Prediction of human papilloma virus antigen in cervical squamous epithelium by koilocyte nuclear morphology and "wart scores": confirmation by immunoperoxidase.

Koilocytes (balloon cells) in cervical squamous epithelium can be distinguished by their nuclear morphology as members of two populations A and B. The proposition that population A was infected with human papilloma virus (HPV) and population B was not, was examined immunohistologically. A peroxidase-antiperoxidase technique using polyclonal HPV antibody failed to support the hypothesis and showed small fractions of both populations to be infected with the virus (A = 5 of 25; B = 2 of 19). Nuclear morphology alone is thus inadequate to distinguish infected from non-infected koilocytes, or balloon cells. When a number of well established histological changes in squamous epithelia infected with HPV were examined, graded, and summated to obtain a "wart score," however, a reasonably accurate prediction of HPV infection emerged.