Role of Major Histocompatibility Complex and Ethnicity in Acute Renal Graft Rejection.

Background. The major histocompatibility complex (MHC) plays a main role in antigen presentation. Class I, II, and III genes form defined "blocks" of conserved DNA sequences (conserved extended haplotypes) that are useful to follow the ancestry of a population. Each variant encodes a specific peptide that determines a particular individual's immune response. In addition, differential expression of HLA antigens in certain physiological and pathological conditions may participate in the pathogenesis of allograft rejection versus tolerance.Objectives. The aim of this study was to determine whether the specific HLA ancestry was associated with acute renal graft rejection among the Mexican mestizo population.Materials and Methods. We studied 544 Mexican mestizo renal donors and their respective recipients for their serologically determined HLA and based on antigens haplotype assignments. The acute rejection group was compared with the nonrejection group among donors and recipients, correspondingly.Results. Frequent Mexican alleles were observed in this study. Moreover, HLA-B*61/-DR*04, HLA-A*35/-DR*06 (Amerindian ancestry), HLA-A*68/-DR*01, HLA-A*28/-B*65/-DR*01 (African ancestry), and HLA-A*33/-B*65 (Caucasian ancestry) in donors were associated with acute renal graft rejection episodes..Conclusion. Knowing the ancestry of a donor's HLA molecules may help to individualize immunosuppressive therapy for postransplant surveillance, because they may be more membrane-exposed in parenchymal cells, making them more susceptible of being recognized by the recipient's immune system.