Cytotoxic crossmatch analysis before allo-SCT is a poor diagnostic tool for prediction of rejection

The predictive value of cytotoxic crossmatch analysis before allo-SCT remains unclear. We retrospectively analyzed the clinical impact of cytotoxic T- and B-cell crossmatch testing before allo-SCT between January 2000 and June 2005. Cytotoxic crossmatches were performed in 157 patients receiving stem cells from matched unrelated donors or an HLA-A, -B or -DRB1 allele mismatched graft. Ninety patients are still alive. Eleven patients rejected their grafts. One of 11 patients with rejection was positive in a T-cell crossmatch before allo-SCT and 4 of 11 in B-cell crossmatches. T-cell crossmatches showed a sensitivity of 9% and a specificity of 97% compared with 36 and 86% for B-cell crossmatches. Positive T- and/or B-crossmatch before SCT had no predictive value for survival in this study as compared with patients with a negative crossmatch. In conclusion, the pretransplant cytotoxic T- and/or B-crossmatch is a poor predictor of rejection after allo-SCT.