or/and an increase in the number of LGLs above 2 × 109/L were stratified into RA-associated T-LGLL (N = 56) or FS (N = 25) groups based on the presence or absence of T-cell clonality. STAT3 and STAT5b gene mutations were assessed in each group by means of allele-specific polymerase chain reaction assays. Clinical, immunological, laboratory data and the results of immunophenotyping of blood and bone marrow lymphocytes were also evaluated.Mutations of the STAT3 gene and an increase in the number of LGLs above 2 × 109/L were detected in RA-associated T-LGLL, but not in FS (39% vs 0% and 21% vs 0%, respectively). Mutations in the STAT5b gene were not observed in either group. Expression of CD57, CD16, and CD5−/dim on CD3+CD8+ T-lymphocytes was observed in both RA-associated T-LGLL and FS.STAT3 gene mutations or LGL counts over 2 × 109/L in RA patients are indicative of T-LGLL.

The Prevalence and Clinical Impact of Neutropenia Among Arab Population with Iron Deficiency Anemia an Experience from Qatar

Introduction Iron deficiency anemia (IDA) is a major public health issue, with widespread prevalence and negative impact on health care system. IDA occurs when iron stores diminish to the level that disturbs erythropoiesis and causes anemia. Neutropenia is an abnormal reduction in the number of neutrophils. A little is known about the association between iron deficiency anemia and neutropenia. The aim of this study is to investigate the prevalence of neutropenia in a large cohort of adult patients with IDA and to find possible correlation between neutrophil levels with haemoglobin concentration and iron stores. We studied associated infections in this neutropenic group. Materials and Methods We retrospectively reviewed the electronic medical records of 1567 patients attended haematology clinic with the diagnosis of IDA ((haemoglobin level less than 12 gm/dl for women, less than 13 gm/dl for men) over the past 2 years in Hamad Medical Corporation, Qatar. Other causes of anemia and anemia associated with any systemic or endocrine disease were excluded. The values of complete blood count (CBC) and iron parameters were collected. Neutropenia was defined as neutrophils count to be less than 1.5x 109/L Results Sixty four patients of the 1567 cohort with IDA had neutropenia (4.084%) Their mean neutrophils count = 1.18 +/- 0.28x 109/L before iron replacement. Neutrophil count increased significantly to 2.33 +/- 1x 109/L after iron therapy (p&amp;lt; 0.05) . No significant correlation was detected between neutrophil count on the one hand and iron level, iron saturation, TIBC, Transferrin and ferritin level on the other hand. Eight out of the 64 patients with neutropenia had infection at the time of presentation; 5 upper respiratory tract infections, 1 gastroenteritis, 1 lymphadenitis, 1 urinary tract infections. Five of these patients received antibiotics, with no complications reported. Discussion In our cohort with IDA the prevalence of neutropenia was 4.08%. In all patients, the neutrophil count returned to normal after proper iron therapy. The effect of iron deficiency on neutrophils count is through its effect on haematopoiesis progenitors and bone marrow microenvironment which regulates the production of cell lineages. In addition, the high level of erythropoietin (observed in IDA) has been shown to down-regulate neutrophil production in animal models. In another relatively smaller study on 516 patients with IDA, neutropenia was found in 17.6% However, unlike in our study the neutrophil count was correlated with Hb level. On the other hand in 97 patients with unexplained neutropenia, IDA was found in 2.1% with correction of neutrophil count after correction of the anemia. In addition, the associated infection rate was low and was treated without complications. Our findings support a possible link between IDA and neutropenia evident by the improvement of neutrophils count after iron replacement, (1.18 vs 2.33x 109/). Conclusions: The finding of neutropenia is not uncommon in patients with IDA. This neutropenia markedly improved after iron replacement. Iron is essential for proper development and maintenance of the immune system in general and further studies are required to elaborate further in this unique association. Figure 1 Disclosures No relevant conflicts of interest to declare.

