NO ADVANTAGE OF FLOW-CYTOMETRY CROSS-MATCH OVER COMPLEMENT-DEPENDENT CYTOTOXICITY IN IMMUNOLOGICALLY WELL-DOCUMENTED RENAL-ALLOGRAFT RECIPIENTS

The effect of flow cytometry crossmatches on clinical outcome was stud ied retrospectively in two groups of immunologically well-documented p atients who had received transplants with a negative complement-depend ent cytotoxicity crossmatch. The first group consisted of 114 consecut ive renal allograft recipients, and the second group consisted of 76 i mmunologically at-risk recipients. Flow cytometry crossmatches were pe rformed with current and historic sera. In group 1, positive flow cyto metry (FC) crossmatches were shown in 15/114 (13%) recipients. Rejecti on occurred in 8/15 (53%) FC-positive versus 41/99 (41%) FC-negative r ecipients. The 1-year graft survival rate was 80% for FC-positive pati ents and 87% for FC-negative patients, Sixty-seven patients were nonse nsitized patients; 4 of them had a positive FC crossmatch but no rejec tion episodes, graft loss, or patient loss. Of 47 retransplanted and/o r sensitized recipients, 11 had a positive FC crossmatch. Rejection tr eatment was needed in 8/11 (73%) FC-positive patients compared with 19 /36 (53%) FC-negative patients. Their 1-year graft survival rates were 73% and 81%. None of these differences reached statistical significan ce. Group 2 consisted of 76 at-risk recipients; 37 were retransplant p atients and 39 were sensitized first-transplant patients, Twenty-one ( 28%) patients showed a positive FC crossmatch. Rejection episodes did not differ between the FC-positive (48%) and FC-negative patients (46% ). There was no difference in 1-year graft survival rate (76% vs, 80%) or in 1-year patient survival rate (100% vs. 95%). We conclude that F C crossmatches in our patient group are not superior to the classical complement-dependent cytotoxicity crossmatches with regard to clinical outcome. On the contrary, transplantation with a mandatory negative F C crossmatch would have excluded 28% of the recipients from transplant ation, who in fact are doing well.