Background: Positive crossmatch (CM) in liver transplantation (LT) is associated with worse outcomes. Role of induction immunosuppression in this setting remains to be studied.
Methods: One thousand consecutive LT patients receiving rabbit antithymocyte globulin±rituximab induction were studied. Pretransplantation sera of 55 CM-positive (CM+) patients were tested for C1q-fixing donor-specific antibodies (DSA). Diagnosis of antibody-mediated rejection required presence of diffuse vascular C4d expression on liver biopsies.
Results: CM was positive in 112 (11%) recipients. Antibody-mediated rejection was observed in 3 (0.03%) patients, whereas acute cellular rejection (ACR) occurred in 31 (3%) patients. CM+ status was associated with a higher incidence of ACR (9% in CM+ vs. 2% in CM-negative [CM−]; P<0.01) and chronic rejection (4% in CM+ vs. 1% in CM−; P<0.01). Graft survival was slightly lower in CM+ patients (at 1 year; 85% in CM+ vs. 89% in CM−; P=0.26). Patients with autoimmune hepatitis, primary sclerosing cholangitis, and primary biliary cirrhosis as a group had a tendency toward CM+ status as well as developing ACR. Upon multivariate analysis, CM status was the strongest predictor of ACR (B=1.14; P=0.02). Only half of CM+ patients harbored C1q-fixing DSA. Presence of C1q-fixing DSA was not associated with increased incidence of ACR.
Conclusions: In LT, CM+ status is associated with an increased incidence of acute rejection, chronic rejection, and slightly worse graft survival. With the use of rabbit antithymocyte globulin±rituximab induction, overall low rejection rates can be achieved in CM+ LT.