Targeted high-throughput sequencing for genetic diagnostics of hemophagocytic lymphohistiocytosis

Background: Hemophagocytic lymphohistiocytosis (HLH) is a rapid-onset, potentially fatal hyperinflammatory syndrome. A prompt molecular diagnosis is crucial for appropriate clinical management. Here, we validated and prospectively evaluated a targeted high-throughput sequencing approach for HLH diagnostics. Methods: A high-throughput sequencing strategy of 12 genes linked to HLH was validated in 13 patients with previously identified HLH-associated mutations and prospectively evaluated in 58 HLH patients. Moreover, 2504 healthy individuals from the 1000 Genomes project were analyzed in silico for variants in the same genes. Results: Analyses revealed a mutation detection sensitivity of 97.3 %, an average coverage per gene of 98.0 %, and adequate coverage over 98.6 % of sites previously reported as mutated in these genes. In the prospective cohort, we achieved a diagnosis in 22 out of 58 patients (38 %). Genetically undiagnosed HLH patients had a later age at onset and manifested higher frequencies of known secondary HLH triggers. Rare, putatively pathogenic monoallelic variants were identified in nine patients. However, such monoallelic variants were not enriched compared with healthy individuals. Conclusions: We have established a comprehensive high-throughput platform for genetic screening of patients with HLH. Almost all cases with reduced natural killer cell function received a diagnosis, but the majority of the prospective cases remain genetically unexplained, highlighting genetic heterogeneity and environmental impact within HLH. Moreover, in silico analyses of the genetic variation affecting HLH-related genes in the general population suggest caution with respect to interpreting causality between monoallelic mutations and HLH. A complete understanding of the genetic susceptibility to HLH thus requires further in-depth investigations, including genome sequencing and detailed immunological characterization.Peer reviewe

Diagnostic Value of Neopterin during Neutropenic Fever and Determination of Disease Activity in Childhood Leukemias

Neopterin, a pteridine group compound that is secreted from macrophages is shown to be increased in adult leukemia; however there are few studies in childhood leukemia. This study aimed to investigate neopterin levels during childhood leukemia treatment and neutropenic fever episodes for the possibility of using as a marker for disease activity and differentiation of infections

Prognostic Factors and Long-Term Outcome in 52 Turkish Children With Hemophagocytic Lymphohistiocytosis

Albayrak, Meryem/0000-0003-2711-5150WOS: 000358289900002PubMed: 25901543Objectives: Hemophagocytic lymphohistiocytosis is a syndrome of pathologic immune activation that shares similar clinical and laboratory phenotypes with severe sepsis. Recent studies led to better recognition of hemophagocytic lymphohistiocytosis by clinicians, but no consensus exists on the criteria for high-risk patients. Design: We retrospectively reviewed the medical records of patients diagnosed with hemophagocytic lymphohistiocytosis to analyze the risk factors associated with poor outcome. Setting: Pediatric intensive care and hematology units of three tertiary hospitals in Turkey. Participants: Fifty-two children with hemophagocytic lymphohistiocytosis. Interventions: None. Measurement and Main Results: There were a total of 52 children meeting the diagnostic criteria of Histiocytic Society. Of them, 28 (54%) had a primary hemophagocytic lymphohistiocytosis. Mutation studies were performed in 18 of 28 patients (65%). Fourteen of them had PRF1, STX11, STXBP2, and UNC13D mutations, and four had Rab27a and LYST mutations. The remaining 24 patients (46%) were defined as having secondary hemophagocytic lymphohistiocytosis. Twenty-one of them had infection-associated hemophagocytic lymphohistiocytosis, and three had lysinuric protein intolerance. The mortality rate was significantly higher in primary hemophagocytic lymphohistiocytosis (64%) than in secondary hemophagocytic lymphohistiocytosis (16%) (p 0.05). Age below 2 years, hyperferritinemia, thrombocytopenia, high disseminated intravascular coagulation score at diagnosis, and no clinical response at 2 weeks of treatment were independent prognostic factors for poor prognosis. Conclusions: Our data suggest that disseminated intravascular coagulation score greater than or equal to 5 can be used in the definition of high-risk patients. Early recognition of poor risk factors has important prognostic and therapeutic implications

Severe Myelotoxicity Associated with Thiopurine S-Methyltransferase*3A/*3C Polymorphisms in a Patient with Pediatric Leukemia and the Effect of Steroid Therapy

WOS: 000348688800010PubMed: 25541649Myelosuppression is a serious complication during treatment of acute lymphoblastic leukemia and the duration of myelosuppression is affected by underlying bone marrow failure syndromes and drug pharmacogenetics caused by genetic polymorphisms. Mutations in the thiopurine S-methyltransferase (TPMT) gene causing excessive myelosuppression during 6-mercaptopurine (MP) therapy may cause excessive bone marrow toxicity. We report the case of a 15-year-old girl with T-ALL who developed severe pancytopenia during consolidation and maintenance therapy despite reduction of the dose of MP to 5% of the standard dose. Prednisolone therapy produced a remarkable but transient bone marrow recovery. Analysis of common TPMT polymorphisms revealed TPMT *3A/*3C

Inherited coagulation disorders in Turkish children: A retrospective, single-center cohort study

Albayrak, Meryem/0000-0003-2711-5150WOS:000538124200008PubMed: 31980335Objective: This study aims to investigate the distribution, clinical characteristics and outcome of inherited coagulation disorders (ICD) in Turkish children. Subjects and methods: Data from all children (age < 18 years) with ICD examined in our center were retrospectively reviewed. Results: There were 403 children with ICD (233 males and 170 females) with a median age of four years at diagnosis. The percentages of von Willebrand disease (vWd), hemophilia and rare bleeding disorders (RBD) were 40 %, 34 % and 26 %, type-1, type-2 and type-3 vWd were 63 % 17 % and 20 %, hemophilia A and B were 84 % and 16 %, and severe, moderate and mild hemophilia were 48 %, 30 % and 22 %, respectively. Factor VII and FXI deficiencies were the most prevalent, comprising 56 % and 22 % of all children with RBD, respectively. Parental consanguinity rates were 72 % in type-3 vWd and 61 % in severe RBD. The overall prevalence of gastrointestinal bleedings was 4.5 % (18/403), intracranial bleeding (ICB) was 4.96 % (20/403), mortality from ICB was 30 % (6/20) and the overall mortality rate was 1.49 % (6/403). No life-threatening bleeding was seen during regular prophylaxis. Chronic arthropathy prevalence in severe hemophilia was 8 % with primary prophylaxis and 53 % with demand therap. Inhibitor prevalence was 14 % in hemophilia-A and 5 % in hemophiliaB. Conclusions: These data show that vWd is the most common ICD, type-3 vWd and RBD are prevalent due to frequent consanguineous marriages and diagnosis of ICD is substantially delayed in Turkish children. Prophylactic replacement therapy prevents occurrence of life-threatening bleedings and reduces the development of hemophilic arthropathy