[Do effects of biological response modifiers in vitro correspond to clinical results?]

There has been renewed interest in drug-host defence interaction because of increasing numbers of immunocompromised individuals in whom even a marginal influence on host response may have a beneficial effect on clinical outcome. The immunomodulating activity of several antibiotics has been investigated in the past. Unfortunately most of these studies have focussed on in vitro effects. Many controversies arise from the use of non-standardized techniques. In vivo experiments performed in animals might be far from the clinical situation. The effect of antibiotics on pagocyte function has been studied most intensively. Immunostimulating and depressing activities of antibiotics have been described. The clinical relevance is still controversial, e.g., the intracellular uptake of an antibiotic does not necessarily mean better microbial killing. Synergistic activities have been found with some macrolides and newer cephalosporins, but until now clinical studies in humans are still missing. Not only patients with abnormal host defence mechanisms, but also patients with transient immunosuppression during operations or after burns, could benefit from antibiotics with additional immunomodulating activities. More studies in humans are required before optimal clinical applications can be recommended.