Several cases of post-CHIKV rheumatoid arthritis (RA)-like illnesses have been reported, with the persistence of CHIKV IgM possibly linked to the sanctuarization of the virus as observed in synovial macrophages in chronic patients but without the classical inflammation and erosion of the cartilage and bone observed in autoimmune RA [12,14]. The gene discussed is CD40LG; the disease is rheumatoid arthritis.