Our results provide the basis for a detailed prospective evaluation of autoimmunity and inflammation in the context of PIDs, with a view to accurately assessing these risks and describing the possible effect of medical intervention.

Key Points• Mutations of key transcription factor in myeloid malignancies.Congenital neutropenia is a group of genetic disorders that involve chronic neutropenia and susceptibility to infections. These neutropenias may be isolated or associated with immunologic defects or extra-hematopoietic manifestations. Complications may occur as infectious diseases, but also less frequently as myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Recently, the transcription factor GATA2 has been identified as a new predisposing gene for familial AML/MDS. In the present study, we describe the initial identification by exome sequencing of a GATA2 R396Q mutation in a family with a history of chronic mild neutropenia evolving to AML and/or MDS. The subsequent analysis of the French Severe Chronic Neutropenia Registry allowed the identification of 6 additional pedigrees and 10 patients with 6 different and not previously reported GATA2 mutations (R204X, E224X, R330X, A372T, M388V, and a complete deletion of the GATA2 locus). The frequent evolution to MDS and AML in these patients reveals the importance of screening GATA2 in chronic neutropenia associated with monocytopenia because of the frequent hematopoietic transformation, variable clinical expression at onset, and the need for aggressive therapy in patients with poor clinical outcome. (Blood. 2013;121(5):822-829)

The chikungunya epidemic that occurred on La Reunion Island revealed for the first time the possibility of mother-to-child transmission in the perinatal period with a high rate of morbidity.

Heterozygous germline GATA2 mutations strongly predispose to leukemia, immunodeficiency, and/or lymphoedema. We describe a series of 79 patients (53 families) diagnosed since 2011, made up of all patients in France and Belgium, with a follow up of 2249 patients/years. Median age at first clinical symptoms was 18.6 years (range, 0-61 years). Severe infectious diseases (mycobacteria, fungus, and human papilloma virus) and hematologic malignancies were the most common first manifestations. The probability of remaining symptom-free was 8% at 40 years old. Among the 53 probands, 24 had missense mutations including 4 recurrent alleles, 21 had nonsense or frameshift mutations, 4 had a whole-gene deletion, 2 had splice defects, and 2 patients had complex mutations. There were significantly more cases of leukemia in patients with missense mutations (n=14 of 34) than in patients with nonsense or frameshift mutations (n=2 of 28). We also identify new features of the disease: acute lymphoblastic leukemia, juvenile myelomonocytic leukemia, fatal progressive multifocal leukoencephalopathy related to the JC virus, and immune/inflammatory diseases. A revised International Prognostic Scoring System (IPSS) score allowed a distinction to be made between a stable disease and hematologic transformation. Chemotherapy is of limited efficacy, and has a high toxicity with severe infectious complications. As the mortality rate is high in our cohort (up to 35% at the age of 40), hematopoietic stem cell transplantation (HSCT) remains the best choice of treatment to avoid severe infectious and/or hematologic complications. The timing of HSCT remains difficult to determine, but the earlier it is performed, the better the outcome.

Congenital neutropenias (CNs) are rare heterogeneous genetic disorders, with about 25% of patients without known genetic defects. Using whole-exome sequencing, we identified a heterozygous mutation in the gene, encoding the signal recognition particle (SRP) 54 GTPase protein, in 3 sporadic cases and 1 autosomal dominant family. We subsequently sequenced the gene in 66 probands from the French CN registry. In total, we identified 23 mutated cases (16 sporadic, 7 familial) with 7 distinct germ line mutations including a recurrent in-frame deletion (Thr117del) in 14 cases. In nearly all patients, neutropenia was chronic and profound with promyelocytic maturation arrest, occurring within the first months of life, and required long-term granulocyte colony-stimulating factor therapy with a poor response. Neutropenia was sometimes associated with a severe neurodevelopmental delay (n = 5) and/or an exocrine pancreatic insufficiency requiring enzyme supplementation (n = 3). The SRP54 protein is a key component of the ribonucleoprotein complex that mediates the co-translational targeting of secretory and membrane proteins to the endoplasmic reticulum (ER). We showed that SRP54 was specifically upregulated during the in vitro granulocytic differentiation, and that mutations or knockdown led to a drastically reduced proliferation of granulocytic cells associated with an enhanced P53-dependent apoptosis. Bone marrow examination of -mutated patients revealed a major dysgranulopoiesis and features of cellular ER stress and autophagy that were confirmed using-mutated primary cells and knockdown cells. In conclusion, we characterized a pathological pathway, which represents the second most common cause of CN with maturation arrest in the French CN registry.

