Browsing by Author "Oguz, Fatma Savran"

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    Distribution of HLA epitope frequencies in Turkish population
    (Walter De Gruyter Gmbh, 2022) Oguz, Fatma Savran; Oguz, Suleyman Rustu; Ogret, Yeliz; Karadeniz, Tanju Sedat; Ciftci, Hayriye Senturk; Karatas, Sule; Kivanc, Demet
    Objectives The antibodies interact with the Human Leukocyte Antigen (HLA) antigens at specific epitopes. Epitopes are present on a single HLA or shared by multiple antigens. In this study, we aim to determine the frequency of prevalent epitopes common in the Turkish population. Methods Non-related 644 healthy volunteers were recruited, and The HLA-A, -B, -C, -DR -DQ's were typed using the Next Generation Sequencing. The provisional and confirmed epitopes were identified using the HLA Epitope Registry databases, HLA Epitopia Maps and Immucor Epitope databases dated 07.02.2018. Epitope frequencies were calculated by counting the shared epitopes in the total number of shared HLA Class epitopes in our sample database. Results Class I HLA's had 298 epitopes that repeated a total of 158,117 times with frequencies ranging between 0.0006 and 2.03%, and the most frequent epitope was 170RY found on 119 different alleles. Class II HLA's had 193 epitopes that repeated a total of 93,082 times with frequencies ranging between 0.002 and 1.36%, and the most frequent epitope was 108P found on 42 different alleles. Conclusions Our findings summarize both the provisional, and confirmed epitope frequencies in the Turkish population and may help clinicians and immunogeneticists develop a better understanding of HLA epitope mismatches.
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    Uncommon HLA Alleles Observed in a Population of Istanbul Province
    (Pera Yayincilik Hizmetleri, 2024) Ogret, Yeliz Duvarci; Oguz, Rustu; Karadeniz, Sedat; Ciftci, Hayriye Senturk; Kivanc, Demet; Oguz, Fatma Savran
    Objective: New polymorphisms are formed in human leucocyte antigen (HLA) genes with point mutations, gene conversions, and duplication, and the diversity continues to increase. Various new HLA alleles have significant roles in transplantation, and epidemiologic and population studies. The aim of our study was to determine the status of HLA alleles in the Turkish population, which is uncommon, well-defined, and non-defined in the world population according to the international ImMunoGeneTics information system (R) (IMGT) database. Methods: We performed HLA-A,-B,-C,-DQB1, and DRB1 loci at the four-field resolution level, using Sanger- sequence-based typing (SBT) for 5592 healthy, unrelated bone marrow donor volunteers from Istanbul Province. The uncommon alleles were also confirmed using high-throughput next-generation sequencing (NGS). Results: Uncommon alleles were determined at five loci as follows: HLA-A*01:155, 02:66, 02:90, 02:110, 02:343, 03:82, 24:28, 24:146, 24:276, 24:356, 31:23,33:33, 68:38; HLA-B *07:240, 18:19, 35:193, 40:303, 51:69, 51:169; HLA-C*04:39, 06:40, 07:93, 12:149, 15:73; HLA-DRB1*11:149, 13:14:02 and HLA-DQB1*03:27. All alleles were arranged according to the common and well-documented (CWD) 3.0.0 catalog. Conclusion: This is the first study to show uncommon alleles in our population. These reported data increase the knowledge of HLA polymorphisms in the Turkish population and provide a basis for further studies in population genetics. This information may also be useful in determining whether a matched, unrelated donor is unlikely to be found so that a mismatch strategy, an extended family search, or alternate therapy, can be pursued, thus saving time and cost for patients.