Increase in Con A-induced suppressor cell activity after indomethacin treatment

Immunomodulatory effects of treatment with naproxen in patients with rheumatic disease

We evaluated the effects of a nonsteroidal antiinflammatory drug, naproxen, on phytohemagglutinin (PHA)-induced lymphocyte proliferation. When added in vitro to cultures of peripheral blood mononuclear cells, naproxen enhanced the proliferative response toward PHA of lymphocytes from rheumatoid arthritis (RA) patients but not from healthy volunteers, and it reduced prostaglandin E2 (PGE2) synthesis in the cultures. Oral treatment for 7 days with naproxen also resulted in a significant enhancement of the in vitro PHA-induced proliferation of lymphocytes from RA patients and from age-matched control patients with noninflammatory rheumatic diseases, but not from young healthy controls. This enhancement of PHA-induced lymphocyte proliferation after oral intake of naproxen was not accompanied by diminished in vitro PGE2 production in the cultures. It did occur when PGE2-producing monocytes were removed and when in vitro PGE2 synthesis was blocked with indomethacin. We conclude that oral treatment with naproxen has an immunomodulatory effect and improves in vitro PHA-induced proliferation of lymphocytes from rheumatic disease patients. This effect is not due to reduced PGE2 synthesis in the in vitro cultures, but reflects a more fundamental in vivo change in immunoregulation.

Lymphocyte-macrophage co-operation during induction of T-suppressor cell activity in rats with adjuvant arthritis

The role of macrophages and of macrophage-lymphocyte co-operation in the induction of T-suppressor cell activity in rats with adjuvant arthritis was investigated. Macrophages from arthritic rats had no direct effect on the induction of T-suppressor cells, but, in the presence of arthritic rats' lymphocytes or supernatants from such lymphocytes, macrophages inhibited the induction of T-suppressor cell activity. Addition of indomethacin during the induction of T-suppressor cells reduced the inhibitory effects, suggesting that prostaglandins released from lymphocyte-activated macrophages might be involved in the defective induction of T-suppressor cell activity in rats with adjuvant arthritis.

Regulation of the immune response by prostaglandins

Of all the arachidonic acid metabolites, only prostaglandin E (PGE) has been shown to have a clear role in the regulation of cellular and humoral immune responses. In cellular immune responses such as T cell proliferation, lymphokine production, and cytotoxicity, PGE usually acts as a feedback inhibitor of the response. This is also true of macrophage and natural killer cytotoxicity. In some instances PGE is responsible for cellular activation rather than inhibition. This is clearest in the control of humoral immunity, where PGE production is a necessary component in the generation of some type of T suppressor cells. Disturbances in immune function found in several human conditions and diseases have been linked to changes in PGE mediated immunoregulation. Either increased production of PGE or increased sensitivity to PGE results in depressed cellular immunity. Conversely drugs which inhibit PGE production act as stimulants of cellular immune function in vitro and in vivo.

Impaired conA suppressor cell activity in patients with rheumatoid arthritis shows normalization during fasting

Normal controls and patients with rheumatoid arthritis (RA) were investigated with respect to quantitative lymphocyte proliferation (LP) after concanavalin-A (conA) activation and to conA-induced suppressor cell activity (conA-SC). Measurements and assessment of RA activity were made at the beginning and end of a 10-day fast. The controls showed depressed (p less than 0.05) LP at the end of the fast, but no change in conA-SC activity. The RA group showed subnormal (p less than 0.05) LP and conA-SC (p less than 0.01) at the beginning of the experiment. After fasting they showed clinical improvement, the LP was not further depressed, and the initially low conA-SC had become normal.