Frequency and Functional Analysis of Myeloid-Derived Suppressor Cells (MDSCs) in the Peripheral Blood and Bone Marrow of Patients with Chronic Idiopathic Neutropenia (CIN)

Myeloid-derived suppressor cells (MDSCs) are myeloid cells with immunoregulatory properties characterized mainly by suppression of T-cell responses (Bizymi et al, HemaSphere 2019). They are divided in HLA-DRlow/-/CD11b+/CD33+/CD15+ polymorphonuclear (PMN-MDSCs) and HLA-DRlow/-/CD11b+/CD33+/CD14+ monocytic (M-MDSCs) subsets and they are implicated in inflammatory and malignant diseases. Chronic idiopathic neutropenia (CIN), is a (usually benign) neutrophil disorder characterized by persistent and unexplained neutropenia following a detailed clinical/laboratory investigation including anti-neutrophil antibody testing, bone marrow (BM) biopsy and karyotype (Dale &amp; Bolyard, Curr Opin Hematol 2017). Previous studies have shown that neutropenia in CIN is associated with increased apoptosis of BM granulocytic progenitor cells due to an inflammatory BM microenvironment consisting of oligoclonal T-lymphocytes, proinflammatory monocytes and proapoptotic cytokines. The aim of the present study is to explore the possible involvement of the MDSCs in the pathophysiology of CIN by investigating their number in peripheral blood (PB) and BM in association with their functional characteristics. We have studied 100 CIN patients and 49 age- and sex-matched healthy controls. The patients fulfilled the previously described diagnostic criteria for CIN (Papadaki et al, Blood 2003) and had mean neutrophil counts 1095.67 ± 479.52 (median 1215, range 100-1700). MDSC subsets were quantitated by flow cytometry in the PB mononuclear cell (PBMC) fraction using the combination of CD33PC7/CD15PC5/HLA-DRECD/CD14PE/CD11bFITC monoclonal antibodies and the Kaluza analysis software. MDSC subsets were also studied in the BMMC fraction of 24 CIN patients and 8 healthy controls from the study population. The T-cell suppression function of patient MDSCs was evaluated in coculture experiments of immunomagnetically sorted, CFSE stained, normal CD3+ cells with immunomagnetically sorted M-MDSCs and PMN-MDSCs from 4 patients and 4 healthy donors using recombinant human IL-2 as activating factor. CFSE staining was detected in the CD3+ cells on day 0 and day 3 of coculture and analysis was performed with the Fcs Express 7 software. Statistical analysis was performed with the Statistica software. We found that the proportion of PB M-MDSCs was statistically significant lower in CIN patients (1.45% ± 1.82%) compared to controls (3.68% ± 3.12%, Mann-Whitney test, p &amp;lt; 0.0001) (Figure a) whereas the proportion of PB PMN-MDSCs, although lower in patients, did not differ significantly from the controls. The proportion of BM M-MDSCs did not differ significantly between CIN patients and controls whereas the proportion of BM PMN-MDSCs was statistically significant lower in patients (13.27% ± 11.27%) compared to controls (19.49% ± 4.46%; Mann-Whitney test, p = 0.0291) (Figure b). Paired analysis showed that the proportion of PMN-MDSCs were higher in the BMMC compared to PBMC fraction in both CIN patients (13.27% ± 11.27% vs 1.14% ± 1.64%, respectively; Wilcoxon test, p = 0.005) (Figure c) and healthy controls (19.49% ± 4.46% vs 9.92% ± 9.08%, respectively; Wilcoxon test, p = 0.0118). Interestingly, the proportion of increase of PMN-MDSCs (in BMMC vs PBMC fraction) was significantly higher in patients (86.71% ± 21.26%) compared to controls (55.95% ± 38.59%; Mann-Whitney test, p = 0.0357) (Figure d). The above data indicate low production of PMN-MDSCs in CIN patients compared to controls but a trend for accumulation of these cells in patients' BM. No statistically significant difference was documented in paired analysis of M-MDSCs between BMMC and PBMC fractions in either CIN patients or healthy controls. Patient PMN-MDSCs and M-MDSCs displayed normal capacity to suppress T-cell proliferation as was indicated by the T-cell generations in coculture experiments of normal CD3+ cells in the presence or absence of patient MDSCs (Figure e). In conclusion, CIN patients display low proportion of MDSCs in the PB and lower proportion of PMN-MDSC in the BM compared to normal individuals. Patient MDSCs display normal capacity to suppress T-cell activation. The low proportions of MDSCs may sustain the inflammatory process associated with CIN whereas the accumulation of PMN-MDSCs in the BM represents probably a compensatory mechanism to suppress the inflammatory processes within patients' BM microenvironment. Figure Disclosures Papadaki: Genesis pharma SA: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Neutropenia in Incarcerated Adolescents Secondary to Intranasal Quetiapine Misuse.

