Double immunofluorescence confocal microscopy showed that PGE2 and mPGES-1 as well as COX2 colocalized predominantly in granulocytes and P4HB-IR fibroblasts of patients with JT (data not shown) and in CD68-IR macrophages as well as P4HB-IR fibroblasts of patients with OA and RA (data not shown). This evidence concerns the gene PTGS2 and rheumatoid arthritis.