The original SPF10 LiPA25 algorithm is more sensitive and suitable for epidemiologic HPV research than the SPF10 INNO-LiPA Extra

Two commercial HPV tests target the same 65 bp fragment of the human papillomavirus genome (designated SPF10): the original HPV SPF10 PCR-DEIA-LiPA25 system, version 1, (LiPA25) and the INNO-LiPA HPV Genotyping Extra (INNO-LiPA). The original SPF10 LiPA25 system was designed to have high analytical sensitivity and applied in HPV vaccine and epidemiology studies worldwide. But due to apparent similarities, this test can be easily confused with INNO-LiPA, a more recent assay of which the intended use, i.e., epidemiological or clinical, is currently unclear. The aim was to compare the analytical sensitivity of SPF10 LiPA25 to that of INNO-LiPA on the level of general HPV detection and genotyping. HPV testing by both assays was performed on the same DNA isolated from cervical swab (n = 365) and biopsy (n = 42) specimens. In cervical swabs, SPF10 LiPA25 and INNO-LiPA identified 35.3% and 29.3% multiple infections, 52.6% and 51.5% single infections, and no HPV type in 12.1% and 19.2%, respectively. Genotyping results were 64.7% identical, 26.0% compatible and 9.3% discordant between both methods. SPF10 LiPA25 detected significantly more genotypes (p < 0.001). The higher analytical sensitivity of SPF10 LiPA25 was confirmed by the MPTS123 genotyping assay. HPV positivity by the general probes in SPF10 DEIA was significantly higher (87.9%) than by those on INNO-LiPA (77.0%) (kappa = 0.592, p < 0.001). In cervical biopsies, SPF10 LiPA25 and INNO-LiPA identified 21.4% and 9.5% multiple types, 76.2% and 81.0% single types, and no type in 2.4% and 9.5%, respectively. Between both tests, the identification of genotypes was 76.3% identical, 14.3% compatible and 9.5% discordant. Overall, significantly more genotypes were detected by SPF10 LiPA25 (kappa = 0.853, p = 0.022). HPV positivity was higher by the SPF10 DEIA (97.6%) than by the INNO-LiPA strip (92.9%). These results demonstrate that SPF10 LiPA25 is more suitable for HPV genotyping in epidemiologic and vaccine-related studies, due to its higher analytical sensitivity.

Human papillomavirus DNA prevalence and type distribution in anal carcinomas worldwide

Knowledge about human papillomaviruses (HPV) types involved in anal cancers in some world regions is scanty. Here, we describe the HPV DNA prevalence and type distribution in a series of invasive anal cancers and anal intraepithelial neoplasias (AIN) grades 2/3 from 24 countries. We analyzed 43 AIN 2/3 cases and 496 anal cancers diagnosed from 1986 to 2011. After histopathological evaluation of formalin-fixed paraffin-embedded samples, HPV DNA detection and genotyping was performed using SPF-10/DEIA/LiPA25 system (version 1). A subset of 116 cancers was further tested for p16(INK4a) expression, a cellular surrogate marker for HPV-associated transformation. Prevalence ratios were estimated using multivariate Poisson regression with robust variance in the anal cancer data set. HPV DNA was detected in 88.3% of anal cancers (95% confidence interval [CI]: 85.1-91.0%) and in 95.3% of AIN 2/3 (95% CI: 84.2-99.4%). Among cancers, the highest prevalence was observed in warty-basaloid subtype of squamous cell carcinomas, in younger patients and in North American geographical region. There were no statistically significant differences in prevalence by gender. HPV16 was the most frequent HPV type detected in both cancers (80.7%) and AIN 2/3 lesions (75.4%). HPV18 was the second most common type in invasive cancers (3.6%). p16(INK4a) overexpression was found in 95% of HPV DNA-positive anal cancers. In view of the results of HPV DNA and high proportion of p16(INK4a) overexpression, infection by HPV is most likely to be a necessary cause for anal cancers in both men and women. The large contribution of HPV16 reinforces the potential impact of HPV vaccines in the prevention of these lesions.

