Hemophagocytic Lymphohistocytosis Research Articles

English

English

Hemophagocytic lymphohistocytosis presenting as septic shock in a neonate

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening disease that usually occurs in infants and young children. It is characterized by severe hyper inflammation due to uncontrolled proliferation of activated lymphocytes and monocytes which are morphologically normal cells. This can lead to production and release of immense number of cytokines referred to as cytokine storm. It is typically a systemic disease with multiorgan involvement. Here we report a case of HLH in a twenty-eight days old baby presenting a clinical picture of septic shock, persistent metabolic acidosis multiple organ failure and disseminated intravascular coagulation (DIC).

L-DEP Is an Effective Treatment for Adult and Adolescent Patients with Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis

Epstein-Barr virus-associated hemophagocytic lymphohistocytosis (EBV-HLH) is the most frequent subtype of secondary HLH with infectious triggers. In addition to meet the HLH-2004 diagnostic criteria, the diagnosis of EBV-HLH requires the evidence of EBV infection and exclusion of primary HLH and lymphoma-associated HLH. The prognosis of EBV-HLH is generally dismal. To assess the efficacy of current treatment protocols in adult and adolescent patients with EBV-HLH, we retrospectively analyzed 171 HLH patients presented at our institution from March 2009 to April 2016. Of those, 133 patients were EBV-HLH; 35 patients were lymphoma-associated HLH; 3 of 68 patients who underwent genetic test were diagnosed with primary HLH including one with homozygous mutation in UNC13D, one with homozygous mutation in RAB27A, and one with hemizygous mutation in SH2D1A. The rest of the 68 patients exhibited various levels of genetic defects. Of the 133 EBV-HLH patients, 91 male and 42 female cases (2.2:1) were aged between 14 - 77 years with a median age of 26 years. EBV-DNA load on admission was at a median of 6.6 × 105 copies/ml (range: from 5.0 × 103 - 7.8 × 109 copies/ml). One-year mortality rate for them was 66.4%. One hundred and twelve cases were initially treated by HLH-94 or HLH-2004 regimen. Of those, 52 cases (46.4%) had response including 22 cases (19.6%) of complete response (CR) and 30 cases (26.8%) of partial response (PR). Six patients received L-DEP regimen as initial treatment, of which 5 cases had response consisting 3 cases of CR and 2 cases of PR. The overall response rate (ORR) was 83.3%. The rest 15 patients received initial treatment without etoposide, 5 patients (33.3%) achieving PR and 10 patients (66.7%) showing no response. Sixty-nine refractory or relapsed cases received DEP or L-DEP regimen, ORR of which was 79.7%. For those cases, 26 cases received DEP regimen, of which 17 cases (65.4%) had response including 5 cases of CR and 12 cases of PR. Forty-three patients received L-DEP as salvage therapy, of which 38 cases (88.4%) had response including 13 cases of CR (30.2%) and 25 cases of PR (58.1%). Compared to DEP treatment, who received L-DEP had a higher effective rate (65.4% versus 88.4%, p=0.031). Of 133 EBV-HLH patients, only 36 patients received allogeneic hematopoietic stem cell transplantation, the survival rate was 61.1%. In conclusion, EBV-HLH is a fatal disease. Our results indicate DEP or L-DEP is an effective salvage therapy. Additionally, L-DEP may be a more effective therapy than HLH-94/2004 regimen to be used as an initial treatment. Finally, allogeneic hematopoietic stem cell transplantation is an effective approach for the treatment of EBV-HLH. DisclosuresNo relevant conflicts of interest to declare.

