Renal After Cardiothoracic Transplant: The Effect of Repeat Mismatches on Outcome

Background. Histocompatibility matching is not considered important in nonrenal solid organ transplants (NRSOT). There is no evidence to base guidance on whether mismatched human leukocyte antigen (HLA) antigens should be avoided in subsequent renal transplantation. Methods. This study examines the effect of repeat HLA mismatches on renal allograft survival and function in all renal after cardiothoracic transplants undertaken in the United Kingdom between 1997 and 2003 using the UK Transplant data. Results. A repeat HLA-A, -B, or -DR mismatch occurred in 16 of 53 (30%) cases. Recipients without a repeat mismatch were more likely to be male, but recipient age, donor age, recipient-donor age difference, donor gender, donor type, or cold ischemia time were comparable. Immunosuppressive therapy was similar in both groups. No differences were observed in renal allograft function at 1 or 5 years between the repeat mismatch group (estimated glomerular filtration rate [mean +/- standard deviation] 41.6 +/- 16.6 and 37.5 +/- 12.8 mL/min/1.73 m(2)) and the no repeat mismatch group (47.2 +/- 15.7 and 48.0 +/- 15.9 mL/min/1.73 m(2)). Renal allograft survival was also similar in the two groups at 1 and 5 years. Conclusions. In this limited, heterogeneous, observational cohort of cardiothoracic transplant patients who went on to receive a sequential kidney transplant, a repeated HLA antigen mismatch was not associated with a detrimental effect oil kidney transplant outcome.