Preformed donor-specific class II DQ antibodies are associated with graft loss after liver transplantation: A prospective multicenter study.

The aim of this study was to assess whether preformed donor-specific HLA antibodies (DSA) are associated with graft loss after liver transplantation. We conducted a prospective multicenter study at four liver transplant centers. Presence of preformed HLA antibodies was analyzed using Single-antigen bead assay and a virtual crossmatch unknown to clinicians at a central laboratory. Graft survival was assessed using Kaplan-Meier analysis and Cox regressions during a 2-year follow-up. Class I DSA were observed in 106 of 832 patients (13%) and showed no association with graft loss. Class II DSA were detected in 131 of 831 patients (16%), and DQ in 79 (10%). Class II DQ subtype was the only independent predictor of graft loss (adjusted HR 2.0, 95% CI: 1.1-3.6, P = 0.02) with a 2-year graft loss rate of 23% (95% CI: 15-34%) compared to 10% (95% CI: 8-12%) without class II DSA and 7% (95% CI: 2 - 20%) for DR-specific antibodies (log-rank P = 0.002). Mean fluorescence intensity was not independently associated with graft loss after adjustment for DQ status. Preformed class II DQ DSA are independently associated with an increased risk of graft loss even at low mean fluorescence intensity.