TEMPORARY REMOVAL: The original SPF10 LiPA25 algorithm is more sensitive and suitable for epidemiologic HPV research than the SPF10 INNO-LiPA Extra

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Long-term follow-up of HPV16-positive women: persistence of the same genetic variant and low prevalence of variant co-infections

HPV16 variants correlate with geographic origin and ethnicity. The association between infection with a specific variant and the cervical disease risk remains unclear. We studied the prevalence, persistence and association with cervical intraepithelial neoplasia (CIN) of different HPV16 variants, using cervical swabs and whole tissue sections (WTS) of biopsies from 548 women in the placebo group of a HPV16/18 vaccine trial. In HPV16-positive samples, HPV16 variants were identified by a reverse hybridization assay (RHA). Laser-capture micro-dissection (LCM) was performed for localized detection of HPV. HPV16 variants were determined in 47 women. Frequency of mixed HPV16 variant infections was lower (8.5%) than for multiple HPV genotypes (39.1%). Among 35 women having consecutive HPV16 variant-positive swabs, 32 (91.4%) had the same variant while in three (8.6%) women a change in variant(s) was observed. HPV16-positive WTS were obtained from 12 women having consecutive HPV16 variant-positive swabs. The same variant was present in WTS of 10 women, while two were negative. WTS of five women were histologically normal. A single HPV16 variant was detected in four women having CIN1-3, while additional HPV genotypes were found in three other women having CIN2 and CIN3. In the WTS of one woman with mixed genotypes, the HPV16 variant was assigned to a CIN2 lesion by LCM. HPV16 variant infections can be effectively studied in cervical swabs and tissue specimens by the HPV16 variant RHA. Multiple HPV16 variants in one woman are rare. The HPV16 genotype consistently detected in follow-up samples usually involves a persistent infection with the same variant.

Evaluation of a novel Chlamydia trachomatis microsphere suspension assay for detection and genotyping of the different serovars in clinical samples

A novel Chlamydia trachomatis (Ct) microsphere suspension (MS) assay was evaluated for identification of the different serovars, using the same PCR primer set established for the Ct Detection and genoTyping assay. Both assays can detect and identify all 14 major serovars (A, B/Ba, C, D/Da, E, F, G/Ga, H, I/Ia, J, K, L1, L2/L2a, and L3) and one genovariant of serovar J. The probe specificity for the Ct-MS assay was determined using 14 Ct reference strains and 1 clinical isolate from a genovariant of serovar J. Also, the Ct-MS assay and the Ct detection and genoTyping assay were compared in 712 Ct-positive clinical samples. The Ct-MS assay showed a highly specific reaction for all probes with the amplicons of the reference strains, giving a very low background median fluorescence intensity signal (median fluorescence intensity ≤ 10). An excellent overall agreement in the Ct detection (kappa = 0.947, 95% confidence interval, 0.89 to 0.999; McNemar's test, P = 1.000) and the Ct genotyping (kappa = 0.993, 95% confidence interval, 0.977 to 1.000; McNemar's test, P = 0.053) was observed between the Ct detection and genoTyping (DT) assay and the Ct-MS assay. In conclusion, the novel Ct-MS assay permits simultaneous detection and genotyping of Ct serovars, making the Ct-MS assay an excellent high throughput method.

Universal human papillomavirus genotyping by the digene HPV Genotyping RH and LQ Tests

BACKGROUND

High-risk (hr)HPV testing plays an important role in primary cervical cancer screening. Subsequent hrHPV genotyping might contribute to better risk stratification. The majority of hrHPV tests do not include identification of individual hrHPV genotypes.

OBJECTIVES

The digene HPV Genotyping RH Test (strip-based) and LQ Test (xMAP-based) allow genotyping of GP5+/6+ amplimers, but their probes target a region in the L1 ORF, which is also amplified by other broad-spectrum hrHPV assays, e.g., the Roche Amplicor HPV Test (Amplicor) and the Roche Linear Array. The goal was to test whether the RH Test and LQ Test can be used as an universal hrHPV genotyping test.

STUDY DESIGN

Self-collected cervico-vaginal specimens (n=416) from an epidemiologic study were analyzed with Amplicor. The amplimers obtained were also tested with the RH Test and LQ Test for identification of 18 HPV types, including the 13 hrHPVs targeted by Amplicor.

RESULTS

197 specimens were positive by Amplicor, in which the RH Test and LQ Test identified one of the 13 hrHPVs in 94.4% and 98.0%, respectively. In 219 specimens remaining negative by Amplicor, the RH Test and LQ Test, performed on the Amplicor amplification products, still detected one of the 13 hrHPVs in 3.7% and 5.5%, respectively, and include identification of HPV53, 66, and 82. Overall, the RH and LQ Tests demonstrated high concordance with Amplicor for hrHPV detection (κ=0.908 and κ=0.923, respectively).

