HLA-A, HLA-B AND HLA-DR PHENOTYPE FREQUENCIES AMONG RENAL TRANSPLANT DONORS AND RECIPIENTS IN LATVIA

Background: Human Leukocyte Antigen (HLA) genotyping is crucial for solid organ transplantation. HLA coding sequence is one of the most polymorphic, hence HLA genotype is extremely variable among different population. Till now no studies have examined HLA phenotype diversity in Latvian population undergoing renal allotransplantation.
Methods: We examined case files of 121 deceased and living kidney donors and their 173 kidney transplant recipients Latvia who were treated during 2013-2015 in Transplantation Center of Latvia. Due to incomplete information available 55 case files were excluded, so files of 105 donors and 134 recipients were analyzed. HLA phenotyping was done using microcytotoxicity test. We have analyzed frequencies (f ) of HLA-A, HLA-B and HLA-DR phenotypes.
Results: Overall 20 different HLA-A phenotypes are identified. The most prevalent HLA-A phenotypes among all patient are A*02 (f=0,336), A*03 (f=0,148), A*24 (f=0,109), A*01 (f=0,100). In donor population the most prevalent phenotypes are A*02 (f=0,348), A*03 (f=0,143) and A*24 (f=0,129). In recipient population – A*02 (f=0,321), A*03 (f=0,153) and A*01 (f=0,108). There are 34 HLA-B phenotypes identified, the most prevalent of them are B*07 (f=0,144), B*35 (f=0,117), B*44 (f=0,100). In donor population the most prevalent phenotypes are B*07 (f=0,143) and B*35 (f=0,109), but in recipient population – B*07 (f=0,145) and B*44 (f=0,104).
19 HLA-DR phenotypes are identified and the most frequent are DR*01 (f=0,136), DR*11 (f=0,136), DR*07 (f=0,134) and DR*13 (f=0,115). In donor population the most prevalent phenotypes are DR*11 (f=0,152), DR*01 (f=0,148), DR*07 (f=0,143) and DR*15 (f=0,133), but in recipient population – DR*13 (f=0,131), DR*01 (f=0,127), DR*07 (f=0,127) and DR*11 (f=0,123).
Conclusions: Our study provides the first data on the HLA-A, HLA-B and HLA-DR phenotype frequencies in Latvian population, in patients who donated kidney or who were organ recipient. Since in Latvia for cross-matching complement-dependent lymphocytotoxicity test is still used widely our data maybe applied for purchase of more specific antigen panels for tests, increasing specificity and sensitivity of test. That in future may lead to decrease of immunological complications among kidney recipients in perioperative and long term period.