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 × 10(9)) 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.