Kinetics of serum and local cytokine profile in experimental intravaginal trichomoniasis induced with Trichomonas vaginalis isolates from symptomatic and asymptomatic women

Abstract

Trichomoniasis, the most common non-viral sexually transmitted disease, is caused by infection with the protist Trichomonas vaginalis. The clinical spectrum varies from an asymptomatic to a severe symptomatic state. However, the exact factors leading to varied symptomatology have not been well elucidated. The role of cytokines in the pathogenesis of many microbial diseases has been reported. The present study reports the cytokine levels (IL-2, IL-4, IFN-gamma) on different days post infection (3rd, 7th, 14th, 21st and 28th d.p.i.) in serum and vaginal washes (VWs) of mice infected intravaginally with T. vaginalis isolates from 15 symptomatic and 15 asymptomatic women. Significantly higher production of IL-2 and IFN-gamma was observed on the 3rd to 28th d.p.i., and IL-4 on the 7th to 21st d.p.i., in infected as compared to uninfected mice. A significant increase in cytokine IL-2 and IFN-gamma was observed on the 3rd to 28th d.p.i. in serum and VWs of mice infected with T. vaginalis isolates from asymptomatic as compared to symptomatic women. IL-2 (P < 0.001) and IFN-gamma (P < 0.05) concentrations were significantly higher on the 14th d.p.i. in serum samples as compared to VWs of mice infected with T. vaginalis isolates from asymptomatic and symptomatic women, while no significant difference was observed in IL-4 concentration between the two groups of mice. The study indicates the involvement of a Th-1 (IL-2 and IFN-gamma) like response in mice infected with isolates from asymptomatic women as compared to symptomatic women and suggests that Th-1 type cytokines might be playing a role in maintaining low levels of infection.