RESUMEN
BACKGROUND & AIMS: The oral Toll-like receptor (TLR) 7 agonist GS-9620 has antiviral effects in woodchuck and chimpanzee models of chronic hepatitis B virus (HBV) infection. We investigated, in a clinical trial, the capacity of this agent to reconstitute protective immunity in patients with chronic HBV infection. METHODS: We performed a prospective study of 28 patients with suppression of HBV infection by nucleos(t)ide analogue therapy and who tested negative for hepatitis B e antigen at 4 medical centers in Italy. Patients were randomly assigned (1:3:3:3) to groups given placebo or different doses of GS-9620 (1, 2, and 4 mg, weekly for 12 weeks). We added data from 8 patients receiving nucleos(t)ide analogue therapy to the placebo group (controls); 13 treatment-naïve patients with chronic HBV infection and 15 subjects who spontaneously recovered from an acute HBV infection served as additional controls. Peripheral blood mononuclear cells were collected at baseline, during administration of GS-9620 or placebo, and 12 weeks afterward. Phenotype and function of natural killer (NK) and HBV-specific T cells were analyzed by flow cytometry. T cells were expanded by incubation with peptides from the entire HBV proteome and studied after overnight or 10 days culture. NK-cell inhibition of T-cell responses was measured by assessing cytokine production by T cells stimulated with peptides in the presence or absence of NK cells. RESULTS: T cells collected at baseline before addition of GS-9620, when patients were receiving only nucleos(t)ide therapy, had greater responses to HBV than T cells from treatment-naïve patients, based on cytokine production in response to HBV peptides. However, during or after administration of GS-9620, T cells produced higher levels of cytokines compared to baseline. NK-cell activation and function increased after patients were given GS-9620, but the ability of NK cells to suppress T-cell responses was lower during GS-9620 therapy than before. Changes in T-cell or NK-cell function did not correlate with levels of hepatitis B surface antigen. Serum levels of hepatitis B surface antigen did not decrease significantly compared to baseline in patients given any dose of GS-9620. CONCLUSIONS: Twelve weeks administration of GS-9620 had no significant effect on serum hepatitis B surface antigen levels, but did appear to increase T-cell and NK-cell responses and reduce the ability of NK to suppress T cells. GS-9620 might therefore be included in therapies to increase the immune response to HBV.
Asunto(s)
Antivirales/administración & dosificación , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/tratamiento farmacológico , Células Asesinas Naturales/efectos de los fármacos , Pteridinas/administración & dosificación , Linfocitos T/efectos de los fármacos , Adulto , Femenino , Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis B Crónica/inmunología , Hepatitis B Crónica/virología , Humanos , Masculino , Persona de Mediana Edad , Nucleósidos/uso terapéutico , Estudios Prospectivos , Receptor Toll-Like 7/agonistasRESUMEN
Treatment options for chronic hepatitis B (CHB) are pegylated interferon (Peg-IFN) in minimal-mild liver fibrosis and nucleot(s)ide analogues (NUC) in more advanced disease. Since little is known about their use in daily clinical practice, we conducted a multicentre prospective study to investigate treatment regimens applied to naïve CHB patients in real life. HBV-RER is an observational multicentre Italian network that collect clinic and virologic data of patients with CHB. Among the 2527 CHB patients seen during the study period (2009 - 2012), 502 patients started a first line antiviral treatment. Liver biopsy was performed in 30.9% of the patients, with high levels of fibrosis being detected in 19.4% of them. In 216 patients (43%) Peg-IFN was used as first-line therapy while the remaining patients started NUC therapy (entecavir and tenofovir in 75%, lamivudine in 15%, telbivudine and adefovir 10%). By multivariate logistic regression, an age under 40 (OR 0.92, 95%IC 0.90-0.94; p <0.001) and the execution of liver biopsy (OR 3.83; 95%IQR 1.76-8.36; p <0.001) were the only determinants of choice between Peg-IFN vs NUC. Peg-IFN was expected to be used in first-line treatment for CHB in 70% of the patients based on Italian recommendations, but a much lower proportion of patients were actually treated with Peg-IFN with a limited use of the biopsy. Thus, in daily clinical practice physicians prefer to use NUCs, presumably because of their optimal tolerability and anti-viral efficacy, even if they frequently require life-long treatment as opposed to the short duration of Peg-IFN.
