Neutrophil Gelatinase-Associated Lipocalin Concentration in Vaginal Fluid: Relation to Bacterial Vaginosis and Vulvovaginal Candidiasis

Objective: Neutrophil gelatinase-associated lipocalin (NGAL) is a component of innate immunity that prevents iron uptake by microorganisms. We evaluated whether NGAL was present in vaginal fluid and whether concentrations were altered in women with bacterial vaginosis (BV) or vulvovaginal candidiasis (VVC). Methods: Vaginal secretions from 52 women with VVC, 43 with BV, and 77 healthy controls were assayed by enzyme-linked immunosorbent assay for NGAL and for concentrations of l-lactic acid. Results: The median concentration of NGAL in vaginal fluid was significantly higher in control women (561 pg/mL) than in women with BV (402 pg/mL; P = .0116) and lower in women with VVC (741 pg/mL; P = .0017). Median lactic acid levels were similar in controls (0.11 mmol/L) and women with VVC (0.13 mmol/L) and were lower in women with BV (0.02 mmol/L; P < .0001). The NGAL and lactic acid concentrations were highly correlated (P < .0001). Conclusion: A decrease in Lactobacilli and/or lactic acid plus the absence of leukocytes results in lower vaginal NGAL levels that might facilitate the growth of bacteria associated with BV.