[Effect of cephalosporins on lymphocyte proliferation and immunoglobulin E production]

We studied the effects of three cephalosporins (cefadroxil, cefaclor, cephalexin) on an in vitro model of human mononuclear cell proliferation in response to polyclonal mitogens. Cefadroxil, and to a lesser extent cefaclor and cephalexin, induced a decrease of proliferative responses to phytohaemagglutinin and concanavalin A. This decrease was not due to a direct effect on lymphocytes, but depended on the presence of adherent monocytes in the cultures. Cephalosporins stimulated the release of prostaglandins E2 by monocytes, generating a suppressive activity. Cefadroxil and cephalexin were in vivo given to Brown-Norway rats sensitized to DNP-OVA to induce a primary and secondary IgE specific response. The administration of cefadroxil provoked a clear decrease of the secondary IgE response. As the IgE production closely depends on T suppressor cells, we hypothesize that cefadroxil could interfere with that production by stimulating a suppressor cell activity linked to an increased PGE2-release.