Sex-Driven Differences in the Effectiveness of Individualized Clinical Management of Alzheimer's Disease Risk.

BACKGROUND: The Comparative Effectiveness Dementia and Alzheimer's Registry (CEDAR) trial demonstrated that individualized, multi-domain interventions improved cognition and reduced the risk of Alzheimer's disease (AD). As biological sex is a significant risk factor for AD, it is essential to explore the differential effectiveness of targeted clinical interventions in women vs. men. METHODS: Patients were recruited from an Alzheimer's Prevention Clinic. Subjects with normal cognition, subjective cognitive decline, or asymptomatic preclinical AD were classified as "Prevention". Subjects with mild cognitive impairment due to AD or mild AD were classified as "Early Treatment." The primary outcome was the change from baseline to 18-months on the modified-Alzheimer's Prevention Cognitive Composite. Secondary outcomes included a cognitive aging composite, AD and cardiovascular (CV) risk scales, and serum biomarkers. Subjects who adhered to > 60% of recommendations in the CEDAR trial were included in this a priori sub-group analysis to examine whether individualized intervention effects were modified by sex (n=80). RESULTS: In the Prevention group, both women (p=0.0205) and men (p=0.0044) demonstrated improvements in cognition with no sex differences (p=0.5244). In the Early Treatment group, there were also no significant sex differences in cognition (p=0.3299). In the Prevention group, women demonstrated greater improvements in the Multi-Ethnic Study of Atherosclerosis risk score (MESA-RS) than men (difference=1.5, p=0.0013). Women in the Early Treatment group demonstrated greater improvements in CV Risk Factors, Aging and Incidence of Dementia (CAIDE) risk score (difference=2.3, p=0.0067), and the MESA-RS (difference=4.1, p<0.001). CONCLUSIONS: Individualized multi-domain interventions are equally effective at improving cognition in women and men. However, personally-tailored interventions led to greater improvements in calculated AD and CV risk, and CV blood biomarkers, in women compared to men. Future study in larger cohorts is necessary to further define sex differences in AD risk reduction in clinical practice.

A prediction model of military combat and training exposures on VA service-connected disability: a CENC study.

Background: Research has shown that number of and blast-related Traumatic Brain Injuries (TBI) are associated with higher levels of service-connected disability (SCD) among US veterans. This study builds and tests a prediction model of SCD based on combat and training exposures experienced during active military service.Methods: Based on 492 US service member and veteran data collected at four Department of Veterans Affairs (VA) sites, traditional and Machine Learning algorithms were used to identify a best set of predictors and model type for predicting %SCD ≥50, the cut-point that allows for veteran access to 0% co-pay for VA health-care services.Results: The final model of predicting %SCD ≥50 in veterans revealed that the best blast/injury exposure-related predictors while deployed or non-deployed were: 1) number of controlled detonations experienced, 2) total number of blast exposures (including controlled and uncontrolled), and 3) the total number of uncontrolled blast and impact exposures.Conclusions and Relevance: We found that the highest blast/injury exposure predictor of %SCD ≥50 was number of controlled detonations, followed by total blasts, controlled or uncontrolled, and occurring in deployment or non-deployment settings. Further research confirming repetitive controlled blast exposure as a mechanism of chronic brain insult should be considered.

Comorbid TBI-depression costs in veterans: a chronic effect of neurotrauma consortium (CENC) study.

BACKGROUND: The U.S. Veterans Health Administration (VHA) provides depression treatment to veterans with Traumatic Brain Injury (TBI). VHA costs of comorbid TBI-depression were estimated by Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) status over 14 years. METHODS: VHA-USING veterans with TBI DIAGNOSED IN 2000-2010 were followed through FY2014. TBI severity was determined using the Department of Defense criteria. Depression was identified by the Elixhauser algorithm. Generalized linear and seemingly unrelated regression models were used to estimate the impact of depression on annual per veteran and total VHA inpatient, outpatient, and pharmaceutical costs, by OEF/OIF status. RESULTS: A total of 66.57% of pre-OEF/OIF and 87.46% of OEF/OIF veterans had depression. Depression was estimated to increase annual total ($1,847), outpatient ($1,558), and pharmaceutical ($287) costs for pre-OEF/OIF, and $1,228, $1,685, and $191 for OEF/OIF veterans. However, depression was estimated to lower annual inpatient costs by $648 per OEF/OIF veteran. The annual VHA cost for all veterans with comorbid TBI-depression was estimated at $1,101,329,953. CONCLUSIONS: The estimated annual cost for Veterans with comorbid TBI-depression was more than $1 billion. TBI and depression screening/treatment may result in reduced inpatient VHA costs in OEF/OIF veterans exposed to TBI. VHA policymakers should consider screening for TBI and depression in pre-OEF/OIF veterans.

