IMMUNOGLOBULIN-A RESPONSE AGAINST GARDNERELLA-VAGINALIS HEMOLYSIN ANDSIALIDASE ACTIVITY IN BACTERIAL VAGINOSIS

OBJECTIVE: The aim of this study was to investigate the correlation be tween the immunoglobulin A immune response to Gardnerella vaginalis he molysin and sialidase activity in vaginal fluids from patients with ba cterial vaginosis. STUDY DESIGN: Nonpregnant women who were examined a t a gynecologic clinic, in an age range of 18 to 62 years, were enroll ed. The study population comprised 131 healthy volunteers, 32 women wi th bacterial vaginosis that was positive for immunoglobulin A to Gardn erella vaginalis hemolysin, 40 women with bacterial vaginosis that was negative for immunoglobulin A to Gardnerella vaginalis hemolysin, and 19 women with Candida vaginitis. Bacterial vaginosis was diagnosed by clinical criteria and Gram stain. RESULTS: Sialidase activity was pre sent in 75% (54/72) of patients with bacterial vaginosis. Women having bacterial vaginosis and lacking a specific immunoglobulin A response had a significantly higher level of sialidase activity than patients w ho had an immune response against Gardnerella vaginalis hemolysin. Sia lidase activity was detected in 87% (35/40) of the former subgroup of patients with bacterial vaginosis and in 59% (19/32) of women of the l atter subgroup. No sialidase activity was measured in patients with ca ndidiasis. Specificity of the assay for healthy controls was 95% (124/ 131 women without sialidase activity). CONCLUSIONS: Sialidases produce d by Prevotella bivia and other microorganisms present in the microflo ra of patients with bacterial vaginosis are very likely a virulence fa ctor not only by destroying the mucins and enhancing adherence of bact eria but also by impairing a specific immunoglobulin A immune response against other virulence factors such as cytotoxin from Gardnerella va ginalis.