Hematopoietic Stem Cell Recipients Research Articles

Impact of chronic graft-versus-host-disease on intensive care outcome in allogeneic hematopoietic stem cell recipients

Chronic graft-vs-host-disease (cGvHD) is the most relevant long-term complication after allogeneic stem cell transplantation (HSCT) with major impact on non-relapse mortality, but data on intensive care unit (ICU) outcome are missing. In this retrospective, multicenter study we analyzed 174 adult HSCT recipients with cGvHD requiring intensive care treatment. Skin, pulmonary, liver, and intestinal involvement were present in 76.7%, 47.1%, 38.1% and 24.1%, respectively, and a total of 63.2% had severe cGvHD. Main reasons for ICU admission were respiratory failure (69.7%) and sepsis (34.3%). Hospital- and 3-year OS rates were 51.7% and 28.6%, respectively. Global severity of cGvHD did not impact short- and long-term survival. However, patients with severe liver cGvHD or the overlap subtype had a reduced hospital survival, while severe pulmonary cGvHD was associated with worse long-term survival. In multivariate analysis need for invasive ventilation (HR 1.08 (95% CI 1.02–1.14)) or hemodialysis (HR 1.73 (95% CI 1.14–2.62)) and <1 year since HSCT (HR 1.56 (95% CI 1.03–2.39)) were independently associated with a poorer survival. While the global severity of cGvHD does not per se affect patients’ survival after intensive care treatment, pre-existing severe hepatic, intestinal or pulmonary cGvHD is associated with worse outcomes.

Bcl11b-Edited Lymphoid Progenitors for the Generation of CAR-Engineered Natural Killer-like Cells with Potent Anti-Leukemic Activity

BACKGROUND: The transcription factor B cell CLL/lymphoma 11B (BCL11B) is indispensable for T lineage development of lymphoid progenitors. Tonic signaling of chimeric antigen receptors (CARs) during early phases of in vitro generation of hematopoietic stem cell (HSC)-derived lymphoid progenitors leads to suppressed T cell development and acquisition of NK cell-like properties (CAR-induced killer cells, termed CARiK cells) by suppression of BCL11B. Co-transplantation of CARiK cells into hematopoietic stem cell recipients mediates strong antigen-specific anti-leukemic effects. Here we investigated whether CRISPR/Cas9-based editing of Bcl11b would allow the generation of CARiK cells using clinically more relevant CARs w/o tonic signaling activity. METHODS: Antigen binders against murine CD123 were identified using phage display technology. High affinity binders were cloned into a 2nd generation murine CAR backbone (CD28CD3zeta configuration) and comparatively assessed for expression strength, functionality, specificity, and the lack of tonic signaling activity. Aiming for an all in one vector approach, a sgRNA sequence against Bcl11b was added to the construct for CRISPR-mediated gene disruption. Transduced murine LSK cells were then differentiated into lymphoid CARiK progenitors using the OP9-DLI feeder layer system. Double edited progenitors (8 x 106) and respective controls were co-transplanted into leukemia-bearing murine stem cell recipients. BCL11B suppression was assessed by Western-blotting, correlated with the appearance of a CARiK phenotype, and finally tested for in vivo functionality. RESULTS: A suitable CD123 CAR of high expression strength, specificity, and devoid of tonic signaling was generated. Despite the lack of tonic signaling, early stimulation via CD123 in culture was sufficient for some degree of NK-directed developmental shift. The degree of fratricide was limited. Early Bcl11b disruption allowed for further lymphoid cell differentiation. Bcl11b editing only let to complete BCL11B suppression as did the combined all in one vector construct (Figure 1A). CAR transduction w/o Bcl11b editing resulted in incomplete BCL11B suppression. After transduction with the lentiviral all in one construct, the strongest developmental NK cell shift was observed (Figure 1B). After co-transplantation of CARiK cells up to 100% leukemia free survival was achieved. Low expression strength of CD123 on physiologic hematopoiesis allowed for undisturbed recovery of myelopoiesis as compared to controls. CONCLUSION:Bcl11b editing of hematopoietic stem cell-derived CAR-engineered lymphoid progenitors allows the generation of a NK cell-like cell product with considerable anti-tumor activity. Genetic stability remains to be determined. Figure 1: Natural killer-like cell differentiation of HSC-derived mCD123 CAR-engineered lymphoid progenitors can be enforced by Bcl11b editing. (A) Partial suppression of BCL11B by early CAR-signaling and finally complete disruption by Bcl11b editing as shown by Western Blotting (iTom = neg. control). (B) The extent of BCL11B suppression correlates positively with the amount of NKp46+ cells within the CAR-expressing gate in flow cytometry analysis (n=3). (B) Statistics was performed using Student's t test (2 tailed). Data are shown as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Non-Myelofibrosis Chronic Myeloproliferative Neoplasm Patients Show Better Seroconversion Rates after SARS-CoV-2 Vaccination Compared to Other Hematologic Diseases: A Multicentric Prospective Study of KroHem.

