Standardization of a Molecular Technique for Human Papillomavirus Genotyping in a Public-Health Service

To standardize a molecular technique for genotyping human papillomavirus (HPV) and to evaluate its distribution and relationship with vaginal cytology.

Women aged 25 years or older with altered cytology were selected from three public-health hospitals and underwent HPV genotyping by molecular biology. Samples were processed, stored, and subjected to extraction and amplification. Amplification was performed for 28 HPV types (19 of high-risk and 9 types of low-risk). The frequencies of the most prevalent HPV types and those with multiple genotypes, were calculated. The association between categorical variables was analyzed using the chi-square (χ²) and Fisher's exact test. Statistical significance was set at p < 0.05.

The samples were divided into two groups: 1) without previous cervical treatment (177, 55%); and 2) with previous cervical treatment (142, 45%). The frequency of positive HPV was 126 (71%) and 67 (47%), respectively. The predominant high-risk HPVs were: 16, 58, 52 and 53; HPV53, HPV68 and HPV35 were associated with multiple infection in both groups. HPV16 and multiple infections were more prevalent between group age 25-35 years (p = 0,036; p = 0,034). High-grade intraepithelial lesions were associated with HPV16 in both groups (p = 0.001; p = 0.009) and with HPV53 in group 2 (p = 0.020). Cytology classified as atypical squamous cells of undetermined significance (ASCUS) (group 1) and negative for intraepithelial lesions and malignancy (NILM) (group 2) were associated with reduction of HPV16 (74.4%; 65.4%).

The two groups differed in the frequency of HPV types and the chance of single and multiple infections. High-grade intraepithelial lesions were associated with HPV16 in both groups.