Tigecycline attenuates polymorphonuclear leukocyte (PMN) receptors but not functions

Tigecycline achieves high intracellular concentrations in polymorphonuclear leukocytes (PMNs). To evaluate the effects of tigecycline on human PMNs, PMNs were incubated with tigecycline dilutions (0.1 to 100 mg L^-1). Phagocytosis-associated PMN Fcγ- and complement receptors as well as phagocytosis and oxidative burst induced by Staphylococcus aureus were measured by flow cytometry. Incubation with tigecycline caused small but significant decreases in the density of complement receptors CD11b and CD35 (all concentrations) and Fcγ receptors CD16 and CD32 (high concentrations), but not in the percentages of receptor-bearing cells, except for small reductions in the proportions of CD16 positive cells at high concentrations. Tigecycline had no effect on phagocytosis or oxidative burst induced by S. aureus. Tigecycline was thus associated with decreased density of PMN complement and (at high concentrations) Fcγ receptors. Although statistically significant, the differences were small and did not influence the PMN function as measured by phagocytosis and oxidative burst.