Aim: To evaluate if the presence of de novo IgG3 subclass donor-specific HLA antibodies (DSA) help to identify patients at risk of graft loss after liver transplantation (LT).

Methods: We analyzed 1099 adult LT recipients from 1/1/00 to 5/31/09 with a pre- and post-transplant serum sample available for DSA determination (83% of all patients transplanted). All sera were analyzed for DSA using LABScreen single antigen beads, and MFI >5000 was considered to be positive. All DSA positive sera were tested for IgG3 subclass DSA and an MFI >500 was considered positive.

Results: 66% of patients were male, 73% were Caucasian, with a median age of 52. The most common indications for LT were HCV in 31%, HCC in 25%, and autoimmune conditions in 15%. 41% of patients received induction therapy. Immunosuppression at 1 year included tacrolimus 64%, MMF 50%, sirolimus 17%, and steroids 44% of the time. De novo DSA was observed in 7.8% of patients. Patients with de novo DSA showed significant lower graft survival rates when compared to patients without de novo DSA (Figure 1). Patients with de novo DSA had a 76% 5-year graft survival compared to 83% in patients without de novo DSA. IgG3 DSA was positive in 61% of patients with de novo DSA and these patients showed reduced graft survival. Patients with de novo IgG3 DSA showed a 73% 5-year graft survival compared to 83% in IgG3 DSA negative patients–including all-IgG DSA negative (Figure 2).

Conclusions: The development of de novo DSA affects graft survival after LT, but the production of antibodies of the IgG3 subclass may have a more pronounced negative effect on post-liver transplant survival rates.

BaÑuelos, N.: Employee, One Lambda, Inc. Terasaki, P.: Stockholder, One Lambda, Inc.

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