Notably, however, IL-10 was produced by both IL-7R- and IL-7R+ T-cell subsets (Additional file 4: Figure S4), which contain respectively mainly regulatory and helper T cells [11, 15], suggesting that IL-10 is not exclusively derived from regulatory T cells in patients with OA and patients with RA, in particular in the synovial compartment. This evidence concerns the gene IL10 and rheumatoid arthritis.