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.

Post hoc analysis of the PATRICIA randomized trial of the efficacy of human papillomavirus type 16 (HPV-16)/HPV-18 AS04-adjuvanted vaccine against incident and persistent infection with nonvaccine oncogenic HPV types using an alternative multiplex type-specific PCR assay for HPV DNA.

The efficacy of the human papillomavirus type 16 (HPV-16)/HPV-18 AS04-adjuvanted vaccine against cervical infections with HPV in the Papilloma Trial against Cancer in Young Adults (PATRICIA) was evaluated using a combination of the broad-spectrum L1-based SPF10 PCR-DNA enzyme immunoassay (DEIA)/line probe assay (LiPA25) system with type-specific PCRs for HPV-16 and -18. Broad-spectrum PCR assays may underestimate the presence of HPV genotypes present at relatively low concentrations in multiple infections, due to competition between genotypes. Therefore, samples were retrospectively reanalyzed using a testing algorithm incorporating the SPF10 PCR-DEIA/LiPA25 plus a novel E6-based multiplex type-specific PCR and reverse hybridization assay (MPTS12 RHA), which permits detection of a panel of nine oncogenic HPV genotypes (types 16, 18, 31, 33, 35, 45, 52, 58, and 59). For the vaccine against HPV types 16 and 18, there was no major impact on estimates of vaccine efficacy (VE) for incident or 6-month or 12-month persistent infections when the MPTS12 RHA was included in the testing algorithm versus estimates with the protocol-specified algorithm. However, the alternative testing algorithm showed greater sensitivity than the protocol-specified algorithm for detection of some nonvaccine oncogenic HPV types. More cases were gained in the control group than in the vaccine group, leading to higher point estimates of VE for 6-month and 12-month persistent infections for the nonvaccine oncogenic types included in the MPTS12 RHA assay (types 31, 33, 35, 45, 52, 58, and 59). This post hoc analysis indicates that the per-protocol testing algorithm used in PATRICIA underestimated the VE against some nonvaccine oncogenic HPV types and that the choice of the HPV DNA testing methodology is important for the evaluation of VE in clinical trials. (This study has been registered at ClinicalTrials.gov under registration no. NCT00122681.).

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.

A human papilloma virus testing algorithm comprising a combination of the L1 broad-spectrum SPF10 PCR assay and a novel E6 high-risk multiplex type-specific genotyping PCR assay.

Human papillomavirus (HPV) epidemiological and vaccine studies require highly sensitive HPV detection and genotyping systems. To improve HPV detection by PCR, the broad-spectrum L1-based SPF10 PCR DNA enzyme immunoassay (DEIA) LiPA system and a novel E6-based multiplex type-specific system (MPTS123) that uses Luminex xMAP technology were combined into a new testing algorithm. To evaluate this algorithm, cervical swabs (n = 860) and cervical biopsy specimens (n = 355) were tested, with a focus on HPV types detected by the MPTS123 assay (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, 6, and 11). Among the HPV-positive samples, identifications of individual HPV genotypes were compared. When all MPTS123 targeted genotypes were considered together, good overall agreement was found (κ = 0.801, 95% confidence interval [CI], 0.784 to 0.818) with identification by SPF10 LiPA, but significantly more genotypes (P < 0.0001) were identified by the MPTS123 PCR Luminex assay, especially for HPV types 16, 35, 39, 45, 58, and 59. An alternative type-specific assay was evaluated that is based on detection of a limited number of HPV genotypes by type-specific PCR and a reverse hybridization assay (MPTS12 RHA). This assay showed results similar to those of the expanded MPTS123 Luminex assay. These results confirm the fact that broad-spectrum PCRs are hampered by type competition when multiple HPV genotypes are present in the same sample. Therefore, a testing algorithm combining the broad-spectrum PCR and a range of type-specific PCRs can offer a highly accurate method for the analysis of HPV infections and diminish the rate of false-negative results and may be particularly useful for epidemiological and vaccine studies.

Differences in human papillomavirus type distribution in high-grade cervical intraepithelial neoplasia and invasive cervical cancer in Europe.

