Effects of long-term administration of roxithromycin on neutrophil count and interleukin-8 level in endometrial cavity subjected to pyometra.

We investigated the effect of long-term administration of roxithromycin (RXM) on clinical responses and immune responses to chronic intrauterine infection, pyometra. One hundred and fifty milligrams of RXM were orally administered once a day for 3 months to patients with pyometra. Neutrophils and interleukin-8 (IL-8), which is a neutrophil chemotactic factor, in the lavage fluid of the uterine endometrial cavity obtained from 5 normal women and 18 patients with pyometra were investigated. Sixteen (88.9%) of the 18 patients showed a clinical improvement at the end of treatment. The immune responses occurred in the lavage fluid from the uterine endometrial cavity. Neutrophils accumulated in the lavage fluid of the uterine endometrial cavity before RXM treatment (p < 0.001 vs. normal subjects and decreased after RXM treatment (p < 0.001). The levels of IL-8 were significantly higher in the lavage fluid of pyometra patients than in normal women (p < 0.001), and tended to decrease after RXM treatment (p < 0.01). These results indicate that RXM decreases uterine endometrial cavity inflammation through reduction of neutrophil migration in inflammatory sites and is effective in treating chronic intrauterine infection.