IL21 and rheumatoid arthritis: Consistent with these findings, as well as with the recognition that IL-21 is predominantly produced by Tfh cells, it was perhaps not surprising that circulating Tfh-like cells have been detected in a broad array of autoimmune conditions including not only SLE, rheumatoid arthritis, and Sjogren’s syndrome, but also multiple sclerosis, autoimmune thyroid disease, myasthenia gravis, and juvenile dermatomyositis [reviewed in Ref.