Table 1.
Summary of published works about hepatitis C virus-specific cytotoxic T lymphocyte during anti-hepatitis C virus treatment pointing-out the data in favor and against hepatitis C virus-specific cytotoxic T lymphocyte response restoration either during or after treatment
| Ref. | Year | Treatment | Samples | CTL visualization | In favor | Against |
| Martin et al[89] | 2014 | DAA | Frozen PBMC | Tetramer staining | Restoration of HCV-specific CTL response during treatment in SVR cases | |
| Larrubia et al[60] | 2013 | PEG-IFN/RBV | Fresh PBMC | Pentamer staining | HCV-CTLs detection at week 12 of treatment correlates with infection resolution Detection of PD-1low HCV-specific CTLs after treatment correlates with SVR | |
| Humphreys et al[82] | 2012 | PEG-IFN/RBV | Frozen PBMC | γ-IFN ELISPOT assay | Treatment induced genotype-3a viral clearance is not associated with an enhancement of antiviral T cell response | |
| Tatsumi et al[78] | 2011 | PEG-IFN/RBV | Fresh PBMC | γ-IFN ELISPOT assay | HCV-specific CTL frequency increase between base-line and treatment week 4 was observed in SVR but not in non SVR patients | |
| Barnes et al[83] | 2009 | PEG-IFN/RBV | Frozen PBMC | γ-IFN and IL-2 ELISPOT assay | Not enhanced specific T cell response during high dose IFNa therapy was reported | |
| Caetano et al[77] | 2008 | PEG-IFN/RBV | Fresh PBMC | Pentamer staining | Chronically infected patients who responded to treatment showed a higher HCV-specific CTL frequency than non-responders during and post-treatment Terminally differentiated effector cells increased more rapidly in responders, and their frequency was always higher than in non-responder patients | |
| Golden-Mason et al[85] | 2008 | PEG-IFN/RBV | PBMC | Pentamer staining | Patients with sustained viral response showed a decrease in PD-1 expression on HCV-specific CTLs after therapy completion | |
| Badr et al[73] | 2008 | PEG-IFN | Frozen PBMC | Tetramer staining | Early therapeutic intervention during the acute phase of HCV infection reconstituted a long-lived polyfunctional memory T cell response | |
| Pilli et al[81] | 2007 | PEG-IFN/RBV | Frozen PBMC | γIFN ELISPOT assay and tetramer staining | No significant correlation between HCV-specific CTL kinetics and viral decay during treatment | |
| Morishima et al[75] | 2003 | IFN/RBV | Fresh PBMC | Chromium-51 release assay | Subjects who had completed the treatment and had undetectable HCV RNA levels after therapy had a detectable HCV-specific CTL response more frequently than those who were viraemic | |
| Vertuani et al[76] | 2002 | IFN | Fresh PBMC | Chromium-51 release assay | Increase in the intensity of HCV epitope recognition by HCV-specific CTL after 1 to 5 m of treatment | |
| Barnes et al[79] | 2002 | IFN/RBV | Frozen PBMC | γIFN ELISPOT assay | T cell responses induced during high dose of IFNa treatment appear not to influence the virological outcome |
DAA: Direct acting anti-viral; IFN: Interferon-α2; RBV: Ribavirin; PBMC: Peripheral blood mononuclear cells; γ-IFN: Gamma-interferon; SVR: Sustained viral response.