Prognostic value and cost-effectiveness of different screening strategies for HLA antibodies prior to kidney transplantation

HLA antibody screening is conducted routinely prior to kidney transplantation, but the comparative prognostic value and cost-effectiveness of different methods are unclear. Pre-transplant sera of 141 patients transplanted between 1998 and 2000 were screened by ELISA and Luminex assays, and antibody specificities of reactive sera determined using bead array techniques. ELISA screening detected donor-specific antibodies (DSA) in 19 patients, who had a higher incidence of impaired graft function (60% vs. 20%, p = 0.04) and antibody-mediated rejection (AMR) within 90 d after transplantation (AMR, 35% vs. 5%, p = 0.02). Luminex screening detected eight additional patients with DSA, among those one with AMR. Six of eight patients with Luminex-only-DSA reported no prior immunizing events. Death-censored graft survival was shorter only in patients with DSA and AMR (median, 1.7 yr instead of between 9.5 and 11.0 yr for patients without DSA or patients with DSA but no AMR, p < 0.001). Material costs per detected clinically relevant DSA were about 57% higher for Luminex screening, but this increase could be avoided by modifying the cut-off recommended by the manufacturer. Conclusively, specification of antibodies only in sera reactive in screening tests was cost-effective to prevent shortened graft survival. Preformed DSA were only harmful if AMR was diagnosed within 90 d after transplantation.