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Antivirales/uso terapéutico , Hepatitis B Crónica/tratamiento farmacológico , Adulto , Antivirales/administración & dosificación , Biopsia , Femenino , Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis B Crónica/complicaciones , Hepatitis B Crónica/patología , Humanos , Interferones/administración & dosificación , Interferones/uso terapéutico , Italia , Hígado/patología , Cirrosis Hepática/etiología , Cirrosis Hepática/patología , Masculino , Persona de Mediana Edad , Polietilenglicoles/administración & dosificación , Estudios Prospectivos , Purinas/administración & dosificación , Purinas/uso terapéuticoRESUMEN
Hepatitis B virus (HBV)-specific CD8 T cells are functionally exhausted in chronic hepatitis B infection, and this condition can be corrected only partially through the modulation of inhibitory pathways, which suggests that a more complex molecular interplay underlies T cell exhaustion. To gain broader insight into this process and identify additional targets for the restoration of T cell function, we compared the transcriptome profiles of HBV-specific CD8 T cells from patients with acute and chronic disease with those of HBV-specific CD8 T cells from patients able to resolve HBV infection spontaneously and influenza (FLU)-specific CD8 T cells from healthy participants. The results indicate that exhausted HBV-specific CD8 T cells are markedly impaired at multiple levels and show substantial downregulation of various cellular processes centered on extensive mitochondrial alterations. A notable improvement of mitochondrial and antiviral CD8 functions was elicited by mitochondrion-targeted antioxidants, which suggests a central role for reactive oxygen species (ROS) in T cell exhaustion. Thus, mitochondria represent promising targets for novel reconstitution therapies to treat chronic hepatitis B infection.
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Linfocitos T CD8-positivos/inmunología , Hepatitis B Crónica/inmunología , Mitocondrias/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Enfermedad Aguda , Adulto , Anciano , Antioxidantes/farmacología , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/metabolismo , Citocinas/inmunología , Regulación hacia Abajo , Femenino , Hepatitis B/inmunología , Hepatitis B Crónica/genética , Hepatitis B Crónica/metabolismo , Humanos , Masculino , Potencial de la Membrana Mitocondrial , Persona de Mediana Edad , Mitocondrias/efectos de los fármacos , Reacción en Cadena de la Polimerasa , Superóxidos/metabolismo , Transcriptoma , Adulto JovenRESUMEN
UNLABELLED: Natural killer (NK) and hepatitis B virus (HBV)-specific T cells are functionally impaired in chronic hepatitis B (CHB). Understanding to what extent nucleos(t)ide analogue (NUC) therapy can improve T- and NK-cell responses is important in the perspective of immunomonitoring strategies for a safe and earlier NUC withdrawal and of novel combination therapies based on modulation of antiviral immunity. To gain further insights into T/NK-cell interplay, we studied NK-cell phenotype and function in hepatitis B e antigen-negative chronic HBV patients either untreated (25) or NUC treated (36 hepatitis B surface antigen [HBsAg](+) and 10 HBsAg(-)/hepatitis B surface antibody [anti-HBs](+)). Interferon-gamma, interleukin-2, and tumor necrosis factor alpha (TNF-α) production by HBV-specific T cells was also analyzed in NUC-treated patients. NK cells from chronic naïve patients showed an "inflammatory" phenotype defined by increased expression of TNF-related apoptosis-inducing ligand (TRAIL), CD38, and Ki67 that significantly declined upon viremia suppression and alanine aminotransferase normalization induced by NUC therapy. Reversion to a quiescent NK-cell phenotype was associated with restoration of the HBV-specific T-cell function. T- and NK-cell responses showed an inverse correlation, with an opposite behavior in individual NUC-treated patients. NK-cell depletion as well as TRAIL and NKG2D pathway blockade induced a significant improvement of the HBV-specific T-cell function. CONCLUSIONS: NK cells can express regulatory activity on T cells in NUC-treated patients with prevalent inhibition of CD4 T cells, likely needed to limit persistent T-cell activation. NK-cell phenotype is modulated by NUC therapy and its reversion to quiescence mirrors efficient HBV-specific T-cell responses. Thus, changes of NK-cell phenotype may predict acquisition of antiviral control before anti-HBs seroconversion and represent the groundwork for future studies aimed at assessing whether NK phenotyping can be translated into the clinical practice to guide NUC suspension.