Long-term protection in hamsters against human parainfluenza virus type 3 following mucosal or combinations of mucosal and systemic immunizations with chimeric alphavirus-based replicon particles.

No licensed vaccines are available to protect against parainfluenza virus type 3 (PIV3), a significant health risk for infants. In search of a safe vaccine, we used an alphavirus-based chimeric vector, consisting of Sindbis virus (SIN) structural proteins and Venezuelan equine encephalitis virus (VEE) replicon RNA, expressing the PIV3 hemagglutinin-neuraminidase (HN) glycoprotein (VEE/SIN-HN). We compared different routes of intramuscular (i.m.), intranasal (i.n.), or combined i.n. and i.m. immunizations with VEE/SIN-HN in hamsters. Six months after the final immunization, all hamsters were protected against live PIV3 i.n. challenge in nasal turbinates and lungs. This protection appeared to correlate with antibodies in serum, nasal turbinates and lungs. This is the first report demonstrating mucosal protection against PIV3 for an extended time following immunizations with an RNA replicon delivery system.

Infection of human dendritic cells by a sindbis virus replicon vector is determined by a single amino acid substitution in the E2 glycoprotein.

The ability to target antigen-presenting cells with vectors encoding desired antigens holds the promise of potent prophylactic and therapeutic vaccines for infectious diseases and cancer. Toward this goal, we derived variants of the prototype alphavirus, Sindbis virus (SIN), with differential abilities to infect human dendritic cells. Cloning and sequencing of the SIN variant genomes revealed that the genetic determinant for human dendritic cell (DC) tropism mapped to a single amino acid substitution at residue 160 of the envelope glycoprotein E2. Packaging of SIN replicon vectors with the E2 glycoprotein from a DC-tropic variant conferred a similar ability to efficiently infect immature human DC, whereupon those DC were observed to undergo rapid activation and maturation. The SIN replicon particles infected skin-resident mouse DC in vivo, which subsequently migrated to the draining lymph nodes and upregulated cell surface expression of major histocompatibility complex and costimulatory molecules. Furthermore, SIN replicon particles encoding human immunodeficiency virus type 1 p55(Gag) elicited robust Gag-specific T-cell responses in vitro and in vivo, demonstrating that infected DC maintained their ability to process and present replicon-encoded antigen. Interestingly, human and mouse DC were differentially infected by selected SIN variants, suggesting differences in receptor expression between human and murine DC. Taken together, these data illustrate the tremendous potential of using a directed approach in generating alphavirus vaccine vectors that target and activate antigen-presenting cells, resulting in robust antigen-specific immune responses.

Increased expression and immunogenicity of sequence-modified human immunodeficiency virus type 1 gag gene.

A major challenge for the next generation of human immunodeficiency virus (HIV) vaccines is the induction of potent, broad, and durable cellular immune responses. The structural protein Gag is highly conserved among the HIV type 1 (HIV-1) gene products and is believed to be an important target for the host cell-mediated immune control of the virus during natural infection. Expression of Gag proteins for vaccines has been hampered by the fact that its expression is dependent on the HIV Rev protein and the Rev-responsive element, the latter located on the env transcript. Moreover, the HIV genome employs suboptimal codon usage, which further contributes to the low expression efficiency of viral proteins. In order to achieve high-level Rev-independent expression of the Gag protein, the sequences encoding HIV-1(SF2) p55(Gag) were modified extensively. First, the viral codons were changed to conform to the codon usage of highly expressed human genes, and second, the residual inhibitory sequences were removed. The resulting modified gag gene showed increases in p55(Gag) protein expression to levels that ranged from 322- to 966-fold greater than that for the native gene after transient expression of 293 cells. Additional constructs that contained the modified gag in combination with modified protease coding sequences were made, and these showed high-level Rev-independent expression of p55(Gag) and its cleavage products. Density gradient analysis and electron microscopy further demonstrated that the modified gag and gag protease genes efficiently expressed particles with the density and morphology expected for HIV virus-like particles. Mice immunized with DNA plasmids containing the modified gag showed Gag-specific antibody and CD8(+) cytotoxic T-lymphocyte (CTL) responses that were inducible at doses of input DNA 100-fold lower than those associated with plasmids containing the native gag gene. Most importantly, four of four rhesus monkeys that received two or three immunizations with modified gag plasmid DNA demonstrated substantial Gag-specific CTL responses. These results highlight the useful application of modified gag expression cassettes for increasing the potency of DNA and other gene delivery vaccine approaches against HIV.

