Interleukin-6, interleukin-10 and interleukin-12 in vaginal fluid from women with bacterial vaginosis

There has been a recent recognition on the influence of local vaginal immunity on the acquisition of vulvovaginal disorders and their adverse consequences. Variations in local immune responses seem to play an important role in susceptibility to different vaginal infections as well as to the likelihood of recurrences. Bacterial vaginosis (BV), the most frequent vaginal disorder in most populations, is enigmatic in that the etiology is unknown, recurrences are common and vaginal inflammation is absent. We investigated the influence of BV on the vaginal concentration of the pro-inflammatory cytokine interleukin (IL)-12, the pleiotropic cytokine IL-6 and the anti-inflammatory cytokine IL-10 in non-pregnant women. Vaginal lavage samples were obtained from 45 patients with BV and from 46 asymptomatic controls. The supernatant fractions were examined for IL-6, IL-10 and IL-12 by commercial ELISAs. Analysis of the cytokine levels in the two groups was by the Mann-Whitney test. IL-6 concentrations varied considerably among women in the BV and control groups but the median levels were almost identical. The median concentrations of IL-10 and IL-12 were uniformly low in both groups but median levels were not statistically different. The marked alteration in the vaginal bacterial flora that is characteristic of BV does not result in enhancement or inhibition of the vaginal levels of IL-6, IL-10 and IL-12. Mechanisms to explain this striking lack of immune system variation remain to be determined.