HPV-specific T-cell Responses Research Articles

Safety and Efficacy of MEDI0457 plus Durvalumab in Patients with Human Papillomavirus-Associated Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma.

Tumoral programmed cell death ligand-1 (PD-L1) expression is common in human papillomavirus (HPV)-associated head and neck squamous cell carcinoma (HNSCC). We assessed whether a DNA vaccine targeting HPV-16/18 E6/E7 with IL12 adjuvant (MEDI0457) combined with the PD-L1 inhibitor durvalumab could enhance HPV-specific T-cell response and improve outcomes in recurrent/metastatic HPV-16/18-associated HNSCC. In this phase Ib/IIa study, immunotherapy-naïve patients with ≥1 previous platinum-containing regimen (neoadjuvant/adjuvant therapy or for recurrent/metastatic disease) received MEDI0457 7 mg intramuscularly with electroporation on weeks 1, 3, 7, and 12, then every 8 weeks, plus durvalumab 1,500 mg intravenously on weeks 4, 8, and 12, then every 4 weeks, until confirmed progression and/or unacceptable toxicity. Coprimary objectives were safety and objective response rate (ORR; H0: ORR ≤ 15%); secondary objectives included 16-week disease control rate (DCR-16), overall survival (OS), and progression-free survival (PFS). Of 35 treated patients, 29 were response evaluable (confirmed HPV-associated disease; received both agents). ORR was 27.6% [95% confidence interval (CI), 12.7-47.2; four complete responses, four partial responses]; responses were independent of PD-L1 tumor-cell expression (≥25% vs. <25%). DCR-16 was 44.8% (95% CI, 26.5-64.3). Median PFS was 3.5 months (95% CI, 1.9-9.0); median OS was 29.2 months (15.2-not calculable). Twenty-eight (80.0%) patients had treatment-related adverse events [grade 3: 5 (14.3%); no grade 4/5], resulting in discontinuation in 2 (5.7%) patients. HPV-16/18-specific T cells increased on treatment; 4 of 8 evaluable patients had a >2-fold increase in tumor-infiltrating CD8+ T cells. MEDI0457 plus durvalumab was well tolerated. While the primary efficacy endpoint was not reached, clinical benefit was encouraging.

LBA32 Efficacy and safety of GX-188E, a therapeutic DNA vaccine, combined with pembrolizumab in HPV 16- and/or 18- positive advanced cervical cancer (phase II): Safe and effective in both PD-L1 positive and negative

GX-188E (tirvalimogene teraplasmid) is a therapeutic DNA vaccine that encodes HPV-16 and HPV-18 E6 and E7 and induces HPV-specific T-cell responses. Pembrolizumab was approved for the treatment of advanced cervical cancer, based on an objective response rate (ORR) of 14.3% in patients with PD-L1 positive (CPS≥1). However, patients who were PD-L1 negative (CPS<1) showed no response to treatment with pembrolizumab. We aimed to investigate whether a combination of GX-188E plus pembrolizumab showed antitumor activity against advanced cervical cancer regardless of PD-L1 expression. In this open-label, single-arm, phase 2 trial, patients with HPV-16 or HPV-18 positive advanced cervical cancer, and who had progressed after standard-of-care therapy were recruited in South Korea. Patients received intramuscular 2 mg GX-188E at weeks 1, 2, 4, 7, 13, 19 and optional dose at week 46, and intravenous pembrolizumab 200 mg every 3 weeks for up to 2 years or until disease progression. The primary endpoint was ORR assessed by the blinded independent central reviewers (BICR) using RECIST v1.1. A total of 65 patients have been enrolled and 60 patients were analyzed as efficacy population based on having at least one post-baseline tumor assessment. Among 60 patients, 36 patients had PD-L1 positive tumors and 24 patients were PD-L1 negative. According to BICR evaluation, 19 of 60 patients (31.7%) achieved best overall response; 6 patients had a complete response and 13 patients had a partial response. Especially, in PD-L1 negative population with 24 patients, this combination treatment showed significant efficacy (25.0% ORR). Median DOR was 12.3 months and median OS was 17.2 months. 22 of 65 patients (33.8%) had treatment-related adverse events (TRAEs) of any grade with three patients (4.6%) presenting with grade 3 or 4 TRAEs. GX-188E vaccine combined with pembrolizumab in advanced cervical cancer was safe and tolerable, and showed significant efficacy compared with pembrolizumab alone particularly in patients with PD-L1 negative. This combination therapy could represent a new potential treatment for this patient population.