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Antivirales/uso terapéutico , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis B Crónica/inmunología , Células Asesinas Naturales/fisiología , Linfocitos T/fisiología , Femenino , Antígenos e de la Hepatitis B/sangre , Hepatitis B Crónica/sangre , Humanos , Masculino , Nucleósidos , Nucleótidos , FenotipoRESUMEN
OBJECTIVE: Treatment with peginterferon α-2a (PegIFN) for 48 weeks is the standard of care for selected HBeAg-negative patients chronically infected with hepatitis B virus (HBV), but with limited treatment efficacy. A study was undertaken to investigate whether treatment extension to 96 weeks improves the outcome in this patient population. METHODS: 128 HBeAg-negative patients (120 genotype D) were randomised to weekly 180 µg PegIFN for 48 weeks (group A, n=51), 180 µg PegIFN for 48 weeks followed by 135 µg weekly for an additional 48 weeks (group B, n=52) or 180 µg PegIFN plus lamivudine (100 mg/day) for 48 weeks then 135 µg PegIFN for 48 weeks (group C, n=25). Endpoints were alanine aminotransferase normalisation plus HBV DNA <3400 IU/ml (primary), HBV DNA <2000 IU/ml and HBsAg clearance at 48 weeks after treatment. RESULTS: Forty-eight weeks after treatment, six patients in group A and 13 in group B achieved alanine aminotransferase normalisation plus HBV DNA <3400 IU/ml (11.8% vs 25.0%, p=0.08), 6 vs 15 patients had HBV DNA <2000 IU/ml (11.8% vs 28.8%, p=0.03), 0 vs 3 achieved HBsAg clearance (0% vs 5.8%, p=0.24) and 0 vs 5 had HBsAg <10 IU/ml (0% vs 9.6%, p=0.06). While extended PegIFN treatment was the strongest independent predictor of response, the combination with lamivudine did not improve responses. Discontinuation rates were similar among the groups (19.6%, 23.1%, 32.0%, p=0.81) and were mostly due to PegIFN-related adverse events. CONCLUSIONS: In HBeAg-negative genotype D patients with chronic hepatitis B, PegIFN treatment for 96 weeks was well tolerated and the post-treatment virological response improved significantly compared with 48 weeks of treatment. TRIAL REGISTRATION NUMBER: http://ClinicalTrials.gov registration number: NCT01095835.
Asunto(s)
Antivirales/uso terapéutico , Antígenos e de la Hepatitis B/sangre , Virus de la Hepatitis B/genética , Hepatitis B Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Polietilenglicoles/uso terapéutico , Adulto , Alanina Transaminasa/sangre , Fármacos Anti-VIH/efectos adversos , Fármacos Anti-VIH/uso terapéutico , Antivirales/efectos adversos , ADN Viral/sangre , Quimioterapia Combinada , Femenino , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/sangre , Hepatitis B Crónica/genética , Humanos , Interferón-alfa/efectos adversos , Lamivudine/efectos adversos , Lamivudine/uso terapéutico , Masculino , Persona de Mediana Edad , Polietilenglicoles/efectos adversos , Proteínas Recombinantes/efectos adversos , Proteínas Recombinantes/uso terapéutico , Factores de Tiempo , Resultado del TratamientoRESUMEN
BACKGROUND & AIMS: In patients with chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, antiviral functions of T cells are impaired; these might be increased by blocking T-cell co-inhibitory pathways, such as preventing interaction between the receptor programmed death (PD)-1 and its ligand, PD-L1. We attempted to optimize the restoration of T-cell functions in patients with chronic HBV or HCV infection with a combination of reagents that block PD-1 interaction with PD-L1 and stimulate T-cell signaling via CD137, a member of the tumor necrosis factor-receptor family. METHODS: We assessed the effects of CD137 stimulation (via CD137L), alone or in combination with antibodies that block PD-1 interaction with PD-L1 (anti-PD-L1), on proliferation and production of interferon-γ and interleukin-2 by intrahepatic and peripheral T cells from patients with chronic HBV or HCV infection. We also analyzed expression of different co-stimulatory molecules on virus-specific CD8+ and forkhead box P3+CD4+ cells by flow cytometry. RESULTS: