Vaginal innate immunity in response to microbial perturbation is still poorly understood and could be crucial for protection from adverse outcomes. We investigated the relationship between interleukin (IL)-8, IL-1beta and neutrophils in vaginal fluid obtained from 60 healthy women and 51 women who were bacterial vaginosis (BV) positive. Concentrations of IL-8 and IL-1beta were highly correlated with counts of neutrophils in vaginal fluid of the entire population examined (111 subjects). Vaginal IL-1beta concentrations were significantly higher (P < 0.001) in BV positive women. There was no significant difference in IL-8 levels or number of neutrophils between healthy controls and BV positive women. None of the healthy controls with high neutrophil counts (> or =75th percentile, 14 average count per field) had high concentrations of IL-1beta (> or =75th percentile, 220 pg/ml), whereas 84% of BV positive women with high neutrophil counts had high IL-1beta concentrations (P < 0.001). On the contrary, no difference in the percentage of subjects with elevated concentrations of IL-8 (> or =75th percentile, 2842 pg/ml) was found between healthy and BV positive women with high numbers of neutrophils (55.5% of healthy versus 53% of BV positive women). Our findings show that BV causes a large increase in IL-1beta concentrations which is not paralleled by an increase in IL-8 concentrations in vaginal fluid, suggesting that BV-associated factors more specifically dampen IL-8 rather than IL-1beta. The lack of an increase in IL-8 may explain the absence of an increase in neutrophil numbers in most women exposed to abnormal vaginal colonization (BV).