IL6R and rheumatoid arthritis: Elevated serum levels of IL-6 are detected in majority of untreated GCA patients and correlate with disease activity.[7,8] It is likely that IL-6 is produced in the lesional artery since increased levels of mRNA for IL-6 are detected in situ in GCA temporal biopsy samples.[9] Tocilizumab, a monoclonal antibody to IL-6R, blocks IL-6 signaling and was initially approved for treating rheumatoid arthritis (RA).