Late-onset neutropenia and acute rejection in ABO-incompatible kidney transplant recipients receiving rituximab and mycophenolate mofetil.

INTRODUCTION: Using rituximab, we have performed successful ABO-incompatible kidney transplantations in recipients without splenectomy as well as in those with high pretransplant anti-A/B antibody titers. A common and increasingly recognized toxicity of rituximab is late-onset neutropenia (LON), defined as unexplained grades III to IV neutropenia occurring at least 4weeks after the last dose of rituximab in the absence of an alternative explanation.

PATIENTS AND METHODS: Between May 2006 and December 2011, 25 patients who received rituximab underwent successful ABO-incompatible kidney transplantation and were enrolled as the subjects in this study. The incidence rate and clinical features of LON as well as the relationship between LON and acute rejection in these patients were studied.

RESULTS: Twelve recipients (48%) experienced LON 2 to 12months after transplantation. Five of the 12 patients (41.6%) who developed LON had an episode of biopsy-confirmed acute cellular rejection, as compared with one of the 13 patients (7.7%) who did not develop LON. Moreover, 3 patients who experienced LON developed steroid and deoxyspergualin-resistant acute cellular rejection requiring OKT-3 administration.

CONCLUSIONS: The frequency of acute cellular rejection was higher in ABO-incompatible kidney transplant recipients with LON than in those without LON. Our findings suggested that these recipients who developed LON after rituximab administration may be at an increased risk for acute cellular rejection.