Correlation of Pretransplant Donor-specific Antibody Assay Using Luminex Crossmatch with Graft Outcome in Renal Transplant Patients

The significance of pretransplant anti-human leukocyte antigen antibody levels that are detectable by more sensitive platforms (including the Luminex platform) yet undetected by complement-dependent cytotoxicity (CDC) assay remains unclear. The aim of this study was to determine the clinical significance of the donor-specific antibody (DSA) assay Luminex crossmatch and its impact on short-term renal graft outcome such as acute rejections, graft survival, and graft function. The results of pretransplant DSA-lymphocyte crossmatching (LCXM) assay in 126 renal allograft recipients whose CDCs crossmatches were negative were retrospectively analyzed for correlation with posttransplant outcomes. Of the 126 recipients, 32 (25.4%) had pretransplant DSA positive. Statistically significant association was found between DSA-LCXM positivity with 14(th) day estimated glomerular filtration rate (eGFR) (P = 0.05), DSA Class I with 3(rd) (P = 0.014) and 6(th) month (P = 0.02) eGFR, DSA Class II with 14(th) day (P = 0.06) and 1(st) month (P = 0.10) eGFR, mean fluorescent intensity (MFI) DSA with 7(th) day (P = 0.08) and 14(th) day (P = 0.09) eGFR, and maximum MFI DSA with 7(th) day eGFR (P = 0.09). The posttransplant eGFR was higher at various time intervals in DSA-LCXM-negative patients as compared to DSA-positive patients. However, pretransplant DSA-LCXM results did not predict the rejection episodes, graft loss, and 1-year posttransplant 24 h urine protein. Pretransplant DSA detected by LCXM in patients with a negative CDC does not predict adverse short-term outcomes. However, the difference in posttransplant eGFR supports further investigation in long-term effects.