Evans syndrome (ES) is a rare severe autoimmune disorder characterized by the combination of autoimmune hemolytic anemia and immune thrombocytopenia. In most cases, the underlying cause is unknown. We sought to identify genetic defects in pediatric ES (pES), based on a hypothesis of strong genetic determinism. In a national, prospective cohort of 203 patients with early-onset ES (median [range] age at last follow-up: 16.3 years ([1.2-41.0 years]) initiated in 2004, 80 nonselected consecutive individuals underwent genetic testing. The clinical data were analyzed as a function of the genetic findings. Fifty-two patients (65%) received a genetic diagnosis (the M+ group): 49 carried germline mutations and 3 carried somatic variants. Thirty-two (40%) had pathogenic mutations in 1 of 9 genes known to be involved in primary immunodeficiencies (TNFRSF6, CTLA4, STAT3, PIK3CD, CBL, ADAR1, LRBA, RAG1, and KRAS), whereas 20 patients (25%) carried probable pathogenic variants in 16 genes that had not previously been reported in the context of autoimmune disease. Lastly, no genetic abnormalities were found in the remaining 28 patients (35%, the M− group). The M+ group displayed more severe disease than the M− group, with a greater frequency of additional immunopathologic manifestations and a greater median number of lines of treatment. Six patients (all from the M+ group) died during the study. In conclusion, pES was potentially genetically determined in at least 65% of cases. Systematic, wide-ranging genetic screening should be offered in pES; the genetic findings have prognostic significance and may guide the choice of a targeted treatment.

Pediatric acute myeloid leukemia (AML) is a rare disease whose prognosis is highly variable according to factors such as chromosomal abnormalities. Recurrent genomic rearrangements are detected in half of pediatric AML by karyotype. NUcleoPorin 98 (NUP98) gene is rearranged with 31 different fusion partner genes. These rearrangements are frequently undetected by conventional cytogenetics, as the NUP98 gene is located at the end of the chromosome 11 short arm (11p15). By screening a series of 574 pediatric AML, we detected a NUP98 rearrangement in 22 cases (3.8%), a frequency similar to CBFB-MYH11 fusion gene (4.0%). The most frequent NUP98 fusion gene partner is NSD1. These cases are homogeneous regarding their biological and clinical characteristics, and associated with bad prognosis only improved by bone marrow transplantation. We detailed the biological characteristics of these AML by exome sequencing which demonstrated few recurrent mutations (FLT3 ITD, WT1, CEBPA, NBPF14, BCR and ODF1). The analysis of the clonal structure in these cases suggests that the mutation order in the NUP98-rearranged pediatric AML begins with the NUP98 rearrangement leading to epigenetic dysregulations then followed by mutations of critical hematopoietic transcription factors and finally, activation of the FLT3 signaling pathway.

Evans syndrome (ES) is a rare autoimmune disorder whose long-term outcome is not well known. In France, a collaborative pediatric network set up via the National Rare Disease Plan now provides comprehensive clinical data in children with this disease. Patients aged less than 18 years at the initial presentation of autoimmune cytopenia have been prospectively included into a national observational cohort since 2004. The definition of ES was restricted to the simultaneous or sequential association of autoimmune hemolytic anemia (AIHA) and immune thrombocytopenic purpura (ITP). Cases were deemed secondary if associated with a primitive immunodeficiency or systemic lupus erythematosus. In December 2014, we analyzed the data pertaining to 156 children from 26 centers with ES whose diagnosis was made between 1981 and 2014. Median age (range) at the onset of cytopenia was 5.4 years (0.2–17.2). In 85 sequential cases, the time lapse between the first episodes of AIHA and ITP was 2.4 years (0.1–16.3). The follow-up period as from ES diagnosis was 6.5 years (0.1–28.8). ES was secondary, revealing another underlying disease, in 10% of cases; various associated immune manifestations (mainly lymphoproliferation, other autoimmune diseases, and hypogammaglobulinemia) were observed in 60% of cases; and ES remained primary in 30% of cases. Five-year ITP and AIHA relapse-free survival were 25 and 61%, respectively. Overall, 69% of children required one or more second-line immune treatments, and 15 patients (10%) died at the age of 14.3 years (1.7–28.1). To our knowledge, this is the first consistent long-term clinical description of this rare syndrome. It underscores the high rate of associated immune manifestations and the burden of long-term complications and treatment toxicity. Future challenges include (1) the identification of the underlying genetic defects inducing immune dysregulation and (2) the need to better characterize patient subgroups and second-line treatment strategies.