Thoracic, abdominal and pelvic CT and US imaging features in children with hemophagocytic lymphohistocytosis

Background : Hemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS) is a life threatening condition characterized by uncontrolled autoimmune hyperinflammation based on various inherited or acquired immune deficiencies. Main symptoms and signs include fever, neurological symptoms, hepatosplenomegaly and cytopenia. This study aims to describe the chest, abdomen and pelvis CT findings as well as the US findings of the abdomen and pelvis, in a large series of patients diagnosed with HLH in a single institution. Methods: This is a retrospective case review of the US and CT imaging features of the chest, abdomen and pelvis in 39 bone marrow biopsy-proven patients diagnosed with HLH/MAS that has been approved by our institutional review board (IRB). The study was done at one institution, The Hospital for Sick Children, Toronto, Canada. The imaging data of the 39 patients were retrieved using the PAC system. Two patients lacked available studies in the hospital records. The chest CT (26 patients), abdominal and pelvic CT (25 patients) and abdominal and pelvic US (34 patients) examinations in 37 children at presentation were retrospectively reviewed blindly by 2 pediatric radiologists. Discrepancy was resolved by consensus. Statistical analysis utilizing logistic regression and odds ratio have been used to estimate the patient's outcome. Results: The major CT findings in the chest included pleural effusion in 16/26 patients (61.5%), lymphadenopathy in 15/26 patients (57.7%) and air space disease in 12/26 patients (46.2%). In the abdomen and pelvis, the major CT findings were as follows: ascites in 17/25 patients (68%), hepatomegaly in 16/25 patients (64%), splenomegaly in 14/25 patients (56%), abdominal wall edema and periportal edema in 13/25 patients (52%). Regarding ultrasound, hepatomegaly and splenomegaly were observed in 23/34 patients (67.6%), ascites and echogenic kidneys were seen in 19/34 patients (55.9%), and gall bladder wall thickening was found in 18/34 patients (52.9%). A logistic regression model and odds ratio was used. We found that abdominal wall edema detected on CT has 8 times the risk of having a severe clinical outcome. Conclusion: Large series of children with HLH/MAS demonstrated nonspecific imaging findings; however, in the appropriate clinical setting in acutely ill child, these findings should suggest the diagnosis of HLH/MAS to the radiologist. Early diagnosis and early management of this disorder can be life-saving.

Primary Immunodeficiencies Associated with EBV Disease.

Epstein-Barr virus (EBV) infects nearly all humans and usually is asymptomatic, or in the case of adolescents and young adults, it can result in infectious mononucleosis. EBV-infected B cells are controlled primarily by NK cells, iNKT cells,CD4 T cells, and CD8 T cells. While mutations in proteins important for B cell function can affect EBV infection of these cells, these mutations do not result in severe EBV infection. Some genetic disorders affecting T and NK cell function result in failure to control EBV infection, but do not result in increased susceptibility to other virus infections. These include mutations in SH2D1A, BIRC4, ITK, CD27, MAGT1, CORO1A, and LRBA. Since EBV is the only virus that induces proliferation of B cells, the study of these diseases has helped to identify proteins critical for interactions of T and/or NK cells with B cells. Mutations in three genes associated with hemophagocytic lymphohistocytosis, PRF1, STXBP2, and UNC13D, can also predispose to severe chronic active EBV disease. Severe EBV infection can be associated with immunodeficiencies that also predispose to other viral infections and in some cases other bacterial and fungal infections. These include diseases due to mutations in PIK3CD,PIK3R1, CTPS1, STK4, GATA2, MCM4, FCGR3A, CARD11, ATM, and WAS. In addition, patients with severe combined immunodeficiency, which can be due to mutations in a number of different genes, are at high risk for various infections as well as EBV B cell lymphomas. Identification of proteins important for control of EBV may help to identify new targets for immunosuppressive therapies.

