Abstract
HLA typing and matching have been crucial in kidney transplantation, but methods for assessing tissue histocompatibility have advanced significantly. While serological-level HLA typing remains common, it captures only a small fraction of true HLA variation, and molecular matching is already replacing traditional HLA matching. Recent studies have expanded our understanding of genetic tissue compatibility beyond HLA loci. Candidate gene analyses and genome-wide association studies (GWAS) have identified genetic factors linked to post-transplant complications, though replication of these findings is challenging. An alternative approach involves genome-wide matching of genes or genetic variations. This method has shown promise in hematopoietic stem cell and kidney transplantation. For instance, homozygous gene deletions in LIMS1 or complement factor H (CFH) genes have been associated with acute rejection risk. This may be due to alloimmune responses against proteins absent in the patient but present in the graft, or due to the missing protein's function. Genetic studies in clinical medicine face challenges due to the interplay of genetic and environmental factors, necessitating large datasets for meaningful associations. International collaboration and large consortia, like iGeneTRAin, are essential for validating findings and advancing the field. This review highlights recent advancements in immunogenetics and tissue histocompatibility, emphasizing future research directions.