Mutations in the perform gene in children with hemophagocytic lymphohistiocytosis

Background Recent studies have reported germline mutations in the perforin gene (PRF1) in some types of hemophagocytic lymphohistiocytosis (HLH). However, the prevalence of PRF1 mutations in HLH in Chinese pediatric patients has not been extensively studied. The aim of this study was to investigate the prevalence of mutations and sequence variations in the PRF1 gene in Chinese pediatric patients with HLH.Methods Polymerase chain reaction (PCR) was performed with five pairs of primers for the coding exons and the flanking intron sequences of PRF1. Sequencing of PCR products was subsequently applied in 30 pediatric patients with HLH and in 50 controls.Results Three heterozygous mutations in a coding region were found, which resulted in amino acid changes (C102F, S108N and T450M) in three patients. These mutations were not detected in control subjects. One patient had compound heterozygous mutations (S108N and T450M) in PRF1 as the background defect, and documented familial HLH type 2 (FHL2). One synonymous sequence variant (Q540Q) was observed in one patient but not in the controls. Two SNPs (A274A, H300H) in the coding region were detected in HLH patients and controls, but without differences in the heterozygosity rate between the two groups (P＞0.05 for all comparisons).Conclusions We have identified three patients with three heterozygous missense mutations in PRF1; two of those three mutations (C102F and S108N) have so far been found only from Chinese patients. These findings are useful in evaluating the prevalence of PRF1 mutations in Chinese pediatric patients with HLH, and to correlate their genotype with phenotype. Some patients without familial history probably have primary HLH, which should be suspected even beyond the usual age range.     

Inherited defects in lymphocyte cytotoxic activity

Summary: The granule-dependent cytotoxic activity of lymphocytes plays a critical role in the defense against virally infected cells and tumor cells. The importance of this cytotoxic pathway in immune regulation is evidenced by the severe and often fatal condition, known as hemophagocytic lymphohistiocytic syndrome (HLH) that occurs in mice and humans with genetically determined impaired lymphocyte cytotoxic function. HLH manifests as the occurrence of uncontrolled activation of T lymphocytes and macrophages infiltrating multiple organs. In this review, we focus on recent advances in the characterization of effectors regulating the release of cytotoxic granules, and on the role of this cytotoxic pathway in lymphocyte homeostasis and immune surveillance. Analysis of the mechanisms leading to the occurrence of hemophagocytic syndrome designates γ-interferon as an attractive therapeutic target to downregulate uncontrolled macrophage activation, which sustains clinical and biological features of HLH.     

Toxoplasmosis-associated hemophagocytic syndrome in renal transplantation

Toxoplasmosis is an infrequent, often difficult to diagnose and potentially lethal disease in kidney transplant recipients. Among reported cases, a few were associated with hemophagocytic syndrome (HPS), a rare condition characterized by widespread proliferation of macrophages phagocytizing blood elements, accompanied by fever and pancytopenia. We report here the case of a patient who received a Toxoplasma gondii positive kidney allograft and developed invasive toxoplasmosis 10 days after surgery, with high fever, skin rash, arthralgias, and renal failure, followed by pneumonia, anemia, thrombocytopenia, liver dysfunction, and encephalitis. Mislead by the absence of Toxoplasma on blood smears, alveolar fluid, renal graft biopsy, and negative brain computed tomography, confusion with serum sickness, and simultaneous herpetic infection, we failed to make the right diagnosis and the patient died with septic shock 11 days later. An HPS was revealed by a late bone marrow analysis. This may well be the fourth case ever reported of toxoplasmosis-associated HPS in renal transplant recipients.     

CCR2基因rs1799864多态性与儿童噬血性淋巴组织细胞增生症的关联研究

目的 探讨CCR2基因单核苷酸多态性(SNP)位点V64I(rs1799864)与儿童噬血性淋巴组织细胞增生症(HLH)发病的关联性.方法 收集2007年1月至2013年12月确诊为HLH的86例患儿的临床资料,采用SNaPshot基因分型技术对HLH患儿和128例健康对照进行CCR2基因rs1799864位点分型,比较两组该SNP位点基因型和等位基因频率的差异;以及HLH患儿不同临床特征与rs1799864位点基因型分布的关系.结果 与对照组相比,HLH组rs1799864位点的基因型和等位基因频率差异均无统计学意义(均P>0.05);就发病年龄是否<1岁、治疗后1 d体温是否恢复正常及治疗后2~3周血小板是否恢复正常等不同临床特征的HLH患儿基因型分布进行比较后发现差异均具有统计学意义(均P<0.05).结论 CCR2基因 rs1799864位点多态性与儿童HLH的发病无关,但其基因型不同可能与HLH患儿的临床表现及预后有关.     

Fulminant Epstein–Barr virus‐associated hemophagocytic syndrome in a renal transplant patient and review of the literature

We describe a rare fulminant case of Epstein–Barr virus‐associated hemophagocytic syndrome (HPS) in a 37‐year‐old female renal transplant patient, indistinguishable from severe sepsis clinically and in the laboratory. HPS involves rapidly escalating immune system activation, resulting in a cytokine cascade, which can, especially in immunocompromised patients, lead to multi‐organ failure, and even death. Thirty‐two Herpesviridae‐associated HPS cases in renal transplant patients have been reported and are reviewed. Overall mortality is 47% (15/32 cases).