B cells identified according to their expression of CD19 and surface ig are depleted from peripheral blood by rituximab in patients with rheumatoid arthritis: Comment on the article by Jones et al

摘要

We read with great interest the report by Jones et al (1), wherein they described the expression of CD19 by human B cells during in vitro incubation of peripheral blood mono-nuclear cells (PBMCs) with rituximab (RTX), the B cell-depleting anti-CD20 monoclonal antibody approved for treatment of rheumatoid arthritis (RA) and non-Hodgkin's lymphoma. The authors reported not only the loss of CD19-expressing cells in these cultures, but also the reduction of CD19 expression levels in individual cells after coincubation with RTX. They therefore suggested that the application of CD19 as a marker to monitor B cell depletion in vivo might be compromised by RTX, and that studies relying on the quantification of CD 19+ cells may overestimate the degree of actual B cell depletion.