A case of refractory polyarteritis nodosa successfully treated with rituximab.

A 59-year-old man who presented with continuous fever, livedo reticularis, and left leg ischemia with multiple tibial artery stenosis and renal artery aneurysm, as demonstrated by arteriography, was diagnosed with polyarteritis nodosa (PAN) 6 years ago. Although he frequently relapsed in spite of intensive immunosuppressive therapies, the disease activity of PAN was controlled with repeated rituximab (RTX) therapies and steroid doses were tapered safely. Peripheral CD19 B-cells disappeared soon after the 1st administration of RTX. Although CD19 B-cells remained absent, 3.1% of CD3CD20 T-cells were observed in the peripheral blood prior to the 2nd administration of RTX. Recent studies have suggested the pathogenic role of CD3CD20 T-cells in autoimmune diseases in the context of RTX therapy; therefore, their roles in the pathogenesis of PAN also need to be considered.