Objective: Between April 2015 and May 2016, a number of young males incarcerated at a Youth Justice center in New South Wales, Australia, were noted to have unexplained and significant neutropenia. None of the adolescents were prescribed quetiapine; however, it was prescribed for other young people in the center for this time period. The authors undertook a case series review to investigate the cause of this neutropenia. Methods: Case series review, including review of all pathology, electrocardiograms, medication charts, and medical file notes. Results: Quetiapine was used in the center; however, none of the young people with neutropenia were prescribed quetiapine (or any other medication causing neutropenia). During the assessments of these young people, it was found that the administration of quetiapine had changed during this time period to using pulverized quetiapine powder, administered after hours to young people when there were no health center staff available to supervise. On questioning, two neutropenic young people admitted to "snorting" diverted quetiapine powder. All instances of neutropenia resolved once the medication was removed from the center. Conclusions: Quetiapine has a high potential for abuse, especially in custodial settings. Quetiapine should never be crushed as this increases the potential for diversion, misuse, and serious side effects. Quetiapine misuse should be considered part of the differential diagnosis of unexplained neutropenia, especially in a setting where the drug is available.

Fresh Versus Cryopreserved/Thawed Bispecific Anti-CD19/CD20 CAR-T Cells for Relapsed, Refractory Non-Hodgkin Lymphoma

