No abstract

Human papillomavirus (HPV) is the main etiological agent of cervical cancer. There is a large number of HPV genotypes and therefore a need to distinguish the high risk HPV genotypes associated with invasive cancer from the low risk. Because persistence of high risk HPV infection is necessary for progression of a pre-invasive cervical change one needs to identify the individual genotype to see if it persists. PCR amplification of HPV DNA is described using two consensus primer systems from cervical cells. Amplified HPV DNA was genotyped using a reverse hybridization line probe assay (LiPA). HPV DNA was amplified from 42% of samples by MY09/11 and from 80% by SPF10. In 42 samples HPV DNA was detected by both primer sets and in 38 samples only the SPF10 primers detected HPV DNA. The LiPA detected 21 different HPV genotypes (13 high risk) in this cohort of samples. Forty-three percent contained a single HPV genotype and 24% contained multiple infections (2-5 genotypes). Overall, high risk HPV genotypes were detected in 48% of the cervical samples, the most frequent types were 16, 18, 31, and 51. The proportion of high risk HPV genotypes increased with more severe cytological abnormalities. This study demonstrates that the SPF10 primer set is more sensitive than the MY09/11 primer set and that genotyping by LiPA tells us if the HPV infection is caused by a high risk type and if the infection is mixed. Additionally LiPA provides information about the individual genotype when looking for persistence of infection. HPV DNA detection and genotyping is therefore a useful tool in the colposcopy clinic, used in conjunction with cytology.

This is an audit of a new technique to improve the colposcopy service. Samples were tested for high risk HPV DNA using Digene Hybrid Capture II. Sixty-four percent of the sampled women under 30 had detectable high risk HPV DNA, decreasing to 44% in 30--39 year olds and to 27% in women over 40. High risk HPV prevalence increased with severity of cytology, although 22% with normal colposcopy had detectable high risk HPV. Of those women treated for cervical dysplasia, 83% had detectable high risk HPV prior to treatment, compared to only 32% afterwards. The audit has shown that high risk HPV testing has considerable discriminatory value. It has been integrated successfully into the service, particularly to manage low grade cervical abnormalities and to add valuable information following treatment for cervical dysplasia. Results need to be interpreted alongside colposcopy, cytology, and histology, and care must be taken in the interpretation of a single high risk HPV result.