Detection of Y chromosome DNA as evidence of semen in cervicovaginal secretions of sexually active women

The detection of traces of semen in cervicovaginal secretions (CVS) from se xually active women practicing unprotected sex is a prerequisite for the ac curate study of cervicovaginal immunity. Two semen markers, the prostatic-s pecific antigen (PSA) and the Y chromosome, were detected in parallel in CV S obtained by a standardized vaginal washing of consecutive women attending the principal medical center for sexually transmitted diseases of Bangui, Central African Republic. PSA was detected by immunoenzymatic capture assay in the cell-free fraction of CVS, and the Y chromosome was detected by a s ingle PCR assay of DNA extracted by silica from the cell fraction (Y PCR). Fifty (19%) cell-free fractions of the 264 beta -globin-positive CVS sample s were positive for PSA, and 100 (38%) cell fractions of the CVS samples we re positive for the Y chromosome. All the 50 (19%) PSA-containing CVS sampl es were also positive for the Y chromosome. Fifty (19%) CVS samples were po sitive only for the Y chromosome, with no detectable PSA. The remaining 164 (62%) CVS samples were both PSA and Y chromosome negative. These findings demonstrate that CVS from sexually active women may contain cell-associated semen residues unrecognized by conventional immunoenzymatic assays used to detect semen components. The detection of cell-associated male DNA with a highly sensitive and specific procedure such as Y PCR constitutes a method of choice to detect semen traces in female genital secretions.