Ekrem Unal

Hypomorphic homozygous mutations in phosphoglucomutase 3 (PGM3) impair immunity and increase serum IgE levels

BACKGROUND Recurrent bacterial and fungal infections, eczema, and increased serum IgE levels characterize patients with the hyper-IgE syndrome (HIES). Known genetic causes for HIES are mutations in signal transducer and activator of transcription 3 (STAT3) and dedicator of cytokinesis 8 (DOCK8), which are involved in signal transduction pathways. However, glycosylation defects have not been described in patients with HIES. One crucial enzyme in the glycosylation pathway is phosphoglucomutase 3 (PGM3), which catalyzes a key step in the synthesis of uridine diphosphate N-acetylglucosamine, which is required for the biosynthesis of N-glycans. OBJECTIVE We sought to elucidate the genetic cause in patients with HIES who do not carry mutations in STAT3 or DOCK8. METHODS After establishing a linkage interval by means of SNPchip genotyping and homozygosity mapping in 2 families with HIES from Tunisia, mutational analysis was performed with selector-based, high-throughput sequencing. Protein expression was analyzed by means of Western blotting, and glycosylation was profiled by using mass spectrometry. RESULTS Mutational analysis of candidate genes in an 11.9-Mb linkage region on chromosome 6 shared by 2 multiplex families identified 2 homozygous mutations in PGM3 that segregated with disease status and followed recessive inheritance. The mutations predict amino acid changes in PGM3 (p.Glu340del and p.Leu83Ser). A third homozygous mutation (p.Asp502Tyr) and the p.Leu83Ser variant were identified in 2 other affected families, respectively. These hypomorphic mutations have an effect on the biosynthetic reactions involving uridine diphosphate N-acetylglucosamine. Glycomic analysis revealed an aberrant glycosylation pattern in leukocytes demonstrated by a reduced level of tri-antennary and tetra-antennary N-glycans. T-cell proliferation and differentiation were impaired in patients. Most patients had developmental delay, and many had psychomotor retardation. CONCLUSION Impairment of PGM3 function leads to a novel primary (inborn) error of development and immunity because biallelic hypomorphic mutations are associated with impaired glycosylation and a hyper-IgE-like phenotype.

Comparison of primary human cytotoxic T-cell and natural killer cell responses reveal similar molecular requirements for lytic granule exocytosis but differences in cytokine production.

Cytotoxic lymphocytes, encompassing cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells, kill pathogen-infected, neoplastic, or certain hematopoietic cells through the release of perforin-containing lytic granules. In the present study, we first performed probability-state modeling of differentiation and lytic granule markers on CD8(+) T cells to enable the comparison of bona fide CTLs with NK cells. Analysis identified CD57(bright) expression as a reliable phenotype of granule marker-containing CTLs. We then compared CD3(+)CD8(+)CD57(bright) CTLs with NK cells. Healthy adult peripheral blood CD3(+)CD8(+)CD57(bright) CTLs expressed more granzyme B but less perforin than CD3(-)CD56(dim) NK cells. On stimulation, such CTLs degranulated more readily than other T-cell subsets, but had a propensity to degranulate that was similar to NK cells. Remarkably, the CTLs produced cytokines more rapidly and with greater frequency than NK cells. In patients with biallelic mutations in UNC13D, STX11, or STXBP2 associated with familial hemophagocytic lymphohistiocytosis, CTL and NK cell degranulation were similarly impaired. Therefore, cytotoxic lymphocyte subsets have similar requirements for Munc13-4, syntaxin-11, and Munc18-2 in lytic granule exocytosis. The present results provide a detailed comparison of human CD3(+)CD8(+)CD57(bright) CTLs and NK cells and suggest that analysis of CD57(bright) CTL function may prove useful in the diagnosis of primary immunodeficiencies including familial hemophagocytic lymphohistiocytosis.

Genetic, immunological, and clinical features of patients with bacterial and fungal infections due to inherited IL-17RA deficiency