Impaired HPV-specific T-cell response in juvenile-onset recurrent respiratory papillomatosis patients

Immunologic dysfunction is one of the most important mechanisms underlying the initiation and development of JORRP. The study aimed to explore whether HPV-specific T-cell response was impaired in JORRP patients. We found JORRP patients had a Th2-biased cytokine profile correlated with disease severity in peripheral system. JORRP patients had an increased memory T cells and a reduced naive T cells in circulation. Upon HPV6/11 antigens stimulation, T cells from JORRP patients exhibited a greater activation profile. Of note, JORRP patients presented with a greater number of IL-10- and IL-4-secreting HPV6/11 antigen responding cells than that of IFN-γ and TNF-α secreting responders. Furthermore, in response to HPV6/11 antigen stimulation, JORRP patients showed a reduced level of cell proliferation, an increased level of apoptosis and higher percentage of the differentiated T cells expressing the replicative senescent cell marker CD57. Impaired HPV-specific T-cell responses could be partly responsible for JORRP development.

HPV-16 E6/E7 DNA tattoo vaccination using genetically optimized vaccines elicit clinical and immunological responses in patients with usual vulvar intraepithelial neoplasia (uVIN): a phase I/II clinical trial

BackgroundUsual vulvar intraepithelial neoplasia (uVIN) is a premalignancy caused by persistent infection with high-risk types of human papillomavirus (HPV), mainly type 16. Even though different treatment modalities are available (eg,...

1903P - Myeloid derived suppressor cells but not regulatory T cells are associated with adaptive immunity and clinical outcomes in anal squamous cell carcinoma

BackgroundAnal squamous cell carcinoma (SCCA) is associated with E6 and E7 oncoproteins encoded by human papillomavirus (HPV) 16. Addition of Docetaxel to 5-Fluorouracil plus Cisplatin (DCF) induces favorable disease control and complete remission rate in recent clinical trials. Taking this observation into account, we decided to analyze the impact of DCF chemotherapy on adaptive immunity and immunosuppressive cells in SCCA. MethodsPeripheral blood mononuclear cells from healthy donors and SCCA patients included in Epitopes-HPV01 and 02 studies were analyzed. The presence of T-cell responses after short term T-cell stimulation against HPV16-E6/E7 and TERT-antigens was measured by IFNγ-ELISpot. Immune checkpoint expression and immunosuppressive cells were monitored by flow cytometry. ResultsWe first observed an enhanced HPV-specific T-cell response following DCF chemotherapy. Our investigations also suggest that TERT might be a relevant antigen in HPV-driven cancers. TERT-restricted CD4 Th1 were correlated to E6 responses and also enhanced following DCF treatment of SCCA patients. The distribution of T-cell exhaustion markers on peripheral T lymphocytes unraveled a drop of CD226 expression and the emergence of CD226-TIGIT+ T-cell subset. Monocytic-myeloid-derived-suppressor cells (M-MDSC) and regulatory T-cell (Treg) rates were increased. Treg levels and T-cell exhaustion markers did not influence clinical outcomes and frequencies of specific immune responses. M-MDSC levels monitored after DCF chemotherapy were correlated with progression free survival and antigen-specific T-cell response intensity and diversity. ConclusionsDCF chemotherapy did not impair antigen-specific T-cell responses, supporting the potential interest to combine DCF chemotherapy with immunotherapies. Moreover, our study identifies post-therapy M-MDSC as a prognostic factor in SCCA patients. Clinical trial identificationEpitopes-HPV01: NCT01845779 Epitopes-HPV02: NCT02402842. Legal entity responsible for the studyUniversity Hospital of Besançon. FundingBesancon University Hospital, Ligue Contre le cancer Grand-Est and Association Nationale de la Recherche et de la Technologie. DisclosureAll authors have declared no conflicts of interest.