Pediatric Hemophagocytic Lymphohistocytosis (HLH): A Single Institution Experience in the Diagnosis and Management of This Variable Disease

Background:Hemophagocytic Lymphohistocytosis (HLH) is a rare disease that can be fatal if left untreated. We present a single institution series of pediatric patients diagnosed with HLH. Infants and children can present acutely ill with a febrile illness, and a high index of suspicion is required to make the diagnosis. Diagnosing HLH is challenging due to the rare occurrence, variable presentation, and nonspecific findings of this disorder. We report on 17 patients diagnosed with HLH in this series.Methods:This is a single institution review of pediatric cases of HLH diagnosed from 1996 to 2014 at the Medical University of South Carolina (MUSC).Results:A total of seventeen pediatric patients were diagnosed with HLH at the MUSC. All patients presented with vague symptoms. The median time from admission to diagnosis was 35 days. Age at presentation varied from 2 weeks to 19 years. Interestingly, 73 % of patients in our series are minorities. All patients met the diagnostic criteria for HLH with a median of 7/8 criteria. The median values for Hemoglobin, absolute neutrophil count (ANC), and platelet count were 9 g/dl, 905 cells/ul, and 47,00 cell/ul respectively. The median values for ferritin, triglycerides, and fibrinogen were 11,000 ng/ml, 265 mg/dl, and 128 mg/dl. The median Il-2 soluble activity level and NK functional activity levels were 6,144 unit/ml and 0% for patients who underwent testing.Our patients were divided into two groups- those who received HLH directed therapy, and those who did not. Eleven patients were treated according to an HLH study (HLH-94 or HLH-2004). Two patients succumbed to disease, and a third patient experienced recurrence and and died.Five of the treated patients were found to have genetic mutations. Two had a perforin gene mutation, and three had STXBP2 gene mutation. These five patients underwent hematopoietic stem cell transplant (Matched sibling-1, MUD-2, and UCB-2). All engrafted. Two patietns are surviving, disease free. Three patients died due to BMT complications including GvHD, Respiratory failure, and GI perforation.Six patients met the diagnostic criteria and did not receive treatment. Two of the 6 showed signs of clinical improvement prior to the start of treatment, and 4 received supportive care with or without anti-viral treatment. For this group there was a trend toward higher ferritin values and higher platelet counts.Viral infections were identified in 7/17 patients. Two patients with CMV infection required treatment. The remaining 5 patients had either EBV or HSV and did not require HLH directed therapy.Conclusion:There was no difference in the mean values for the diagnostic criteria between the group that received HLH therapy and the group that did not. Hemophagocytic Lymphohistocytosis is a rare disease and requires high index of suspicion for the diagnosis. For patients who were treated according to HLH protocols, 6/11 are alive and well. Three died due to BMT complications, and two patients died due to treatment related issues. Six patients met the diagnostic criteria but did not receive immuno-suppressive treatment, of those 4 had EBV, 1 had HSV, another did not have an identified viral infection. Our data suggest that patients with EBV viral associated HLH may spontaneously improve and not require HLH directed therapy. DisclosuresNo relevant conflicts of interest to declare.

Marked Hyperferritinemia Does Not Predict for Hemophagocytic Lymphohistiocytosis (HLH) in the Adult Population

