Comparison of clinical outcome between high and low baseline anti-ABO antibody titers in ABO-incompatible kidney transplantation.

High baseline anti-ABO antibody titer is still an important obstacle for successful ABO-incompatible kidney transplantation (ABO IKT). This study aims to investigate the clinical outcome of ABO IKT in patients with a high baseline titer in comparison with patients with a low baseline titer. Fourteen patients who received ABO IKT at our center were classified as the high-titer group (≥1:256, n = 8) or the low-titer group (≤1:128, n = 6). We used a protocol composed of rituximab, plasmapheresis, and intravenous immunoglobulin (RTX/PP/IVIG). We compared the intensity of preparation, complications, and clinical outcome between the two groups. The high-titer group required more sessions of pretransplant (10.5 ± 3.5 vs. 6.0 ± 1.3 times, p = 0.01) and posttransplant (1.6 ± 1.8 vs. 0 ± 0 times) PP/IVIG than the low-titer group did. All patients from both groups showed immediate recovery of graft function. The antibody titer and allograft function in the high-titer group were stable and did not differ significantly from those of the low-titer group up to 1 year after kidney transplantation. There was no antibody-mediated rejection in either group during follow-up, but three cases of acute cellular rejection developed in the high-titer group. The high-titer group showed two cases of opportunistic viral infection (herpes gingivitis and cytomegalovirus viremia) and one case of graft loss due to postoperative bleeding. ABO IKT can be safely performed even in patients with a high baseline anti-ABO antibody titer, but the risk for infection and bleeding should be considered before transplantation.