Melinda Erdős

Novel and recurrent STAT3 mutations in hyper-IgE syndrome patients from different ethnic groups

We performed clinical, immunological and genetic studies of 12 hyper-IgE syndrome (HIES) patients from 4 Hungarian, 2 Lebanese, one Russian, one Polish, and one Swedish families with autosomal dominant (AD) or sporadic forms of the disease to reveal cross-ethnicity of recurrent and novel mutations in the signal transducer and activator of transcription-3 gene (STAT3). Four patients from 3 Hungarian families, and one Russian, and one Swedish patient carried the heterozygous R382W germline mutation at the DNA-binding site of STAT3. The recurrent V637M mutation affecting the SRC homology 2 (SH2) domain was detected in one Lebanese and one Polish family, and the V463del deletion located in the DNA-binding domain was unveiled in another Lebanese family. A novel H332Y mutation affecting the DNA-binding site of STAT3 in three Hungarian patients from a Gypsy family was also found. The segregation of this mutation with HIES, restriction fragment length polymorphism analysis of STAT3 from patients and controls and the negligible production upon IL-6 stimulation of monocyte chemotactic protein-1 by the patients blood mononuclear cells suggested that the H332Y mutation was disease-causing. These data suggest, that dominant negative mutations of the DNA-binding and SH2 domains of STAT3 cause AD and sporadic cases of HIES in different ethnic groups with R382W as the predominant mutation found in 5 of the 9 families. Functional and genetic data support that the novel H332Y mutation may result in the loss of function of STAT3 and leads to the HIES phenotype.

Genetic and demographic features of X-linked agammaglobulinemia in Eastern and Central Europe: A cohort study

Primary immunodeficiency disorders are a recognized public health problem worldwide. The prototype of these conditions is X-linked agammaglobulinemia (XLA) or Brutons disease. XLA is caused by mutations in Brutons tyrosine kinase gene (BTK), preventing B cell development and resulting in the almost total absence of serum immunoglobulins. The genetic profile and prevalence of XLA have not previously been studied in Eastern and Central European (ECE) countries. We studied the genetic and demographic features of XLA in Belarus, Croatia Hungary, Poland, Republic of Macedonia, Romania, Russia, Serbia, Slovenia, and Ukraine. We collected clinical, immunological, and genetic information for 122 patients from 109 families. The BTK gene was sequenced from the genomic DNA of patients with a high susceptibility to infection, almost no CD19(+) peripheral blood B cells, and low or undetectable levels of serum immunoglobulins M, G, and A, compatible with a clinical and immunological diagnosis of XLA. BTK sequence analysis revealed 98 different mutations, 46 of which are reported for the first time here. The mutations included single nucleotide changes in the coding exons (35 missense and 17 nonsense), 23 splicing defects, 13 small deletions, 7 large deletions, and 3 insertions. The mutations were scattered throughout the BTK gene and most frequently concerned the SH1 domain; no missense mutation was detected in the SH3 domain. The prevalence of XLA in ECE countries (total population 145,530,870) was found to be 1 per 1,399,000 individuals. This report provides the first comprehensive overview of the molecular genetic and demographic features of XLA in Eastern and Central Europe.

Autoantibodies to IL-17A may be Correlated with the Severity of Mucocutaneous Candidiasis in APECED Patients

The relative roles of various autoantibodies against IL-17-type cytokines in susceptibility to chronic mucocutaneous candidiasis (CMC) in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) remain poorly defined. The purpose of this longitudinal study was to analyze the relationship between the occurrence of mucocutaneous candidiasis and levels of anti-IL-17A, anti-IL-17F and anti-IL-22 autoantibodies. We studied six APECED patients from four families with various disease manifestations. Clinical data were collected during regular follow-up. Anti-endocrine organ antibody levels and clinical chemistry and immunology parameters were determined in routine laboratory assays on freshly isolated serum. Levels of autoantibodies against IL-17A, IL-17F, IL-22, IFN-α, IFN-ω and TNF-α, and cytokine release by Candida-exposed blood cells were determined by ELISA. Mutations were analyzed by sequencing genomic DNA. Four patients carried the germline c.769C > T homozygous nonsense mutation, which results in R257X truncation of the AIRE protein, and two patients from the same family were compound heterozygous for the c.769C > T/c.1344delC mutation. We found persistently high levels of antibodies against IL-17A in the serum samples of one patient presenting CMC since infancy and low or undetectable anti-IL-17A antibody levels in the sera of five patients with no candidiasis or without severe candidiasis. By contrast, levels of autoantibodies against IL-17F and IL-22 were higher in all patients than in healthy controls. Release of IL-17-type cytokines by Candida-exposed blood mononuclear cells was low or negligible in all patients tested. We suggest that anti-IL-17A antibodies may play an important role in the predisposition to candidiasis of APECED patients. However, the lack of severe CMC in APECED patients with high levels of IL-17F and anti-IL-22 autoantibodies clearly calls into question the role of these antibodies as the principal cause of cutaneous and mucosal candidiasis in at least some APECED patients. These data also suggest that the impaired release of IL-17-type cytokines by blood cells may be an element of the immunopathology of CMC in APECED patients.

