Virus expression. EGF and transferrin receptors in human papillomas.

Thirty five non regressing cutaneous and mucosal human papillomas were studied for the expression of EGF and transferrin receptors by indirect immunofluorescence on frozen sections. The lesions were also examined for the presence of human papillomavirus (HPV) DNA by in situ-hybridization with biotinylated probes and viral capsid antigen. The mapping of EGF and transferrin receptors was modified in cutaneous lesions with drastic viral cytopathic effects and was enhanced in mucosal lesions mainly in laryngeal papillomas, which are poor virus producers. The greatest increase in EGF and transferrin receptor reactivity was observed in the group of mucosal lesions in which viral DNA was more frequently detected than viral antigen. This suggests that viral DNA may play a role in basal cell stimulation. Moreover some of these lesions with dense inflammatory reactions showed DR antigen expression by epithelial cells. Our findings indicate that epithelial cell activation in papillomas might be modulated by other factors than HPV such as mediators of the local immune response.