Knowledge of differences in human papillomavirus (HPV)-type prevalence between high-grade cervical intraepithelial neoplasia (HG-CIN) and invasive cervical cancer (ICC) is crucial for understanding the natural history of HPV-infected cervical lesions and the potential impact of HPV vaccination on cervical cancer prevention. More than 6,000 women diagnosed with HG-CIN or ICC from 17 European countries were enrolled in two parallel cross-sectional studies (108288/108290). Centralised histopathology review and standardised HPV-DNA typing were applied to formalin-fixed paraffin-embedded cervical specimens dated 2001-2008. The pooled prevalence of individual HPV types was estimated using meta-analytic methods. A total of 3,103 women were diagnosed with HG-CIN and a total of 3,162 with ICC (median ages: 34 and 49 years, respectively), of which 98.5 and 91.8% were HPV-positive, respectively. The most common HPV types in women with HG-CIN were HPV16/33/31 (59.9/10.5/9.0%) and in ICC were HPV16/18/45 (63.3/15.2/5.3%). In squamous cell carcinomas, HPV16/18/33 were most frequent (66.2/10.8/5.3%), and in adenocarcinomas, HPV16/18/45 (54.2/40.4/8.3%). The prevalence of HPV16/18/45 was 1.1/3.5/2.5 times higher in ICC than in HG-CIN. The difference in age at diagnosis between CIN3 and squamous cervical cancer for HPV18 (9 years) was significantly less compared to HPV31/33/'other' (23/20/17 years), and for HPV45 (1 year) than HPV16/31/33/'other' (15/23/20/17 years). In Europe, HPV16 predominates in both HG-CIN and ICC, whereas HPV18/45 are associated with a low median age of ICC. HPV18/45 are more frequent in ICC than HG-CIN and associated with a high median age of HG-CIN, with a narrow age interval between HG-CIN and ICC detection. These findings support the need for primary prevention of HPV16/18/45-related cervical lesions.

E4 antibodies facilitate detection and type-assignment of active HPV infection in cervical disease.

High-risk human papillomavirus (HPV) infections are the cause of nearly all cases of cervical cancer. Although the detection of HPV DNA has proved useful in cervical diagnosis, it does not necessarily predict disease presence or severity, and cannot conclusively identify the causative type when multiple HPVs are present. Such limitations may be addressed using complementary approaches such as cytology, laser capture microscopy, and/or the use of infection biomarkers. One such infection biomarker is the HPV E4 protein, which is expressed at high level in cells that are supporting (or have supported) viral genome amplification. Its distribution in lesions has suggested a role in disease staging. Here we have examined whether type-specific E4 antibodies may also allow the identification and/or confirmation of causal HPV-type. To do this, type-specific polyclonal and monoclonal antibodies against three E4 proteins (HPV-16, -18, and -58) were generated and validated by ELISA and western blotting, and by immunohistochemistry (IHC) staining of epithelial rafts containing these individual HPV types. Type-specific detection of HPV and its associated disease was subsequently examined using formalin-fixed paraffin-embedded cervical intra-epithelial neoplasias (CIN, (n = 247)) and normal controls (n = 28). All koilocytotic CIN1 lesions showed type-specific E4 expression of their respective HPV types. Differences were noted amongst E4 expression patterns in CIN3. HPV-18 E4 was not detected in any of the 6 HPV-18 DNA-positive CIN3 lesions examined, whereas in HPV-16 and -58 CIN3, 28/37 (76%) and 5/9 (55.6%) expressed E4 respectively, usually in regions of epithelial differentiation. Our results demonstrate that type-specific E4 antibodies can be used to help establish causality, as may be required when multiple HPV types are detected. The unique characteristics of the E4 biomarker suggest a role in diagnosis and patient management particularly when used in combination.

One virus, one lesion--individual components of CIN lesions contain a specific HPV type.

In 20-40% of cervical intra-epithelial neoplasia (CIN) and in 4-8% of cervical carcinoma tissue specimens, multiple HPV genotypes have been detected. Whole tissue section (WTS) PCR does not determine how the individual types relate causally to complex and multiple CIN. Our objective was to determine whether laser capture micro-dissection (LCM) with HPV PCR genotyping (LCM-PCR) could accurately recover type-specific HPV DNA from epithelial cells in individual areas of CIN and normal epithelium, and whether one or more viruses are present in one lesion. For that, histologically selected samples of CIN and normal epithelium were isolated by LCM and analysed by the SPF(10) PCR/LiPA(25) (version 1) HPV genotyping system for 25 HPV genotypes. HPV genotypes detected in 756 areas of CIN (grade 1, 2 or 3) by LCM-PCR were compared with results obtained by WTS-PCR in 60 cases (74 biopsies). We showed that when a single HPV type is detected by WTS-PCR, that type was almost always (94%; 29/31) recovered by LCM-PCR from CIN. When multiple HPV types were present by WTS-PCR, their distribution within histological sections could be mapped by LCM-PCR. Association of a single HPV type with a discrete area of CIN was found for 93% (372/399) of LCM fragments analysed by PCR. We found colliding CIN lesions associated with separate HPV types and only 62% (61/99) of HPV types detected by WTS-PCR were found in CIN by LCM-PCR. Therefore, the LCM-PCR technique was found very accurate for high-resolution HPV genotyping and for assigning an individual HPV type to an area of CIN. At LCM level, in cervical biopsy sections with multiple HPV infections, the relation between HPV types and CIN lesions is often complex. Almost every HPV type found in CIN by LCM-PCR is associated with a biological separate independent CIN lesion-one virus, one lesion.

