Mohammed Ayesh Mohammed Al-Madol2018-10-152018-10-152011http://hdl.handle.net/123456789/13214M.Sc degree in medical laboratory sciences Histopathologv and CytologySynovium membrane can become irritated and thickened in inflammatory conditions such as rheumatoid arthritis. Prostaglandins are involved in the inflammatory response, PGE; receptors have been classified into four subtypes, designated the EP 1, EP2, EP3, and EP4 receptors. In addition, microsomal prostaglandin E2 synthase-1 (1nPGES-1) is induced by proinflammatoiy mediators and is down-regulated by glucocorticoids in various cells. Although, there is a growing body of data suggesting that PGE2 are implicated in arthritic diseases via its receptors, the exact cell types and disease-specific differences in the occurrence of EP receptors subtypes have not been examined so far. In the present study, we have (28) samples, were taken from (28) patients ( 9 patients with RA, 9 patients with OA, and 10 patients with JT). Light immunohistochemistry and immunoflourescence confocal microscopy analysis revealed that EPl, EP2, EP3, EP4 were expressed mostly by macrophage-like (CD68+) and fibroblast-like (P4PF) cells within synovium tissue of IT patients. However, in synovial tissue from OA patients, these receptor subtypes were mostly expressed by fibroblast-like (P4H+) cells. In synovial tissue from RA patients, these receptor subtypes were mostly expressed by fibroblast-like (P4}F) and plasma cells. Parallel to the severityenrostaglandin E synthaseThesis