Editorial on histocompatibility section 2017
Once the human leukocyte antigen (HLA) system was identified as the human major histocompatibility system, there began a long-standing symbiotic, if not always agreeable, relationship between histocompatibility testing and solid organ transplantation. The requirement for histocompatibility testing for kidney transplantation was a factor in improving the characterization of HLA genes and their products and in developing increasingly better methods for assessing compatibility between donors and recipients. In turn, better matching yielded improved graft survival and function; antibody screening and characterization prevented shipping of incompatible organs; and the lymphocytotoxicity crossmatch prevented hyperacute rejection. However, for decades, histocompatibility testing was performed on cell-based assays that required an adequate supply of viable lymphocytes with sufficient expression of HLA antigens and were subject to interference by antibodies to non-HLA, cell surface antigens. As the disparity between the number of patients needing a transplant and the number of available organs grew and immunosuppression improved, the perceived value of histocompatibility testing diminished. In this volume of Current Opinion in Organ Transplantation, there are two articles on current state of the art methods for HLA typing and antibody definition along with three articles that discuss the value and utility of current histocompatibility testing in clinical transplantation.