Detection and genotyping of human rotavirus VP4 and VP7 genes by reverse transcriptase PCR and reverse hybridization.

Rotavirus infections can be diagnosed in stool samples by serological and molecular methods. We developed a novel reverse transcriptase PCR (RT-PCR) method for the amplification of rotavirus RNA and a reverse hybridization assay on a strip to detect amplimers and identify the specific G and P genotypes present in human stool specimens. An additional aim was to permit specific identification of the rotavirus G1P[8] strain, used in the Rotarix vaccine. Novel broad-spectrum PCR primers were developed for both VP4 and VP7, permitting the amplification of a wide range of rotavirus genotypes. Primer sets comprise mixtures of defined primer sequences. For the identification of G and P genotypes, two reverse hybridization strip assays were developed. Both the VP4 and the VP7 strip contain universal probes for the detection of VP4 and VP7 sequences, irrespective of the G or P genotype. The VP4 strip contains type-specific probes for P[4], P[6], P[8], P[9], and P[10]. The VP7 strip contains type-specific probes for G1, G2, G3, G4, G5, G6, G8, and G9. In addition, probes to distinguish between wild-type G1 and G1 vaccine strain sequences were present. Testing by analysis of multiple reference strains confirmed that both RT-PCR methods allowed the detection of a broad spectrum of genotypes. RT-PCR for VP7 was more sensitive than RT-PCR for VP4, but all samples identified as positive for rotavirus antigen by an enzyme-linked immunosorbent assay (ELISA) were also positive for both VP4 and VP7. The high specificity of the reverse hybridization method was confirmed by sequence analysis as well as by type-specific PCR, and the vaccine strain could also be specifically identified. The reverse hybridization method permits accurate identification of mixed infections with different genotypes. Rotavirus genotypes for which no type-specific probes were present on the strip were adequately identified by the universal detection probes. The assay was formally validated by analyses of specificity, sensitivity, precision, accuracy, and robustness. In a panel of 149 ELISA-positive stool samples, comparison with conventional type-specific RT-PCR methods revealed the superiority of the novel method, mainly in cases of mixed rotavirus infections. This novel method permits highly accurate detection and identification of human rotavirus infections in stool samples. This validated assay could be useful for large-scale epidemiological and clinical trials.

Highly effective detection of human papillomavirus 16 and 18 DNA by a testing algorithm combining broad-spectrum and type-specific PCR.

The use of a single broad-spectrum human papillomavirus (HPV) DNA-based PCR test may fail to detect lower concentrations of HPV DNA due to competition between different genotypes in mixed infections. To improve HPV detection by PCR, broad-spectrum and type-specific (TS) PCRs were combined, with a focus on HPV-16 and HPV-18. Cervical and cervicovaginal cell samples were obtained from 1,113 healthy women (age range, 15 to 25 years) participating in an HPV-16/HPV-18 candidate vaccine efficacy trial. These samples were tested by a broad-spectrum SPF(10) PCR-DNA enzyme immunoassay, followed by a primer SPF(10)-based line probe assay (SPF(10) LiPA), and HPV-16- and HPV-18-TS PCRs. The results for the majority of the HPV-16/18 SPF(10) LiPA-positive samples were confirmed by TS-PCR (kappa values, 0.775 for HPV-16 and 0.785 for HPV-18). However, TS PCR revealed additional positive samples among those that contained other HPV genotypes due to competition. Conversely, SPF(10) LiPA identified HPV-16 or -18 in samples that remained negative by TS PCR as a result of sampling variation. Analysis of follow-up samples from more than 1,000 women confirmed that the combination of SPF(10)-LiPA with additional HPV-16- and HPV-18-TS PCR diminishes the rate of false-negative diagnosis. The combination of broad-spectrum and TS PCRs resulted in a novel testing algorithm. This combination of assays is more accurate than either method alone, and the novel algorithm offers a highly accurate and effective method for the analysis of HPV infections.

