Effects of long-term/low-dose clarithromycin on neutrophil count and interleukin-8 level in pyometra.

We investigated the effects of clarithromycin (CAM) on clinical and endometrial immune responses in chronic intrauterine infection (pyometra). CAM was orally administered in a dose of 200 mg once a day for 4 months (long-term/low-dose treatment) in patients with pyometra. Lavage fluid of the uterine endometrial cavity was obtained from 5 healthy women (controls) and 5 patients with pyometra to investigate the levels of neutrophil and interleukin-8 (IL-8), which is a neutrophil chemotactic factor. All patients showed clinical improvement at the end of treatment. In the assessment of the immune responses, neutrophils were accumulated in the lavage fluid of the uterine endometrial cavity in pyometra (p < 0.001, versus controls) and decreased by CAM treatment (p < 0.001). The level of IL-8 was significantly higher in the lavage fluid of patients with uterine endometritis than in the controls (p < 0.001), and decreased by CAM treatment (p < 0.01). There was a close correlation (r = 0.982) between neutrophil count and IL-8 level in the endometrial lavage of patients with pyometra. The reduction of the uterine endometrial neutrophil migration in chronic inflammatory sites may partially be a direct effect of CAM.