Clinical Validation of the Vitro HPV Screening Assay for Its Use in Primary Cervical Cancer Screening

Many scientific societies have issued guidelines to introduce population-based cervical cancer screening with HPV testing. The Vitro HPV Screening assay is a fully automatic multiplex real-time PCR test targeting the L1 GP5+/GP6+ region of HPV genome. The assay detects 14 high risk (HR) HPV genotypes, identifying individual HPV16 and HPV18 genotypes, and the HPV-positive samples for the other 12 HR HPV types are subsequently genotyped with the HPV Direct Flow Chip test. Following international guidelines, the aim of this study was to validate the clinical accuracy of the Vitro HPV Screening test on ThinPrep-collected samples for its use as primary cervical cancer screening, using as comparator the validated cobas® 4800 HPV test. The non-inferiority analysis showed that the clinical sensitivity and specificity of the Vitro HPV Screening assay for a diagnosis of cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) were not inferior to those of cobas® 4800 HPV (p = 0.0049 and p < 0.001 respectively). The assay has demonstrated a high intra- and inter-laboratory reproducibility, also among the individual genotypes. The Vitro HPV Screening assay is valid for cervical cancer screening and it provides genotyping information on HPV-positive samples without further sample processing in a fully automated workflow.

HPV testing by cobas HPV test in a population from Catalonia

Background

HPV testing in cervical cancer screening has been proposed as an alternative or complementary to cytology in women older than 30 years. However, adequate clinical sensitivity and specificity are crucial for a new test to be implemented. Hybrid Capture 2 (HC2) has proved good clinical performance in selecting women at risk for high-grade intraepithelial lesions with a high sensitivity and specificity. cobas HPV Test has been recently launched and its performance in different clinical settings needs to be determined.

Objectives

The aim of this study was to evaluate the cobas HPV Test for the detection of cervical HPV infection in a population of women in Catalonia (Spain) using HC2 as a reference.

Materials and Methods

Cervical liquid cytology samples from 958 women have been studied. Sensitivity was analyzed in 60 samples from patients with a high-grade intraepithelial lesion (≥CIN2) on histology and specificity was determined in 898 samples from women with no ≥CIN2. All cases had HC2 and cobas HPV Test performed. Statistical analyses of sensitivity, specificity and comparison between HC2 and cobas HPV Test by a non-inferiority test were applied.

Results

Sensitivity of HC2 and cobas HPV Test for detecting ≥CIN2 proved identical (98.3%) while specificity was 85.3% and 86.2% respectively. The non-inferiority test demonstrated that cobas HPV Test surpassed 90% sensitivity and 98% specificity of HC2.

Conclusion

The cobas HPV Test results fulfilled sensitivity and specificity requirements for HPV based cervical cancer screening and for the triage of minor cytological abnormalities, allowing its introduction in clinical settings.

Detection of HPV by in situ hybridization in thin-layer (ThinPrep) cervicovaginal samples

We have studied an automated in situ hybridization (ISH) method as a possible alternative approach for detecting high-risk human papillomavirus (HPV) in monolayer (ThinPrep) cervico-vaginal samples, comparing the results with those obtained by polymerase chain reaction (PCR) using consensus primers and studying the relationship between the ISH staining pattern and the viral integration in HPV 16-positive cases. Eighty atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL) cases were used for our purposes. The patients were monitored through periodic cytologies. ISH with was performed with an automated Ventana System, analysis by PCR was performed with consensus primers and integration of HPV16 was performed by realtime PCR analyzing E2 and E6 genes. Additionally, 27 HSIL cases were also studied to observe the ISH staining patterns. HPV infection was detected by ISH in 21.7% of the ASCUS cases and 55.8% of the LSIL cases. Two distinct staining patterns were observed: multipunctated (MP) and diffuse (DI). In some cases, a mixed pattern (MP + DI) was observed and these cases were considered as MP. The MP pattern increased with the degree of lesion and seemed to have a prognostic value in ASCUS/LSIL cases. The lesion in MP pattern cases persisted throughout the entire study in 77% of cases, whereas in cases with a DI staining pattern, only 41% of them showed persistence of the lesion (p <0.001). No correlation was found between HPV integration and the ISH staining pattern. Given the lower sensitivity and negative predictive value of ISH and its incapacity to demonstrate the integration of high-risk HPV in ASCUS and LSIL cases using liquid-based cytology, we do not recommend this technique for the triage of ASCUS and LSIL cases.

Biological activities of fragments derived from Bordetella pertussis endotoxin: isolation of a nontoxic, Shwartzman-negative lipid A possessing high adjuvant properties

Endotoxin from fresly sedimented Bordetella pertussis cells, isolated by the phenol/water procedure when submitted to kinetically controlled, mild acidic hydrolysis released a polysaccharide (polysaccharide 1), a complex lipid (lipid X), and a glycolipid. When treated with somewhat stronger acid, the glycolipid yielded a second polysaccharide (polysaccharide 2) and another complex lipid (lipid A). The intact pertussis endotoxin had all the usual properties of endotoxins extracted from enteric bacteria. Lipid X and the intermediary glycolipid retained all the endotoxic properties of the unfractionated endotoxin. In lipid A, pyrogenicity was reduced to a very low level and toxicity and Shwartzman reactivity were absent; however, this fraction retained most of the endotoxin's antiviral activity, and its adjuvant power was considerably higher than that of the intact endotoxin. Lipid A elicited nonspecific resistance against challenge with certain bacteria, but not against others.