Abstract CT002: A strong HPV-specific T-cell response after chemo-immunotherapy for advanced cervical cancer is associated with prolonged survival

Abstract The therapeutic synthetic long peptide (SLP) vaccine ISA101 selectively enlarges the pool of tumor-specific T cells recognizing the human papillomavirus type 16 (HPV16) antigens E6 and E7. Vaccine monotherapy for HPV16-induced pre-malignant anogenital lesions is effective, inducing durable complete regressions in approximately 50% of treated patients. However, cancer treatment requires appropriate countermeasures to overcome the suppression of T-cell activation, expansion and effector function imposed by suppressive myeloid cell populations, regulatory T cells and co-inhibitory molecule expression. We recently showed that carboplatin/paclitaxel chemotherapy can normalize the abnormally high levels of immune suppressive myeloid cells, allowing the development of much stronger therapeutic ISA101-induced tumor immunity1. Here we show the effects of ISA101 vaccination during chemotherapy in 77 patients with advanced, recurrent or metastatic cervical cancer in a dose assessment study. Study design involved a single arm dose escalation study with four different ISA101 doses (20, 40, 100 and 300 µg per peptide) with or without immunomodulator pegylated interferon alpha (Pegitron), given concomitantly with standard of care chemotherapy (carboplatin, AUC 6; paclitaxel, 175 mg/m2). Objective regressions were observed in 43% of 72 evaluable patients. The depletion of myeloid suppressive cells by carboplatin/paclitaxel was associated with detection of low level spontaneous HPV16-specific immunity in 26 of the 61 tested patients. Patients mounted type 1 T-cell responses to the vaccine across all doses. No significant differences were observed between the different doses and strength of vaccine-induced T cell responses; the results were therefore combined. Patients with an above median HPV16-specific T cell immune response to ISA101, measured by a validated IFNγ-Elispot, displayed a significantly prolonged median overall survival (OS) of 16.8 months compared to those with a lower HPV-specific immune response (OS 11.2 months, logrank p=0.012). Importantly, this effect was not due to differences in general immune status, as measured by T-cell reactivity to unrelated common microbial recall antigens. In conclusion, our study demonstrates that chemo-immunotherapy can be exploited to the benefit of patients with cervical cancer and warrants confirmation of the benefit of this type of chemo-immunotherapy in a randomized controlled study in HPV16-induced cancer patients. 1Welters, M. J. et al. Vaccination during myeloid cell depletion by cancer chemotherapy fosters robust T cell responses. Sci Transl Med 8, 334ra352, doi:10.1126/scitranslmed.aad8307 (2016). Citation Format: Cornelis J M Melief, Marij J. Welters, Ignace Vergote, Judith R. Kroep, Gemma G. Kenter, Nelleke Ottevanger, Wiebren A. Tjalma, Hannelore Denys, Mariette van Poelgeest, Hans W. Nijman, Anna K. Reyners, Thierry Velu, Frederic Goffin, Roy Lalisang, Willem-Jan Krebber, Leon Hooftman, Sonja Visscher, Brent A. Blumenstein, Richard B. Stead, Winald Gerritsen, Sjoerd van der Burg. A strong HPV-specific T-cell response after chemo-immunotherapy for advanced cervical cancer is associated with prolonged survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT002.

Prediction the clinical outcomes of cancer patients after peptide vaccination.

e14295 Background: Neoantigen vaccines can activate T-cells that specifically kill tumor cells. However, most vaccine peptides, selected either as HLA-binders or as HLA-presented epitopes, do not induce T-cell responses in HLA allele-matched individuals. We hypothesized that personal-epitopes (PEPIs) binding to multiple autologous HLA-alleles induce potent T-cell responses. Methods: Epitopes binding to single HLA and PEPIs binding to 3 autologous HLA-alleles were identified with our novel and validated PEPI Test (CE Marked) and correlated with CD8+ and CD4+ T-cell responses of (pre)malignant patients vaccinated with Synthetic Long Peptides (SLPs) in 2 clinical trials. A Model Population of 433 HLA-genotyped individuals was used to determine the percentage of subjects with PEPIs from SLPs (PEPI-Score). As a proof of principle, a personal vaccine was developed matching with 14 HLA-alleles of a cancer patient with PEPIs from 12 tumor-antigens. T-cell reactivities were tested by interferon-γ ELISPOT. Results: There was no correlation between single HLA-binding epitopes and HPV-specific T-cell responses of patients. In contrast, there was 90% and 69% agreement between HLA-class-I PEPIs and CD8+ T-cell responses (p &lt; 0.001) and HLA-class-II PEPIs and CD4+ T-cell responses (p = 0.005), respectively. PEPI-Score predicted the T-cell response rate of SLP vaccine clinical trials. As predicted by the PEPI Test, personal vaccine treatment activated tumor-specific T-cells: 91% and 100% of the vaccine peptides elicited CD8+ and CD4+ T-cell responses, respectively. Conclusions: A patient’s HLA genotype is a major determinant of vaccine responses and PEPIs are genetic biomarkers of T-cell responses. PEPI Test prediction of vaccine responses can be utilized by clinicians for selecting the vaccine treatment and for the development of highly immunogenic personal vaccines matched to a patient’s complete HLA genotype (NCT03391232).

