DILUTION ASSESSMENT OF CERVICOVAGINAL SECRETIONS OBTAINED BY VAGINAL WASHING FOR IMMUNOLOGICAL ASSAYS

Local immunological defense mechanisms in the cericovaginal mucosa cur rently remain incompletely defined, especially from a quantitative poi nt of view, Addition of an inert substance, lithium chloride (LiCl), i nto the washing buffer used to carry out the vaginal washing for colle cting cericovaginal secretions and measurement of its concentration wi th a flame absorption spectrophotometer, before and after the specimen is sampled, permits the quantification of the volume of cericovaginal secretions collected and the approximation of the dilution factor of a soluble component introduced by the washing, Lithium, at a concentra tion of 10 mM, gives the best precision of measurement and has no effe ct on the results of the immunoassays, In a population of 27 nonpregna nt women (age range, 18 to 45 years), the volume of cericovaginal secr etions collected by vaginal washing with 3 mi of LiCl-phosphate-buffer ed saline was 12% +/- 3.2% (mean a standard deviation) of the total vo lume and showed large interindividual variations (range, 5.6 to 18.8%) ; the mean dilution factor of a soluble component from the vaginal sec retions was 9.9% +/- 2.8% (range, 6.3 to 18.8%), According to the date of the menstrual cycle, the mean volume of collected cervicovaginal s ecretions was significantly increased in the luteal phase in compariso n with the follicular phase; conversely, the mean dilution factor of a soluble component was more important in the follicular than in the lu teal phase, These features strengthen the need to quantify accurately the dilution factor introduced by vaginal washing when studying cervic ovaginal immunity.