Enhanced humoral and memory B cellular immunity using HPV16/18 L1 VLP vaccine formulated with the MPL/aluminium salt combination (AS04) compared to aluminium salt only.

An effective virus-like particle (VLP) based prophylactic vaccine designed to protect against persistent infection with human papillomavirus (HPV) types 16 and 18 and subsequent lesion development will need to induce a strong humoral and cellular immune response capable of providing long-term protection. Our objective was to evaluate the ability of an HPV16/18 L1 VLP vaccine formulated with the AS04 adjuvant system (3-O-desacyl-4'-monophosphoryl lipid A (MPL) and aluminium salt) to induce an immune response of higher magnitude and persistence compared to a vaccine formulated with aluminium salt only. We demonstrated that MPL adsorbed onto aluminium salt retains its capacity to activate an innate immune response as assessed by the production of TNFalpha by human monocytes (U937). In addition, vaccination of mice, monkeys or human subjects with AS04 formulations induced higher total anti-L1 VLP16 and L1 VLP18 antibody responses (1.6-8.5-fold) than the aluminium salt only formulations. The enhanced antibody response induced by the AS04 vaccine formulation (1.6-4.1-fold) in monkeys and humans was shown to be targeted to functional neutralising L1 VLP16 and L1 VLP18 epitopes as assessed by V5/J4 specific ELISAs or HPV16 and HPV18 pseudo-neutralization assays. The enhanced immune profile observed with the AS04 formulation in terms of both total, V5/J4 specific and neutralizing antibodies was shown to persist for at least 3.5-year post-vaccination in human subjects. Finally, using the newly developed B cell ELISPOT assay we also demonstrated that the AS04 formulation elicited an increased frequency (2.2-5.2-fold) of HPV L1 VLP specific memory B cells when compared with the aluminium salt only formulations. These data strongly support the role of the AS04 adjuvant, which includes the immunostimulant MPL, in triggering a persistent vaccine-induced immune response of high quality.

Comparative pre-clinical and clinical experience with oral polio vaccine produced on MRC-5 cells or on primary monkey kidney cells.

The need to avoid using primates has prompted the replacement of primary monkey kidney cells (PMKC) as a substrate for oral polio vaccine (OPV) production. Here, we report on OPV produced on MRC-5 cells using an industrial process capable of producing over 1 billion doses. All serotypes produced on MRC-5 cells proved satisfactory in the monkey and transgenic mice neurovirulence tests. All the type 3 MRC-5 lots tested by Mutant Analysis by PCR and Restriction Enzyme Cleavage (MAPREC) had a 472-C content below the acceptable limit and similar to that of PMKC derived lots. The safety/reactogenicity and immunogenicity profiles following vaccination in infants and children were similar for OPV MRC-5 and OPV PMKC vaccine lots. Excretion rates and prevalence of revertants for the three serotypes following vaccination were also similar for both vaccines. These data support the use of MRC-5 cells as an alternative to PMKC for OPV production.

Genotyping of human papillomavirus in liquid cytology cervical specimens by the PGMY line blot assay and the SPF(10) line probe assay.

A comparison of two PCR-based human papillomavirus (HPV) DNA detection and genotyping systems (PGMY LBA and SPF(10) LiPA) was conducted in two laboratories. Both systems are based on broad-spectrum PCR for the detection of HPV DNA, followed by reverse hybridization with type-specific probes. A total of 400 selected cervical scrape specimens in PreservCyt solution (55% normal cytology, 18% atypical squamous cells of unknown significance, 14.8% low-grade squamous intraepithelial lesions [SIL], and 12.5% high-grade SIL) were tested for the presence of HPV DNA. In this selected group of specimens, the overall agreement between the two methods for the detection of any HPV DNA was high (kappa = 0.859). When the 20 common HPV genotypes identified by both methods were considered (HPV types 6, 11, 16, 18, 31, 33, 35, 39, 40, 42, 45, 51, 52, 53, 54, 56, 58, 59, 66, and 68), compatible genotype-specific results were observed in 96.5% of the samples, even when multiple HPV genotypes were present. However, for some specific HPV genotypes, there were significant differences in HPV detection by the two methods. PGMY LBA detected more HPV type 42 (P = 0.002), HPV type 56 (P = 0.039), and HPV type 59 (P < 0.001), whereas SPF(10) LiPA detected more HPV type 31 (P < 0.001) and HPV type 52 (P = 0.031). For the remaining genotypes, including HPV types 16 and 18, the results obtained by the two methods were not significantly different. In general, both genotyping methods are highly suitable for clinical and epidemiological studies.