Successful umbilical cord blood stem cell transplantation in a child with WHIM syndrome.

To the Editor: Warts hypogammaglobulinemia infections myelokathexis (WHIM) syndrome is an autosomal dominant primary immunodeficiency disorder caused by mutation of the cysteine-X-cysteine chemokine receptor 4 (CXCR4) gene (1, 2). Affected patients suffer from recurrent infections of the respiratory tract and soft tissues, and marked susceptibility to warts caused by human papilloma viruses from the second decade of life (3, 4). Granulocyte colony-stimulating factor (G-CSF) has been used to increase and maintain an adequate number of circulating neutrophils, and administration of intravenous immunoglobulin (IVIG) concentrates may help to decrease the number of infectious episodes caused by extracellular pathogens (5, 6). Nevertheless, the optimal therapy of patients with WHIM has not been clearly defined, and patients continue to develop infections despite combination therapy with G-CSF and IVIG. None of the patients reported earlier has received hematopoietic stem cell transplantation (HSCT). We describe here a successful allogeneic HSCT in a girl with WHIM syndrome caused by c.1013C>G sequence variant in the CXCR4 gene. Clinical and genetic details of this girl were described in the Journal before (2). IVIG infusions and varying doses of G-CSF were started at 6.5 yr of age. She showed clinical improvement in the beginning but continued to develop respiratory infections leading to chronic obstructive pulmonary disease. At age 8, she was treated for a prolonged episode of dental periostitis complicated with purulent lymphadenitis. We counseled the family on the possibility of HSCT and umbilical cord blood (UCB) transplantation, and the mother decided to become pregnant. She presented with a new pregnancy, and at 11 wk of gestation, prenatal genetic testing revealed wild-type CXCR4 sequences, and human leukocyte antigen genotyping showed matching between the patient and the fetus (Fig. 1). Informed consent was obtained from the parents, and the UCB transplantation was approved by the Hungarian National Transplant Committee. UCB stem cells were collected using standard methods (7). Pretransplant conditioning regimen consisted of intravenous busulphan and cyclophosphamide, followed by a course of rabbit antithymocyte globulin. An UCB graft containing 1.2 · 10 CD34 cells ⁄kg and 3.8 · 10 nucleated cells ⁄kg was infused without any adverse effects. Graft versus host disease (GvHD) prophylaxis consisted of methyl-prednisolone and cyclosporin A. A flare up of chronic obstructive bronchitis was observed, and on day +49, she developed pneumonia caused by Str. pneumoniae. Meropenem therapy and bronchodilatator drugs resolved this lung infection. No signs or symptoms of acute or chronic GvHD were observed. An absolute neutrophil count of >500 ⁄mm was achieved on post-transplant day 32, and platelet transfusion independence was achieved on day 48. Reconstitution of the humoral immune system was also robust with normal-for-age serum IgG, IgM, and IgA levels by 100 d after HSCT. Interphase chromosome analysis and serial varying number of tetraand pentanucleotid repeats examinations were used to confirm donor cell engraftment. The

Neuroendocrine carcinoma associated with X-linked hyper-immunoglobulin M syndrome: Report of four cases and review of the literature

X-linked hyper-immunoglobulin M syndrome (XHIGM) is a primary immunodeficiency disorder characterized by severe defects of both cellular and humoral immunity due to impaired expression of CD40 ligand on activated T lymphocytes. Patients with XHIGM usually present with a wide variety of infections caused by common and opportunistic pathogens including Pneumocystis jirovecii. In addition, subjects with XHIGM have an increased risk for hepatocellular and bile duct carcinomas, which are rarely observed in other primary immunodeficiencies. We present here clinical, immunological, and molecular findings of four patients with CD40 ligand deficiency associated with neuroendocrine carcinoma (NEC). NEC developed as a rapidly disseminated solid cancer leading to death in three patients. Data presented here and published previously suggest that CD40 ligand deficiency may predispose patients for the development of NEC. Histochemical findings suggested that CD56, in addition to cytokeratin and chromogranin A, may be a useful marker for early detection of NEC. We conclude that patients with XHIGM should be carefully followed to diagnose and treat NEC, a formidable neuroendocrine cancer.