IntroductionMarkedly elevated serum ferritin levels are often thought to be exclusively seen in rheumatologic and inflammatory disorders including adult-onset Still’s disease (AOSD), macrophage activation syndrome (MAS), and hemophagocytic lymphohistocytosis (HLH). In the pediatric population, ferritin >10,000 µg/L is highly sensitive and specific for HLH (Allen CE, et al. Pediatr Blood Cancer. 2008). In order to determine what conditions are associated with profoundly elevated ferritin levels in the adult population, we performed a retrospective analysis of patients with serum ferritin >50,000 µg/L in a large academic healthcare system.MethodsUsing a centralized clinical data registry, we searched for all patients at Brigham and Women’s Hospital (BWH), Massachusetts General Hospital (MGH), and Faulkner Hospital (FH) who had serum ferritin levels >50,000 µg/L between 8/1/1988-1/29/2014 for BWH and MGH, and 8/9/1995-1/29/2014 for FH. For patients who had multiple ferritin levels >50,000 µg/L, we used the highest value. Patients <18 years old were excluded and the medical charts of the remaining patients were manually reviewed. We collected demographic data including age, race, and gender. Each patient was categorized as having HLH, MAS, rheumatologic/inflammatory disorder, hematologic malignancy, solid tumor, renal failure, sepsis/infection, liver failure, iron overload, hemolytic anemia, or none of these conditions. Causes were not considered mutually exclusive. Univariate and multivariable linear regressions were used to evaluate the association of those factors with ferritin levels modeled using the logarithmic transformation of the actual ferritin levels. The Wilcoxon rank sum test was also performed along with the univariate analysis. Those covariates statistically significant at an alpha level of 0.2 were included in the multivariable stepwise linear regression model. In the multivariable analysis, a p-value <0.05 was considered statistically significant.ResultsWe identified 113 total patients with ferritin levels above 50,000 µg/L at BWH, MGH, and FH during the study period. The patients ranged from 20 years old to 88 years old (mean 56 years old). The majority of patients were male (58%). The racial distribution included White (75%), Black (16%), Hispanic (4%), Asian (2%), and unknown (3%). Ferritin levels ranged from 50,129 to 439,500 µg/L with a median of 82,930 µg/L (notably, two patients had ferritin levels more than the assay of >100,000 µg/L). The characteristics of the patients with ferritin levels >50,000 µg/L included renal disease (65%), liver disease (54%), sepsis/infection (46%), hematologic malignancy (33%), rheumatologic/inflammatory conditions (18%), HLH (17%), iron overload (11%), hemolytic anemia (4%), solid malignancy (4%), and MAS (3%) (table 1). The majority of patients with HLH were thought to have secondary HLH triggered by a malignancy (9/19) or infection (6/19), with the minority having no clear precipitating cause (4/19). All 9 patients with malignancy-associated HLH had a hematologic malignancy (4/9 had T-cell lymphoma, 3/9 had DLBCL, 1/9 had transformed AML, and 1/9 had erythroleukemia). The stepwise linear regression showed that presence of hemolytic anemia was the only variable associated with a differential ferritin level (β=1.51, p=0.03).ConclusionsExtremely elevated ferritin levels are associated with many conditions and most often seen in patients with hematologic malignancies, liver failure, and renal failure. Although less common in our cohort, those patients with hemolytic anemia had higher ferritin levels compared to patients without hemolytic anemia. In contrast to what has been described in the pediatric population, there does not appear to be any value above which ferritin is specific for HLH in the adult population. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A mutation in the STAT1 DNA-binding domain associated with hemophagocytic lymphohistocytosis

Introduction: The transcription factor Signal Transducer and Activator of Transcription 1 (STAT1) is a key element in many of the signalling cascades involved in immune system function. Different mutations in STAT1 are associated with heterogeneous clinical phenotypes that range from early fatality due to overwhelming infection to limited involvement of the mucus membrane with recurrent Candida infections. Multiple genes related to immune function have been associated with the development of hemophagocytic lymphohistiocytosis (HLH), but the association between STAT1 mutation and HLH has not been described in detail. Methods: We report the genetic background of a patient with chronic mucocutaneous candidiasis (CMC) as well as an unusual clinical course. Results: In this study we describe a patient with a mutation in the STAT1 DNA-binding domain and a history of CMC who developed a refractory and fatal case of HLH despite having bone marrow transplantation. Conclusion: We describe a patient with refractory and fatal HLH who was found to have a mutation in the DNA-binding domain of STAT1. Statement of novelty: The association of chronic mucocutaneous candidiasis with HLH.

Acute Pain Transfusion Reaction

A 34-year-old woman with a diagnosis of hemophagocytic lymphohistocytosis (HLH) received a double umbilical cord blood transplantation following a myeloablative chemotherapy preparative regimen with busulfan and cyclophosphamide. HLH is a rare, potentially fatal hematologic disorder characterized by the overactivation of histocytes and T lymphocytes, leading to organ infiltration and acute illness. On day 25 post-transplantation, the patient required a platelet transfusion for a platelet count of 6,000 per ml (normal range = 150,000-450,000 per ml). The patient's blood type prior to the cord blood transplantation was B positive and, although both umbilical cord blood donors were O positive, the patient was still B positive per blood bank testing on that day. Although the recipient of an allogenic stem cell transplantation will eventually become the blood type of the donor, the time for this process to occur varies for each person. That process must be monitored by the blood bank for the purpose of cross-matching blood products to decrease hemolysis as much as possible. The patient was premedicated with the facility's standard for platelet transfusions: acetaminophen 650 mg and diphenhydramine 25 mg about 30 minutes prior to the platelet transfusion.