Intratumoral HPV16-Specific T Cells Constitute a Type I-Oriented Tumor Microenvironment to Improve Survival in HPV16-Driven Oropharyngeal Cancer.

Purpose: Human papillomavirus (HPV)-associated oropharyngeal squamous cell cancer (OPSCC) has a much better prognosis than HPV-negative OPSCC, and this is linked to dense tumor immune infiltration. As the viral antigens may trigger potent immunity, we studied the relationship between the presence of intratumoral HPV-specific T-cell responses, the immune contexture in the tumor microenvironment, and clinical outcome.Experimental Design: To this purpose, an in-depth analysis of tumor-infiltrating immune cells in a prospective cohort of 97 patients with HPV16-positive and HPV16-negative OPSCC was performed using functional T-cell assays, mass cytometry (CyTOF), flow cytometry, and fluorescent immunostaining of tumor tissues. Key findings were validated in a cohort of 75 patients with HPV16-positive OPSCC present in the publicly available The Cancer Genome Atlas database.Results: In 64% of the HPV16-positive tumors, type I HPV16-specific T cells were present. Their presence was not only strongly related to a better overall survival, a smaller tumor size, and less lymph node metastases but also to a type I-oriented tumor microenvironment, including high numbers of activated CD161+ T cells, CD103+ tissue-resident T cells, dendritic cells (DC), and DC-like macrophages.Conclusions: The viral antigens trigger a tumor-specific T-cell response that shapes a favorable immune contexture for the response to standard therapy. Hence, reinforcement of HPV16-specific T-cell reactivity is expected to boost this process. Clin Cancer Res; 24(3); 634-47. ©2017 AACRSee related commentary by Laban and Hoffmann, p. 505.

ETIOPATHOGENESIS OF RECURRENT LARYNGEAL PAPILLOMATOSIS AND CONTEMPORARY TREATMENT STRATEGIES

Recurrent laryngeal papillomatosis is a rare and chronic disease of the larynx caused by infection with human papillomaviruses type 6 or 1. Larynx is the most common location of papillomas with changes in voice as the first presenting symptom. Patients suffer from wart-like growths in the aerodigestive tract, recurrences and possible life-threatening obstruction of the airway. The course of the disease is unpredictable. Although spontaneous remission is possible, variable clinical course may include frequent recurrence of disease, significant morbidity and frequent surgical procedures. The mechanisms responsible for the variability in the clinical course and the persistence of latent HPV infection remain unknown. It is considered that both adaptive and innate immune response made by patients with papillomatosis support chronic infection. Patients with laryngeal papillomas are unable to produce an effective HPVspecific T-cell response, as shown by an altered CD8+ subset and the Th1/Th2 cytokine imbalance with suppression of Th1 response. There is a genetic association between certain HLA type II genes with severe course of disease and downregulation of HLA type I genes. Surgical excision, including new methods such as microdebrider, aims to secure an adequate airway and improve and maintain an acceptable voice, but may cause serious complications like stenosis of the airway. When papillomas recur, old and new adjuvant methods may be tried. Intralesional cidofovir injection is shown as effective and secure in the majority of cases. Recent advances in immune system research may provide the improvement of our treatment modalities and prevention strategies. Acta Medica Medianae 2014;53(4):64-74.

Chemoradiotherapy-Induced Upregulation of PD-1 Antagonizes Immunity to HPV-Related Oropharyngeal Cancer

