No Advantage of Flow Cytometry Crossmatch Over Complement-Dependent Cytotoxicity in Immunologically Well-Documented Renal Allograft Recipients

Abstract

The effect of flow cytometry crossmatches on clinical outcome was studied retrospectively in two groups of immunologically well-documented patients who had received transplants with a negative complement-dependent cytotoxicity crossmatch. The first group consisted of 114 consecutive renal allograft recipients, and the second group consisted of 76 immunologically at-risk recipients. Flow cytometry crossmatches were performed with current and historic sera. In group 1, positive flow cytometry (FC) crossmatches were shown in 15/114 (13%) recipients. Rejection occurred in 8/15 (53%) FC-positive versus 41/99 (41%) FC-negative recipients. The 1-year graft survival rate was 80% for FC-positive patients and 87% for FC-negative patients. Sixty-seven patients were nonsensitized patients; 4 of them had a positive FC crossmatch but no rejection episodes, graft loss, or patient loss. Of 47 retransplanted and/or sensitized recipients, 11 had a positive FC crossmatch. Rejection treatment 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 significance. Group 2 consisted of 76 at-risk recipients; 37 were retransplant patients 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 FC 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 FC crossmatch would have excluded 28% of the recipients from transplantation, who in fact are doing well.

Sensitized renal transplant recipients: current protocols and future directions

“…reviewing the transplant literature up to the year 2000 reveals many reports of small series of transplantations with important differences in histocompatibilitytesting protocols from center to center, and markedly differ ent conclusions drawn regarding the utility of differ ent crossmatch tests. [21][22][23][24][25][26] as the determination of Dsa speci ficity was severely limited by the use of cellbased tests, donor selection focused on optimiza tion of Hla match ing, with the assumption that the closer the match, the lower the likelihood of Dsa presence. the identifica tion of acceptable donors for highly sensitized trans plant candidates was dependent on the identification of a donor whose Hla phenotype most closely matched that of the patient.…”

Clinical significance of anti-HLA antibodies detected by Luminex®: Enhancing the interpretation of CDC-BXM and important post-transplantation monitoring tools

“…However several studies have shown that flow cytometry is not superior to CDC in predicting graft survival [35,36].…”

Analysis of positive kidney, heart, and liver transplant crossmatches reported to the Collaborative Transplant Study

“…The decision to go ahead with the transplant operation was apparently based on the negative lymphocytotoxic T-cell result, which was associated with good subsequent graft outcome. In operational terms, these are "false positive" flow crossmatches because they potentially exclude patients from transplantation who were found in this study and by others to have a successful outcome [16]. It will be important to clarify in future studies whether the higher sensitivity of the flow crossmatch, as compared with the lymphocytotoxic test, is clinically adventageous.…”