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.