CD6 and rheumatoid arthritis: Importantly, in mouse models of MS and RA, in both CD6-/- mice and CD6-humanized mice treated with UMCD6, an anti-human CD6 monoclonal antibody targeting the CD6/CD318 interaction, striking reductions in clinical signs of disease, pathogenic Th1/Th17 responses and inflammatory cell infiltration into the target organs are observed (24, 29).