Disease- and treatment-mediated immunodeficiency might render SARS-CoV-2 vaccines less effective in patients with hematologic diseases. We performed a prospective non-interventional study to evaluate humoral response after one and two doses of mRNA-1273, BNT162b2, or ChAdOx1 nCoV-19 vaccine in 118 patients with different malignant or non-malignant hematologic diseases from three Croatian treatment centers. An electrochemiluminescent assay was used to measure total anti-SARS-CoV-2 S-RBD antibody titers. After one vaccine dose, 20/66 (33%) achieved seropositivity with a median antibody titer of 6.1 U/mL. The response rate (58/90, 64.4%) and median antibody titer (&gt;250 U/mL) were higher after two doses. Seropositivity varied with diagnosis (overall p &lt; 0.001), with the lowest rates in lymphoma (34.6%) and chronic lymphocytic leukemia (52.5%). The overall response rate in chronic myeloproliferative neoplasms (CMPN) was 81.3% but reached 100% in chronic myeloid leukemia and other non-myelofibrosis CMPN. At univariable analysis, age &gt; 67 years, non-Hodgkin's lymphoma, active treatment, and anti-CD20 monoclonal antibody therapy increased the likelihood of no vaccine response, while hematopoietic stem cell recipients were more likely to respond. Age and anti-CD20 monoclonal antibody therapy remained associated with no response in a multivariable model. Patients with the hematologic disease have attenuated responses to SARS-CoV-2 vaccines, and significant variations in different disease subgroups warrant an individualized approach.

Intensive care of life-threatening complications in allogeneic hematopoietic stem cell recipients

Introduction. Life-threatening complications of allogeneic hematopoietic stem cell transplantation (allo-HSCT) can have a significant influence on the short-term and long-term prognosis in recipients of hematopoietic stem cells (allo-HSCs).Aim — to determine the life-threatening complications and the risk factors of their occurrence and to evaluate the short-term and long-term prognosis in critically ill allo-HSCs recipients.Materials and methods. All patients over the age of 18 who underwent allo-HSCT from 01.01.2012 to 01.01.2022 were included in the retrospective study. Patients were divided into two groups: those who required intensive care unit (ICU) admission and those who did not require ICU admission. In the group of ICU admitted allo-HSCs recipients the reasons of ICU admission, timing of their occurrence and the results of life support were recorded. The risk factors of life-threatening complications occurrence and prognostic factors were analyzed.Results. In total, 174 (26.7 %) of 652 allo-HSCs recipients required ICU admission. The risk factors of life-threatening complications were: allo-HSCT in patients with acute leukemia who did not achieve complete remission (hazard ratio (HR) = 2.10; 95 % confidence interval (95% CI): 1.28–3.44; p = 0.003), allo-HSCT without conditioning in patients with hematopoietic aplasia after chemotherapy (HR = 30.63; 95% CI: 8.787–107.04; p &lt; 0.001), graft failure (HR = 2.51; 95% CI: 1.58–3.97; p &lt; 0.001) and poor graft function (HR = 2.85; 95% CI: 1.6–5.05; p &lt; 0.001), acute graft versus host disease (GVHD) (HR = 2.04; 95% CI: 1.459–2.85; p &lt; 0.001). The main reasons of ICU admission were sepsis and/or septic shock (SS) (27.9 %), acute respiratory failure (23.9 %), neurological disorders (17.7 %). The type and periods of allo-HSCT influenced the timing and structure of critical illnesses. The ICU mortality rate after all ICU admissions and readmissions was 59.8 % with a maximum follow-up of 9 years. The risk factors of ICU mortality were the occurrence of critical conditions after +30 days of allo-HSCT, the need for mechanical ventilation and vasopressors. The overall survival (OS) rate of ICU admitted allo-HSCs recipients was 13.8 %. Sepsis and/or SS that occurred in the early phase after allo-HSCT were characterized by the most favorable long-term outcome (OS — 43.8 %) among all complications of the peritransplantation period. The OS of patients discharged from the ICU was worse than OS of patients who did not require ICU admission (34.6 % vs. 58.3 %; p = 0.0013). Conclusion. Transplant centers should have a specialized ICU because more than a quarter of allo-HSCT recipients experience life-threatening complications at different allo-HSCT periods. Sepsis and SS occurring in the early pre-engraftment phase had a more favorable prognosis than other life-threatening complications. The long-term outcomes in allo-HSCs recipients who survived critical illness are worse than in recipients who did not require ICU admission.