Diagnosis value of γ-IFN on the specific pathogen infection associated hemophagocytic lymphohistocytosis

Diagnosis value of γ-IFN on the specific pathogen infection associated hemophagocytic lymphohistocytosis

Persistent defective membrane trafficking in epithelial cells of patients with familial hemophagocytic lymphohistiocytosis type 5 due to STXBP2/MUNC18‐2 mutations

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare primary immune disorder defined by mutations in the syntaxin binding protein 2 (STXBP2) alias MUNC18-2. Despite defective immunity and a hyper-inflammatory state, clinical findings such as neurological, gastrointestinal, and bleeding disorders are present in a significant number of patients and suggest an impaired expression and function of STXBP2 in cells other than cytotoxic lymphocytes. We investigated four patients with FHL5 suffering from severe enteropathy and one of whom also had renal tubular dysfunction despite successful hematopoietic stem cell transplantation (HSCT). Gastrointestinal and renal biopsy specimens were analyzed by immunohistochemistry and electron microscopy. Histopathology revealed an intracytoplasmatic accumulation of PAS-positive granules and an enlarged intracytoplasmatic CD10-positive band along the apical pole of enterocytes. Electron microscopy revealed short microvilli and granules filled with electro lucent material. In addition, we described mildly dilated renal tubules and electron micrographs displayed a higher number of cytoplasmic inclusions, electrodense lysosomal and electrolucent endosomal vesicles. Mutations in STXBP2 do not only affect cytotoxic T lymphocytes but also cause changes in the intestinal and renal epithelium resulting in severe, osmotic diarrhea and renal proximal tubular dysfunction. These defects persist after successful treatment of hemophagocytic lymphohistocytosis by HSCT. Clinical manifestations in FHL5 patients despite successful HSCT may therefore be related to defective membrane trafficking in the gut and kidney.

Development of classical Hodgkin's lymphoma in an adult with biallelic STXBP2 mutations

Experimental model systems have delineated an important role for cytotoxic lymphocytes in the immunosurveillance of cancer. In humans, perforin-deficiency has been associated with occurrence of hematologic malignancies. Here, we describe an Epstein-Barr virus-positive classical Hodgkin's lymphoma in a patient harboring biallelic mutations in STXBP2, a gene required for exocytosis of perforin-containing lytic granules and associated with familial hemophagocytic lymphohistocytosis. Cytotoxic T lymphocytes were found infiltrating the tumor, and a high frequency of Epstein-Barr virus-specific cytotoxic T lymphocytes were detected in peripheral blood. However, lytic granule exocytosis and cytotoxicity by cytotoxic T lymphocytes, as well as natural killer cells, were severely impaired in the patient. Thus, the data suggest a link between defective lymphocyte exocytosis and development of lymphoma in STXBP2-deficient patients. Therefore, with regards to treatment of familial hemophagocytic lymphohistocytosis patients with mutations in genes required for lymphocyte exocytosis, it is important to consider both the risks of hemophagocytic lymphohistocytosis and malignancy.

Profile of EBV- associated infectious mononucleosis

During a 5 year period, 33 children (22 males) were diagnosed to have infectious mononucleosis (M:F::2:1; age 9 mo-15 y). The common clinical features observed were fever (100%), lymphadenopathy (84%) hepatosplenomegaly (81%), tonsillar enlargement (45%), neck swelling (30%), upper respiratory symptoms (21%), epitrochlear node enlargement (20%), vomiting and diarrhea (1%). Ten children had complications; upper airway obstruction and hemophagocytic lymphohistocytosis occurred in four each and septic shock in two. EBV associated infectious mononucleosis in hospitalized children was found to affect mainly preschool children and had a favorable prognosis.

