Evaluation of commercial HPV assays in the context of post-treatment follow-up: Scottish Test of Cure Study (STOCS-H)

AIMS

Human papillomavirus (HPV) testing is more sensitive than cytology for detection of residual/recurrent cervical disease after lesion treatment. Several HPV test comparison studies have been performed within triage and screening populations, but data on their comparative performance in a test of cure context is lacking. This study aims to address this gap.

METHODS

We compared the technical and clinical performance of Abbott RealTime High risk (HR)-HPV, Genprobe Aptima PV, Hologic Cervista HPV-HR, Qiagen Hybrid Capture 2 and Roche cobas HPV in the Early Implementation phase of a 'test of cure' service within the Scottish Cervical Screening Programme.

RESULTS

Valid results with all five HPV Tests from 1020 first samples taken ∼6 months post-treatment showed HPV positivity ranging from 17.84% to 26.96%. There was perfect agreement in 74%, and greatest variation between assays was observed in cytologically negative samples. Clinical performance was judged on cumulative incidence of cervical intraepithelial neoplasia 2+ (CIN2+) during follow-up (mean: 13.2 months). There were 23 cases of CIN2+ of which 14 were CIN3+. All assays, including cytology, were 100% sensitive for detection of CIN3+. Of the nine cases of residual CIN2, three assays detected all, one assay missed one and one assay missed two cases. Specificity ranged from 75% to 84% according to assay.

CONCLUSIONS

All assays were sensitive for detection of CIN2+ at 6 months post-treatment. The range of positivity equated to a 50% increase between assays with the lowest and highest positivity rates. The relevance of HPV positivity in the absence of cytological abnormalities requires longer follow-up to determine whether additional tools for risk stratification are required.

Brown adipose tissue in lean and fat selection lines of sheep identified by immunodetection of uncoupling protein in western blots of tissue homogenates

1. Uncoupling protein (UCP) was purified from perirenal adipose tissue of 2-day-old lambs by a procedure involving Triton solubilization and hydroxyapatite treatment. It has an apparent Mr of 34,000. 2. Rabbit anti-sheep UCP and rabbit anti-rat UCP each cross-reacted with both rat and sheep UCP in Western blots, indicating that the major antigenic determinants of the sheep UCP and rat UCP are similar. 3. In Western blots, the anti-sheep UCP showed tissue specificity by detecting a band corresponding to UCP only in brown adipose tissue, but not in heart or liver homogenates. 4. The Western blotting procedure was used to analyse sheep tissues. UCP was detected in samples of perirenal, omental, back and lymph node fat from 2-day-old lambs, but not in heart, liver, muscle or kidney samples. 5. UCP was not detected in any tissue samples from 34-day-old or 7-month-old lambs. 6. Comparison of the amount of UCP in perirenal fat of 2-day-old lambs from lean, fat and control selection lines, using the Western blotting procedure, showed no apparent difference.