Introduction Chimeric Antigen Receptor modified T (CAR-T) cell therapies have revolutionized the relapsed, refractory B cell malignancy landscape. Due to the complex steps involved with cell production, some third-party companies require T cells to be cryopreserved prior to shipping, while most manufacturers deliver modified CAR-T cells to the treating center in a cryopreserved state. This is vastly different to the approach taken with traditional cell based therapies, specifically allogeneic transplant (allo-HCT), an immunological treatment that relies on a graft-versus-tumor (GVT) effect to prevent disease relapse. Historically, "fresh" stem cells were felt to be superior to cryopreserved products due to concerns that cryopreservation may damage T cells and other mononuclear cells delaying engraftment and limiting GVT reactivity. As a result, in clinical practice most allo-HCT products are still given as fresh infusions without cryopreservation. In a Phase 1 clinical trial evaluating the safety of a bispecific anti-CD19, anti-CD20 CAR (LV20.19CAR), CAR-T cells were produced in a point-of-care fashion utilizing the CliniMACS Prodigy device. Local manufacturing allowed flexibility to administer either fresh LV20.19CAR-T cells without cryopreservation, or if indicated, thawed CAR-T cells post-cryopreservation. Methods Patients (pts) were treated on a Phase 1 dose escalation + expansion trial (NCT03019055) to demonstrate safety of 41BB/CD3z LV20.19CAR-modified T cells for adults with relapsed, refractory B cell NHL including DLBCL, MCL, FL, and CLL. The starting dose was 2.5x10^5 cells/kg with a target dose of 2.5x10^6 cells/kg. All pts received low dose fludarabine (30 mg/m2) x 3 days +cyclophosphamide (500 mg/m2) x 1 day for lymphodepletion. In the Phase 1 dose-escalation cohorts, pts received fractionated CAR-T cells over two days (30% on Day 0 and 70% on Day+1), while expansion cohort pts received CAR-T cells as a single infusion. The goal for all pts was to infuse fresh CAR-T cell prior to cryopreservation, however, CAR-T cell could be cryopreserved and infused at a later date for clinical / logistical reasons. Results A total of 20 pts received LV20.19CAR T cell therapy (Table 1). Fourteen pts received fresh CAR-T cells immediately post-harvest, 5 pts received post-thaw CAR-T cells, and 1 patient received a mixed fresh/cryopreserved product and was not included in this analysis. Reasons for cryopreserved administration was delay due to active infection (N=3), patient preference (N=1), and unexplained neutropenia (N=1). Among 19 evaluable pts, the CR rate (79% vs 40%), mean ferritin, mean CRP, and incidence of CRS and neurotoxicity were all higher in the fresh infusion group (Table 1), but not statistically significant. In terms of LV20.19 CAR-T product characteristics, mean cell viability at infusion was 93% for the fresh infusion group versus 63% for cryopreserved pts (p&lt;0.01). Point-of-care administration allowed final cell doses to be adjusted for diminished viability among pts receiving cryopreserved product. Figure 1 demonstrates the in-vivo expansion and persistence of LV20.19CART cells among fresh versus post-thaw pts. The peak percentage of CAR-T cells within the CD3 compartment was higher in pts given fresh cell infusions (Figure 2), but was not statistically significant (p=0.08). Conclusions Cryopreservation is known to diminish cell viability and increase clinical costs associated with freezing and storage. To date, there is limited clinical data evaluating outcomes of pts receiving fresh CAR-T cells compared to thawed CAR-T cells post-cryopreservation. Although it is presumed that in-vivo CAR-T cell activity is comparable in both scenarios, among our pts, both cell viability and in-vivo expansion favored pts who received a fresh infusion. Unlike third-party CAR-T cell products where viability is unknown at the time of infusion, we adjusted the final dose to accommodate decreased cell viability. CR rates and incidence of CRS and NTX were higher among fresh infused pts suggesting greater in-vivo activity, although findings were not statistically significant, partially a result of the small sample size. While our findings are limited by small numbers in each cohort and variability in cell dose and diagnosis, these data suggest that cryopreservation of CAR-T cells may impact clinical responses and is a logistical step that needs further investigation. Disclosures Shah: Cell Vault: Consultancy, Equity Ownership; Oncosec: Equity Ownership; Lentigen: Honoraria, Research Funding; Exelexis: Equity Ownership; Geron: Equity Ownership; Celgene: Other: Advisory Board; Incyte: Consultancy; Oncosec: Equity Ownership; Kite Pharma: Other: Advisory Board. Zhu:Miltenyi Biotec: Research Funding. Schneider:Lentigen Technology, A Miltenyi Biotec Company: Employment. Krueger:Lentigen Technology, A Miltenyi Biotec Company: Employment. Worden:Lentigen Technology, A Miltenyi Biotec Company: Employment. Hamadani:Sanofi Genzyme: Research Funding, Speakers Bureau; Otsuka: Research Funding; ADC Therapeutics: Consultancy, Research Funding; Takeda: Research Funding; Celgene: Consultancy; Janssen: Consultancy; Pharmacyclics: Consultancy; Merck: Research Funding; Medimmune: Consultancy, Research Funding. Dropulic:Lentigen Technology, A Miltenyi Biotec Company: Employment. Hari:Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Amgen: Research Funding; Spectrum: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding; Cell Vault: Equity Ownership; AbbVie: Consultancy, Honoraria. Johnson:Miltenyi Biotec: Research Funding; Cell Vault: Equity Ownership.