Lymphocyte-depleted Hodgkin Lymphoma Complicating Hemophagocytic Lymphohistiocytosis as an Initial Manifestation: A Case Report and Review of the Literature

Hemophagocytic lymphohistocytosis (HLH) is commonly associated with infectious diseases or T/NK cell-lymphoma; however that with Hodgkin lymphoma (HL) was rarely reported. Herein, we describe a young male diagnosed with lymphocyte-depleted HL (LD-HL) complicated by HLH as an initial manifestation. He was given high-dose steroid therapy plus recombinant thrombomodulin, and subsequent ABVd (doxorubicin, bleomycin, vinblastine, dacarbazine) treatment. In spite of the achievement of a partial remission treated with one cycle of ABVd, he relapsed after 3 cycles. To our knowledge, the present case is very rare, and more intensive treatment might be needed for the long-term control of HLH-complicated HL.

Hematopoietic stem cell transplantation with reduced intensity conditioning from a family haploidentical donor in an infant with familial hemophagocytic lymphohistocytosis

Allogeneic hematopoietic stem cell transplantation is the only curative method for patients with familial hemophagocytic lymphohistiocytosis (FHL). We present a case of a 3-month-old girl with Munc13-4 mutation (FHL3), who underwent bone marrow transplantation (BMT) from her human leukocyte antigen-haploidentical mother following reduced intensity conditioning (RIC) with fludarabine, melphalan, and busulfan. Engraftment after BMT was generally uneventful, with only mild acute graft versus host disease. Munc13-4 protein was restored following BMT, and she is well and free of disease 14 months after BMT. These results suggest that BMT with RIC from a family haploidentical donor may sufficiently restore immune regulation in infants, while lessening treatment-related mortality and long-term sequelae.

High Frequency of Familial Hemophagocytic Lymphocytosis Associated Immune Gene Defects In Refractory Viral Infection of Unknown Origin