Significance Chronic mucocutaneous candidiasis (CMC) is defined as persistent or recurrent infections of the skin and/or mucosae by commensal fungi of the Candida genus. It is often seen in patients with T-cell deficiencies, whether inherited or acquired, who typically suffer from multiple infectious diseases. Rare patients are otherwise healthy and display isolated CMC, which often segregates as a Mendelian trait. In 2011, we described the first genetic cause of isolated CMC, with autosomal recessive (AR), complete IL-17 receptor A (IL-17RA) deficiency, in a single patient. We report here 21 patients from 12 unrelated kindreds, homozygous for 12 different mutant alleles that underlie AR IL-17RA deficiency. All patients have isolated CMC and their cells do not respond to IL-17A, -17F, and -17E/IL-25. Chronic mucocutaneous candidiasis (CMC) is defined as recurrent or persistent infection of the skin, nails, and/or mucosae with commensal Candida species. The first genetic etiology of isolated CMC—autosomal recessive (AR) IL-17 receptor A (IL-17RA) deficiency—was reported in 2011, in a single patient. We report here 21 patients with complete AR IL-17RA deficiency, including this first patient. Each patient is homozygous for 1 of 12 different IL-17RA alleles, 8 of which create a premature stop codon upstream from the transmembrane domain and have been predicted and/or shown to prevent expression of the receptor on the surface of circulating leukocytes and dermal fibroblasts. Three other mutant alleles create a premature stop codon downstream from the transmembrane domain, one of which encodes a surface-expressed receptor. Finally, the only known missense allele (p.D387N) also encodes a surface-expressed receptor. All of the alleles tested abolish cellular responses to IL-17A and -17F homodimers and heterodimers in fibroblasts and to IL-17E/IL-25 in leukocytes. The patients are currently aged from 2 to 35 y and originate from 12 unrelated kindreds. All had their first CMC episode by 6 mo of age. Fourteen patients presented various forms of staphylococcal skin disease. Eight were also prone to various bacterial infections of the respiratory tract. Human IL-17RA is, thus, essential for mucocutaneous immunity to Candida and Staphylococcus, but otherwise largely redundant. A diagnosis of AR IL-17RA deficiency should be considered in children or adults with CMC, cutaneous staphylococcal disease, or both, even if IL-17RA is detected on the cell surface.

Inherited biallelic CSF3R mutations in severe congenital neutropenia

Severe congenital neutropenia (SCN) is characterized by low numbers of peripheral neutrophil granulocytes and a predisposition to life-threatening bacterial infections. We describe a novel genetic SCN type in 2 unrelated families associated with recessively inherited loss-of-function mutations in CSF3R, encoding the granulocyte colony-stimulating factor (G-CSF) receptor. Family A, with 3 affected children, carried a homozygous missense mutation (NM_000760.3:c.922C>T, NP_000751.1:p.Arg308Cys), which resulted in perturbed N-glycosylation and aberrant localization to the cell surface. Family B, with 1 affected infant, carried compound heterozygous deletions provoking frameshifts and premature stop codons (NM_000760.3:c.948_963del, NP_000751.1:p.Gly316fsTer322 and NM_000760.3:c.1245del, NP_000751.1:p.Gly415fsTer432). Despite peripheral SCN, all patients had morphologic evidence of full myeloid cell maturation in bone marrow. None of the patients responded to treatment with recombinant human G-CSF. Our study highlights the genetic and morphologic SCN variability and provides evidence both for functional importance and redundancy of G-CSF receptor-mediated signaling in human granulopoiesis.

Childhood Stroke: Results of 130 Children From a Reference Center in Central Anatolia, Turkey

BACKGROUND Although stroke among children is rare, it can cause significant morbidity and mortality. We aim to share our experience of children with arterial ischemic stroke. METHODS The initial symptoms, demographical features, risk factors, neurological examination, neuroradiological findings, and clinical follow-up data of 130 Turkish children seen between 2002 and 2013 were retrospectively analyzed. RESULTS Sixty-eight patients were male. Thirty of the children were aged from 1 to 12 months (seven of them died in this period). Focal neurological signs were the most common presentation, and hemiplegia or hemiparesis were the most common focal signs. Underlying risk factors were detected in 103 patients. Infections and congenital heart disease were the most common risk factors. Seven of the nine children with recurrent arterial ischemic strokes had one or more underlying diseases (moyamoya disease in two children along with factor V Leiden mutation, tuberculous meningitis, congenital heart disease, homocystinuria, and hemiconvulsion-hemiplegia-epilepsy syndrome). The arterial ischemic stroke was located in the middle cerebral circulation in 68 (36 left and 32 right) and in the posterior cerebral artery in 41. Eighteen children died. The neurological outcome was assessed in 98 children. Of these children, 66 children have neurological deficits and 52 children have seizures. Stroke in the first year of life is more often fatal. Recurrent stroke is associated with poor prognosis. CONCLUSION Tuberculous meningitis is still a risk factor for arterial ischemic stroke in Turkey. Arterial ischemic stroke in the first year of life and recurrent arterial ischemic stroke represent poor prognostic features.

Atypical Severe Combined Immunodeficiency Caused by a Novel Homozygous Mutation In Rag1 Gene in a Girl who Presented with Pyoderma Gangrenosum: A Case Report and Literature Review

Severe combined immunodeficiency (SCID) is a heterogeneous group of inherited defects involving the development of T- and/or B-lymphocytes. We report a female with atypical severe combined immunodeficiency caused by a novel homozygous mutation at cDNA position 2290 (c.2290C > T) in exon 2 of the RAG1 gene. The patient presented with bronchopneumonia, pyoderma gangrenosum (PG), pancytopenia and splenomegaly. She presented to us with pancytopenia and splenomegaly at the age of 11. Her condition was complicated by PG on left lower ankle at the age of 12. She experienced bronchopneumonia at the age of 15. She was diagnosed with RAG1 deficiency at the age of 16. Her immunological presentation included leucopenia and diminished number of B cells.

