Human Papillomavirus 16 Variants May Be Identified by E6 Gene Analysis

The aims of the study were (1) to characterize the genetic variability of human papillomavirus (HPV) genotype 16 in the E6 region when this genotype is present in multiple infection samples, (2) to assess the prevalence of variants in our region and (3) to analyze the relationship between variants, patients' ages and pathology.

The Clinical Microbiology and Infection Control Department analyzed samples which were positive for genotype 16 and other genotypes from 2007 to 2013. Variants were assigned to European, Euro-German, Asian, Asian-American or African lineage by sequence analysis. The relationship among variants, age and different types of lesion was studied.

In HPV-16 sequence analysis, the European variant was detected in 85.10% of samples, the Asian-American in 7.80%, the African in 4.25% and the Euro-German in 2.83% of specimens. Sequence genetic variability showed 16 nucleotide substitutions. Moreover, non-European variants were mainly found in old women and in isolates from high-grade squamous intraepithelial lesions since European variants were mainly detected in negative cytologies.

Multiple infections may take effect on nucleotide substitution and the appearance of recombinant samples. Single gene analysis makes it impossible to detect recombination which has a great influence on drug response and vaccine strategies. Thus, E6 gene analysis would be enough to identify HPV-16 intratypic variants but not to confirm the results.