This work demonstrated that Col-Tregs (collagen type II-specific Tr1 cells), induced ex vivo by the incubation of collagen type II TCR-specific splenocytes with IL-10 and collagen type II antigen, resulted in the generation of RA-specific Tr1 cells capable of reducing erosion, cell infiltration, B cell response and hyperplasia in the paws from arthritic mice. The gene discussed is IL10; the disease is rheumatoid arthritis.