Peginterferon-α does not improve early peripheral blood HBV-specific T-cell responses in HBeAg-negative chronic hepatitis.

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.

Clinico-Immunological Profile of a 67-Year-Old Woman Affected by HER2-Positive Breast Cancer and Autoimmune Dermatomyositis.

A patient with HER2-positive early breast cancer (BC) developed dermatomyositis (DM), which disappeared after the first administration of adjuvant trastuzumab. No HER2 overexpression/amplification was observed in DM skin biopsies. Both BC and skin immune infiltrates were composed mostly of CD3+ T-lymphocytes. Interestingly, tumor-infiltrating lymphocytes expressed PD-1, which was negligible in skin-infiltrating lymphocytes, while both BC cells and keratinocytes were PD-L1-positive. High serum levels of endogenous anti-HER2 antibodies were detected, confirming the induction of a HER2-specific adaptive immune response. It may be argued that HER2-specific T-lymphocytes cross-reacted with one or more unknown skin antigens, causing DM. Trastuzumab may have silenced skin cross-reaction by eliminating any residual HER2-positive micrometastatic disease and, thus, inducing DM remission.

Targeting p53 and histone methyltransferases restores exhausted CD8+ T cells in HCV infection.

Hepatitis C virus infection (HCV) represents a unique model to characterize, from early to late stages of infection, the T cell differentiation process leading to exhaustion of human CD8+ T cells. Here we show that in early HCV infection, exhaustion-committed virus-specific CD8+ T cells display a marked upregulation of transcription associated with impaired glycolytic and mitochondrial functions, that are linked to enhanced ataxia-telangiectasia mutated (ATM) and p53 signaling. After evolution to chronic infection, exhaustion of HCV-specific T cell responses is instead characterized by a broad gene downregulation associated with a wide metabolic and anti-viral function impairment, which can be rescued by histone methyltransferase inhibitors. These results have implications not only for treatment of HCV-positive patients not responding to last-generation antivirals, but also for other chronic pathologies associated with T cell dysfunction, including cancer.

Outcome of acute hepatitis C is related to virus-specific CD4 function and maturation of antiviral memory CD8 responses.

A timely, efficient, and coordinated activation of both CD4 and CD8 T cell subsets following HCV infection is believed to be essential for HCV control. However, to what extent a failure of the individual T cell subsets can contribute to the high propensity of HCV to persist is still largely undefined. To address this issue, we analyzed the breadth, vigor, and quality of CD4 and CD8 responses simultaneously with panels of peptides covering the entire HCV sequence or containing the HLA-A2-binding motif, and with recombinant HCV proteins in 16 patients with acute HCV infection by tetramer staining, ELISPOT, and intracellular cytokine staining for interferon gamma, interleukin (IL)-2, IL-4, and IL-10. Our results indicate that at clinical onset, CD8 responses are similarly weak and narrowly focused in both self-limited and chronically evolving infections. At this stage, CD4 responses are deeply impaired in patients with a chronic outcome as they are weak and of narrow specificity, unlike the strong, broad and T helper 1-oriented CD4 responses associated with resolving infections. Only patients able to finally control infection show maturation of CD8 memory sustained by progressive expansion of CD127+ CD8 cells. Thus, a poor CD8 response in the acute stage of infection may enhance the overall probability of chronic viral persistence. In conclusion, the presence of functional CD4 responses represents one of the factors dictating the fate of infection by directly contributing to control of the virus and by promoting maturation of protective memory CD8 responses.

Intrahepatic and circulating HLA class II-restricted, hepatitis C virus-specific T cells: functional characterization in patients with chronic hepatitis C.

To compare the functional features of circulating and intrahepatic hepatitis C virus (HCV)-specific CD4+ T cells in chronic HCV infection, peripheral blood and liver-infiltrating lymphocytes from 29 patients with chronic hepatitis C were stimulated with structural and nonstructural HCV proteins to produce antigen-specific T-cell lines and clones. Antigen specificity, fine specificity, phenotype, cytokine production, and T-cell receptor (TCR)-vbeta chain expression were analyzed. The results indicate a hierarchy of stimulatory capacity by the different HCV proteins, core being the antigen most frequently recognized by CD4+ intrahepatic lymphocytes, followed by NS4 and NS5. The CD4 response was directed simultaneously against different HCV proteins in individual patients, but fine-specificity analysis indicated that the response was generally focused on a limited number of immunodominant epitopes. Although the narrowly focused nature of this response may favor the emergence of escape mutations, this event was not observed by following-up over time the sequence of 2 epitopes strongly immunodominant for intrahepatic CD4 cells of a patient with chronic HCV infection. In conclusion, simultaneous analysis of peripheral blood and intrahepatic CD4 cells in the same patients indicated a predominant Th1 profile of HCV-specific CD4 cells and suggests a specific compartmentalization of virus-specific T cells into the liver.

Antiviral CD8-mediated responses in chronic HCV carriers with HBV superinfection.

Hepatitis B virus (HBV) superinfection in chronic hepatitis C represents a natural model to investigate whether or not hepatitis C virus (HCV) can influence priming and maturation of antiviral T cells; whether or not HBV superinfection, which is known to determine control of HCV replication, can restore HCV-specific T cell responsiveness; and whether or not cytokines stimulated by HBV infection can contribute to HCV control. To address these issues, the function of CD8 cells specific for HBV and HCV was studied longitudinally in two chronic HCV patients superinfected with HBV. Patients with acute hepatitis B were also examined. Frequency and function of HBV tetramer+ CD8 cells were comparable in patients acutely infected with HBV with or without chronic HCV infection. HBV-specific CD8 cell function was efficiently expressed irrespective of serum HCV-RNA levels. Moreover, fluctuations of HCV viremia at the time of HBV superinfection were not associated with evident changes of CD8 responsiveness to HCV. Finally, no correlation was found between serum levels of interferon alpha, interleukin (IL)-12, IL-10, or IL-18 and control of HCV replication. In conclusion, HCV did not affect the induction of primary and memory HBV-specific CD8 responses. HCV-specific CD8 responses were undetectable when HCV-RNA was negative, showing that inhibition of HCV replication in the setting of a HBV superinfection was not sufficient to induce a restoration of CD8 reactivity against HCV.

Oral lichen planus pathogenesis: A role for the HCV-specific cellular immune response.

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.