Antibody based conditioning for allogeneic hematopoietic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative therapeutic option for many patients with hematological malignancies and nonmalignant hematopoietic disorders. To achieve stable engraftment of donor hematopoietic stem cells (HSCs), recipient HSC deletion is needed to create space for incoming donor HSCs and donor HSCs must escape immune rejection by the recipient. Conventional allo-HSCT requires high dose of irradiation and/or chemotherapy to produce sufficient host stem cell and immune system ablation to permit donor HSC engraftment. However, these procedures also result in nonspecific tissue injury that can cause short- and long-term adverse effects as well as incite and amplify graft-versus-host-disease (GVHD). The delivery of targeted radiotherapy to hematopoietic tissues with the use of a radioimmunoconjugate (ROIC) as a part of transplant preparative regimen has shown clinical benefits. ROIC clinical data provide evidence for decreased relapse without increased transplant-related mortality by delivering higher targeted radiation to sites of malignancy than when given in a nontargeted fashion. An alternative approach to allo-HSCT has been developed and tested in preclinical mouse models in which nonmyeloablative preconditioning with low dose of the alkylating agent (busulfan) or lower systemic dose of irradiation combined with co-stimulatory pathway blockade (CTLA4-Ig, anti-CD40L monoclonal antibody) and/or immunosuppressive drugs have been used. Under these conditions, mixed chimerism and transplantation tolerance to fully MHC mismatched donor marrow was observed. Recently, several novel proof-of-concept antibody-mediated preconditioning methods have been developed that can selectively target hematopoietic stem and immune cells with minimal overall toxicity. Antibody-drug-conjugate (ADC) combined with reduced intensity conditioning or high dose ADC as single dose monotherapy have shown promise for allo-HSCT in preclinical models. The purpose of the current review is to discuss the literature exploring antibody-based conditioning that includes native antibody, radiolabeled antibody conjugates, and ADC for allo-HSCT.

Strong SARS-CoV-2 T-Cell Responses after One or Two COVID-19 Vaccine Boosters in Allogeneic Hematopoietic Stem Cell Recipients.

A full exploration of immune responses is deserved after anti-SARS-CoV-2 vaccination and boosters, especially in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although several reports indicate successful humoral responses in such patients, the literature is scarce on cellular specific immunity. Here, both B- (antibodies) and T-cell responses were explored after one (V3 n = 40) or two (V4 n = 12) BNT162b2 mRNA vaccine boosters in 52 allo-HSCT recipients at a median of 755 days post-transplant (<1 year n = 9). Results were compared with those of 12 controls who had received only one booster (BNT162b2 n = 6; mRNA-1273 n = 6). All controls developed protective antibody levels (>250 BAU/mL) and anti-spike T-cell responses. Similarly, 81% of the patients developed protective antibody levels, without difference between V3 and V4 (82.5% vs. 75%, p = 0.63), and 85% displayed T-cell responses. The median frequency of anti-spike T cells did not differ either between controls or the whole cohort of patients, although it was significantly lower for V3 (but not V4) patients. COVID-19 infections were solely observed in individuals having received only one booster. These results indicate that four vaccine injections help to achieve a satisfactory level of both humoral and cellular immune protection in allo-HSCT patients.

