Assessment of lymphocyte and phagocytic cell function in healthy volunteers undergoing short-term phenytoin...

The effect of short-term (2 weeks) administration of the anticonvulsant drug phenytoin on humoral and cellular immune function and phagocytic cell system activity was tested in nine healthy volunteers. No change either in the absolute or relative counts of leukocytes was found after drug treatment. Moreover, immunoglobulin serum concentration and lymphocyte subsets positive for OKT3, OKT4, OKT8, OKDRIA, OKB2, Leu 7, Leu 11a, anti-beta 2-microglobulin and antitransferrin monoclonal antibodies were not affected by phenytoin administration. A significant impairment of both polymorphonuclear neutrophil migrating activity and stimulated metabolism as measured by nitro blue tetrazolium reduction and superoxide anion generation was found after drug treatment or when phenytoin was added in vitro to the cells at concentrations lying within the anticonvulsant therapeutic range. Monocyte function was unaffected both after phenytoin administration and after direct application to the cells. The phenytoin-induced changes of polymorphonuclear neutrophil function was completely reverted within 2 weeks after drug withdrawal. The phenytoin-induced alterations of the phagocytic cell system are discussed in relation not only to the possible implications in the pathogenesis of adverse effects of anticonvulsant therapy but also to the potential therapeutic exploitation in immunologically mediated disorders.