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Sequence variants in cytokine genes are related to affect cytokine gene levels. In this study, it was aimed to examine eight single nucleotide polymorphisms (SNPs) in five cytokine genes (TNF-α, INF-γ, IL-6, IL10, TGF-β) for the Turkish population living in Marmara region and to reveal the genetic distance between the study group and other populations.

Graft-versus-host disease (GvHD) is a complex clinical syndrome with organ dysfunction as a consequence of a severe immunological reaction mediated by mainly T cells after hematopoietic stem cell transplantation. Our aim is to evaluate the association of HLA-DRB1 alleles, IFN-γ and TGF-β gene variations, with childhood ALL (c-ALL) patients and with GvHD after transplantation.

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.

Aging is an exceptionally complex process that depends on genetic, environmental, and lifestyle factors. Previous studies within the International HLA and Immunogenetics Workshop (IHIWS) component "Immunogenetics of Ageing" showed that longevity is associated with positive selection of HLA-DRB1*11- and DRB1*16-associated haplotypes, shown to be protective against diseases. Within the 18th IHIWS, we aimed to investigate the relevance of telomere length for successful aging and its association with classical HLAs. In total 957 individuals from Bulgaria, Turkey, Romania, and Poland in two age groups, elderly individuals (age 65–99 years) and ethnically matched young group (age 18–64 years), were investigated. The obtained results confirmed interpopulation differences in the distribution of HLA alleles, documented the lengths of telomeres in analyzed populations, and demonstrated significant associations of telomere length with aging as well as with the presence of some HLA class I or class II alleles. They suggest that telomere length assessment combined with HLA genotyping may help identify immunogenetic profiles associated with longevity. The associations between HLA and telomeres support the theory that HLA genes influence the aging process. However, further research is needed to clarify the biological basis of the observed relationships. [ABSTRACT FROM AUTHOR]

The primary goal of the HLA‐DPA1 ~ promoter ~ HLA‐DPB1 haplotype component of the 18th IHIWS was to characterise the extended haplotypes within the HLA‐DP region and survey the extent of genetic diversity in this region across human populations. In this report, we analysed single‐nucleotide polymorphisms (SNPs) in 255 subjects from 6 different cohorts. The results from the HLA‐DP haplotype component have validated findings from the initial pilot study. SNPs in this region were inherited in strong linkage, particularly HLA‐DPA1, SNP‐linked promoter haplotypes and motifs in exon 2 of HLA‐DPB1. We reported 17 SNP‐linked haplotypes in the promoter region. Together with HLA‐DPA1 and HLA‐DPB1 alleles, they formed 74 distinct extended HLA‐DP haplotypes in 438 sequences. We also observed the presence of region‐specific alleles and promoter haplotypes. Our approach involved phasing extended SNPs including promoter SNPs, HLA‐DPA1 and HLA‐DPB1 alleles, in a 22 kb region, GRCh38/hg38 (chr6:33,064,111‐33,086,679), followed by clustering of these SNPs as one extended haplotype. This hierarchical clustering revealed four major clades, suggesting that haplotypes within each clade may have diverged from a common ancestral haplotype and undergone similar evolutionary processes. The correlation between HLA‐DPA1 and the promoter region raises questions about the role of HLA‐DPA1 antigen in the heterodimer. This finding requires validation on a larger sample size specifically designed for anthropological analysis. Nevertheless, the results from this study highlight the clinical potential of selecting better‐matched donors for patients awaiting haematopoietic stem cell transplants from genetically overlapping groups that share common ancestral haplotypes. [ABSTRACT FROM AUTHOR]

