Southern blot hybridization and PCR in detection of oral human papillomavirus (HPV) infections in women with genital HPV infections.

The presence of human papillomavirus (HPV) in biopsies taken from clinically normal buccal mucosa (n = 212) and clinical lesions (n = 60) was examined by Southern blot hybridization (SBH) using 32P-labelled HPV DNA probes. Furthermore, one hundred formalin-fixed, paraffin-embedded biopsies were analyzed by using polymerase chain reaction (PCR), combined with dot blot hybridization and biotinylated HPV DNA probes. With SBH and PCR, 15.4% and 29.4% of the biopsies, respectively, contained HPV DNA. In clinically normal epithelium, 15.6% and 23.1% of the samples were HPV-positive with SBH and PCR, respectively. The HPV types detected in the genital and oral mucosa of index patients differed in all except two cases. Histology could not be relied on distinguishing HPV DNA positive and HPV DNA negative samples. Hand warts were encountered significantly more frequently in patients with a concomitant oral HPV infection. To conclude, oral HPV infections as detected by SBH and PCR are surprisingly common, but similar to the genital tract, the virus seems to exist in a latent form in the vast majority of cases. The frequent concomitant finding of skin warts and oral HPV infection may suggest some kind of HPV-specific immunosuppression.