INHIBITORY EFFECT OF MACROLIDES ON INTERLEUKIN-8 SECRETION FROM CULTURED HUMAN NASAL EPITHELIAL-CELLS

The mechanism of macrolide therapy in chronic sinusitis patients is un clear. The authors studied the effect of macrolides on interleukin (IL )-8 secretion from cultured human nasal epithelial cells, Epithelial c ells harvested from the nasal polyps of patients with chronic sinusiti s were primary-cultured, and secreted IL-8 in culture media was measur ed by enzyme immunoassay. The cells secreted considerable amounts of I L-8 constitutively and in response to lipopolysaccharide. The secretio n was significantly inhibited by 10(-5) M of erythromycin, clarithromy cin, roxithromycin, and josamycin. 10(-6) M erythromycin still showed the inhibitory effect, whereas the same concentration of josamycin did not, These results indicate that macrolide antibiotics may act as an immunomodulator to reduce IL-8 in inflammatory sites and, at least par tially, account for the clinically discrepant effects between 14- and 16-membered ring macrolides in long-term low-dose therapy for chronic sinusitis.