HPV DNA testing in population-based cervical screening (VUSA-Screen study): results and implications

BACKGROUND

Human papillomavirus (HPV) testing is more sensitive than cytology for detecting high-grade cervical intraepithelial neoplasia (CIN). We evaluated the performance of high-risk HPV (hrHPV) testing in routine screening.

METHODS

In all, 25,871 women (29-61) enrolled in our population-based cohort study were offered both cytology and hrHPV testing. High-risk HPV-positive women with normal cytology and an age-matched subcohort of hrHPV-negative women with normal cytology were invited for repeat testing after 1 and/or 2 years and were referred for colposcopy if they presented with abnormal cytology and/or a positive hrHPV test. The hrHPV-positive women with borderline or mild dyskaryosis (BMD) and all women with moderate dyskaryosis or worse (>BMD) were directly referred for colposcopy. Women with BMD and an hrHPV-negative test were advised to repeat cytology at 6 and 18 months and were referred for colposcopy if the repeat cytology test was abnormal. The main outcome measure was CIN grade 3 or worse (CIN3+). Results were adjusted for non-attendance at repeat testing.

RESULTS

The hrHPV-positive women with abnormal cytology had a CIN3+ risk of 42.2% (95% confidence interval (CI): 36.4-48.2), whereas the hrHPV-positive women with normal cytology had a much lower risk of 5.22% (95% CI: 3.72-7.91). In hrHPV-positive women with normal cytology, an additional cytology step after 1 year reduced the CIN3+ risk to only 1.6% (95% CI: 0.6-4.9) if the repeat test was normal. The CIN3+ risk in women with hrHPV-positive normal cytology was higher among women invited for the first time (29-33 years of age) (9.1%; 95% CI: 5.6-14.3) than among older women (3.0%; 95% CI: 1.5-5.5).

CONCLUSION

Primary hrHPV screening with cytology triage in women aged 30 years is an effective way to stratify women on CIN3+ risk and seems a feasible alternative to cytological screening. Repeat cytology after 1 year for hrHPV-positive women with normal cytology is however necessary before returning women to routine screening.

Characterization of the angR gene of Vibrio anguillarum: essential role in virulence

The ability to utilize the iron bound by high-affinity iron-binding proteins in the vertebrate host is an important virulence factor for the marine fish pathogen Vibrio anguillarum. Virulence in septicemic infections is due to the presence of a highly efficient plasmid-encoded iron transport system. AngR, a 110-kDa protein component of this system, appears to play a role in both regulation of the expression of the iron transport genes fatDCBA and the production of the siderophore anguibactin. Therefore, study of the expression of the angR gene and the properties of its product, the AngR protein, may contribute to the understanding of the mechanisms of virulence of this pathogen. In this work, we present genetic and molecular evidence from transposition mutagenesis experiments and RNA analysis that angR, which maps immediately downstream of the fatA gene, is part of a polycistronic transcript that also includes the iron transport genes fatDCBA and angT, a gene located downstream of angR which showed domain homology to certain thioesterases involved in nonribosomal peptide synthesis of siderophores and antibiotics. In order to dissect the specific domains of AngR associated with regulation of iron transport gene expression, anguibactin production, and virulence, we also generated a panel of site-directed angR mutants, as well as deletion derivatives. Both virulence and anguibactin production were dramatically affected by each one of the angR modifications. In contrast to the need for an intact AngR molecule for anguibactin production and virulence, the regulation of iron transport gene expression does not require the entire AngR molecule, since truncation of the carboxy terminus carrying the nonribosomal peptide synthetase cores, as well as the site-directed mutations, resulted in derivatives that retained their ability to regulate gene expression which was only abolished after truncation of amino-terminal sequences containing helix-turn-helix and leucine zipper motifs and a specialized heterocyclization and condensation domain found in certain nonribosomal peptide synthetases. The evidence, while not rigorously eliminating the possibility that a separate regulatory polypeptide exists and is encoded somewhere within the 5'-end region of the angR gene, strongly supports the idea that AngR is a bifunctional protein and that it plays an essential role in the virulence mechanisms of V. anguillarum. We also show in this study that the angT gene, found downstream of angR, intervenes in the mechanism of anguibactin production but is not essential for virulence or iron transport gene expression.

The role of ADP-ribosylation and G(M1)-binding activity in the mucosal immunogenicity and adjuvanticity of the Escherichia coli heat-labile enterotoxin and Vibrio cholerae cholera toxin

The mucosal route of vaccination has attracted a great deal of attention recently. Not only is mucosal application of vaccines, for example, orally or intranasally, particularly convenient, it also offers the possibility to induce locally produced and secreted S-IgA antibodies in addition to systemic IgG antibodies. These IgA antibodies are known to play a key role in protection against pathogens that invade the host through mucosal surfaces. Induction of such responses is not readily achieved by currently used vaccination strategies, which generally involve intramuscular or subcutaneous injection with inactivated pathogens or antigens thereof. For the induction of a mucosal immune response, the vaccine needs to be applied locally. However, local vaccination with non-replicating antigens is usually ineffective and may result in tolerance unless a mucosal immunoadjuvant is included. The most potent mucosal immunoadjuvants known to date are probably cholera toxin (CT) and the closely related Escherichia coli heat-labile enterotoxin (LT). Although CT and LT have become standard adjuvants for experimental mucosal vaccines, the intrinsic toxicity has thus far precluded their use as adjuvants for human vaccine formulations. In the present review, the mucosal immunogenic and adjuvant properties of LT and CT are described, with special emphasis on the functional role of the individual subunits on their immune-stimulatory properties.

Transthoracic echo/Doppler in the identification of patients with chronic non-valvular atrial fibrillation at risk for thromboembolic events

Left atrial spontaneous echo contrast, detected by transoesophageal echocardiography in patients with non-valvular atrial fibrillation reflects slow blood flow and is associated with an increased risk of cardio-embolism. The purpose of this study was to find echo/Doppler predictors of left atrial spontaneous echo contrast by transthoracic examination. In a retrospective case control study, 17 patients with chronic non-valvular atrial fibrillation who had suffered a recent cerebral ischaemic event (group A) and 17 patients with chronic non-valvular atrial fibrillation who had not suffered such an event (group B) were studied. Both groups were matched for age and sex. All patients underwent standard transthoracic echocardiography with transmitral Doppler as well as transoesophageal echocardiography. Left atrial spontaneous echo contrast was demonstrated by transoesophageal echocardiography in nine group A patients and in two group B patients (P = 0.028); left atrial spontaneous echo contrast was not detected by transthoracic echocardiography in these patients. All patients with left atrial spontaneous echo contrast (11 patients) had a left atrial size, corrected for base index, exceeding 24 mm and a transmitral time velocity integral < 10 cm (sensitivity 100%). Left atrial spontaneous echo contrast was absent in six patients with both characteristics (specificity 74%).

CONCLUSION

transthoracic echo/Doppler aids in the prediction of the presence of left atrial spontaneous echo contrast and the identification of patients with non-valvular atrial fibrillation with increased cardioembolic risk, thus avoiding transoesophageal echocardiography.