SAP and XIAP deficiency in hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a multisystem inflammatory disorder due to cytokine overproduction from excessively activated lymphocytes and macrophages. HLH has been divided into two subgroups: primary HLH and secondary HLH. Primary HLH includes PRF1, UNC13D, STX11, STXBP2, RAB27A, LYST, SH2D1A and XIAP gene mutations; and secondary HLH is associated with infections, malignancies and autoimmune diseases. Among primary HLH‐related genes, SH2D1A and XIAP are genetically responsible for X‐linked lymphoproliferative syndrome (XLP) due to signaling‐lymphocytic‐activation‐molecule‐associated protein (SAP) and XIAP deficiencies, respectively. XLP is characterized by extreme vulnerability to Epstein–Barr virus infection. The major clinical manifestations of XLP consist of HLH (60%), lymphoproliferative disorder (30%) and dysgammaglobulinemia (30%). Analysis of clinical phenotypes of XLP patients suggests that XLP predominantly shows familial HLH phenotypes, whereas some XLP patients present sporadic HLH. For many decades, clinicians and investigators have been concerned with possible XLP in young boys presenting with Epstein–Barr‐virus‐associated HLH. This review aims to describe the new knowledge about XLP and to draw the attention of the pediatrician to XLP, which should be differentiated from other forms of HLH.     

穿孔素基因多态性与儿童噬血细胞综合征的相关性研究

目的了解穿孔素基因(PRF1)多态性在噬血细胞综合征(HLH)患儿中的分布情况,探讨PRF1基因多态性与HLH是否存在易感相关性。方法收集2009年1月至2013年12月确诊为HLH的48例患儿(HLH组)及100名健康体检儿童(对照组)的临床资料,应用聚合酶链反应(PCR)结合直接测序方法对两组患儿的PRF1基因编码区(包括3个外显子和2个内含子)进行基因多态性位点筛查。结果 48例HLH患儿中,在PRF1基因编码序列中共发现3个SNP位点,而在非编码序列中共发现7个SNP位点;PRF1基因非编码序列中还有2个SNP位点rs10999426和rs10999427分别仅在5例对照组儿童中发现(5%);以上12个SNP位点在HLH组和对照组中的基因型及等位基因频率分布差异均无统计学意义(P0.05)。连锁不平衡分析提示rs10999426和rs10999427紧密连锁(D=1,r2=1),但上述2个位点构建的A-T单体型在HLH组和对照组中的分布频率差异无统计学意义(P0.05)。结论 PRF1基因多态性与HLH发病存在易感相关性的可能性不大;rs10999426和rs10999427存在连锁不平衡关系,其构建的A-T单体型虽仅在对照组中发现,但发生率低,可能不是家族性HLH的保护性因素。     

儿童噬血细胞综合征穿孔素基因突变筛查及临床研究

了解穿孔素基因（PRF1）突变和序列变异在中国儿童噬血细胞综合征（HLH）中的发生情况,探讨基因突变型与临床表现之间可能的关系。方法　应用聚合酶链反应（PCR）结合直接测序方法,对2006年1月至2008年5月在首都医科大学附属北京儿童医院治疗的临床诊断为HLH的30例患儿（HLH组）及50名新生儿（对照组）PRF1基因外显子编码区进行突变筛查。 结果　在3例HLH患儿的PRF1基因外显子编码区发现3个杂合错义突变,这3个突变均导致氨基酸改变（C102F、S108N 和T450M）,而在对照组中却未发现。1例患儿为复合杂合错义突变（S108N和 T450M）,从遗传学上可明确诊断为家族性HLH亚型2（FHL2）;1个同义序列变异 （Q540Q） 在1例患儿中发现,而在对照组中未发现;在HLH组和对照组的PRF1基因编码区发现2个单核苷酸多态位点（SNP） （A274A、300H）,但这2个SNP的基因型频率在HLH组和对照组之间的分布差异无统计学意义（P均 > 0.05）。结论　我国HLH患儿中存在PRF1基因突变,而突变位点（C102F和S108N）目前仅在中国患儿中发现。显示了我国HLH患儿PRF1基因突变具有自身的特点。对于无HLH家族史和起病年龄较晚的HLH患儿,也要考虑家族性HLH的可能。     

Allogeneic hematopoietic stem cell transplantation is associated with cure and durable remission of late‐onset primary isolated central nervous system hemophagocytic lymphohistiocytosis