Mutation-Specific Dose Reduction in Functional SRP54 Protein Causes Isolated or Syndromic Neutropenia with Shwachman-Diamond-like Features

Sequencing analyses are increasingly performed on patients presenting with suspected congenital disease but lacking classical mutations linked to the presented phenotype. However, in case a novel mutation is found, its causal contribution to the patients' clinical symptoms is yet unclear and requires further exploration in functional studies. Here we use the zebrafish model to analyze the functional relevance of heterozygous SRP54 gene mutations identified in patients with unexplained neutropenia (T117del) or Shwachman-Diamond like disease involving severe neutropenia and exocrine pancreas insufficiency (T115A, G226E) (Carapito et al, 2017). The function of wildtype SRP54 protein was explored in hematopoiesis and pancreas development using two different antisense morpholino oligonucleotides (MO) and a zebrafish srp54 mutant. Reduced neutrophil numbers were observed in MO versus control injected fish when analyzed by WISH for mpx or using Tg(lyz:DsRed) and Tg(mpx:eGFP) lines. Morphants displayed not only quantitatively but also qualitatively impaired neutrophils, which migrated less to injury sites in tail fin injury assays. Furthermore, exocrine but not endocrine pancreas impairment was observed in MO versus control injected fish. Both neutrophiles and exocrine pancreas development could be rescued by co-injection with wildtype SRP54 mRNA.Interestingly, in the corresponding Sanger mutant, homozygous srp54-/- fish display not only most severe neutropenia but also gross developmental defects which cause early lethality at 2 days post-fertilization and thus impede assessment of pancreas development. Heterozygous srp54+/- fish are viable, show less severe neutropenia than homozygous fish and, interstingly, have no exocrine pancreas defect. The delineated experiments explore thus the effects of different dosages of residual functional SRP54 protein (wildtype > srp54+/- > morpholino treated > srp54-/-) on phenotypic manifestation. The obtained results indicate that the dose of residual SRP54 protein that can functionally act within the SRP may dictate disease phenotype in patients with SRP54 mutations (neutropenia only > more severe neutropenia and exocrine pancreas defects > most severe neutropenia, early lethality).We thus hypothesize that the different mutations observed in patients differentially affect the functionality of the residual wildtype SRP54 protein and thus associate with isolated neutropenia (T117del) or more severe disease with Shwachman-Diamond like features (T115A, G226E). To mimic the heterozygote mutation status observed in patients, we injected the different mutated mRNAs in srp54+/- zebrafish. None of the injected mRNAs was able to rescue the neutropenia phenotype, indicating that all mutated proteins are functionally impaired. Confirming our hypothesis, injection of T115A and G226E in fact further aggravated neutropenia and additionally induced exocrine pancreas defects, while T117del did not.Taken together, these analyses support the notion that full deletion of SRP54 is not compatible with life and therefore homozygous SRP54 are not observed in patients. Instead, heterozygous SRP54 mutations may cause only neutropenia or alternatively the more severe Shwachman-Diamond like syndrom, depending on the nature of the underlying mutation (either functional null or dominant negative). DisclosuresNo relevant conflicts of interest to declare.

Neutropenia caused by hairy cell leukemia in a patient with myelofibrosis secondary to polycythemia vera: a case report

BackgroundPolycythemia vera is a myeloproliferative disease that sometimes evolves to myelofibrosis, causing splenomegaly and neutropenia. In this case report, we describe a patient with polycythemia vera and unexplained neutropenia who later turned out to also have hairy cell leukemia.Case presentationA middle-aged Caucasian man with polycythemia vera presented to our hospital with chronic mouth ulcers. Later he developed leukopenia and pancytopenia. Bone marrow biopsies showed fibrosis. Further morphological analyses of bone marrow and blood smears revealed probable transformation into acute myeloid leukemia. However, there were also cells indicating hairy cell leukemia. Morphological and immunohistochemical analyses later confirmed the presence of hairy cell leukemia in biopsies that had been present for 3 years. Treatment with cladribine temporarily reversed the patient’s neutropenia.ConclusionsHairy cell leukemia may mimic development to myelofibrosis in patients with polycythemia vera.