While viral antigens in human papillomavirus (HPV)-related oropharyngeal cancer (HPVOPC) are attractive targets for immunotherapy, the effects of existing standard-of-care therapies on immune responses to HPV are poorly understood. We serially sampled blood from patients with stage III-IV oropharyngeal cancer undergoing concomitant chemoradiotherapy with or without induction chemotherapy. Circulating immunocytes including CD4(+) and CD8(+) T cells, regulatory T cells (Treg), and myeloid-derived suppressor cells (MDSC) were profiled by flow cytometry. Antigen-specific T-cell responses were measured in response to HPV16 E6 and E7 peptide pools. The role of PD-1 signaling in treatment-related immunosuppression was functionally defined by performing HPV-specific T-cell assays in the presence of blocking antibody. While HPV-specific T-cell responses were present in 13 of 18 patients before treatment, 10 of 13 patients lost these responses within 3 months after chemoradiotherapy. Chemoradiotherapy decreased circulating T cells and markedly elevated MDSCs. PD-1 expression on CD4(+) T cells increased by nearly 2.5-fold after chemoradiotherapy, and ex vivo culture with PD-1-blocking antibody enhanced HPV-specific T-cell responses in 8 of 18 samples tested. Chemoradiotherapy suppresses circulating immune responses in patients with HPVOPC by unfavorably altering effector:suppressor immunocyte ratios and upregulating PD-1 expression on CD4(+) T cells. These data strongly support testing of PD-1-blocking agents in combination with standard-of-care chemoradiotherapy for HPVOPC.

PD-045: HPV Specific T-Cell Responses and Immune Status Before and After Radiotherapy in Patients with Oropharyngeal Cancer

PD-045: HPV Specific T-Cell Responses and Immune Status Before and After Radiotherapy in Patients with Oropharyngeal Cancer

A Phase I Trial of a Human Papillomavirus DNA Vaccine for HPV16+ Cervical Intraepithelial Neoplasia 2/3

To evaluate the safety and immunogenicity of a therapeutic human papillomavirus (HPV)16 DNA vaccine administered to women with HPV16+cervical intraepithelial neoplasia (CIN)2/3. This phase I trial incorporated the standard '3+3'' dose-escalation design with an additional 6 patients allocated to the maximally tolerated dose. Healthy adult women with colposcopically directed, biopsy-proven HPV16+ CIN2/3 received 3 i.m. vaccinations (0.5, 1, or 3 mg) of a plasmid expressing a Sig-E7(detox)-heat shock protein 70 fusion protein on days 0, 28, and 56, and underwent standard therapeutic resection of the cervical squamocolumnar junction at day 105 (week 15). The safety and immunogenicity of the vaccine and histologic outcome based on resection at week 15 were assessed. Fifteen patients were evaluable (3 each at 0.5 and 1mg, 9 at 3 mg). The vaccine was well tolerated: most adverse events were mild, transient injection-site discomfort; no dose-limiting toxicities were observed. Although HPVE7-specific T-cell responses to E7 detected by enzyme-linked immunospot assays (IFN-gamma) were of low frequency and magnitude, detectable increases in response subsequent to vaccination were identified in subjects in the second and third cohorts. Complete histologic regression occurred in 3 of 9 (33%; 7-70% confidence interval) individuals in the highest-dose cohort. Although the difference is not significant, it is slightly higher than would be expected in an unvaccinated cohort (25%). This HPV16 DNA vaccine was safe and well tolerated. Whereas it seems possible to elicit HPV-specific T-cell responses in patients with established dysplastic lesions, other factors are likely to play a role in lesion regression.

Circulating human papillomavirus type 16 specific T‐cells are associated with HLA Class I expression on tumor cells, but not related to the amount of viral oncogene transcripts

Human papillomavirus (HPV) is a necessary factor in the pathogenesis of cervical cancer. Circulating HPV-specific T-cells responding to the E6 and E7 HPV proteins can be detected only in half of cervical cancer patients. Potential explanations for the absence of this response are lack of sufficient amounts of antigen to activate the immune response or local immune escape mechanisms. We studied the relationship between HPV 16 E6/E7 oncogene mRNA expression, human leukocyte antigen (HLA) expression on tumor cells and the presence of circulating E6- and E7-specific T-cell responses in cervical cancer patients. The amount of antigen was assessed by HPV E6/E7 mRNA expression levels measured by quantitative polymerase chain reaction. HLA Class I and Class II expression on tumor cells was analyzed by immunohistochemistry. A proliferative HPV-specific T-cell response was detected in 15/29 patients. The amount of HPV E6/E7 mRNA was not related to the presence of immune response. HLA Class I expression was downregulated in 19 patients and completely lost in 7 patients. HLA Class II expression was upregulated in 18 patients. HLA Class I expression on tumor cells showed a strong correlation with immunity (p = 0.001). Explicitly, all patients with complete HLA loss lacked HPV specific T-cell responses. The presence of circulating HPV-specific T-cells might reflect ongoing antitumor response that is sustained by CD8+ T-cells killing HLA Class I positive cancer cells. We hypothesize that HLA Class I expression status on tumor cells might as well influence the response to HPV E6/E7 directed immunotherapy.