Primary isolated CNS presentation of HLH is exceedingly rare and typically associated with significant morbidity and mortality. We describe an adolescent patient with late‐onset, primary isolated CNS HLH and a compound heterozygous PRF1 mutation (c50delT (p.L17 fs); c.1229G>C (p.R410P)), not previously reported with this phenotype. He was successfully treated with allogeneic HSCT following a reduced‐intensity conditioning regimen, despite a high pre‐HSCT comorbidity index. Two years after transplant, he is alive and in disease remission. While patients with systemic HLH and active CNS disease have relatively poorer outcomes, a high index of suspicion may aid with early diagnosis of primary isolated CNS HLH; prompt treatment with HSCT may be associated with improved cure and durable remission of this rare disease.     

Trichosporon Asahii,Sepsis, and Secondary Hemophagocytic Lymphohistiocytosis in Children with Hematologic Malignancy

Trichosporon asahii (T. asahii) is an uncommon fungal pathogen rarely seen in patients with hematologic malignancies. Although appropriate therapy is started, infection with T. asahii usually leads to mortality. Here, we describe two patients developed severe T. asahii infection and secondary HLH. Despite rapid identification of T. asahii and negative blood cultures achieved by prompt initiation of treatment with voriconazole, fever and pancytopenia, persisted and both developed hepatosplenomegaly, and their clinical state worsened. Bone marrow aspiraton revealed hemophagocytosis. Elevated ferritin, triglyceride levels were seen. The first patient did not receive HLH directed therapy and died with multiple organ dysfunctions. Prompt diagnosis and treatment of secondary HLH led to rapid improvement in clinical and laboratory abnormalities in the second patient and kept her alive. We suggest that HLH may present as a secondary condition, accompanying a severe infection with T. asahii may, at least in part, contribute to high mortality rates in these cases.     

Chronic granulomatous disease: Clinical,molecular, and therapeutic aspects

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency caused by defects in the genes encoding any of the NADPH oxidase components responsible for the respiratory burst of phagocytic leukocytes. CGD is a genetically heterogeneous disease with an X‐linked recessive (XR‐CGD) form caused by mutations in the CYBB gene encoding the gp91^phox protein, and an autosomal recessive (AR‐CGD) form caused by mutations in the CYBA, NCF1, NCF2, or NCF4 genes encoding p22^phox, p47^phox, p67^phox, and p40^phox, respectively. Patients suffering from this disease are susceptible to severe life‐threatening bacterial and fungal infections and excessive inflammation characterized by granuloma formation in any organ, for instance, the gastrointestinal and genitourinary tract. An early diagnosis of and the prompt treatment for these conditions are crucial for an optimal outcome of affected patients. To prevent infections, CGD patients should receive lifelong antibiotics and antifungal prophylaxis. These two measures, as well as newer more effective antimicrobials, have significantly modified the natural history of CGD, resulting in a remarkable change in overall survival, which is now around 90%, reaching well into adulthood. At present, hematopoietic stem cell transplantation (HSCT) is the only definitive treatment that can cure CGD and reverse organ dysfunction. Timing, donor selection, and conditioning regimens remain the key points of this therapy. In recent years, gene therapy (GT) for XR‐CGD has been proposed as an alternative to HSCT for CGD patients without a matched donor. After the failure of the first trials performed with retroviral vectors, some groups have proposed the use of regulated SIN‐lentiviral vectors targeting gp91^phox expression in myeloid cells to increase the safety and efficacy of the GT protocols.     

Incidence and treatment of hemophagocytic lymphohistiocytosis in hospitalized children with Ehrlichia infection

We report a large cohort of pediatric patients with human monocytic ehrlichiosis (HME), enabling an estimated incidence of secondary hemophagocytic lymphohistiocytosis (HLH) in hospitalized children with HME. Among 49 children with PCR‐confirmed Ehrlichia infection, 8 (16%) met current criteria for HLH. Those with HLH had more significant hematologic abnormalities and longer durations from symptom onset to admission and definitive anti‐infective therapy. Among these eight, three received chemotherapy plus doxycycline, one of whom died; the other five were treated with doxycycline without chemotherapy, and all survived without HLH recurrence. Our findings demonstrate that antimicrobial therapy alone can successfully resolve Ehrlichia‐associated HLH.     