CONCLUSIONS

The digene HPV Genotyping RH and LQ Tests can be directly used for amplimers generated by the Amplicor HPV Test.

Human papillomavirus genotype attribution in invasive cervical cancer: a retrospective cross-sectional worldwide study

BACKGROUND

Knowledge about the distribution of human papillomavirus (HPV) genotypes in invasive cervical cancer is crucial to guide the introduction of prophylactic vaccines. We aimed to provide novel and comprehensive data about the worldwide genotype distribution in patients with invasive cervical cancer.

METHODS

Paraffin-embedded samples of histologically confirmed cases of invasive cervical cancer were collected from 38 countries in Europe, North America, central South America, Africa, Asia, and Oceania. Inclusion criteria were a pathological confirmation of a primary invasive cervical cancer of epithelial origin in the tissue sample selected for analysis of HPV DNA, and information about the year of diagnosis. HPV detection was done by use of PCR with SPF-10 broad-spectrum primers followed by DNA enzyme immunoassay and genotyping with a reverse hybridisation line probe assay. Sequence analysis was done to characterise HPV-positive samples with unknown HPV types. Data analyses included algorithms of multiple infections to estimate type-specific relative contributions.

FINDINGS

22,661 paraffin-embedded samples were obtained from 14,249 women. 10,575 cases of invasive cervical cancer were included in the study, and 8977 (85%) of these were positive for HPV DNA. The most common HPV types were 16, 18, 31, 33, 35, 45, 52, and 58 with a combined worldwide relative contribution of 8196 of 8977 (91%, 95% CI 90-92). HPV types 16 and 18 were detected in 6357 of 8977 of cases (71%, 70-72) of invasive cervical cancer. HPV types 16, 18, and 45 were detected in 443 of 470 cases (94%, 92-96) of cervical adenocarcinomas. Unknown HPV types that were identified with sequence analysis were 26, 30, 61, 67, 69, 82, and 91 in 103 (1%) of 8977 cases of invasive cervical cancer. Women with invasive cervical cancers related to HPV types 16, 18, or 45 presented at a younger mean age than did those with other HPV types (50·0 years [49·6-50·4], 48·2 years [47·3-49·2], 46·8 years [46·6-48·1], and 55·5 years [54·9-56·1], respectively).

INTERPRETATION

To our knowledge, this study is the largest assessment of HPV genotypes to date. HPV types 16, 18, 31, 33, 35, 45, 52, and 58 should be given priority when the cross-protective effects of current vaccines are assessed, and for formulation of recommendations for the use of second-generation polyvalent HPV vaccines. Our results also suggest that type-specific high-risk HPV-DNA-based screening tests and protocols should focus on HPV types 16, 18, and 45.

High-throughput genotyping of high-risk HPV by the digene HPV Genotyping LQ Test using GP5+/6+-PCR and xMAP technology

BACKGROUND

Epidemiologic studies have classified 18 genotypes of the human papillomavirus (HPV) as (probably) high-risk (HR) based on their association with cervical cancer, i.e., HPV 16, 18, 26, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, 73, and 82. Given the fact that certain HR HPV types confer an increased risk of cervical (pre)cancer, type-specific identification might aid clinical management of women tested positive for HR HPV. Therefore, the development of robust, high-throughput genotyping assays is important.

OBJECTIVES

An analytical comparison of the digene HPV Genotyping LQ Test (digene LQ Test), capable of identifying 18 HR types using bead-based xMAP suspension array technology, with the established Reverse Line Blot (RLB) genotyping assay was carried out on amplimers generated with the clinically validated GP5+/6+-PCR method.

STUDY DESIGN

GP5+/6+ amplimers, generated from 434 digene High Risk HPV HC2 DNA Test (HC2)-positive and 95 HC2-negative cervical smears, were genotyped by both the digene LQ Test and the RLB genotyping assay.

RESULTS

The genotyping assays revealed high agreement for overall HR HPV detection (ú = 0.884) and type-specific identification of the 18 HR HPV types (overall ú = 0.958, individual ú range 0.795 to 1.000). The digene LQ Test demonstrated a very good inter-laboratory reproducibility (ú = 0.987). Among the HC2-positive women, the digene LQ Test revealed positivity for one or more HR HPV type(s) in 85.9%, and negativity was observed in 97.9% of the HC2-negative women.

CONCLUSIONS

The digene LQ Test demonstrated a high genotyping agreement with the established RLB genotyping assay on GP5+/6+ amplimers. This novel assay allows for high-throughput genotyping following HR HPV testing by HC2.