POLYMERASE CHAIN REACTION-ASSISTED EVALUATION OF LOW AND HIGH-GRADE SQUAMOUS INTRAEPITHELIAL LESION CYTOLOGY AND REAPPRAISAL OF THE BETHESDA SYSTEM

Between January 1991 and 1992, 5,652 cervical smears from 4,918 women were classified according to the traditional Papanicolaou/cervical int raepithelial neoplasia (CIN) categories and to the recently developed Bethesda System. Koilocytosis without atypia was identified in 3.7% (1 83 cases), CIN 1 in 1.8% (87 cases) and high grade squamous intraepith elial lesions (SILs) (CIN 2 and 3) in 1.9% (93 cases) (total, 363/4,98 8 = 7.470). Human papillomavirus (HPV)-directed polymerase chain react ion analysis with general primers and subsequent hybridization with HP V 16/18 probe cocktail was carried out in 35% of cases with koilocytos is and dysplasia of any degree (127/363 cases). Seventy-five percent ( 95 cases) were positive in contrast to a detection rate of 30.8% (53/1 72 cases) for nonsuspicious smears. While low grade SILs were HPV posi tive in 67% (koilocytosis only) and 75% (CIN 1), high grade SILs harbo red HPV in 87%. The rate of HPV 16/18 infections varied from :1.9% in low grade SILs to 88.9% in high grade SILs. Our results point to the q uestionable value of koilocytosis as a specific marker of HPV infectio n and call for confirmatory tests prior to classifying cervical smears suggestive of HPV infection in the low grade SIL category.