Synovial fluids of patients with rheumatoid arthritis (RA) suppressed the proliferation of synovial cultured cells taken from patients with RA shown in reduction of the uptake of H3-thymidine into the cells.
Supernatants of cultured macrophages and polymorphonuclear leukocytes (PMN), but not lymphocytes in synovial fluids of RA patients could suppress the proliferation of the synovial cultured cells.
The culture supernatants of the macrophages in the synovial fluids treated with indomethacin could not suppress the proliferation of the synovial cultured cells and purified PGE2 suppressed strongly the proliferation of the synovial cultured cells.
From these results, the suppressive effect of rheumatoid synovial fluids on the proliferation of synovial cultured cells might be to PGE2 which was released from macrophages or PMN in the synovial fluids.