Genetic characteristics of eighty-seven patients with the Wiskott–Aldrich syndrome

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive immune deficiency disorder characterized by thrombocytopenia, small platelet size, eczema, recurrent infections, and increased risk of autoimmune disorders and malignancies. WAS is caused by mutations in the WASP gene which encodes WASP, a 502-amino acid protein. WASP plays a critical role in actin cytoskeleton organization and signalling, and functions of immune cells. We present here the results of genetic analysis of patients with WAS from eleven Eastern and Central European (ECE) countries and Turkey. Clinical and haematological information of 87 affected males and 48 carrier females from 77 WAS families were collected. The WASP gene was sequenced from genomic DNA of patients with WAS, as well as their family members to identify carriers. In this large cohort, we identified 62 unique mutations including 17 novel sequence variants. The mutations were scattered throughout the WASP gene and included single base pair changes (17 missense and 11 nonsense mutations), 7 small insertions, 18 deletions, and 9 splice site defects. Genetic counselling and prenatal diagnosis were applied in four affected families. This study was part of the J Project aimed at identifying genetic basis of primary immunodeficiency disease in ECE countries. This report provides the first comprehensive overview of the molecular genetic and demographic features of WAS in ECE.

The Evolving View of IL-17-Mediated Immunity in Defense Against Mucocutaneous Candidiasis in Humans.

The discovery of interleukin (IL)-17-mediated immunity has provided a robust framework upon which our current understanding of the mechanism involved in host defense against mucocutaneous candidiasis (CMC) has been built. Studies have shed light on how pattern recognition receptors expressed by innate immune cells recognize various components of Candida cell wall. Inborn errors of immunity affecting IL-17+ T cell differentiation have recently been defined, such as deficiencies of signal transducer and activator of transcription (STAT)3, STAT1, IL-12Rβ1 and IL-12p40, and caspase recruitment domain 9. Impaired receptor-ligand coupling was identified in patients with IL-17F and IL-17 receptor A (IL17RA) deficiency and autoimmune polyendocrine syndrome (APS) type 1. Mutation in the nuclear factor kappa B activator (ACT) 1 was described as a cause of impaired IL-17R-mediated signaling. CMC may be part of a complex clinical phenotype like in patients with deficiencies of STAT3, IL-12Rβ1/IL-12p40 and APS-1 or may be the only or dominant phenotypic manifestation of disease which is referred to as CMC disease. CMCD may result from deficiencies of STAT1, IL-17F, IL-17RA and ACT1. In this review we discuss how recent research on IL-17-mediated immunity shed light on host defense against mucocutaneous infection by Candida and how the discovery of various germ-line mutations and the characterization of associated clinical phenotypes have provided insights into the role of CD4+IL-17+ lymphocytes in the regulation of anticandidal defense of body surfaces.

Disorders of phagocytic cells

Patients with defects in phagocytic function are predisposed to intracellular microorganisms and typically have early dissemination of the infection. Recognition of the underlying disorder and aggressive antimicrobial therapy has been beneficial for the patients. Improved understanding of the pathophysiology of the disorder has also affected patient management by allowing specific, targeted immunomodulatory interventions. The cases in this chapter are not common but have had a significant impact on our understanding of the role of phagocytic cells in host defense. Conversely, understanding the role of the neutrophils and macrophages in infection has benefited not just the patients described in this chapter but also other patients with similar disease process.

Molecular Genetic Characterization of Novel Sphingomyelin Phosphodiesterase 1 Mutations Causing Niemann–Pick Disease

Niemann-Pick disease (NPD) types A and B are autosomal recessive disorders caused by acid sphingomyelinase (ASM) deficiency due to mutation in the sphingomyelin phosphodiesterase 1 gene (SMPD1). Although a number of SMPD1 mutations were reported, expression studies were performed for only a small number of missense mutations. We evaluated three unrelated patients with clinical manifestations of NPD. Sequence analysis revealed two previously described (S248R and W391G) and two novel (G247D and F572L) missense mutations. To analyze the effects of the novel mutations on ASM function, cDNA was generated by site-directed mutagenesis and expressed in COS-7 cells. In vitro biochemical assays revealed marked deficiency of ASM activity consistent with the disease phenotype in cells homoallelic for each mutation. We show that each mutation dramatically reduced half-life and catalytic activity of ASM with more pronounced decrease by the G247D mutation. These data suggest that impaired protein stability and decreased enzyme activity are responsible for the disease in sphingomyelinase-deficient patients carrying the G247D and F572L mutations.

Novel sequence variants of the α-galactosidase A gene in patients with Fabry disease

We carried out molecular studies of 15 unrelated Hungarian families diagnosed with Fabry disease (FD). Genetic analysis of the alpha-galactosidase A gene was performed in 22 hemizygous males and 34 females. One of the female patients with severe disease phenotype showed homozygosity for the recurrent c.644A>G mutation due to parental consanguinity. The c.644A>G mutation that has previously been found mostly in patients with the cardiac variant of FD, was associated with renal but not cardiac involvement in this female and in two other family members. In nine families, eight novel sequence variants such as small deletions (c.363delT, c.477delT, c.746delAC) and single nucleotide changes (c.107T>C, c.493G>C, c.796G>T, c.866T>G, c.871G>A) were found in addition to six previously described private mutations. This report contributes to the identification of novel disease-causing mutations in FD, and increases our knowledge on demographics and molecular characteristics of this rare lysosomal storage disorder. This is the first comprehensive overview of molecular genetic features of Hungarian patients with FD.