The comparison of the effect of LTR72 and MF59 adjuvants on mouse humoral response to intranasal immunisation with human papillomavirus type 6b (HPV-6b) virus-like particles.

Infections with genital human papillomaviruses (HPV) are likely to be neutralised more efficiently if a mucosal immune response can be elicited at the viral entry site. Local IgA antibodies are highly induced when antigens are co-administered with mucosal adjuvants, such as cholera toxin (CT) and Escherichia coli heat labile enterotoxin (LT) which, however, are not expected to have wide application because of their pronounced toxicity. We have immunised mice intranasally with HPV-6b virus-like particles (VLPs) and a genetically modified LT-derived molecule with only residual toxicity, LTR72, and compared the humoral responses with those obtained following systemic immunisation with VLPs and the MF59 adjuvant. Titration of anti-HPV antibodies in sera and vaginal secretions established that LTR72 was able to elicit higher serum and mucosal IgA titers, in addition to IgG serum levels, comparable to those obtained by parenteral immunisation. These results confirm the potential of toxin-derived adjuvants and extend their use in combination with HPV antigens.

Seroreactivity to human papillomavirus types 16, 18, 31, and 45 virus-like particles in a case-control study of cervical squamous intraepithelial lesions.

Serum IgG antibodies to human papillomavirus (HPV) types 16, 18, 31, and 45 virus-like particles were measured in a nested case-control study of cervical squamous intraepithelial lesions. HPV-16 seroreactivity was strongly associated with HPV-16 DNA detection (odds ratio, 9.0; 95% confidence interval, 4.4-19.4), and similar type specificity was observed for HPV-31 and -45. In contrast, seroreactivity to any type was associated with elevated seroreactivity to all others. Among cases and controls, HPV-16 showed the highest seroprevalence, with 23.8% of 80 cases and 10.5% of 258 controls seroreactive to HPV-16 alone, and another 27.5% and 5.4%, respectively, seroreactive to HPV-16 plus other types. Overall, 24 (30.0%) cases and 17 (6.6%) controls were seroreactive to multiple types. These data suggest that seroreactivity to a given type reflects mainly type-specific HPV infection as measured by DNA detection and may also signal past exposure to other types that are now only serologically detected.

Detection of human papillomavirus DNA in cytologically normal women and subsequent cervical squamous intraepithelial lesions.

BACKGROUND: Human papillomavirus (HPV) infection has been strongly associated with cervical carcinoma and its cytologic precursors, squamous intraepithelial lesions (SIL). We investigated the risk of SIL prospectively following polymerase chain reaction (PCR)-based DNA testing for a wide range of genital HPV types in a cohort of initially cytologically normal women, to clarify the role of HPV in the etiology of SIL. METHODS: Starting in April 1989, 17,654 women who were receiving routine cytologic screening at Kaiser Permanente (Portland, OR) were followed for the development of incident SIL. During follow-up, 380 incident case patients and 1037 matched control subjects were eligible for this nested case-control study. Cervical lavages collected at enrollment and, later, at the time of case diagnosis (or the corresponding time for selection of control subjects) were tested for HPV DNA using a PCR-based method. The data were analyzed as contingency tables with two-sided P values or, for multivariable analyses, using odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: In comparison with initially HPV-negative women, women who tested positive for HPV DNA at enrollment were 3.8 times (95% CI = 2.6-5.5) more likely to have low-grade SIL subsequently diagnosed for the first time during follow-up and 12.7 times more likely (95% CI = 6.2-25.9) to develop high-grade SIL. At the time of diagnosis, the cross-sectional association of HPV DNA and SIL was extremely strong (OR = 44.4 and 95% CI = 24.2-81.5 for low-grade SIL and OR = 67.1 and 95% CI = 19.3-233.7 for high-grade SIL). HPV16 was the virus type most predictive of SIL, even low-grade SIL. CONCLUSIONS: These findings are consistent with the hypothesis that HPV infection is the primary cause of cervical neoplasia. Furthermore, they support HPV vaccine research to prevent cervical cancer and efforts to develop HPV DNA diagnostic tests.

