Clinical relevance of Luminex donor-specific crossmatches: data from 165 renal transplants

The clinical significance of the presence of donor-specific anti-human leucocyte antigen (HLA) antibodies (DSA) prior to renal transplantation detected solely by solid-phase techniques remains unclear. This study was designed to determine the clinical relevance of the recently introduced bead-based Luminex donor-specific crossmatch (LumXm). A group of 165 patients transplanted between 1997 and 2001 were tested. Of 165 recipients transplanted with a negative complement-dependent cytotoxicity crossmatch, 32 proved to have a positive Luminex crossmatch. Sixteen were positive for class I, 15 were positive for class II, 1 was both class I and II positive and 133 recipients were negative. Acute rejection (AR)-free survival for all recipients was 77%, and there was no difference in AR-free survival between LumXm-positive and LumXm-negative recipients. Overall graft survival after a median follow-up time of 8 years was 56%. Recipients with a positive class I LumXm had worse long-term graft survival (P = 0.006). In recipients with a positive class I LumXm, 5-year graft survival was 41% vs 70% in negative patients and 10-year graft survival was 27% vs 56%. Positivity for class II LumXm was not a significant risk factor for graft failure (P = 0.7). In conclusion, pretransplant DSA detected by the LumXm had no impact on AR episodes. Class II LumXm positivity proved no significant risk factor for graft failure, but the value of the class II LumXm is questionable. A positive class I LumXm resulted in worse long-term graft survival compared with a negative one.