Acute inflammatory demyelinating polyradiculoneuropathy associated with perforin-deficient familial haemophagocytic lymphohistiocytosis

This study reports the first paediatric case of acute inflammatory demyelinating polyradiculoneuropathy (AIDP) associated with a fatal haemophagocytic lymphohistiocytosis (HLH). The patient developed progressive weakness of the lower limbs in the context of a picture of infectious mononucleosis and Epstein-Barr virus (EBV) infection. After an apparent improvement, a fulminant hepatic failure and pancytopenia ensued, leading to death. Molecular genetic studies documented a compound heterozygosity for two mutations in the perforin (PRF1) gene as the background defect for a familial haemophagocytic lymphohistiocytosis (FHL). Conclusion: In this patient EBV infection triggered both AIDP and FHL. The latter condition was due to PRF1 deficiency. Two novel mutations in the PRF1 gene were concomitantly present in the patient. The first caused an amino acid change, while the second introduced a stop codon in the sequence which resulted in a truncated protein.     

Fusarium falciforme infection in a patient with chronic granulomatous disease: Unique long‐term course of epidural abscess

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease characterized by recurrent life‐threatening bacterial and fungal infections with granuloma formation. Species of the genus Fusarium are opportunistic environmental microorganisms that are rarely pathogenic in humans. We report here the first case of X‐linked CGD complicated with epidural abscess caused by Fusarium falciforme infection. The abscesses extended along the dura mater for >7 years and finally resulted in fatal meningitis and cervical myelitis. Early intervention with hematopoietic stem cell transplantation should be considered, especially in patients with severe CGD, before the development of serious infectious complication.     

Severe bacteria-associated hemophagocytic lymphohistiocytosis in an extremely premature infant

Hemophagocytic lymphohistiocytosis (HLH) is a rare condition with high mortality. We report an extremely premature girl, born in the 24th gestational week (BW 732 g), that during her second month developed a severe HLH subsequent to a Serratia marcescens septicemia, with hepatosplenomegaly, cytopenias, hyperbilirubinemia (mostly conjugated, total bilirubin 916 mumol/L), hypertriglyceridemia, hypofibrinogenemia, hyperferritinemia (21266 mug/L), and elevated sIL-2 receptor levels. Genetic analysis revealed no PRF1, STX11 or UNC13D gene mutations. Treatment was provided according to the HLH-2004 protocol with etoposide, dexamethasone, and immunoglobulin, but no cyclosporin because of immature kidneys. She recovered fully from the HLH but developed a severe retinopathy as well as green teeth secondary to the hyperbilirubinemia. We conclude that secondary, bacteria-associated HLH can develop in premature infants, and that HLH can be treated with cytotoxic therapy also in premature infants. It is important to be aware of HLH in premature infants, since it is treatable.     

The outcome of hematopoietic stem cell transplantation in Korean children with hemophagocytic lymphohistiocytosis

Yoon HS, Im HJ, Moon HN, Lee JH, Kim H‐J, Yoo KH, Sung KW, Koo HH, Kang HJ, Shin HY, Ahn HS, Cho B, Kim HK, Lyu CJ, Lee MJ, Kook H, Hwang TJ, Seo JJ. The outcome of hematopoietic stem cell transplantation in Korean children with hemophagocytic lymphohistiocytosis.
Pediatr Transplantation 2010: 14:735–740. © 2010 John Wiley & Sons A/S. Abstract: Chemoimmunotherapy‐based treatments have improved the survival of patients with HLH, but outcomes of the patients are still unsatisfactory. We report here the outcome of Korean children with HLH who underwent HSCT, which was analyzed from the data of a nation‐wide HLH registry. Retrospective nation‐wide data recruitment for the pediatric HLH patients diagnosed between 1996 and 2008 was carried out by the Histiocytosis Working Party of the Korean Society of Hematology. Nineteen patients who received HSCT among the total of 148 enrolled children with HLH were analyzed for the transplant‐related variables and events. The probability of five‐yr survival after HSCT was 73.3% with a median follow‐up of 57. Two months compared to 54.3% for the patients who were treated with chemoimmunotherapy only (p = 0.05). The reasons for HSCT were active disease after eight wk of initial treatment (n = 9), relapsed disease (n = 5), and FHL (n = 5). Fourteen patients are currently alive without disease after HSCT, four patients died of treatment‐related events (infection in two and graft failure in two) at early post‐transplant period, and one patient died of relapse at one yr post transplantation. The survival of patients who were transplanted because of active disease after eight wk of initial treatment was worse compared to those patients who had inactive state at that time (60.6% vs. 100%, respectively, p = 0.06). Of the four patients who received transplants using cord blood, three died of graft failure (n = 2) and relapse (n = 1). The five‐yr probability of survival after HSCT according to the donor type was 85.7% for the MRDs (n = 6), 87.5% for the MUDs (n = 8), and 40% for the MMUDs (n = 5) (p = 0.03). Other variables such as age, CNS involvement at the time of diagnosis, the etiology of HLH (familial or secondary), and the conditioning regimens had no influence on the five‐yr OS of the HLH patients who underwent HSCT. HSCT improved the survival of the patients who had familial, relapsed, or severe and persistent SHLH in the Korean nation‐wide HLH registry. Although numbers were small, these results are similar to other reports in the literature. The disease state after initial treatment, the stem cell source of the transplant, and the donor type were the important prognostic factors that affected the OS of the HLH patients who underwent HSCT.     