AbstractAbstract 2775Refractory virus infection of unknown origin is a series of life-threatening disorders which include virus associated hemophagocytic lymphohistocytosis (HLH), chronic active EB virus infection (CAEBV) and virus associated lymphoma, etc. Familial HLH (FHL) is a kind of autosomal recessive hereditary disease that is caused by inherited immune gene defects. PRF1, UNC13D, STX11, STXBP2, SH2D1A and XIAP genes are most commonly reported as FHL associated genes. To investigate the incidence of six FHL associated gene defects as mentioned above and relevant clinical characteristics in the patients with refractory virus infection of unknown origin, a total of 25 patients were screened for six FHL associated genes. The median age was 9(1-22)years old. For FHL associated gene analysis, the genomic DNA from the patients' peripheral blood (PB) was amplified by PCR. Bi-directional sequencing was performed with AB3130XL, and then gene including full length of coding region and splicing donor and receptor site were analyzed with Variant Reporter V1.0 software. The cDNA and the amino acid number were defined based on the GeneBank. The structural domain and functional locus were defined basing on the data bank in UniProtKB. The PB or lymphoma tissue from the patients was screened for HHV1 to HHV8 DNA by multiplex PCR, the positive virus was then quantified by real-time PCR. The refractory virus infection is defined as the level of the virus DNA continuously or repeatedly positive for more than 3 months after antiviral therapy. HLH is diagnosed according to the criteria by International Society of Histocyte in 2009, and lymphoma is diagnosed according to the criteria by WHO in 2008. All cases were diagnosed or excluded hematological malignancy by morphology, tissue pathology, and immunol histochemistry, flowcytometry, gene rearrangement of IgH, TCR, and cytogenetic analysis. No family history of the same disease was identified in all patients. Thirteen patients carried 1 kind of gene defect (see Table1), among them, 3 cases had only 1 heterozygous gene mutation and their mothers or fathers are healthy carriers. The other patients have 2 mutated genes or the male patients have 1 XIAP or SH2D1A gene defect. One case with EBV associated peripheral T lymphoma gave up the therapy, the other 12 cases survived by Jul. 2010 after therapy. Two cases received allogeneic hematopoietic stem cell transplantation (allo-HSCT) and achieved disease-free survival by now. Twelve cases have no immune gene defects, and 4 of them were EBV associated HLH (developed into peripheral T lymphoma 3 years after diagnosis in one patient, CAEBV in 3 cases). Our results have shown for the first time that high frequency of FHL associated immune gene defects is in refractory virus infection in Chinese. Therefore, FHL associated immune gene defects may be responsible for refractory virus infection of unknown origin and result in HLH, CAEBV and virus associated lymphoma. One heterozygous immune gene mutation may combine with other factors to result in refractory viral infection. DNA sequence analysis of six common FHL associated genes is very helpful to make definite diagnosis and choose appropriate therapy for the patients.Table 1:Data of the patients with familial HLH associated immune gene defectsCaseSex/AgeInfected virusClinical diagnosis and durationType of gene defect/Structural domain1F/13HHV7 (PB)HLH 4 msPRF1 c.503G>A/p.S168N, MACPF domain; c.1177T>C/p.C393R, EGF like domain2M/5EBV (PB)HLH 17 msPRF1 c.83G>A/p.R28H, MACPF domain3M/6EBV (PB)HLH 6 msPRF1 c.394G>A/p.G132R, MACPF domain; c.1146-1168del/p.P383RfsX67, EGF like domain4M/1EBV (PB)HLH 12 msPRF1 c.65delC/p.P22RfsX29; c.1349C>T/p.T450M, C2 domain5M/7EBV (PB)HLH 36 msPRF1 c.65delC/p.P22RfsX29; c.1349C>T/p.T450M, C2 domain6M/18EBV (PB)CAEBV 72 ms, HL 2 wkPRF1 c.1232>A/p.R411Q7M/11EBV (PB)CAEBV 12 msUNC13D 2240G>A/S747N; 2553+5C>G, splicing donor site8M/13EBV (lymph node)HL 12 msUNC13D c.2588G>A/p.G863D, MHD2 domain; c.2588G>A/p.G863D, MHD2 domain9M/9EBV (PB)CAEBV 12 msUNC13D c.1228A>C/p.I410L, RAB27A Interaction domain10F/10EBV (PB)T-NHL 9 msSTX11 c.842T>G/p.F281C11M/5EBV (PB)HLH 18 msSH2D1A gene deletion12M/5EBV (PB)HLH 12 msXIAP c.1099+2T>C, splicing donor site13F/2EBV (PB)CAEBV 6 msSTXBP2 c.1726T>C/p.F576L Disclosures:No relevant conflicts of interest to declare.

Ceftriaxone‐induced acute hemolytic anemia

A 7-year-old Caribbean-American boy with a 5-month history of hemophagocytic lymphohistocytosis and previous ceftriaxone exposure presented with fever. He was empirically given amikacin and ceftriaxone after 1:00 PM on Day 1 and acutely developed back and abdominal pain, vomiting, hematuria, and hypotension. Both plasma (see figure, top panel) and urine showed hemolysis. The peripheral blood smear showed diffuse agglutination of RBCs without schistocytes (see figure, lower left). Serum LDH was elevated (1787 U/L); urine was negative for myoglobin. The patient's Hb dropped from 11.7 to 4.4 g/dL in 32 hours. The symptoms, hemolysis, and agglutination resolved (see figure, lower right) with discontinuation of ceftriaxone and two double-volume whole blood exchange transfusions. Immunohematology studies demonstrated a positive DAT due to C3 only, and serologic drug studies were positive with ceftriaxone, but not with amikacin. The RBC agglutination seen on peripheral smear was most likely due to drug/antidrug immune complexes, a theory supported by the finding of IgM ceftriaxone-dependent antibodies (titer = 32) at presentation. The titer decreased to 8 on Day 2 and to 0 by Day 5, suggesting that the antibody was consumed by the RBCs and/or removed by treatment. Drug-induced immune hemolytic anemia (DIHA) due to ceftriaxone-dependent antibodies is uncommon, but well described. The majority of documented cases have occurred in children with a history of exposure to ceftriaxone. Autoagglutination may be a feature of DIHA due to ceftriaxone. It is important to recognize and treat DIHA early, since it can be fatal, but is reversible with treatment.