A nested case-control study of dietary factors and the risk of incident cytological abnormalities of the cervix.

Several earlier case-control studies reported inverse associations of cervical squamous intraepithelial lesions (SIL) with high dietary or biomarker levels of carotenoids, folate, and vitamins C and E. However, most studies did not measure the primary causal factor, cancer-associated genital human papillomaviruses (HPV), now detected by sensitive viral DNA tests. This nested case-control study assessed whether high dietary intakes of these nutrients, plus zinc and vitamin A, reduced SIL risk in cancer-associated HPV DNA-positive women. Using a 60-item food-frequency questionnaire, nutrient estimates were obtained for 33 incident cases with high-grade lesions, 121 with low-grade lesions, 97 with equivocal SIL, and 806 cytologically normal controls sampled from a large prospective cohort study. Baseline cervicovaginal lavages were tested for HPV DNA by the polymerase chain reaction. Among DNA-positive cases (n = 68) and controls (n = 69), age-adjusted odds ratios (ORs) of SIL in the highest vs. the lowest nutrient quartiles were 1.4 [95% confidence interval (CI) = 0.5-4.2] for vitamin A, 0.6 (CI = 0.2-2.0) for beta-carotene, 1.3 (CI = 0.4-3.6) for vitamin C, 1.0 (CI = 0.4-3.6) for vitamin E, 0.7 (CI = 0.3-2.1) for folate, and 0.8 (CI = 0.3-2.2) for zinc. ORs in HPV DNA-negative women approximated 1.0, with the exception of vitamin E (OR = 0.5, CI = 0.3-0.9). These results do not support a protective role for the above nutrients against low-grade or equivocal SIL, which constituted the majority of diagnoses in this study.

Isolation and characterization of human papillomavirus type 6-specific T cells infiltrating genital warts.

The potential role of T cells in the control of human papillomavirus type 6 (HPV-6) infections is an appealing premise, but their actual role has been sparsely investigated. Since HPV-6 infections are confined to the epithelium, such an investigation should focus on the T cells present at the site of infection (i.e., the warts). Therefore, we isolated wart-infiltrating lymphocytes (WIL) from patients with clinically diagnosed anogenital warts. These WIL were characterized by their phenotype and their specificity for E7 and L1 proteins of HPV-6. The phenotype of WIL varied drastically from patient to patient, as determined by their expression of CD4, CD8, T-cell receptor alpha/beta chain (TCR alpha beta), and TCR gamma delta. Despite this heterogeneity in phenotype, HPV-6 E7 and/or L1-specific WIL, as determined by lymphoproliferation, could be isolated from more than 75% of the patients studied. Among all L1 peptides recognized by WIL, peptides 311-330 and 411-430 were the most consistently detected, with seven of nine patients for whom L1 peptide reactivity was observed responding to at least one of them. Moreover, the HPV-6 epitopic peptides recognized by WIL differed to some extent from those recognized by peripheral T cells.

Human papillomavirus type 16 sequence variation in cervical cancers: a worldwide perspective.

We examined intratype human papillomavirus type 16 (HPV-16) sequence variation in tumor samples that were collected and analyzed in an international study of invasive cervical cancer. The collection included tumors from 22 countries in five continents. Using our recently developed E6 and L1 PCR-based hybridization systems to distinguish HPV-16 variant lineages, we analyzed material from tumors previously found to contain HPV-16 DNA. Of 408 specimens analyzed in the E6 hybridization assay, 376 (92.2%) belonged to previously reported HPV-16 variant lineages. The remaining 32 specimens (7.8%) harbored HPV-16 variants with novel hybridization patterns, novel nucleotide changes, or both. Nucleotide sequences (1,203 bp) were determined for the E6, the MY09/11 region of L1, and the long control region of each novel variant and representative specimens from each hybridization pattern observed. Based on E6 hybridization patterns, most of the variants from European and North American samples were phylogenetically classified as European prototype (E) while samples from Africa contained primarily African 1 (Af1) or African 2 (Af2) variants. The majority of Asian (As) variants were observed in Southeast Asia, and almost all Asian American (AA) variants were from Central and South America or Spain. A single North American 1 (NA1) variant was detected in a tumor from Argentina. Nucleotide changes previously shown to covary between the MY09/11 region of L1 and the E6 coding region were examined in a subset of 249 specimens. We observed 22 combined E6-L1 hybridization patterns, of which 11 (in 21 samples) were novel. No unanticipated nucleotide covariation was observed between the E class and the AA-Af1-Af2-NA1 classes, suggesting the absence or rarity of genomic recombination between HPV-16 lineages. This extensive description of HPV-16 variants forms a basis for further examining the relationship between intratype variation and basic functional differences in biological activities. HPV-16 variants may prove important for the determination of the risk of cervical neoplasia and for the design of HPV-16 vaccine strategies.

