Effect of prostaglandin synthesis inhibition in vivo on the immune response following hepatitis B vaccination in normal subjects

Abstract

Prostaglandin E 2 has been shown in several studies to have immunomodulatory properties. We have now studied the in vitro and in vivo effects of piroxicam, a nonsteroidal antiinflammatory drug with potent prostaglandin-synthetase inhibitory activity, on immune responses in healthy subjects ( n=50). All subjects received three injections of hepatitis B vaccine with a 1 month interval. From 3 days before until 7 days after each vaccination they also received piroxicam or placebo in a double blind way. There was no difference in the humoral immune response to hepatitis B surface antigen between the two groups. Oral intake of piroxicam did not affect in vitro proliferation of T-cells in response to OKT3 monoclonal antibody. However, addition of piroxicam in vitro to cultures of peripheral blood mononuclear cells significantly enhanced OKT3-induced T-lymphocyte proliferation ( P<0.001). The enhancement was observed even in subjects taking piroxicam orally, demonstrating that in vivo piroxicam treatment leaves the cells susceptible to the in vitro immunomodulating effect of this drug. We conclude that, although piroxicam in vitro enhances T-cell functionality, oral intake of this prostaglandin synthetase inhibitor — at least by normal subjects — does not enhance antibody formation to a protein antigen and has no demonstrable effect on T-cell function.