Investigation of typhlitis in bone marrow transplant patients in a stem cell transplant unit.

Typhlitis is a special type of enterocolitis that specifically develops in immunosuppressive patients with hematological malignancies. Typhlitis is a common consideration after bone marrow transplantation due to high-dose chemotherapy that is used in conditioning regimens those contain high-dose cytotoxic chemotherapeutic agents. Although there are several studies about typhlitis during chemotherapy or in leukemia patients, there is not enough data evaluating its relationship between stem cell transplant in adults. Therefore, the current study aimed to analyze the possible causes that may lead to the development of typhlitis in hematopoietic stem cell recipient patients. This retrospective study included 210 adult patients who underwent bone marrow transplantation between January 2017 and December 2019. Pediatric patients (patients younger than 18 years of age) were excluded. Patients’ data were evaluated to determine their effects on typhlitis and the mortality risk of the patients with typhlitis. The analysis of the variables was performed using the IBM SPSS Statistics for Windows version 26 (IBM Corp., Armonk, NY).Variables were analyzed at a 95% confidence level and a P value <0.05 was considered significant. Typhlitis developed in 23 (10.9%) transplant patients. Male sex, length of hospital stay, presence of febrile neutropenia, antibiotic and antifungal use, need for switching antibiotics, duration of neutropenia, diarrhea and antibiotic use in days were risk factors for development of typhlitis. It was observed that 100-days mortality was higher in typhlitis group reaching to a statistical significance (P < .05). In multiple logistic regression analysis, presence of mucositis and additional source of infection were determined as independent risk factors for the development of typhlitis in bone marrow transplant patients. This study provides valuable information for bone marrow transplant patients through an analysis of risk factors for the development of typhlitis. According to our results, mucositis and additional bacterial infections were found as risk factors for typhlitis therefore it would be beneficial for clinicians to consider these factors in patient follow-up. However, due to the retrospective nature of our study, prospective studies are needed to investigate risk factors and optimum treatment methods for typhlitis.

New Perspectives on Antimicrobial Agents: Maribavir.

Maribavir was approved by the U.S. Food and Drug Administration in November 2021 for the treatment of adult and pediatric patients with post-transplant cytomegalovirus (CMV) infection/disease that is refractory to treatment (with or without genotypic resistance) with ganciclovir, valganciclovir, cidofovir, or foscarnet. Maribavir is an oral benzimidazole riboside with potent and selective multimodal anti-CMV activity. It utilizes a novel mechanism of action which confers activity against CMV strains that are resistant to traditional anti-CMV agents, and also offers a more favorable safety profile relative to the dose-limiting side effects of previously available therapies. Maribavir was initially studied as an agent for CMV prophylaxis in solid organ and hematopoietic stem cell recipients, but initial phase III trials failed to meet clinical efficacy endpoints. It has been more recently studied as a therapeutic agent at higher doses for refractory-resistant (R-R) CMV infections with favorable outcomes. After an overview of maribavir's chemistry and clinical pharmacology, this review will summarize clinical efficacy, safety, tolerability, and resistance data associated with maribavir therapy.

Role of the intensive care in allogeneic hematopoietic stem cell transplantation

Introduction. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is often complicated by life-threatening conditions.Aim — an analysis of the life-threatening complications in recipients of allogeneic hematopoietic stem cells (allo-HSCs)Main findings. From 10 to 50 % of allo-HSC recipients need to be admitted to the intensive care unit (ICU) due to the development of life-threatening complications. The reasons for ICU admission are acute respiratory failure, sepsis, graft-versus-host disease, veno-occlusive disease, thrombotic microangiopathy, cytokine release syndrome, engraftment syndrome, etc. Conditioning regimen, donor type, stem cell source, underlying disease state and patient comorbidity are the risk factors associated with development of life-threatening conditions. The main prognostic factors of unfavorable ICU outcomes in allo-HSC recipients are the severity of multiple organ dysfunction and the need for organ support.

