Immunohistochemical identification of the papillomavirus in uterine cervix: relationship with dysplasia, koilocytosis and evolution of the lesions.

Papillomavirus common internal capsid antigen (PV-Ag) was demonstrated using an immunoperoxidase technique in 74 out of 239 (31.0%) cases of cervical condylomata diagnosed histologically. All the positive cases but 2 (72/74) had nuclear changes compatible with dysplasia or cervical intraepithelial neoplasia (CIN). Immunocytochemically determined PV-Ag positivity was found in 54 out of 92 CIN I (58.7%), in 14 out of 32 CIN II (43.8%) and in 4 out of 18 CIN III (22.2%). The extent of koilocytosis in the epithelium had a direct correlation with the PV-Ag positivity: when koilocytosis extended to more than two thirds of the epithelium thickness, 24/41 cases (63.4%) were positive; when between one third and two thirds, 32/105 cases (30.5%) were positive; when present in less than one third 16/93 cases (17.2%) were positive. The positivity was 41.8% under 30 years of age and 20.5% over 30. Out of 16 positive cases followed with multiple biopsies for 6-20 months, 9 remained positive without change in CIN degree and 7 became negative, with CIN regression in 4 cases and progression to CIN III with disappearance of koilocytosis in 3 cases. More specific methods than histocytopathology alone are needed for epidemiologic and follow-up studies, especially in the cases in which the disappearance of antigenic and morphological expression of PV infection is not followed by dysplasia regression.