Effect of panel-reactive antibody in predicting crossmatch selection of cadaveric kidney recipients

Aim. The influence of panel-reactive antibody level (%PRA) on crossmatch results was evaluated among 866 patients on the waiting list for cadaveric renal allografting from January 2001 to August 2005. We evaluated the results for 124 potential donors for a kidney, including 2008 crossmatches. Four hundred eighteen patients were tested against only 1 donor. Methods. Serum samples were screened for anti-HLA antibodies using immunoglobulin (Ig)G enzyme-linked immunosorbent assay (ELISA) PRA kit and the %PRA of the most reactive sample (peak) was used for patient stratification, according to sensitization level. Crossmatches were performed on fresh donor T lymphocytes from peripheral lymph nodes, using classical and anti-human-globulin enhanced complement-dependent cytotoxicity (CDC-T) methods. The tests were performed using peak and current patient sera before and after dithiothreitol treatment. The crossmatch was assumed to be negative when no reactivity was observed in all tests. Results. The incidences of positive crossmatch were as follows: 72.3%,14.6%, and 7.2%, among patients with PRA > 50%, PRA :<= 50%, and PRA = 0%, respectively. A negative crossmatch was observed in 6.5% (4 of 62) of the tests among 100% PRA patients. Conclusion. Although %PRA level reflects the HLA sensitization of the patient, IgG ELISA PRA and CDC-T crossmatch may not reflect the same antibodies, and both results must be considered in a transplantation decision.