Efficacy of Inspiratory Muscle Training on Respiratory Muscle Strength in Hematopoietic Stem Cell Recipients: A Systematic Review and Meta-analysis

Objective: To investigate whether inspiratory muscle training improves respiratory muscle strength and function and reduces dyspnea and fatigue in hematopoietic stem cell recipients. Design: A systematic review and meta-analysis of randomized controlled trials. Participants: People with hematological neoplasms who underwent hematopoietic stem cell transplantation. Intervention: Inspiratory muscle training with POWER breath Plus, POWERbreathe, Classic, and Threshold devices, with a load of 40% of the maximum inspiratory pressure. Outcome Measures: The primary outcomes were maximal inspiratory pressure, maximal expiratory pressure, forced expiratory volume in the first second of expiration (FEV1), forced vital capacity (FVC), and the FEV1/FVC ratio. Secondary outcomes were dyspnea, fatigue, respiratory rate, peripheral O2 saturation, quality of life, and functional capacity. Results: The search identified 3 eligible studies with a sample of 108 participants. Maximal inspiratory pressure was higher in the intervention group in the 3 studies reviewed, with an average difference of −9.3 cm H2O, −31.94 cm H2O, and −16 cm H2O in relation to the control group after inspiratory muscle training. One study found an improvement in the distance covered in the 6-minute walk test (34.22 m) and in the distance covered in the modified incremental shuttle walking test (66.43 m) in the intervention group. Limitation: This systematic review includes only 3 randomized controlled clinical trials. Conclusion: Inspiratory muscle training is effective in increasing inspiratory muscle strength and functional capacity in bone marrow transplant recipients. However, its effects on fatigue and dyspnea remain uncertain.

Systemic antifungal strategies in allogeneic hematopoietic stem cell recipients hospitalized in french hematology units: a post-hoc analysis of the cross-sectional observational AFHEM study\ufeff

BackgroundInvasive fungal diseases (IFD) remain a major complication of allogeneic hematopoietic stem cell transplantation (alloHSCT) and are associated with high mortality rates in patients receiving alloHSCT. Antifungal prophylaxis is increasingly being used in the management of IFDs in patients receiving alloHSCT.MethodsA post-hoc analysis of the cross-sectional observational AFHEM study was carried out to describe the use of antifungal drugs in real-life clinical practice in alloHSCT recipients hospitalized in French hematological units.ResultsA total of 147 alloHSCT recipients were enrolled; most were adults (n = 135; 92%) and had received alloHSCT < 6 months prior to enrollment (n = 123; 84%). Overall, 119 (81%) patients received a systemic antifungal therapy; of these, 95 (80%) patients received antifungal prophylaxis. Rates of patients receiving systemic antifungal treatment were similar irrespective of transplant time, neutropenic, and graft-versus-host disease status. Among patients on systemic antifungal treatment, 83 (70%) received an azole, 22 (18%) received an echinocandin, and 16 (13%) received a polyene.ConclusionsThis work provides evidence of the antifungal strategies used in alloHSCT recipients hospitalized in French hematological units. Unlike earlier studies, the AFHEM study showed that prophylaxis appears to be the leading antifungal strategy used in alloHSCT recipients in France.

SARS-CoV-2 T-Cell Responses in Allogeneic Hematopoietic Stem Cell Recipients following Two Doses of BNT162b2 mRNA Vaccine.

Background: At variance to humoral responses, cellular immunity after anti-SARS-CoV-2 vaccines has been poorly explored in recipients of allogeneic hematopoietic stem-cell transplantation (Allo-HSCT), especially within the first post-transplant years where immunosuppression is more profound and harmful. Methods: SARS-CoV-2 Spike protein-specific T-cell responses were explored after two doses of BNT162b2 mRNA vaccine in 45 Allo-HSCT recipients with a median time from transplant of less than 2 years by using INF-γ ELISPOT assay and flow-cytometry enumeration of CD4+ and CD8+ T lymphocytes with intracellular cytokine production of IFN-γ and TNF-α. Results: A strong TNF-α+ response from SARS-CoV-2-specific CD4+ T-cells was detected in a majority of humoral responders (89%) as well as in a consistent population of non-humoral responders (40%). Conclusions: T-cells are likely to participate in protection against COVID-19 viral infection, even in the absence of detectable antibody response, especially in the first years post-transplant in Allo-HSCT recipients.

