Publications by authors named "Esra H Sayar"

4 Publications

  • Page 1 of 1

Mutational landscape of severe combined immunodeficiency patients from Turkey.

Int J Immunogenet 2020 Dec 22;47(6):529-538. Epub 2020 May 22.

Department of Genetics, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey.

Severe combined immunodeficiency (SCID) has a diverse genetic aetiology, where a clinical phenotype, caused by single and/or multiple gene variants, can give rise to multiple presentations. The advent of next-generation sequencing (NGS) has recently enabled rapid identification of the molecular aetiology of SCID, which is crucial for prognosis and treatment strategies. We sought to identify the genetic aetiology of various phenotypes of SCIDs and assessed both clinical and immunologic characteristics associated with gene variants. An amplicon-based targeted NGS panel, which contained 18 most common SCID-related genes, was contumely made to screen the patients (n = 38) with typical SCID, atypical SCID or OMENN syndrome. Allelic segregations were confirmed for the detected gene variants within the families. In total, 24 disease-causing variants (17 known and 7 novel) were identified in 23 patients in 9 different SCID genes: RAG1 (n = 5), RAG2 (n = 2), ADA (n = 3), DCLRE1C (n = 2), NHEJ1 (n = 2), CD3E (n = 2), IL2RG (n = 3), JAK3 (n = 4) and IL7R (n = 1). The overall success rate of our custom-made NGS panel was 60% (39.3% for NK+ SCID and 100% for NK- SCID). Incidence of autosomal-recessive inherited genes is more frequently found in our cohort than the previously reported populations probably due to the high consanguineous marriages in Turkey. In conclusion, the custom-made sequencing panel was able to identify and confirm the previously known and novel disease-causing variants with high accuracy.
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http://dx.doi.org/10.1111/iji.12496DOI Listing
December 2020

Tuberculosis and impaired IL-23-dependent IFN-γ immunity in humans homozygous for a common missense variant.

Sci Immunol 2018 12;3(30)

St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, Rockefeller University, New York, NY, USA.

Inherited IL-12Rβ1 and TYK2 deficiencies impair both IL-12- and IL-23-dependent IFN-γ immunity and are rare monogenic causes of tuberculosis, each found in less than 1/600,000 individuals. We show that homozygosity for the common P1104A allele, which is found in about 1/600 Europeans and between 1/1000 and 1/10,000 individuals in regions other than East Asia, is more frequent in a cohort of patients with tuberculosis from endemic areas than in ethnicity-adjusted controls ( = 8.37 × 10; odds ratio, 89.31; 95% CI, 14.7 to 1725). Moreover, the frequency of P1104A in Europeans has decreased, from about 9% to 4.2%, over the past 4000 years, consistent with purging of this variant by endemic tuberculosis. Surprisingly, we also show that TYK2 P1104A impairs cellular responses to IL-23, but not to IFN-α, IL-10, or even IL-12, which, like IL-23, induces IFN-γ via activation of TYK2 and JAK2. Moreover, TYK2 P1104A is properly docked on cytokine receptors and can be phosphorylated by the proximal JAK, but lacks catalytic activity. Last, we show that the catalytic activity of TYK2 is essential for IL-23, but not IL-12, responses in cells expressing wild-type JAK2. In contrast, the catalytic activity of JAK2 is redundant for both IL-12 and IL-23 responses, because the catalytically inactive P1057A JAK2, which is also docked and phosphorylated, rescues signaling in cells expressing wild-type TYK2. In conclusion, homozygosity for the catalytically inactive P1104A missense variant of selectively disrupts the induction of IFN-γ by IL-23 and is a common monogenic etiology of tuberculosis.
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http://dx.doi.org/10.1126/sciimmunol.aau8714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6341984PMC
December 2018

Hematopoietic stem cell transplantation from unrelated donors in children with DOCK8 deficiency.

Pediatr Transplant 2017 Nov 30;21(7). Epub 2017 Jun 30.

Faculty of Medicine, Department of Pediatric Bone Marrow Transplantation Unit, MedicalPark Antalya Hospital, Bahçeşehir University, Antalya, Turkey.

DIDS is a unique form of combined immune deficiency characterized by an unusual susceptibility to cutaneous viral infections, severe allergies with eosinophilia and elevated immunoglobulin E titers, autoimmunity, and cancer. HSCT is considered the standard of care for this deadly disease. We have retrospectively analyzed the outcome of allogeneic HSCT from unrelated donors in patients with DIDS. Data from four patients, with five transplants, are presented. All patients received transplants from unrelated donors' BM, except for one patient who received a cord blood transplant. The conditioning regimens were based on myeloablative protocols for BM derived transplants; a NM regimen was pursued for the patient who received a cord blood transplant, which resulted in graft rejection. Although recurrent pneumonia and skin infections resolved immediately after transplantation, all patients subsequently developed human herpesvirus infection, including cutaneous herpetic lesions, cytomegalovirus reactivation, and zona zoster, which could be attributed to the use of ATG. Despite the presence of serious morbidities prior to transplantation, all patients recovered successfully. DIDS can be successfully treated with allogeneic HSCT from unrelated donors following a myeloablative conditioning regimen, with a reasonable safety profile.
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http://dx.doi.org/10.1111/petr.13015DOI Listing
November 2017

DCLRE1C (ARTEMIS) mutations causing phenotypes ranging from atypical severe combined immunodeficiency to mere antibody deficiency.

Hum Mol Genet 2015 Dec 16;24(25):7361-72. Epub 2015 Oct 16.

Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg and University of Freiburg, Freiburg, Germany, Institute of Immunity and Transplantation, University College London, Royal Free Campus, London, UK

Null mutations in genes involved in V(D)J recombination cause a block in B- and T-cell development, clinically presenting as severe combined immunodeficiency (SCID). Hypomorphic mutations in the non-homologous end-joining gene DCLRE1C (encoding ARTEMIS) have been described to cause atypical SCID, Omenn syndrome, Hyper IgM syndrome and inflammatory bowel disease-all with severely impaired T-cell immunity. By whole-exome sequencing, we investigated the molecular defect in a consanguineous family with three children clinically diagnosed with antibody deficiency. We identified perfectly segregating homozygous variants in DCLRE1C in three index patients with recurrent respiratory tract infections, very low B-cell numbers and serum IgA levels. In patients, decreased colony survival after irradiation, impaired proliferative response and reduced counts of naïve T cells were observed in addition to a restricted T-cell receptor repertoire, increased palindromic nucleotides in the complementarity determining regions 3 and long stretches of microhomology at switch junctions. Defective V(D)J recombination was complemented by wild-type ARTEMIS protein in vitro. Subsequently, homozygous or compound heterozygous DCLRE1C mutations were identified in nine patients from the same geographic region. We demonstrate that DCLRE1C mutations can cause a phenotype presenting as only antibody deficiency. This novel association broadens the clinical spectrum associated with ARTEMIS mutations. Clinicians should consider the possibility that an immunodeficiency with a clinically mild initial presentation could be a combined immunodeficiency, so as to provide appropriate care for affected patients.
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http://dx.doi.org/10.1093/hmg/ddv437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664172PMC
December 2015