SHH and rheumatoid arthritis: Compared with systemic lupus erythematosus (SLE), ankylosing spondylitis (AS) and healthy controls, the expression of Shh in serum of RA patients was significantly increased; the level of Shh in RA patients was correlated with rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP Ab) positively, but it had no correlation with erythrocyte sedimentation rate (ESR) (11).