Inflammation: migratory cells spread arthritis

In rheumatoid arthritis (RA), inflammation of the tissues in and around the joints often causes pain, stiffening and joint deformity. Initially, RA is often confined to a single or limited number of joints, but eventually spreads by mechanisms that are not understood. Lefèvre et al. show that migratory fibroblasts known as rheumatoid arthritis synovial fibroblasts (RASFs), which mediate inflammation in human joint tissue, migrate to other joints after transplantation into immunodeficient mice. The RASF cells also move into the adjacently transplanted cartilage. Medical treatment for RA is confined to lifelong physical therapy, corrective surgery and lifelong treatment with anti-inflammatory drugs, many of which have toxic side effects. The contribution of cell migration to the spread of the disease in this mouse model may provide some insight into how RA progression might be inhibited.