The Exocytosis of Lytic Granules Is Impaired in Vti1b- or Vamp8-Deficient CTL Leading to a Reduced Cytotoxic Activity following Antigen-Specific Activation

The exocytosis of cytotoxic proteins stored in lytic granules of activated CTL is a key event during killing of target cells. Membrane fusion events that are mediated by soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) proteins are crucial, as demonstrated by patients with familial hemophagocytic lymphohistocytosis type 4 who have mutations in the SNARE protein syntaxin-11 that result in an impaired degranulation of cytotoxic cells. We found an increased mRNA expression of the SNARE protein genes Vti1b and Vamp8 during Ag-specific activation of CTL from TCR-transgenic OT-I mice. Therefore, we investigated the cytolytic activity of CTL from TCR-transgenic Vti1b and Vamp8 knockout mice. At 3 d as well as at 4 d of Ag-specific stimulation, the degranulation of CTL was significantly reduced in Vti1b and Vamp8 knockout mice, as determined by cell surface expression of the degranulation marker CD107a. After 3 d of Ag-specific stimulation, the cytolytic activity of Vti1b- and Vamp8-deficient CTL was reduced to approximately 50% compared with heterozygous controls. However, 4 d after stimulation, the cytotoxic activity of Vti1b- as well as Vamp8-deficient CTL was not impaired anymore. The capacity of Vti1b- and Vamp8-deficient dendritic cells to process Ags and to stimulate the proliferation of CTL was not reduced, arguing against an indirect effect on the activation of CTL. These findings suggest a role of the SNARE proteins vti1b and vesicle-associated membrane protein 8 in the degranulation of CTL. However, a deficiency can apparently be compensated and affects only transiently the cytotoxic activity of CTL during their development to armed effector cells.

A case of natural killer cell lymphoma presenting with bilateral pleural effusions and hemophagocytic lymphohistocytosis

Natural killer (NK) cell lymphoma of lung is very rare. We report a case of NK cell lymphoma presented in a 17-year-old male with bilateral pleural effusions and hemophagocytic lymphohistocytosis. Morphologic and immunohistochemical tests revealed an association of NK cell lymphoma with Epstein-Barr virus. A literature review helped identify other cases of patients with NK cell lymphoma, their treatment and outcomes.

Lipoprotein Alterations and Plasma Lipoprotein Lipase Reduction in Familial Hemophagocytic Lymphohistiocytosis

Serum lipid abnormalities are common in familial hemophagocytic lymphohistocytosis (FHL), a disorder also characterized by fever, hepatosplenomegaly, pancytopenia and a prominent lymphohistiocytic accumulation in the mononuclear phagocyte system. The lipoprotein pattern in nine children with FHL was studied with a quantitative method measuring cholesterol and triglycerides in each major class of lipoproteins. Triglycerides were markedly elevated during active FHL in serum, very low density lipoproteins, and low density lipoproteins. Cholesterol was increased in very low density lipoproteins whereas both triglycerides and cholesterol were extremely low in high density lipoproteins. These lipoprotein abnormalities, reversible on successful therapy, are compatible with a depressed lipolytic activity. Post-heparin levels of lipoprotein lipase and hepatic lipase in plasma were studied in four children and found to be markedly low during active FHL. We suggest that inflammatory cytokines, which may strongly suppress lipoprotein lipase activity, can be important mediators in the pathophysiology of FHL and that they may participate in the development of the lipid abnormalities.