Relation between HLA TYPES and immunological susceptibility of kidney transplant recipients and recipient candidates

The definitive treatment for end-stage renal disease is kidney transplantation. With kidney transplantation, the patient's survival time and quality of life increase. Transplant success can be achieved by predicting possible immunological reactions with appropriate tests. The determination of HLA tissue groups, which is the most polymorphic system in the body, has constituted an important step in organ transplant immunology. Anti-HLA antibodies represent a significant barrier to transplantation. Antibodies against HLA class I and class II antigens; may occur after pregnancy, blood transfusions, and previous solid organ transplants; however, the occurrence of higher antibody titers in some patients is still not fully elucidated. Anti-HLA antibodies have been identified by the PRA test and high PRA levels pose a significant risk for rejection. In our study, it was aimed to determine the HLA types that cause PRA positivity and to evaluate the relationship of these HLA types to PRA types and levels. Based on this purpose; the study groups were formed according to the sensitivity level detected in PRA screening tests of kidney transplant recipients and recipient candidates (R/RC) whose PRA positivity was defined from the available data in the screening performed in this study and their levels and HLA types according to PRA type, PRA (-) R/RC and HLA types of donor and donor candidates (D/DC) were recorded and the HLA alleles of these groups were compared. Patients with chronic renal failure who underwent kidney transplantation and applied for kidney transplantation in Baskent University Ankara Hospital between 2012-2020 and their relatives and unrelated donor candidates were examined retrospectively, taking into account anamnesis and laboratory findings from the nucleus system. 345 patient study group consisting of PRA (+) kidney R/RC, 300 patients 1st control group consisting of PRA (-) kidney R/RC, (D/DC) consisting of 316 people formed the second control group and a total of 961 people were included in the study. HLA Class I (A, B, C) and HLA Class II (DRB, DQB) of the D/DC and R/RC were performed by PCR method and PRA screening was performed by Luminex method. In the statistical analysis of the study whether there was a difference between groups in terms of numerical variables was tested with the Student's t test when the necessary assumptions were met, while the Mann-Whitney U test was used when the assumptions were not met. The dependency status between categorical variables was evaluated with the Pearson Chi-Square test and the comparisons between the groups were evaluated with the significance test of the difference between the two ratios. Although ABO and Rh blood groups were not found to be statistically significant in PRA (+) R/RC and PRA (-) R/RC (p=0.801) when all R/RC and D/DC were compared; in R/RC, AB Rh (+) and B Rh (+) blood groups were statistically significantly more common than D/DC, 0 Rh (+) and 0 Rh (-) blood groups were statistically significant less common; it suggested that ABO and Rh blood groups may have an effect on the progression of end-stage renal disease. When the relationship of HLA alleles with immunological susceptibility was evaluated in our study; it has been observed that class I HLA molecules may be less related than class II HLA molecules. It is thought that especially HLA-DR allele differences from Class II HLA molecules may be protective and risk factors for the development of panel reactive antibodies (PRA). In addition, some HLA allele types showed a statistically significant difference between R/RC and D/DC, indicating that HLA types of individuals may be associated with the development of end-stage renal disease. Key Words: Human Leukocyte Antigen (HLA), renal transplantation, Panel Reactive Antibody (PRA)