Mannose-binding lectin (MBL) is active in the innate immune defense against microorganisms. In this study, we determined whether vulvar vestibulitis syndrome, a disorder of unknown etiology, was associated with an altered distribution of MBL alleles.

Buccal swabs were obtained from women with vulvar vestibulitis syndrome in New York (62) and from 2 cities in Sweden (60), as well as control women in New York (48) and Sweden (51). DNA was tested for a single nucleotide polymorphism at codon 54 in exon I by polymerase chain reaction, endonuclease digestion, and gel electrophoresis. Blood samples were also obtained from the New York women and tested by ELISA for plasma MBL concentrations. The relationships between genotype, allele frequencies, blood MBL levels, and diagnosis were analyzed by Fisher exact test and one-way analysis of variance.

The variant MBL allele, MBLB, was detected in 35.5% and 26.7% of vulvar vestibulitis patients from New York and Sweden, respectively. Only 12.5% of New York controls (P=.007) and 9.8% of Swedish controls (P=.01) were MBL2-positive. All women, with one exception, who were positive for MBLB were MBLA/MBLB heterozygotes. Women who carried MBLB had almost a 10-fold reduction in median plasma MBL concentrations (278 ng/mL), as opposed to women who were MBLA homozygotes (1980 ng/mL) (P < .0001).

MBLB carriage and reduced plasma MBL levels are more common in women with vulvar vestibulitis syndrome than in control patients, and may contribute to symptomatology in a subset of patients.