Identification of a novel allele HLA-C*03:560N by next-generation sequencing in a hematopoietic stem cell recipient.

A frameshift because of a single nucleotide deletion results in a novel null allele, HLA-C*03:560N.

Bacteremia in Hematopoietic Stem Cell Recipients Receiving Fluoroquinolone Prophylaxis: Incidence, Resistance, and Risk Factors.

BackgroundBacteremia is a common complication in hematopoietic stem cell transplant (HSCT) recipients. Prophylactic fluoroquinolone is recommended and used in these individuals. Breakthrough infections can occur with fluoroquinolone-resistant strains. We aimed to identify the incidence, resistance, and risk factors for bacteremia in HSCT recipients receiving fluoroquinolone prophylaxis.Materials and MethodsThis retrospective study was performed on patients who received fluoroquinolone prophylaxis and underwent autologous and allogeneic HSCT between 2015 and 2019. The incidence of bacteremia, comorbidity, treatment, and invasive procedures was compared in these patients with and without bacteremia.ResultsThere were 553 patients included in the study, 68 (12.3%) had bacteremia. The incidence of bacteremia is 8.2% of autologous HSCT recipients and 18.4% of allogeneic HSCT recipients. The significant risk factors associated with bacteremia were steroid-using (odds ratio [OR]:13.83, 95% confidence interval [CI]: 2.88 - 66.40), higher Charlson Comorbidity Index (CCI)-mean (OR: 1.57, 95% CI: 1.15 - 2.16), diabetes mellitus (OR: 4.29, 95% CI: 1.11 - 16.48) in autologous HSCT, steroid-using (OR: 6.84, 95% CI: 1.44 - 32.33), longer duration of neutropenia (OR: 1.05, 95% CI: 1.01 - 1.09) using central venous catheter (OR: 7.81, 95% CI: 1.00 - 61.23) in allogeneic HSCT. Seventy-three pathogens were isolated from a total of 68 bacteremia episodes. The most commonly occurring agents were Escherichia coli, Klebsiella pneumoniae and Enterococcus spp. Resistance to fluoroquinolones was 87.2%, 70.0% and 60.0% among these strains, respectively.ConclusionHigh CCI, diabetes mellitus, use of steroids and long-term neutropenia and use of central venous catheters were significantly associated with the breakthrough bacteremia in HSCT recipients receiving fluoroquinolone prophylaxis. Fluoroquinolone prophylaxis may reduce the incidence of bacteremia but may select strains resistant to fluoroquinolone.

From the Editor’s Desk...

From the Editor’s Desk...

700. Risk Factors and Molecular Epidemiology of Acute and Chronic Norovirus Infection at a Large Tertiary Care Cancer Center