Autoimmune diseases detected in children with primary immunodeficiency diseases: results from a reference centre at middle anatolia

Primary immunodeficiency diseases (PIDs) are a heterogeneous group of disorders that genetically affect distinct components of the immune system; thus, predispose individuals to recurrent infections, allergy, autoimmunity, and malignancies. In this retrospective study, autoimmune diseases (ADs), which developed during the course of PID in children, were discussed.Twenty-five patients were included in this study. Symptoms related to ADs, such as autoimmune thyroiditis, type 1 diabetes mellitus, coeliac disease, juvenile idiopathic arthritis, dermatomyositis, autoimmune haemolytic anaemia, leukocytoclastic vasculitis, Henoch-Schonlein purpura, hypoparathyroidism, alopecia areata, Addisons disease, vitiligo and systemic lupus erythematosus were detected in these patients, who have been followed with diagnosis of PID including common variable immunodeficiency, selective and partial IgA deficiency, Wiskott-Aldrich syndrome, ataxia telangiectasia, hyperimmunoglobulin E syndrome, chronic mucocutaneous candidiasis, Griscelli syndrome, and partial C4 deficiency.Immunodeficiency and autoimmune phenomenon may concomitantly present in an individual, although they seem to be incompatible ends in the spectrum of the clinical immune response. Patients with primary immune deficiency should be closely monitored for development of autoimmune diseases.

Web-based survey of resources for treatment and long-term follow-up for children with brain tumors in developing countries

IntroductionInformation about pediatric survivors of brain tumors in developing countries is scant.PurposeIn this study, we aimed to investigate the availability of resources for treatment and long-term follow-up of children with central nervous system tumors in developing countries.Materials and methodsA web-based questionnaire on available services and follow-up of brain tumor survivors was posted at www.cure4kids.org, and registered users were invited to participate.ResultsA total of 140 evaluable responses from developing countries (n = 103) and high-income countries (n = 37) were obtained. There was a significant correlation between gross national income and the availability of services for treatment and follow-up and between patient load and the availability of some services.ConclusionThe resources for treatment and long-term follow-up of children with brain tumors need to be improved in developing countries.

Mesenchymal hamartoma of the liver mimicking hepatoblastoma.

Mesenchymal hamartoma of the liver is a cystic benign liver mass occurring in children. Diagnostic confusion with hepatoblastoma may arise when alpha-feto-protein (AFP) level is elevated. We report an extremely rare case of mesenchymal hamartoma in an 11-month-old boy. Serum AFP was elevated and fine-needle aspiration biopsy suggested the lesion as hepatoblastoma, so he received preoperative chemotherapy. At the end of the preoperative chemotherapy, the tumor size and AFP level decreased. A right hepatectomy was performed. The pathologic examination of the specimen revealed mesenchymal hamartoma. Mesenchymal hamartoma of the liver with increased serum AFP levels may mimic hepatoblastoma if a cytological examination samples only the hepatocellular component of mesenchymal hamartoma. According to our knowledge, this is the first case of the mesenchymal hamartoma of the liver, which showed reduction in serum levels of AFP and involution of the tumor size by preoperative chemotherapy.

CARDIAC FUNCTIONS EVALUATED WITH TISSUE DOPPLER IMAGING IN CHILDHOOD CANCERS TREATED WITH ANTHRACYCLINES

Aim: The aim of this study was to assess the cardiac functions using conventional echocardiography and tissue Doppler imaging in childhood cancers treated with anthracyclines. Methods: The study group was selected from the patients admitted to the pediatric oncology department for a treatment protocol that included doxorubicin. Body surface area was calculated and complete 2-dimensional, M-mode, pulse wave Doppler and pulse wave tissue Doppler echocardiographic examinations were performed just before the first treatment and at least 6 months after the last treatment. Results: This study included 20 patients (12 males and 8 females). Mean cumulative antracycline dose was 189 ± 102.90 mg/m2. There were no significant differences between the pre- and post-treatment groups regarding systolic and diastolic blood pressures, heart rates, left ventricular ejection fraction and fractional shortening, right and left ventricular conventional and tissue Doppler diastolic parameters (E and A waves, E/A ratio, E′ and A′ waves, E′/A′ ratio), but there were significant differences between the pre- and post-treatment groups regarding body surface area, right and left ventricular myocardial performance index observed by conventional pulse wave and pulse wave tissue Doppler methods. Conclusion: Tissue Doppler imaging provided additional information on cardiac functions. While systolic and diastolic functions were in normal range, myocardial performance index observed by tissue Doopler method was impaired in children who were treated with anthracyclines.