Chapter 30 : Effects of Quinolones on the Immune System

Abstract:

The immune system consists of a complex network of innate and adaptive host responses that defend the host against microbial invaders and the development of neoplastic processes. For several decades there has been considerable interest mounting in the effects of antimicrobial agents on components of the immune system. Some of the extensive review articles that have covered the subject during the past two decades are summarized in this chapter. There are at least five mechanisms by which antimicrobial agents can affect the host-pathogen relationship besides a direct bacteriostatic/bactericidal effect on the microbe. Dalhoff has written a detailed review that includes a comprehensive summary of the reported effects of antimicrobial agents on eukaryotic cells. It was successful in significantly preventing systemic or bacteremic M. avium infection, thus validating the in vitro observations published. Comparator agents such as clindamycin had no effect on humoral or cellular responses, and cefotaxime, mezlocillin, and amikacin had modest suppressive effects. The explosion in knowledge about immune responses is related, in part, to a better understanding of the complex molecular signals generated when secretory cells of the reticuloendothelial system, particularly monocytes and macrophages, have been studied for cytokine generation. A plethora of quinolone effects on specific components of the immune response have been reviewed. Downregulation of cytokine responses has also been noted for other antimicrobial agents, including macrolides.