BackgroundNorovirus (NoV) is the leading cause of viral diarrhea in patients with cancer. In this study, we describe risk factors associated with acute and chronic NoV infection in this patient population. MethodsWe identified 132 patients with NoV diarrhea (using stool RT PCR) between 2016-2020 at University of Texas MD Anderson Cancer Center (MDACC). Patient data, including demographics, clinical characteristics, NoV treatments, and complications were retrospectively extracted from charts. Stool samples were analyzed for NoV genogroups and genotypes. We compared characteristics and outcomes of patients with acute diarrhea (< 14day; AD) versus chronic diarrhea ( >14day or recurrences within 12 weeks; CD) and analyzed the data using Pearson Chi square or Fisher’s exact for categorical variables and Wilcoxon rank-sum test for continuous variables. ResultsOf 132 patients identified, 124 had an underlying cancer (39 solid tumor, 85 hematological malignancies, Table 1). On univariate analysis, CD patients were more likely to have a hematological malignancy (p=0.002), be a hematopoietic stem cell recipient (p= 0.013), have a history of gastrointestinal graft versus host disease (p= 0.011), or have received immunosuppressants or steroids in the 90 days before diarrhea onset (p=0.001, Table 2). CD patients had significantly lower white blood cell counts (p=0.038), absolute neutrophil counts (p=0.049), IgG levels (p= 0.001), and serum albumin levels (p=0.002) at the time of NoV diagnosis (Table 3). Patients with CD more often received symptomatic or NoV targeting treatment, including anti-diarrheal (p=0.005), nitazoxanide (p< 0.001), intravenous immune globulin (p=0.017), and oral IgG (p=0.042). CD patients more often had diarrheal recurrence in the first 4 weeks (p=0.001) or the second month (p< 0.001) after initial diagnosis and needed enteral or parenteral nutrition (p=0.004). We genotyped NoV in 67 patients (Figure 1), resulting in identification of the following genogroups: GI (n=9, 13%), GII.4 (n=23, 34%), and other types of GII (n=35, 52%). Genotype diversity was higher in patients with CD than AD (Figure 1). ConclusionIn patients with cancer, CD from NoV is associated with severe immunosuppression, is refractory to therapy and can be caused by a variety of NoV genotypes/genogroups. Disclosures Robert L. Atmar, MD, Takeda Vaccines, Inc. (Grant/Research Support) Mary Estes, PhD, Takeda Vaccines (Consultant, Grant/Research Support) Pablo C. Okhuysen, MD, FACP, FIDSA, Deinove Pharmaceuticals (Grant/Research Support)Ferring Pharmaceuticals (Consultant)Melinta Therapeutics (Grant/Research Support)Merck & Co. (Grant/Research Support)Napo Pharmaceuticals (Consultant, Scientific Research Study Investigator, Research Grant or Support)Singulex (Consultant)Summit Therapeutics (Grant/Research Support)

Coronavirus disease 2019 in immunocompromised patients: a comprehensive review of coronavirus disease 2019 in hematopoietic stem cell recipients.

Purpose of reviewImmunocompromised patients are notably vulnerable to severe coronavirus disease 2019. This review summarizes COVID-19 features and outcomes in autologous and allogeneic hematopoietic stem cell transplantation (HSCT) recipients.Recent findingsRecent findings suggest that HSCT recipients exhibit a high burden of comorbidities and COVID-19 clinical features almost similar to the general COVID population. Furthermore, HSCT recipients exhibit a protracted SARS-CoV-2 shedding, prolonging duration of symptoms and promoting the generation of highly mutated viruses. Last, most of studies report a higher COVID-19 mortality in HSCT recipients, mainly driven by age, comorbidities, time from transplantation, and immunosuppression because of both treatments and underlying hematological malignancy.SummaryFurther studies are warranted to determine the proper impact of HSCT-related immune disorders on COVID-19 outcomes, and to evaluate specific treatments and vaccination strategy in this high-risk population. Taken together, those findings emphasize the need for more rigorous surveillance and preemptive measures for all HSCT recipients.

Factors Associated With Cytomegalovirus Infection in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Prospective Single-Center Study.

The human cytomegalovirus is a notorious pathogen in the pediatric transplant setting. Although studies on factors in complicity with cytomegalovirus infection abound, the roles of age, sex, allogeneic hematopoietic stem cell transplant modality, and type of underlying disease (malignant vs nonmalignant) with regard to cytomegalovirus infection and viral load in children are seldom explored. Our aim was to examine the significance of these factors on cytomegalovirus infection and viral load in Serbian pediatric recipients of allogeneic hematopoietic stem cell transplant. Thirty-two pediatric recipients of allogeneic hematopoietic stem cell transplant to treat various malignant and nonmalignant disorders were prospectively monitored for cytomegalovirus infection. The real-time quantitative polymerase chain reaction was used for pathogen detection and quantitation. Demographic and virologic parameters were statistically analyzed with SPSS statistics software (version 20). Cytomegalovirus DNA was detected in 23 patients (71.9%). Infection occurred significantly more often (P = .015) in patients with haploidentical donors. The opposite was noted for matched sibling grafts (P = .006). Viral load was higher in female patients (P = .041) and children with malignant diseases (P = .019).There was no significant relationship between viral infection or load and medical complications. Transplant recipients presented with a high incidence of cytomegalovirus viremia. The modality of allogeneic hematopoietic stem cell transplant was associated with the frequency of cytomegalovirus infection. Age, sex, type of underlying disease, and medically relevant events were not conducive to occurrences of viremia. Notably, we observed substantial viral loads in female patients and patients with neoplastic diseases. Studies comprising larger populations are needed to better understand these results.

