Nerve Growth Factor and Selected Cytokines in Women With and Without Vulvodynia.

Objective: The aim of the study was to assess the association between cytokines/neurokines after in vitro stimulation with Candida antigen or lipopolysaccharide (LPS) in blood samples among women with and without vulvodynia.

Materials And Methods: Women with vulvodynia and asymptomatic controls at three offices at the University of Michigan were examined clinically and completed a comprehensive survey in this cross-sectional study. Cytokine/neurokine levels were determined on blood samples using established ELISA protocols. Analysis of 48 cases and 42 ethnically matched controls included descriptive statistics (median, minimal, and maximal levels of cytokines/neurokines), overall and in cases and controls. Because of left-censored measurements, interval censored survival analysis was used to assess the association between case/control status and pain characteristics with cytokine/neurokine levels.

Results: Participants ranged in age from 19 to 60 years. Levels of IL1β, IL1-RA, TNFα, IL-6, and IL-8 increased substantially after LPS stimulation, whereas no response was seen on IFNγ or nerve growth factor (NGF). Each increased after Candida antigen stimulation, although responses to Candida antigen stimulation of IL1β, IL-6, and TNFα were less robust than after LPS. Only NGF was significantly increased in vulvodynia cases compared with controls (Exp β (95% CI) = 2.08 [1.08-3.98]) after 24-hour Candida antigen stimulation and persisted when controlled for age, use of oral contraceptives, or history of Candida vulvovaginitis. No association between cytokine/neurokine levels and pain characteristics was found.

Conclusions: Compared with that of control women, whole blood from women with vulvodynia demonstrates an enhanced production of NGF, but not of a set of inflammation-related cytokines, in response to Candida antigen stimulation.