Multiple HPV infections with high viral loads are associated with cervical lesions but do not differentiate grades of cervical abnormalities

Multiple human papillomavirus (HPV) genotypes often co-exist within the cervical epithelium and are frequently detected in smears of different grades of cervical neoplasia. Describing the association of multiple infections with cervical disease is important to generate hypotheses regarding its pathogenesis. We analyzed the prevalence of multiple HPV infections and their attribution to cervical disease in a screening population of 999 consecutive BD-SurePath liquid-based cervical cytology samples enriched with additional ASC-US (n=100), LSIL (n=100) and HSIL (n=97). HPV genotyping was performed on cytology specimens only using BSGP5+/6+-PCR/MPG that detects and quantifies 51 HPV genotypes and 3 subtypes. Using a recently defined high viral load cutoff, the quantitative data was scored as high or low viral load. In the 36 month follow-up, 79 histologically confirmed CIN2+ cases were identified. In the screening population, there was a trend of having more multiple infections at a younger age. Multiple HPV infections were common. Multiple HPV types were most prevalent in LSIL (75.9% of HPV positives), followed by HSIL (65.5%), ASC-US (64.6%) and NIL/M (36.8%). In average, 3.2 and 2.5 HPV types were detected per LSIL and HSIL sample, respectively. Multiple HPV types with high viral loads were most prevalent in LSIL (62.6% of high viral load positives), followed by HSIL (51.9%), ASC-US (40.7%) and NIL/M (19.3%). Patients with multiple high viral loads showed a 4- to 6-fold increased risk of having cervical precancerous cytological lesions than patients with single high viral loads. Compared to NIL/M, multiple infections, especially with multiple high viral loads, were significantly associated with cytological precancerous lesions. However, the presence of multiple infection did not distinguish low-grade from high-grade cytological lesions.