Objective: Short tandem repeats (STRs) are short sequences of nucleotides that are repeated and distributed all over the genome. These polymorphisms enable investigation of the forensic, ancestral lineage and evolutionary studies in human population. Owing to the historical migration and ethnic groups, it is very valuable to evaluate genetic distances in Turkey. The aim of the present study is to examine the STR data of Istanbul and compare the genetic distances and allele frequency with the previously published data of 27 countries from Europe, Asia, America, Africa and Middle East. Material and Method: Peripheral blood samples were obtained from 400 healthy individuals. DNA samples were amplified using a commercial kit. Multiplex STRPCR (Applied Biosystems, Foster City, CA, USA) was used and the amplicons were evaluated on an ABI3130 Genetic Analyzer. Results: Among all loci, D21S11 and D18S51 were the most polymorphic loci. The power of discrimination (PD) ranged from 0.8329 (TPOX) to 0.9722 (D18S51). The combined PD and probability of exclusion (PE) were found to be >0.99999999 and 0.99999671, respectively. Conclusion: In (his study, six STR markers tverc selected to compare the genetic distances and allele frequency of the present results with the results of twenty-seven studies which were published previously. This study indicates that the population in Turkey is an intermediate between Europe, Middle East and Central Asia. [ABSTRACT FROM AUTHOR]

Istanbul Medical Faculty, Department of Medical Biology, as the first EFI‐accredited HLA laboratory in Turkey since 1999 has been organizing both national and international quality control tests for HLA typing under the banner of the "Balkan external proficiency testing (BEPT)" encompassing countries from EFI regions 8. The first round of BEPT in 2004 was organized for low‐resolution HLA‐A,‐B typing by molecular methods and 12 centres participated in the exercise. In 2005, low‐resolution HLA‐DR typing was added, and in 2007, low‐resolution HLA‐C and DQ typing were added to the exercise and 28 centres participated. In 2015, high‐resolution (four digits or higher typing) HLA‐A,‐B,‐C,‐DR and –DQ typing added to the exercise and 40 centres participated. In the last 2 years, 2017 and 2018, the number of participating centres increased to 48 and 52, respectively. When the distribution of low‐resolution typing methods applied in the exercises were investigated, it was found that 82% of the centres in the first round of BEPT in 2004 used PCR‐SSP, whereas in the last round in 2018, 26% of the centres preferred SSP, while the rest used SSO (50%) or SSP and SSO (24%) methods. Methods for high‐resolution typing were SBT (41%), NGS (18%), SSO (18%), SSP (6%), SBT + NGS (6%) and SBT + SSP (11%). In 15th trial for BEPT, nomenclature mistake rate was 12%, and erroneous result rate was 6% for HLA samples. The most common mistakes in the exercises were nomenclature mistakes. The EFI Standards Version 7.0 is stated "HLA type can be reported using a hyphen if homozygosity is not proven by family studies." In order to provide standard results among HLA laboratories and since accurate HLA typing leads to significant increase of graft and patient survival, quality control exercises should be performed in all HLA‐based tests periodically. [ABSTRACT FROM AUTHOR]

In this study, we retrospectively examined 34 donor/recipient transplant pairs fully tested for the alleles HLA-A, B, C, DRB1, DQB1 and DPB1 in two different centers in Istanbul, Turkey. HLA-DPB1 disparity in at least one antigen level was 79.6% and only 20.6% of transplant pairs were fully identical for HLA-DPB1, in our study group. Neutrophil and thrombocyte engraftment successfully occurred in the entire study group. When the occurrence of severe (Grade III-IV) aGVHD was taken into account, we have observed that, non-permissive HLA-DPB1 mismatches were a significant factor for development of severe aGVHD (p= 0.019). There was a trend of increasing significance for the gut (p= 0.006) and liver (p: 0.054) aGVHD but not for skin aGVHD in non-permissive HLA-DPB1 mismatched transplantations. In multivariate analysis, non-permissive HLA-DPB1 mismatches remained as an independent factor for severe aGVHD. Our results did not show a significant impact of HLA-DPB1 mismatches on relapse. In survival analysis, both HLADPB1 disparities and non-permissive mismatches showed a decreasing trend of event free and overall survival times. Considering these results during donor selection may improve transplant outcomes in the setting of unrelated ASCT. [ABSTRACT FROM AUTHOR]