62-P

Abstract

After the first year of heart transplant (TX), CAV is the second most common cause of death, with malignancy being more common. Early detection of the CAV process may allow for therapeutic intervention aimed at interrupting or preventing the disease progression. This study is to determine if qDSA and Luminex single antigen (LSA) binding patterns can predict CAV diagnosis. LABScreen ® single antigen and C1qScreen™ kits (One Lambda, CanogaPark) were used for detecting HLA antibodies and qDSA. Sera from 9 patients (pts) with strong binding DSA (>10K MFI) post-TX were tested for C1q binding. 9 of 9 had anti-DQ DSA and of these 4 of 9 DQ antibodies bound C1q. CAV was diagnosed for 5 of 9 pts with HLA-DQ qDSA. The post-TX antibody profiles showed the average time to peak DQ DSA was 1,796 days. The average time to CAV diagnosis was 1,645 days. Fig. 1a shows the post-TX DSA profile for one of these pts. The DSAs DQ7, DQ8 and DR53 were detected at the time of AMR, peaked at day 1,074, decreased at day 1,239, and increased again at day 1,617. Fig. 1b shows the comparison of neat (L-IgG), 1:8 dilution (L-1:8) and C1q (L-C1q) at day 1,617 sample. At the 1:8 dilution, the pt’s DSA DR51, DR53, DQ7 and DQ8 reached about the same MFI levels as undiluted sample. C1q test showed the same strong binding HLA specificities as the 1:8 dilution test. The anti-HLA-DQ DSA was detected 4 years prior to the diagnosis of CAV. Early detection of specificity and function of DSA, by combining L-IgG, L-1:8 and qDSA testing methodologies, may allow for a better understanding of the CAV disease process and allow for early therapeutic intervention aimed at improving graft outcome.