Monitoring efficiency of humoral rejection episode therapy in liver transplantation: any role for complement binding Luminex Single Antigen assays?

• We observed different outcomes after AMR in patients with high MFI DSA.
• Outcome is different regarding c3d binding status of DSA during follow-up after AMR.
• Outcome is different regarding C3d binding DSA titers during follow-up after AMR.
• C3d binding assay may be interesting to monitor efficiency of anti-rejection therapy.
• C3d binding assay may be interesting to predict AMR outcome.

Humoral rejection and its relationship with anti HLA antibodies have been extensively studied in organ transplantation with the exception of liver transplantation (LT). Recently, association between donor specific anti HLA antibodies (DSA) and increased risk of rejection and graft loss has been suggested in LT. When such antibodies appear, adequate treatment and monitoring are needed to avoid or delay allograft loss. We report here three cases of probable antibody-mediated rejection developed after pregnancy in liver transplanted women. Sera at the time of rejection and during follow-up have been retrospectively tested for the ability of DSA to bind complement components. These cases display different outcomes depending on the complement binding DSA capacity and titers after treatment of the rejection episodes. Thus, they highlight the potential interest of complement binding Luminex Single Antigen assays to monitor the efficiency of anti-rejection therapy.