Importance of Phenotyping Minor Blood Group Antigen in Renal Transplant Donors: A Retrospective Cohort Study

Abstract

Introduction: Various studies have implicated minor antigens with increased graft rejection in the long term, especially in alloimmunised patients. Recipient’s antibody testing is done exhaustively during each case of rejection. However, without data on donors’ minor antigen profile, this significant cause of graft failure may be overlooked. Aim: To highlight the necessity of testing and creating a database by documenting the prognostically important minor blood group antigen in kidney transplants donors. Materials and Methods: This was a retrospective cohort study done on 650 kidney transplant donors from Kolkata, West Bengal, India. Data was collected from August 2014 to July 2022, a period of 10 years and analysed from August 2022 to December 2022. Blood group antigens were identified by immunoserological tests and the phenotypes were recorded with specific importance to minor blood groups. Genotype confirmation was done, where possible. The prevalance percentage of minor blood group phenotype was analysed using statistical analysis (Statistical Package for the Social Sciences (SPSS) build 1.0.0.1275 version 26). Results: In 650 donors, mean age was 33±7 years and male: female ratio 1.1:1. The prevalence of clinically important minor blood group phenotypes like Kidd {Jka-499(76.8%), Jkb-449 (69.1%)}, Duffy {Fya-559 (86%), Fyb-396 (60.9%)}, Lewis {Lea-112 (17.2%), Le-b-402 (61.8%)} and MNS {M-567 (87.2%), N-266 (40.9%), S-375 (57.7%), s-572 (88%)} in the kidney transplant donor group was documented. Lewis Le(a-b+) -402 (61.85%), Duffy Fy(a+b+) -306 (47.08%), Kidd Jk(a+b+) -298 (45.84%) and MNS (M+N+) -301 (46.30%), (S+s+) -298 (45.85%) were the most prevalent minor antigens. The phenotypes Lewis Le(a+b+), Kidd Jk(a-b-) had null percent in population and Duffy Fy(a-b-), MNS(S-s-) were present 0.15% and 0.15%, respectively in the population. Conclusion: The result of this study emphasises the importance of testing, registering a database for immunogenic significant minor blood group antigens in transplant donors. This will aid in investigation of graft failure in alloimmunised patients.