Late-onset Neutropenia in Patients with Rheumatoid Arthritis after Treatment with Rituximab

Objective. Late-onset neutropenia (LON) is an adverse effect of rituximab (RTX) in hematological malignancies, a finding that was recently reported in rheumatoid arthritis (RA). The aim of our study was to estimate its incidence in RA. Methods. We retrospectively reviewed complete blood (cell) count of patients with RA who received RTX between October 2007 and July 2011 to identify neutropenia (≤ 1.5 × 109) up to 12 months following RTX. Results. One hundred eight patients received RTX, median age 64 years (range 25–86). A total of 237 cycles were given. Five patients developed LON after a median of 151 days (71–184). Two developed pneumonia. Conclusion. LON occurs infrequently after RTX, but can present with infection.