Analysis of cytokine production patterns of peripheral blood mononuclear cells from a rheumatoid arthritis patient successfully treated with rituximab.

We had a rheumatoid arthritis (RA) patient resistant to multiple drugs and who developed panniculitis due to etanercept treatment, then responded fairly well to rituximab. Intracellular staining of cytokines in the peripheral blood mononuclear cells before and after rituximab administration revealed that the cytokine production, representative of T-helper (Th)1-, Th2-, and Th17-type responses, decreased abruptly after the treatment. Interestingly, this timing coincided with that of the manifestation of the beneficial effect. This relationship may provide useful insight into the mechanism of action of the drug and hence about the pathogenesis of RA.