Abstract
Background and Aims
HLA compatibility between donor and recipient is an important factor that influences graft outcomes after kidney transplantation. Increasing number of class I (HLA-AB) and class II (HLA-DR) mismatches are associated with an increased risk of acute rejection and graft loss. Recent developments have increased our understanding of the structural basis of HLA antigenicity and may allow accurate evaluation of the immunogenic potential of broad antigen HLA mismatches.
The immunogenicity of HLA antigens is determined by continuous and discontinuous short sequences of amino acids that form the antibody-accessible regions within each HLA allele known as epitopes. HLAMatchmaker, a computer algorithm that calculates the number of epitope mismatches between donors and recipients by considering each HLA allele as a combination of distinct epitopes known as triplets (continuous amino acid sequences) or eplets (closely located contiguous amino acid sequences).
Method
A total number of 55 adult patients with LDKT were included in the study. The inclusion criteria: first transplantation of one organ - kidney, use of living donor related or unrelated, emotionally related (spouses) donor. Data concerning donor - sex, age of the donor, type of donation (related or unrelated donor), and data concerning the recipients: sex, age, hemodialysis vintage, underlying disease, type of immunosuppressive therapy, were analyzed. The number of eplet HLA mismatches for each recipient and donor pair at HLA class I (HLA-AB) and class II (HLA-DR) loci was calculated using HLAMatchmaker (Version 1.2)
Results
In our study we have included 55 patients. 44 patients have related and 11 have unrelated donors. From the group of related donors 31 patients were haploidentycal, with 3 HLA miss match, in the group of unrelated donors-recipients 5 of them have 6 miss match. According HLA MM triplets Class 1 + 2 < or> 20 we have devided 2 groups, but no statistical difference on the graft function was observed in the follow up period.
Three acute rejections were reported in the group of patients with HLA miss match triplets Class 1 + 2> 20.
Conclusion
An increasing number of epitope HLA mismatches is associated with an increased risk of acute rejection. Triplet HLA mismatches may provide better risk stratification for acute rejection and graft survival among those who are otherwise classified as low immunological risk at the broad antigen level.
The Association Between Broad Antigen HLA Mismatches, Eplet HLA Mismatches and Acute Rejection After Kidney Transplantation
