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ÖZEN, AHMET OĞUZHAN

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ÖZEN

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AHMET OĞUZHAN

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2015 - 20162
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Author: ÖĞÜLÜR, İSMAİL × Subject: autoimmunity ×

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    PublicationOpen Access
    Severe Early-Onset Combined Immunodeficiency due to Heterozygous Gain-of-Function Mutations in STAT1
    (SPRINGER/PLENUM PUBLISHERS, 2016-10) ÖZEN, AHMET OĞUZHAN; Baris, Safa; Alroqi, Fayhan; Kiykim, Ayca; Karakoc-Aydiner, Elif; Ogulur, Ismail; Ozen, Ahmet; Charbonnier, Louis-Marie; Bakir, Mustafa; Boztug, Kaan; Chatila, Talal A.; Barlan, Isil B.
    Loss and gain-of-function (GOF) mutations in human signal transducer and activator of transcription 1 (STAT1) lead to distinct phenotypes. Although recurrent infections are common to both types of STAT1 mutations, GOF mutations are distinguished by chronic mucocutaneous candidiasis and autoimmunity. However, the clinical spectra of STAT1 GOF mutations continue to expand. We here describe two patients with STAT1 GOF mutations presenting early in life with combined immunodeficiency (CID). Clinical data and laboratory findings including immunophenotyping, level of interferon (IFN)-gamma/IL-17(+) T cells, interferon-induced STAT1 phosphorylation, and JAK inhibitor assays were evaluated. Sequencing of STAT1 gene was performed by Sanger sequencer. Patient 1 (P1) had persistent oral candidiasis and cytomegalovirus (CMV) infection since 2 months of age and later developed cavitary lung lesions due to Mycobacterium tuberculosis. Patient 2 (P2) presented with oral candidiasis and recurrent pneumonia at 4 months of age and subsequently developed CMV pneumonitis. Both patients suffered heterozygous missense mutations in STAT1, leading to deleterious amino acid substitutions in the DNA binding domain (P1: c.1154C > T; p.T385M; P2. c.971G > T; p.C324F). Circulating CD4(+) T cells of both patients exhibited increased interferon-gamma and decreased IL-17 expression as compared to controls. They also exhibited increased IFN-beta and -gamma-induced STAT1 phosphorylation that was reversed upon treatment with the JAK kinase inhibitor ruxolitinib. STAT1 GOF mutations may present early in life with CID, consistent with the clinical heterogeneity of the disease. JAK kinase inhibitors may potentially be useful in some patients as adjunct therapy pending definitive treatment with bone marrow transplantation.
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    Potentially Beneficial Effect of Hydroxychloroquine in a Patient with a Novel Mutation in Protein Kinase C delta Deficiency
    (SPRINGER/PLENUM PUBLISHERS, 2015) ÖZEN, AHMET OĞUZHAN; Kiykim, Ayca; Ogulur, Ismail; Baris, Safa; Salzer, Elisabeth; Karakoc-Aydiner, Elif; Ozen, Ahmet Oguzhan; Garncarz, Wojciech; Hirschmugl, Tatjana; Krolo, Ana; Yucelten, Ayse Deniz; Boztug, Kaan; Barlan, Isil B.
    Protein kinase C delta (PRKCD) has essential functions in controlling B-cell proliferation and apoptosis, development of B-cell tolerance and NK-cell cytolitic activity. Human PRKCD deficiency was recently identified to be causative for an autoimmune lymphoproliferative syndrome like disorder with significant B-cell proliferation particularly of immature B cells. Here we report a child with a novel mutation in PRKCD gene who presented with CMV infection and an early onset SLE-like disorder which was successfully treated with hydroxychloroquine.