Incubation of intrahepatic T cells with CD137L and anti-PD-L1 increased their responses to HBV, but not HCV. However, HCV-specific T cells isolated from peripheral blood were sensitive to these reagents. Virus-specific T cells from some, but not all patients, had increased responses to anti-PD-L1 when CD137L was added because in some cases the combination of anti-PD-L1 and CD137L overstimulated T cells, leading to their inhibition. Intrahepatic HBV- and HCV-specific CD8+ T cells had different costimulatory profiles; liver cells from patients with chronic HBV infection had a higher proportion of forkhead box P3+ regulatory T cells, with higher levels of PD-1, compared with liver cells from patients with chronic HCV infection. CONCLUSIONS: A combination of reagents that prevent interaction between PD-1 and its ligand and activate CD137 signaling increase responses of intrahepatic HBV-specific T cells and circulating HCV-specific T cells. This strategy might be developed to increase T-cell responses to these viruses in patients with chronic hepatitis B or C, and tailoring the dose of CD137L administered will help optimize results.
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Diferenciación Celular/fisiología , Hepacivirus/fisiología , Virus de la Hepatitis B/fisiología , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Linfocitos T/patología , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/fisiología , Adulto , Anciano , Anticuerpos/farmacología , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Femenino , Hepatitis B Crónica/metabolismo , Hepatitis B Crónica/patología , Hepatitis C Crónica/metabolismo , Hepatitis C Crónica/patología , Humanos , Técnicas In Vitro , Interferón gamma/metabolismo , Interleucina-2/metabolismo , Ligandos , Masculino , Persona de Mediana Edad , Linfocitos T/efectos de los fármacos , Linfocitos T/metabolismoRESUMEN
BACKGROUND & AIMS: In patients with chronic hepatitis B virus (HBV) infection, persistent exposure to high concentrations of antigen can disrupt T-cell functions. It is not clear to what extent long-term suppression of HBV by nucleos(t)ide analogues can restore antiviral T-cell functions. We compared HBV-specific T-cell responses of patients treated with nucleos(t)ide analogues with those detected in other conditions of HBV control. METHODS: We analyzed intracellular levels of interferon gamma, interleukin-2, and tumor necrosis factor α in HBV-specific T cells after 10 days of stimulation with peptides covering the overall HBV genotype D sequence and ex vivo with selected CD8 epitopes and the corresponding HLA-A2 dextramers. Findings from patients treated with nucleos(t)ide analogues who had complete (HBV DNA negative/antibody to hepatitis B surface antigen positive) or partial (HBV DNA negative/hepatitis B surface antigen positive) control of their infections were compared with those of patients with spontaneous or interferon alfa-induced resolution of acute or chronic infections, inactive HBV carriers, or untreated hepatitis B e antigen-negative patients with chronic infections. RESULTS: Although HBV-specific T cells from nucleos(t)ide analogue-treated patients with complete control of infection were dysfunctional ex vivo, they had efficient responses after in vitro expansion. These responses were comparable to those of patients who spontaneously resolved acute HBV infection. Nucleos(t)ide analogue-treated patients who were HBV DNA negative but hepatitis B surface antigen positive had lower levels of T-cell responses but responses greater than those of untreated patients with chronic infection. CONCLUSIONS: In vitro reactivity can be restored to T cells from patients with suppressed HBV infection following long-term treatment with nucleos(t)ide analogues, despite prolonged exposure to large loads of antigen. Immune therapies that increase the antiviral T-cell response might increase the likelihood of complete HBV control in patients undergoing long-term nucleos(t)ide analogue treatment.
