HPGDS and rheumatoid arthritis: Expressions of PGD2 and hPGDS were inversely associated with serum C-reactive protein (P < 0.01) and erythrocyte sedimentation rate (P < 0.01).The findings suggest that synovial DCs may be an important source of hPGDS and that systemic disease activity may be influenced by actions of PGD2 in RA and other arthropathies.