Epidemiologic determinants of seroreactivity to human papillomavirus (HPV) type 16 virus-like particles in cervical HPV-16 DNA-positive and-negative women.

The epidemiologic determinants of seroreactivity to human papillomavirus (HPV) type 16 L1/L2 virus-like particles (VLPs) were assessed separately in HPV-16 DNA-positive and -negative women participating in a nested case-control study of incident cervical neoplasia. Seventy-four women with cervical HPV-16 DNA and 656 cytologically normal HPV-16 DNA-negative subjects were interviewed and tested at two time points for viral DNA and once (at the later time) for VLP seroreactivity. Among subjects who were currently HPV-16 DNA-negative, seroreactivity odds ratios increased from 2.9 for 2-5 male sex partners (vs. 0 or 1) to 5.4 for 6-9 partners and 14.0 for > or = 10. Thus, prior cervical infection may be a major determinant of seroreactivity in HPV-16 DNA-negative women. This trend was not observed in HPV-16 DNA-positive subjects. Seroreactivity was independently associated with oral contraceptive use, particularly in HPV-16 DNA-negative subjects with use for > or = 10 years. Consequently, a possible role for virus-steroid hormone interactions in seroconversion is suggested.

Short-term fluctuations in the detection of cervical human papillomavirus DNA.

OBJECTIVE: To obtain point and cumulative prevalence estimates of cervical human papillomavirus (HPV) infection using two HPV DNA detection methods with different end point sensitivities; compare cervical swab and cervicovaginal lavage specimen collection methods for subsequent evaluation by polymerase chain reaction (PCR); and evaluate potential effects of the menstrual cycle on HPV DNA detection. METHODS: Seventy-two college women participated in a 10-week follow-up study. Cervical samples were obtained for HPV DNA detection and typing at each clinic visit, and information was collected concerning menstrual cycle and sexual and hygienic behaviors. Human papillomavirus DNA was detected by the ViraPap HPV DNA dot-blot assay and a broad-spectrum PCR HPV DNA amplification system. RESULTS: On a weekly basis, point prevalence for HPV infection by the ViraPap assay ranged from 4.2 to 9.7%, and the cumulative prevalence was 13.9%. Point prevalence by the broad-spectrum PCR assay ranged from 20.8 to 47.2%, and the cumulative HPV prevalence was 58.3%. Using cervicovaginal lavage specimens, we found lower cervical HPV prevalence estimates when compared with cervical swab specimens in the HPV PCR-based assay. No correlation between HPV DNA detection and phase of menstrual cycle was observed. CONCLUSION: Short-term HPV DNA detection is highly variable within individuals; therefore, single-point measurements of cervical HPV have limitations when assessing an individual's HPV status. The relationship between short-term and long-term HPV DNA persistence profiles may prove relevant to determining the risk of developing cervical intraepithelial neoplasia.

Evaluation of seroreactivity to human papillomavirus type 16 virus-like particles in an incident case-control study of cervical neoplasia.

An ELISA to detect serum IgG antibody response to human papillomavirus (HPV) type 16 virus-like particles (VLPs) was evaluated in a case-control study of cervical neoplasia, nested within a prospective cohort study. Subjects included 688 controls with continued normal cytology and 152 cases with confirmed incident squamous intraepithelial lesions who were tested for DNA for a broad spectrum of HPV types at cohort and follow-up of controls, 16.6% were seropositive compared with 30.8% and 52.4% of cases with low- and high-grade lesions, respectively. Of HPV-16 DNA-negative subjects, 16.5% were seropositive. Seropositivity increased from 22.2% in subjects who were HPV-16 DNA-positive by polymerase chain reaction once only (enrollment or follow-up) to 83.3% in those who were HPV-16 DNA-positive at both time points. These data imply that serum antibody to HPV-16 VLPs is a relatively sensitive indicator of persisting cervical HPV-16 infection.