家族性噬血细胞性淋巴组织细胞增生症分子遗传学及诊疗研究进展

噬血细胞性淋巴组织细胞增生症（HLH）是一组以淋巴细胞、组织细胞增生伴噬血细胞增多而引起多脏器浸润及全血细胞减少为特征的综合征,多威胁生命。HLH分为原发性（又称家族性）和继发性HLH。家族性HLH发病年龄常见于婴幼儿,多与遗传基因的缺陷有关。本文在分子遗传学基础上主要对PRF1、UNC13D、STX11和STXBP2等9种家族性HLH相关基因最近研究进展进行整理,并总结了家族性HLH诊疗方法,以增强对该病的认识与了解。     

Analysis of Fatal Cases of Pandemic Influenza A (H1N1) Virus Infections in Pediatric Patients with Leukemia

Background: Pandemic influenza A/H1N1/2009 virus usually causes mild illness in healthy children. Chronic medical conditions are recognized as increasing the risk for complications of influenza virus infection. Although most studies including children with acute leukemia and H1N1 virus have reported no deaths, some anectodal reports with low patient numbers have reported mortality rates as high as 28.5%. Here, we report patients with leukemia and H1N1 virus and review the literature. Methods: Medical records of all children with leukemia and H1N1 virus in our institution were reviewed for demographic, clinical, and laboratory data. We also carried out a systematic review of the English-language literature. Among the 24 articles found, only patients with leukemia and pandemic H1N1 infections were reviewed by two independent reviewers. Results: Eight of 98 children who received chemotherapy for leukemia were diagnosed with pandemic H1N1 infection. One developed pneumonia and acute respiratory distress syndrome (ARDS) and died. Another one developed hemophagocytic lymphohistiocytosis (HLH) and died due to secondary infection during the 6th week of treatment for HLH. In our study, 2 of 8 patients had a fatal course (25%), compared with an overall mortality of 2.5% in the studies retrieved from PubMed (6/232). Conclusion: Pandemic H1N1 influenza virus caused mortality in patients with ARDS or HLH; an unexpected finding for pandemic H1N1 (2009) influenza virus. Thus, for children with leukemia and infected with H1N1 virus, short- and long-term complications should be kept in mind during evaluation.     

Severe X-linked chronic granulomatous disease in two unrelated females

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency caused by mutations of one of the subunits of phagocyte reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase leading to decreased or complete absence of neutrophil oxidative burst. We report the clinical and laboratory findings in two young unrelated females 14 and 9 years of age and natives of Tahiti and Reunion Islands, respectively, with severe X-linked granulomatous disease. In both cases, the infectious pattern was unusual, with convergent symptoms suggesting underlying mycobacterial infection. Functional analysis revealed low residual NADPH oxidase activity with about 5–10% of normal neutrophil population. De novo null mutations affecting the CYBB gene that encodes the gp91 protein were found in both cases in the heterozygous state (in patient 1, p.Arg130X in exon 5, and in patient 2, a novel insertion in exon 6, c.632_633insCATC). Methylation analysis confirmed that phenotype expression was linked to skewed X inactivation and showed that the de novo mutation arose on the maternally inherited chromosome in one case and on the paternally inherited chromosome in the other case. In conclusion, X-linked CGD carriers could therefore be at risk for severe infectious diseases depending on the skewed X inactivation pattern and the infectious context.     

Two‐year‐old boy with cervical and liver abscesses

Pyogenic liver abscesses are rare in children but relatively common in those with chronic granulomatous disease (CGD). We present a case of a 2 year old boy who initially presented with BCGitis and Staphylococcus aureus cervical adenitis, and then subsequently developed liver abscesses. A diagnosis of X‐linked CGD was confirmed. This case demonstrates the typical radiological features of liver abscesses in CGD, its management without surgical intervention, and the increasingly recognised complications of BCG vaccination in CGD.     

