IMMUNOMODULATORY ACTION OF LEVOFLOXACIN ON CYTOKINE PRODUCTION BY HUMAN PERIPHERAL-BLOOD MONONUCLEAR-CELLS

Levofloxacin (LVFX), the bacteriologically active isomer of ofloxacin, is a fluorinated quinolone. LVFX suppressed the proliferative activit y of peripheral blood mononuclear cells (PBMC) stimulated with phytohe magglutinin (PHA). LVFX increased interleukin-2 (IL-2) production by P BMC stimulated with PHA in a dose-dependent manner, with more than 10 mu g/ml of LVFX causing a significant increase. The granulocyte-macrop hage colony-stimulating factor and soluble IL-2 receptor production by PHA-stimulated PBMC was suppressed at high concentrations of LVFX. In terleukin-1 beta production by lipopolysaccharide-stimulated PBMC was suppressed in a concentration-dependent manner by LVFX, and tumor necr osis factor-alpha production was suppressed at only the highest concen tration. In contrast, interleukin-8 production was little affected by LVFX. These results show that LVFX has action on cytokines production by PBMC independent of its antimicrobial activity.