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Antivirales/uso terapéutico , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/tratamiento farmacológico , Linfocitos T/metabolismo , Adenina/análogos & derivados , Adenina/uso terapéutico , Células Cultivadas , ADN Viral/sangre , Genotipo , Guanina/análogos & derivados , Guanina/uso terapéutico , Antígenos de Superficie de la Hepatitis B/sangre , Antígenos e de la Hepatitis B/sangre , Virus de la Hepatitis B/genética , Hepatitis B Crónica/sangre , Humanos , Interferón gamma/metabolismo , Interleucina-1/metabolismo , Lamivudine/uso terapéutico , Organofosfonatos/uso terapéutico , Tenofovir , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
BACKGROUND & AIMS: The effect of IFN-α therapy on HBV-specific T-cell responses in HBeAg-negative, genotype D, chronic hepatitis B is largely undefined. Understanding to what extent IFN-α can modulate HBV-specific T-cells is important to define strategies to optimize IFN efficacy and to identify immunological parameters to predict response to therapy. METHODS: HBV-specific T-cell responses were analyzed longitudinally ex vivo and after expansion in vitro in 15 patients with genotype D, HBeAg-negative chronic hepatitis B treated with peginterferon-α-2a. HBV proteins and synthetic peptides were used to stimulate T-cell responses. Analysis of the CD4 and CD8 T-cell functions was performed by ELISPOT, intracellular cytokine and tetramer staining. The effect of anti-PD-L1 on T-cell functions was also analyzed. RESULTS: Ex vivo IFN-γ production by total HBV-specific T-cells was significantly greater before therapy in patients who showed HBV DNA <50 IU/ml at weeks 24 and/or 48 of therapy. No significant improvement of T-cell proliferation, Th1 cytokine production and cytotoxicity was observed during IFN therapy by both ex vivo and in vitro analysis. PD-1/PD-L1 blockade showed a modest improvement of cytokine production in a total of 15% of T-cell lines. CONCLUSIONS: IFN-α did not improve peripheral blood HBV-specific T-cell responses in the first 24 weeks of treatment, consistent either with a predominant antiviral/antiproliferative effect or with an immunomodulatory activity on other arms of the immune system which were not analyzed in our study. A better pre-treatment ex vivo IFN-γ production was associated with better chances to control HBV replication during therapy and represents a promising predictor of IFN efficacy.
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Antivirales/uso terapéutico , Antígenos e de la Hepatitis B/sangre , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Polietilenglicoles/uso terapéutico , Linfocitos T/inmunología , Adulto , Anciano , Citocinas/biosíntesis , Femenino , Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis B Crónica/inmunología , Humanos , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Proteínas Recombinantes/uso terapéuticoRESUMEN
BACKGROUND & AIMS: Hepatitis B virus (HBV) DNA detection in serum and/or in the liver of hepatitis B surface antigen (HBsAg)-negative patients with or without serologic markers of previous viral exposure is defined as occult HBV infection. Because the role of the adaptive response in keeping HBV replication under control in occult infection still is undefined, this study was performed to characterize the features of the HBV-specific T-cell response in this condition. METHODS: HBV-specific T-cell frequency and function were tested ex vivo and after in vitro expansion in 32 HBsAg-negative patients undergoing diagnostic liver biopsy for chronic hepatitis C: 18 with occult HBV infection (11 anti-HBc-negative and 7 anti-HBc-positive patients) defined by the detection of intrahepatic HBV DNA by polymerase chain reaction; 14 without detectable intrahepatic HBV DNA (5 anti-HBc-positive and 9 anti-HBc-negative patients). Six patients with chronic hepatitis B and 7 HBsAg-inactive carriers were studied for comparison. RESULTS: The presence or absence of serologic HBV markers defined 2 profiles of HBV-specific T-cell responses in occult infection. Anti-HBc-positive patients showed a T-cell response typical of protective memory, suggesting that this condition represents a resolved infection with immune-mediated virus control. In contrast, HBV-specific T cells in anti-HBc-negative patients did not readily expand and produce interferon-gamma in vitro, suggesting the possibility of a low-dose infection insufficient to allow maturation of protective memory. CONCLUSIONS: Our results suggest different mechanisms of control of viral replication in seropositive and seronegative occult infections. Additional studies aimed at understanding possible different clinical implications are needed.
