Evolution of HLA testing for hematopoietic stem cell transplantation: Importance of the candidate's antibody profile for donor selection

Hematopoietic Stem Cell Transplantation (HSCT) is a curative treatment for several malignant and non-malignant diseases. Access to this life saving therapy was limited by the requirement of an HLA matched donor. Introduction of platforms allowing transplantation with haploidentical and partially mismatched donors has enlarged the donor pool so that most candidates have a possible donor. HLA circulating antibodies specific for the donor's mismatched antigens may cause delayed engraftment and primary graft failure. The role of the HLA laboratory supporting HSCT has expanded to provide HLA antibody detection and monitoring for selection of compatible donors and for monitoring of desensitization treatments. This review gives an outline of the evolution of HSCT and HLA and the current tools available to the HLA team to support donor selection and desensitization treatments in this new era of transplantation.