Prof. dr. Frans Claas

Career overview
 

Prof. Frans Claas was an internationally recognized expert in transplant immunology, with a distinguished career dedicated to improving outcomes in organ and stem cell transplantation. He served as Professor of Immunogenetics and was affiliated with the Department of Immunohematology and Blood Transfusion at Leiden University Medical Center (LUMC). His research focused on histocompatibility, HLA antibody profiling, the immunological mechanisms underlying transplant rejection and immunology of pregnancy. Prof. Claas first introduced a totally new concept to increase the chance of transplantation for highly sensitized patients. This work culminated into the still highly successful Eurotransplant Acceptable Mismatch Program, in which more than 2000 highly sensitized patients have been transplanted to date. He was instrumental in shaping European transplant policy through his involvement in Eurotransplant. He retired in 2017 but remained active in the field until his unexpected passing in 2025. His legacy continues to influence clinical practice and immunogenetics research worldwide.