Intra-Liver Allograft C3d-Binding Donor-Specific Anti-HLA Antibodies Predict Rejection After Liver Transplantation

There is no doubt that antibody-mediated rejection (AMR) due to donor-specific anti-HLA antibodies (DSA) brings a poor outcome for liver transplant recipients. However, the relationship between intragraft DSA (g-DSA), complement-binding abilities, and AMR remains unknown.We enrolled a total of 20 liver transplant recipients who underwent protocol or episode graft biopsies in the mid to long term after liver transplant (median 48.5, range 6-198 months), and their status of g-DSA and complement 3d (C3d)-binding abilities was assessed with the graft immunocomplex capture fluorescence analysis (ICFA) technique.The prevalence of g-DSA was 15.0 % in liver transplant recipients (3/20), and serum DSA (s-DSA) also existed in 15.0% of recipients. The number of g-DSA+/s-DSA+, g-DSA+/s-DSA-, g-DSA-/s-DSA+, and g-DSA-/s-DSA- cases are 1, 2, 2, and 15, respectively. The g-DSA+ group demonstrated a significant high rejection activity index: 3.67 ± 1.53, compared with the g-DSA- group: 1.24 ± 1.15 (P = .0045). Moreover, C3d-binding reaction was notably higher in the g-DSA+ group (C3d index: 1.87 ± 0.38 vs 0.76 ± 0.35) (P < .0001). Overall, the g-DSA+ group was more associated with liver allograft rejection-not only AMR, but also T cell-mediated rejection (P = .031).These results suggest that the existence of g-DSA and intragraft C3d-binding reaction had a negative impact on the liver allografts, but in contrast s-DSA did not have any significant impact.