Comparison of cervical and blood T‐cell responses to human papillomavirus‐16 in women with human papillomavirus‐associated cervical intraepithelial neoplasia

Human papillomaviruses (HPVs) are obligate epithelial pathogens and typically cause localized mucosal infections. We therefore hypothesized that T-cell responses to HPV antigens would be greater at sites of pathology than in the blood. Focusing on HPV-16 because of its association with cervical cancer, the magnitude of HPV-specific T-cell responses at the cervix was compared with those in the peripheral blood by intracellular cytokine staining following direct ex vivo stimulation with both virus-like particles assembled from the major capsid protein L1, and the major HPV oncoprotein, E7. We show that both CD4(+) and CD8(+) T cells from the cervix responded to the HPV-16 antigens and that interferon-gamma (IFN-gamma) production was HPV type-specific. Comparing HPV-specific T-cell IFN-gamma responses at the cervix with those in the blood, we found that while CD4(+) and CD8(+) T-cell responses to L1 were significantly correlated between compartments (P = 0.02 and P = 0.05, respectively), IFN-gamma responses in both T-cell subsets were significantly greater in magnitude at the cervix than in peripheral blood (P = 0.02 and P = 0.003, respectively). In contrast, both CD4(+) and CD8(+) T-cell IFN-gamma responses to E7 were of similar magnitude in both compartments and CD8(+) responses were significantly correlated between these distinct immunological compartments (P = 0.04). We therefore show that inflammatory T-cell responses against L1 (but not E7) demonstrate clear compartmental bias and the magnitude of these responses do reflect local viral replication but that correlation of HPV-specific responses between compartments indicates their linkage.

T-cell responses to human papillomavirus type 16 among women with different grades of cervical neoplasia

Infection with high-risk genital human papillomavirus (HPV) types is a major risk factor for the development of cervical intraepithelial neoplasia (CIN) and invasive cervical carcinoma. The design of effective immunotherapies requires a greater understanding of how HPV-specific T-cell responses are involved in disease clearance and/or progression. Here, we have investigated T-cell responses to five HPV16 proteins (E6, E7, E4, L1 and L2) in women with CIN or cervical carcinoma directly ex vivo. T-cell responses were observed in the majority (78%) of samples. The frequency of CD4+ responders was far lower among those with progressive disease, indicating that the CD4+ T-cell response might be important in HPV clearance. CD8+ reactivity to E6 peptides was dominant across all disease grades, inferring that E6-specific CD8+ T cells are not vitally involved in disease clearance. T-cell responses were demonstrated in the majority (80%) of cervical cancer patients, but are obviously ineffective. Our study reveals significant differences in HPV16 immunity during progressive CIN. We conclude that the HPV-specific CD4+ T-cell response should be an important consideration in immunotherapy design, which should aim to target preinvasive disease.

Spontaneous Regression of Grade 3 Vulvar Intraepithelial Neoplasia Associated with Human Papillomavirus-16–Specific CD4+ and CD8+ T-Cell Responses

Cell-mediated immunity directed against human papillomavirus 16 (HPV-16) antigens was studied in six patients affected with grade 3 vulvar intraepithelial neoplasia (VIN3, also known as bowenoid papulosis). Five of the patients presented with a chronic and persistent disease that relapsed after destructive treatments. They showed no detectable anti-HPV blood T-cell responses and no T-cell intraepidermal vulvar infiltrate containing both CD4+ and CD8+ lymphocytes. The last patient had a complete clearance of viral lesions, 8 months after disease onset and 2 months after electrocoagulation of <50% of the VIN3 lesions. She showed high frequency anti-E6 and anti-E7 effector blood T cells by ex vivo ELISpot-IFNgamma assay before clinical regression. Immunohistochemical study of her vulvar biopsy revealed a marked dermal infiltrate containing a majority of CD4+ T lymphocytes and an epidermal infiltrate made up of both CD4(+) and CD8(+) T cells. This seems to be the first evidence of an association between spontaneous regression of VIN3 lesions and HPV-specific T-cell responses detectable in the blood. Hence, an increase of HPV-specific effector T lymphocyte responses by vaccine-based therapeutic strategies might be useful to clear the lesions in bowenoid papulosis disease.