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

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

Method: 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 (χ) and Fisher's exact test. Statistical significance was set at  < 0.05.

Results: 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 ( = 0,036; = 0,034). High-grade intraepithelial lesions were associated with HPV16 in both groups ( = 0.001;  = 0.009) and with HPV53 in group 2 ( = 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%).

Conclusion: 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.