Incidence of Profound Hypogammaglobulinemia and Infection Rate in Lymphoma Patients Following the Combination of Chemotherapy and Rituximab

Background: The Anti-CD20 monoclonal antibody Rituximab suppresses B-lymphocytes and may induce hypogammaglobulinemia in treated patients. The incidence and clinical significance of rituximab induced hypogammaglobulinemia in lymphoma patients is underestimated. Methods: We retrospectively analyzed the rates of hypogammaglobulinemia, infection and infectionrelated mortality in 136 lymphoma patients who were treated with a combination of chemotherapy and rituximab. Results: Rituximab given in more than 8 doses (OR 6.05, 95% CI: 1.24-29.5), relative hypogammaglobulinemia at time of lymphoma diagnosis (OR 4.2, 95% CI: 1.26-14.1) and the combination of fludarabine with rituximab (OR 3.4, 95% CI: 1.24-9.47) were factors significantly associated with prolonged (more than 6 months) hypogammaglobulinemia. The combination of fludarabine and rituximab (OR 6.4, 95% CI: 1.49-27.0) and secondarily prolonged hypogammaglobulinemia (OR 4.5, 95% CI: 1.19-18.5) were found to be predictive factors for severe infections and infection-related mortality. Conclusion: These data suggest the importance of following serum immunoglobulin levels before and after combination immuno-chemotherapy, particularly in patients with recurrent infections or relapsed/refractory disease.