Histologic and immunologic associations of an HPV16 variant in LoSIL smears

Background. Human papillomavirus type 16 variants have been described and may have different biologic activities: this has implications for the design of HPV vaccines. Objectives. The aim of this study was to see if the HPV16 variant E-C 131 can be detected in women with preinvasive disease and to consider the histological and immunological implications of such infection. Design. A prospective observational cross-sectional study on a cohort of women with minor cervical cytological abnormalities was performed. Methods. Samples were tested for HPV DNA by polymerase chain reaction and restriction enzyme digestion. Blood samples were tested for antibodies to HPV16 virus-like particles (VLP) and to determine class I HLA types. Women found to have abnormal colposcopy were treated by large-loop excision of the transformation zone on a see-and-treat basis. Results. Two hundred forty-one women were included in the study. Infection with the variant was detected in 20.9% of cases and was not associated with any specific HLA type. These cases were more likely to have high-grade CIN than those with wildtype HPV16 or no HPV16 (chi(2) = 18.85, P < 0.001). There were significant differences in seropositivity to HPV16 virus-like particles between the three groups (chi(2) = 32.43, P < 0.001). Conclusions. The E-C 131 variant may have increased oncogenic potential by evading host immune responses, but its identification is only weakly predictive of high-grade disease in stepwise logistic regression. The lack of seropositivity to HPV16 VLP has implications for the design of prophylactic vaccines based on VLP to HPV16. (C) 1999 Academic Press.