Incidence of Non-Neutropenic Infection (NNI) in Patients with Follicular Lymphoma and Small Lymphocytic Lymphoma: The Effects of Rituximab Therapy

Rituximab is an anti-CD20 monoclonal antibody that has demonstrated efficacy in patients with indolent and aggressive forms of non-Hodgkin's lymphoma and has become part of the standard therapy for patients with B-cell malignancies. The study was designed to examine if rituximab increases the risk to develop non-neutropenic infection (NNI). Medical records of 202 patients diagnosed as follicular lymphoma or small lymphocytic lymphoma were reviewed. Negative binomial regression was used to estimate relative risk (RR) of NNI. Rituximab (n= 41) and non,rituximab (n= 161) groups had a total of 31.636 and 195.691 reviewed patient days, and recorded a total of 67 and 154 infections, respectively. Negative binomial regression analysis revealed significant effects for the treatment (rituximab vs. non-rituximab) and age (p< 0.01). The RRs of viral and bacterial NNI for rituximab group compared to non-rituximab group were 3.33 and 2.60, respectively; while the RRs for one year increment of age were 1.03 and 1.04, respectively. The time-to-first viral and bacterial NNI for rituximab group were significantly faster than non-rituximab group. Rituximab may increase the risk of NNI in patients with follicular lymphoma or small lymphocytic lymphoma.