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Linfocitos T CD8-positivos/inmunología , ADN Viral/análisis , Virus de la Hepatitis B/fisiología , Hepatitis B Crónica/inmunología , Inmunidad Celular/fisiología , Replicación Viral/genética , Adulto , Anciano , Biopsia , Linfocitos T CD8-positivos/metabolismo , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Genotipo , Antígeno HLA-A2/genética , Antígeno HLA-A2/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Hepatitis B Crónica/patología , Hepatitis B Crónica/virología , Humanos , Hígado/patología , Hígado/virología , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , RecurrenciaRESUMEN
Dysfunctional CD8+ T cells present in chronic virus infections can express programmed death 1 (PD-1) molecules, and the inhibition of the engagement of PD-1 with its ligand (PD-L1) has been reported to enhance the antiviral function of these T cells. We took advantage of the wide fluctuations in levels of viremia which are typical of chronic hepatitis B virus (HBV) infection to comprehensively analyze the impact of prolonged exposure to different virus quantities on virus-specific T-cell dysfunction and on its reversibility through the blocking of the PD-1/PD-L1 pathway. We confirm that chronic HBV infection has a profound effect on the HBV-specific T-cell repertoire. Despite the use of a comprehensive panel of peptides covering all HBV proteins, HBV-specific T cells were rarely observed directly ex vivo in samples from patients with chronic infection, in contrast to those from patients with acute HBV infection. In chronic HBV infection, virus-specific T cells were detected mainly in patients with lower levels of viremia. These HBV-specific CD8+ T cells expressed PD-1, and their function was improved by the blocking of PD-1/PD-L1 engagement. Thus, a broad spectrum of anti-HBV immunity is expressed by patients with chronic HBV infection and this spectrum is proportional to HBV replication levels and can be improved by blocking the PD-1/PD-L1 pathway. This information may be useful for the design of immunotherapeutic strategies to complement and optimize available antiviral therapies.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/inmunología , Antígenos CD/análisis , Antígenos CD/inmunología , Proteínas Reguladoras de la Apoptosis/análisis , Proteínas Reguladoras de la Apoptosis/antagonistas & inhibidores , Antígeno B7-H1 , Células Cultivadas , Hepatitis B/inmunología , Hepatitis B/virología , Hepatitis B Crónica/virología , Humanos , Tolerancia Inmunológica , Leucocitos Mononucleares , Estudios Longitudinales , Receptor de Muerte Celular Programada 1 , Subgrupos de Linfocitos T/inmunología , ViremiaRESUMEN
Hepatitis C virus infection can be associated with different extrahepatic manifestations, including lichen planus; however, no clear role for HCV in their pathogenesis has been established. T cells were isolated from lichen biopsy specimens of 7 HCV positive patients with oral lichen planus. HCV-specific CD4(+) T-cell lines were obtained in 4 patients from lichen lesions but only in 2 of them from the peripheral blood. Different clonal populations were found in oral tissue and peripheral blood of individual patients, as shown by TCR-Vbeta analysis of antigen-specific T cells. Frequency of HCV-specific CD8(+) cells tested with 4 different HCV tetramers was significantly higher in the lichen tissue than in the circulation; moreover, lichen-derived HCV-specific CD8(+) T cells showed the phenotype of recently activated T cells because most of them were CD69(+) and produced interferon gamma (IFN-gamma) but expanded poorly in vitro upon antigen stimulation. The specificity of HCV-reactive T-cell recruitment into the lichen tissue was further confirmed by the absence of HBV-specific T cells within lichen lesions in 3 additional patients with lichen planus associated with HBV infection. Our study shows HCV-specific T-cell responses at the site of the lesions of an HCV-associated dermatologic disease, sustained by HCV-specific T cells with phenotypic and functional characteristics of terminally differentiated effector cells. In conclusion, this finding and the detection of HCV RNA strands in the lichen tissue strongly suggest a role for HCV-specific T-cell responses in the pathogenesis of oral lichen planus associated with HCV infection.