Is real-time PCR the correct method to evaluate the incidence of human papillomavirus in prepuces of asymptomatic boys and men?

Abstract

To investigate the prevalence of human papillomavirus (HPV) in prepuces of asymptomatic boys and men, the present study was designed. Two hundred and fifty male prepuce specimens who underwent circumcision due to phimosis were collected. Samples were subdivided into groups regarding their age: children (group I, 0-10 years), adolescents (group II, 11-20 years) and adults (group III, >20 years). HPV High Screen Real-TM Quant 2x kit detecting HPV 6 and 11 (low risk) as well as another kit for identification of HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59 (high risk) were used. Additionally, a Taq Man assay has been designed targeting the L1 gene of HPV 6, 11, 16 and 18. Evaluating the number of low-risk HPV subtypes, we found HPV 6 and 11 in 5.3 % of samples (n = 12/226). Concerning high-risk HPV, we found a positivity in 4 % of samples (n = 9/224). In contrast to low-risk data where no age distribution was observed, we found an age-specific accumulation of high-risk HPV subtypes in the children group (n = 6/9). A second independent assay (Taq Man PCR assay) measuring HPV 6, 11, 16 and 18 of all positive samples confirmed only the high-risk HPV subtypes of the Real-TM Quant 2x assay. Our study provides evidence that qPCR estimation for HPV infection obviously underestimates the incidence rate of infected prepuces in boys and men with phimosis. Contrary, an overestimation of the HPV infection rate with the in situ hybridization method of phimotic prepuces cannot be excluded.