Late Onset Neutropenia and Immunoglobulin Suppression of the Patients with Malignant Lymphoma Following Autologous Stem Cell Transplantation with Rituximab

Background Recently, decrease of immunoglobulin concentrations or neutrophil counts were reported in some cases several months after administration of rituximab. We examined a number of episodes of late onset neutropenia or immunoglobulin decrease in patients with malignant lymphoma who were in complete remission following autologous transplantation with or without rituximab. Method Patients with follicular lymphoma and diffuse large B cell lymphoma transplanted with or without rituximab in our institutes were analyzed. Immunoglobulin concentrations and neutrophil counts after transplantation, both with and without rituximab were measured serially. Results Four weeks after transplantation, blood samples revealed lower concentrations of IgG and IgA in the rituximab group than in the non-rituximab group. Neutrophil numbers did not fall below 0.5x10(9)/L four weeks or more after transplantation in the non-rituximab group. Neutrophil numbers dropped below 0.5x10(9)/L in 6 of 14 cases in the rituximab group. Conclusion Although the present study was retrospective and disease composition and pre-transplantation regimens differed between the two groups, the addition of rituximab to autologous transplantation might bring about a decrease of immunoglobulin levels and transient LON.