Transplantation with positive complement-dependent microcytotoxicity crossmatch in contemporary kidney transplantation : practice patterns and associated outcomes

Abstract EN

We analyzed clinical factors and graft survival associated with complement dependent micro cytotoxicity (CDC) cross match (XM) positive (+) kidney transplants in 1995 to 2009 United Network of Sharing (UNOS) registry data.

CDCXM negative (–) transplants were selected from centers and years in which at least one CDCXM+ transplant was performed at a given center in a given year.

CDCXM+ and CDCXM– results were compared with bivariate and multivariate survival analysis.

Our observations are as follows : (1) The risk of graft loss with CDCXM+ vs.

CDCXM– results was markedly lower than the risk observed historically, e.g., living donor (LD)-CDCXM+ absolute all-cause graft survival reductions were 0.7 % at 24 hours (P = 0.007), 2.9 % at one year (P < 0.0001), 3.7 % at five years (P < 0.0001) ; deceased donor (DD).CDCXM+ absolute graft survival reductions were 0.7 % at 24 hours (P = 0.02), 3.5 % at one year (P > 0.0001), 2.7 % at five years (P=0.0009).

On covariate adjustment, the only significant association of CDCXM+ vs.

CDCXM– results was with one-year graft loss risk : LD aHR 1.44 (95 % CI 1.05–1.96), DD aHR 1.33 (CI 1.10–1.61).

(2) CDCXM+ transplantation was more commonly performed among groups disadvantaged with respect to transplant access, including sensitized, previously transplanted women and black recipients.

(3) In CDCXM+ recipients, there was a high percentage of flow cytometry (FC) XM– and autoXM+ results.

After removing these groups, outcomes with CDCXM+ results were relatively good.

(4) CDCXM+ / FCXM+ vs.

CDCXM– / FCXM–graft loss risk was observed only in LD recipients transplanted at centers performing fewer than 10 such transplants during the study period : 11.0 % reduction (P < 0.0001) and aHR of 2.86 (CI 1.18–6.94) at one year ; 14.7 % reduction (P < 0.0001) and aHR of 1.77 (CI 0.88-3.58) at five years.

Although using CDCXM+ as a contraindication to transplantation has been associated with virtual elimination of hyperacute rejection, the negative effect of a CDCXM+ in contemporary practice is relatively small, questioning the value of the CDCXM as a standalone test.