ABO blood group influences a candidate's likelihood of receiving an HLA zero antigen mismatch kidney

: National sharing of HLA zero‐mismatched kidneys has improved long‐term graft survival. The distribution of those HLA‐matched kidneys by ABO blood group, however, has not been examined. Utilizing the UNOS/OPTN (United Network for Organ Sharing/Organ Procurement Transplantation Network) database, we analysed 112 971 kidney waiting list registrations added during 6/3/95–31/12/00, and 8162 HLA zero‐mismatched (0 mm) primary kidney transplants in the USA during 1/1/88–31/3/02. We also analyzed A isoagglutinin titer histories for 87 blood group B end stage renal disease (ESRD) patients for whom at least 1 yr of testing was done. Blood group A patients received 40.1% of the HLA‐0 mm kidneys while having a 26.5% representation on the national waiting list. Blood group B patients comprised 17.4% of the waiting list, but received only 10.4% of the HLA‐0 mm kidneys. Most (89.6%) blood group B patients awaiting kidney transplantation have low levels of A isoagglutinins, making them eligible to receive a blood group A2 kidney transplant. The national HLA‐0 mm kidney allocation sharing system's imbalance by ABO blood group could be partially resolved in the future by allocating HLA‐0 mm blood group A2 kidneys to B patients.