GENETIC VARIABILITY OF THE HLA SYSTEM AND ITS INFLUENCE ON TRANSPLANTATION: A LITERATURE INTEGRATIVE REVIEW

Abstract

 The human leukocyte antigen (HLA) system constitutes the human major histocompatibility complex and is highly polymorphic, a condition that broadens the repertoire of peptides presented to T lymphocytes while increasing the complexity of donor-recipient matching. This study aimed to analyze the influence of HLA genetic variability on histocompatibility, allorecognition, and major transplant-related outcomes. A literature integrative review with a structured search was conducted for publications from 2016 to 2026 in PubMed/MEDLINE, SciELO, and ScienceDirect using descriptors related to HLA, genetic polymorphism, histocompatibility, transplantation, and donor-specific antibodies. The available methodological record reports 50 publications initially identified and 10 included in the final synthesis. The studies showed that HLA mismatch remains associated with increased immunological risk and poorer graft outcomes in selected settings, whereas donor-specific antibodies and class II molecular mismatches refine risk stratification. It is concluded that HLA assessment should integrate antigen-level compatibility, clinical context, humoral sensitization, and, increasingly, molecular mismatch metrics.