N.W. risk (0-2 broad antigen HLA-ABDR mismatch), those with 20 or greater eplet mismatches experienced an increased risk of rejection compared to those with less than 20 mismatches (adjusted HR, 1.85; 95% CI, 1.11-3.08; = 0.019). Conclusions Increasing quantity of eplet mismatches is usually associated with acute rejection in kidney transplant recipients. Concern of eplet HLA mismatches may improve risk stratification for acute rejection in a selected group of kidney transplant candidates. HLA compatibility between donor and recipient is an important factor Fludarabine Phosphate (Fludara) that influences graft outcomes after kidney transplantation whereby an increasing number of class I (HLA-AB) and II (HLA-DR) mismatches are associated with an increased risk of acute rejection and graft loss.1,2 Even in the era of modern immunosuppression, HLA matching remains one of the major criterion in deceased donor kidney allocation in Australia and worldwide.3-5 Serological typing at the HLA-ABDR loci is used universally to determine the number broad antigen HLA mismatches and is the standard triage test for the assessment of immunological compatibility between potential donors and recipients. However, molecular HLA typing 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 Rabbit Polyclonal to OR10H2 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). Mismatches of these Fludarabine Phosphate (Fludara) HLA epitopes have been linked to the development of de novo anti-HLA donor-specific alloantibodies after transplantation,6,7 which is usually associated with up to a 20-fold increased risk of acute rejection and graft loss after kidney transplantation.8 Although a direct and positive association between HLA epitope mismatches and transplant glomerulopathy has been reported, it remains unclear whether epitope HLA mismatches may improve the discrimination HLA mismatches in predicting acute rejection compared to broad antigen HLA mismatches. We aimed to determine the association between broad antigen HLA mismatches, eplet HLA mismatches and acute rejection in a cohort of kidney transplant recipients. MATERIALS AND METHODS Study Populace Using data from your Australia and New Zealand Dialysis and Transplant (ANZDATA) registry and National Organ Matching System (NOMS), all main living and deceased Fludarabine Phosphate (Fludara) donor kidney transplant recipients in Australia between 2006 and 2011 were included in this study. All transplant recipients experienced unfavorable complement-dependent cytotoxicity T-cell crossmatch before transplantation. Circulation cytometry and B cell complement-dependent cytotoxicity crossmatches are not routinely performed before deceased donor transplantation in the Australian populace. Multiple-organ transplant recipients and recipient-donor pairs without recorded HLA-A, B, or -DR typing were excluded (n = 395). Serological HLA-A, -B, and -DR typing for donors and recipients were performed by local tissue typing laboratories, which were extracted from NOMS and linked to a dataset with matching recipients’ details from ANZDATA. Our local institutional ethics committee (Sir Charles Gairdner Hospital, Perth, Australia) granted a waiver of consent for this study. Data Collection The baseline data included recipient characteristics, such as age, sex, race, causes of end-stage renal disease, preemptive transplantation, peak percentage panel-reactive antibody (PRA), waiting time on dialysis (in months), diabetes, coronary artery disease.