Our immunofluorescence confocal microscopy analysis revealed that prostanoid receptor subtypes (EP1-4) were expressed predominantly in synovial granulocytes (CD15) of JT patients, in fibroblast-like synoviocytes (P4HB) and macrophages (CD68) of OA patients and in macrophages as well as plasma cells of RA patients. Here, CD68 is linked to rheumatoid arthritis.