Hemophagocytic lymphohistiocytosis in children with chronic granulomatous disease

Hemophagocytic lymphohistiocytosis (HLH) is characterized by fever, cytopenias, splenomegaly, and hemophagocytosis by macrophages activated by high cytokine levels. Chronic granulomatous disease (CGD) is characterized by recurrent infections, hyperinflammation, and excessive cytokine release. This may predispose patients with CGD to developing HLH during an infection. We conducted a retrospective review of patients with CGD, treated at our institution between 1999 and 2008. Three out of 17 patients developed HLH. Patients with CGD may be at increased risk for developing HLH. Remission of HLH was achieved after treatment with antimicrobials, steroids, and intravenous immunoglobulin This approach to treatment appears to be effective.     

Hemophagocytic lymphohistiocytosis triggered by Gaucher disease in a preterm neonate

Objective: To present the diagnostic workup in an extremely low birth weight infant patient with signs of both sepsis and hemophagocytosis. Participants: A preterm infant presented with clinical and laboratory signs of early-onset sepsis including hepatosplenomegaly, thrombocytopenia, direct hyperbilirubinemia, and elevated liver enzymes. Methods: Despite extensive septic workup, no underlying infection was detected. Additional hyperferritinemia and other elevated inflammatory parameters raised the suspicion of a primary or secondary hemophagocytic lymphohistiocytosis (HLH). Results: However, further metabolic analysis yielded a positive result for Gaucher disease (GD) type 2, a rare, but possible trigger of HLH. Conclusions: Our case shows that GD may lead to the picture of a secondary HLH and that a metabolic workup should always be performed in patients in whom primary HLH has been excluded.     

Hemophagocytic lymphohistiocytosis secondary to Varicella zoster infection in a child with Henoch–Schönlein purpura

Hemophagocytic lymphohistiocytosis (HLH) is a fatal, hyper‐inflammatory syndrome that is characterized by untimely activation of macrophages, and manifests as cytopenia, organ dysfunction, and coagulopathy. Secondary HLH can be associated with infection, drugs, malignancy, and transplantation, and is mostly triggered by infection. Herein, we report the case of a patient with Henoch–Schönlein purpura (HSP) who developed severe HLH secondary to Varicella zoster infection.     

Haploidentical hematopoietic stem cell transplantation for a case with X‐linked chronic granulomatous disease

CGD is a rare primary immunodeficiency with high mortality rates when treated conventionally, especially for the X‐chromosome‐linked form. HSCT is the only curative therapy for CGD; however, haploidentical transplantation in CGD is rare. Here, we report a case of X‐linked CGD treated successfully by haploidentical HSCT. The patient showed a positive result with full donor chimerism, good quality of life, and the absence of recurrent infectious diseases at follow‐up (68 months). Thus, haploidentical HSCT may serve as an acceptable treatment approach for patients who have CGD, but no HLA‐matched related or unrelated donor.     

Patients of African ancestry with hemophagocytic lymphohistiocytosis share a common haplotype of PRF1 with a 50delT mutation

Mutations of the perforin gene (PRF1) are present in a proportion of patients with hemophagocytic lymphohistiocytosis (HLH). We found that all identified infants with HLH of African descent (17 from USA, 4 from Europe) have 50delT-PRF1 (16 homozygotes, 5 compound heterozygotes), accounting for the most frequently observed PRF1 mutation. Two additional patients with HLH, self-reporting as Hispanic, carried 50delT, but no Caucasians were identified with 50delT. To test the hypothesis that this mutation represents a single haplotype, DNA from 23 patients with HLH and 30 African-American control subjects was sequenced for the PRF1 gene, including portions of the intron containing known single nucleotide polymorphisms (SNPs). The same groups were genotyped at 3 microsatellites proximal to PRF1. The SNP profiles of patients with 50delT-PRF1 were identical, and 5 novel SNPs were identified among African-American control subjects. Patients with 50delT-PRF1 were also found to have had an earlier age of disease onset than patients with other PRF1 mutations. Extent of haplotype sharing and variability of microsatellite alleles in 50delT-PRF1 chromosomes suggest that this mutation arose approximately 1000 to 4000 years ago and is restricted to patients of African descent.