Detection of infection by human papillomavirus in genital condylomata. A comparison study using immunocytochemistry and in situ nucleic acid hybridization.

One hundred eighty exophytic genital lesions clinically suspicious for infection by human papillomavirus (HPV) were analyzed by hematoxylin and eosin light microscopy, immunocytochemistry for HPV capsid antigen; and in situ nucleic acid hybridization for HPV messenger RNA (mRNA). Of 96 cases morphologically consistent with infection by HPV, 53% were antigen-positive, and 83% were mRNA positive (P less than 0.01). Of 55 cases suggestive but not diagnostic of HPV infection, 13% were antigen-positive and 26% were mRNA positive. Negative results were obtained in all lesions not believed to be indicative of HPV infection by morphologic criteria. In mRNA positive diagnostic cases, two thirds were of HPV type 6 and one third were HPV type 11. Two cases of coinfection with HPV types 6 and 16 were found. The study concludes that in situ hybridization for HPV mRNA is a more sensitive indicator of HPV infection, and in addition, provides HPV type, which may have prognostic significance.