Imipenem and immune response: in vitro and in vivo studies

Imipenem is a new beta-lactam antibiotic endowed with very high antimicrobial activity; it is used in severe infections which often occur in those conditions characterized by impairment of the immune system. The aim of this study was to evaluate the effect of imipenem on some immune functions, both in vitro and in vivo. The authors studied the effect in vitro of three different drug concentrations (15, 30 and 60 mg/l) on polymorphonuclear leucocyte (PMN) phagocytosis and superoxide anion production, as well as on lymphomonocyte proliferative response and cytokine production. Preincubation of PMN with the highest dosages (30 and 60 mg/l) was found to increase phagocytosis evaluated via both cytofluorimeter and chemiluminescence, while no effect was detected on superoxide anion production or on lymphomonocyte tests. In the in vivo study, the authors administered imipenem/cilastatin (1500 mg/day) to 15 elderly and diabetic patients, in whom both PMN functions (phagocytosis and superoxide anion production) and lymphocyte tests (CD3, CD4, CD8, CD19, IL2 and sIL2R serum levels) were studied before and on the 3rd and 7th days of treatment. The drug assimilation did not modify the lymphocyte parameters, whereas it increased PMN superoxide anion production and phagocytosis which were depressed in basal conditions. In the former case, such increase was slight and insignificant, whereas in the latter it was significant.