Long-term Persistence of Allosensitization After Islet Allograft Failure.

Allosensitization has been reported after discontinuation of immunosuppression following graft failure in islet transplantation (ITx) recipients, though duration of its persistence is unknown. We evaluated 35 patients with type 1 diabetes who received ITx, including 17 who developed graft failure (ITx alone, n = 13; ITx plus bone marrow-derived hematopoietic stem cells, n = 4) and 18 with persistent graft function. Panel-reactive antibody (PRA) was measured yearly for the duration of graft function within 1 y after graft failure at enrollment and yearly thereafter. In ITx alone graft failure patients, 61% (8/13) were PRA-positive at 6 y postgraft failure, and 46% (6/13) developed donor-specific anti-HLA antibodies (DSA to 2 ± 1 donors) during follow-up. The degree of sensitization was variable (cPRA ranging between 22% and 100% after graft failure). Allosensitization persisted for 7-15 y. Three subjects (3/13) were not allosensitized. In ITx plus bone marrow-derived hematopoietic stem cell recipients, cPRA-positivity (88%-98%) and DSA positivity persisted for 15 y in 75% (3/4) of subjects. Allosensitization was minimal while subjects remained on immunosuppression, but after discontinuation of immunosuppressive therapy, the majority of subjects (77%) became allosensitized with persistence of PRA positivity for up to 15 y. Persistence of allosensitization in this patient population is of clinical importance as it may result in longer transplant waiting list times for identification of a suitable donor in the case of requiring a subsequent transplant.

Risk of transfusion-transmitted hepatitis E virus infection from pool-tested platelets and plasma

Immunocompromised patients are at risk of chronic hepatitis E which can be acquired by blood transfusions. Currently, screening of blood donors (BDs) for HEV RNA with a limit of detection (LOD) of 2,000 IU/ml is required in Germany. However, this may result in up to 440,000 IU of HEV RNA in blood products depending on their plasma volume. We studied the residual risk of transfusion-transmitted (tt) HEV infection when an LOD of 2,000 IU/ml is applied. Highly sensitive individual donor testing for HEV RNA on the Grifols Procleix Panther system (LOD 7.89 IU/ml) was performed. HEV loads were quantified by real-time PCR. Of 16,236 donors, 31 (0.19%) were HEV RNA positive. Three BDs had viral loads between 710 and 2,000 IU/ml, which pose a significant risk of tt hepatitis E with any type of blood product. Eight BDs had viral loads of >32 to 710 IU/ml, which pose a risk of tt hepatitis E with platelet or plasma transfusions because of their higher plasma volume compared to red blood cell concentrates. Eight of these 11 potentially infectious BDs were seronegative for HEV, indicating a recent infection. Only 8 of 31 donors had viral loads >2,000 IU/ml that would also have been detected by the required screening procedure and 12 had very low HEV loads (<32 IU/ml). Screening of BDs with an LOD of 2,000 IU/ml reduced the risk of tt HEV infection by about 73% for red blood cell concentrates but by just 42% for platelet and fresh frozen plasma transfusions. Single donor screening (LOD <32 IU/ml) should lead to an almost 100% risk reduction. Immunocompromised patients, such as solid organ or hematopoietic stem cell recipients, are at risk of chronic hepatitis E, which can be acquired via blood transfusions. The risk of transfusion-transmitted hepatitis E in these patients may not be sufficiently controlled by (mini-)pool hepatitis E virus RNA screening of blood donors. Single donor screening should be considered to improve the safety of blood products.