Human papillomavirus and cervical neoplasia: a case-control study in Taiwan.

As part of a large-scale, community-based cervical neoplasia screening project in rural Taiwan, a case-control study was undertaken to evaluate the etiologic role of human papillomavirus (HPV) infection in this mainly monogamous (2% reported having multiple sexual partners) female population. A total of 88 biopsy-confirmed cases and 261 cytologically normal controls were selected for the study. The case group included 40 cases of cervical intraepithelial neoplasia (CIN) 1, 9 of CIN 2, 36 of CIN 3 and 3 cases of invasive cancer. Cervical swabs collected at screening from study subjects were tested for HPV DNA by an LI consensus primer polymerase chain reaction (PCR)-based technique. HPV DNA was found in 92% of high-grade cases (CIN 2-3 and invasive cancer); 54% of low-grade cases (CIN 1); and 9% of controls. HPV was significantly associated with both high-grade and low-grade cervical neoplasia. As reported in Western countries, HPV 16 was the predominant type among HPV-positive high-grade cases. However, HPVs 52 and/or 58 combined were the most common types among HPV-positive low-grade cases and controls. Among women without any high-risk HPV infection (types 16, 18, 31 or 45), those with multiple-type HPV infection had a higher risk for high-grade cervical neoplasia than those with single-type infection. Overall, 91% of high-grade cases and 50% of low-grade cases could be attributed to HPV infection. Our results show that, even in this monogamous population, HPV is the major risk factor for high-grade cervical neoplasia.

Human papillomavirus (HPV) type distribution and serological response to HPV type 6 virus-like particles in patients with genital warts.

Thirty-nine patients with condylomas (12 women and 27 men) attending a dermatology clinic were tested for genital human papillomavirus (HPV) DNA and for seroprevalence to HPV type 6 (HPV6) L1 virus-like particles. The L1 consensus PCR system (with primers MY09 and MY11) was used to determine the presence and types of HPV in sample specimens. All 37 (100%) patients with sufficient DNA specimens were positive for HPV DNA, and 35 (94%) had HPV6 DNA detected at the wart site. Three patients (8%) had HPV11 detected at the wart site, and one patient had both HPV6 and -11 detected at the wart site. Thirteen additional HPV types were detected among the patients; the most frequent were HPV54 (8%) and HPV58 (8%). Baculovirus-expressed HPV6 L1 virus-like particles were used in enzyme-linked immunosorbent assays to determine seroprevalence among the patients with warts. Seronegativity was defined by a control group of 21 women who were consistently PCR negative for HPV DNA. Seroprevalence was also determined for reference groups that included cytologically normal women who had detectable DNA from either HPV6 or HPV16 and women with HPV16-associated cervical intraepithelial neoplasia. Among the asymptomatic women with HPV6, only 2 of 9 (22%) were seropositive, compared with 12 of 12 (100%) female patients with warts. A similar trend in increased HPV6 seropositivity with increased grade of disease was found with the HPV16 DNA-positive women, whose seroprevalence increased from 1 in 11 (9%) in cytologically normal women to 6 in 15 (40%) among women with cervical intraepithelial neoplasia 1 or 3. However, only 4 of 25 (16%) male patients were seropositive. No factors examined, such as age, sexual behavior, or a history of warts, were found to definitively account for the gender difference in seroresponse.

Epidemiology and partial nucleotide sequence of four novel genital human papillomaviruses.

Polymerase chain reaction (PCR)-based genital human papillomavirus (HPV) detection methods that use consensus primers have enabled the broad-spectrum detection of most characterized HPV types. In addition, these techniques have allowed the identification of potentially novel viral sequences in clinical specimens. These methods were used to determine the partial L1 nucleotide sequence (the region generated by L1 consensus primers MY09 and MY11) of four novel viruses. The prevalence of these viruses in cytologically normal and dysplastic cervical specimens and in invasive cervical cancer was also determined. The partial DNA sequences of W13B (MM4), PAP291 (MM7), PAP155 (MM8), and PAP238a (MM9) are most similar to HPV-51, -61, -61, and -34, respectively. Prevalence studies suggest that W13B and PAP238a are cancer-associated, while PAP155 and PAP291 appear to be lower-risk viruses.