T cell responses in chronic and resolved HCV genotype-3a were analysed in comparison with genotype-1 infection (total n=85) using specific peptide panels in IFN-γ ELISpot assays.
Increased levels of chemokine interferon-gamma (IFN-γ)-inducible protein-10 (CXCL10), soluble CD163 (sCD163) and soluble CD14 (sCD14) have been reported in HCV infection.
Ex vivo interferon gamma (IFN-gamma) ELISPOT analysis detected HCV-specific CD4(+) T-helper cell reactivity in only 35% of cases, whereas HCV-specific CD8(+) T-cell responses were found in 4 of 5 HLA-A2-positive individuals.
HIV/HCV coinfection had a detrimental effect on the HCV-specific cytokine production in acute HCV infection, particularly on HCV-specific interferon γ (IFN-γ) production (magnitude P = .004; breadth P = .046), which correlated with peripheral CD4(+) T-cell counts (ρ = 0.605; P = .005) but not with detectable HIV viremia (ρ = 0.152; P = .534).
Most HCV T cell epitopes that elicited an IFN-γ response in the source did not in the recipient, despite the pair sharing human leukocyte antigen alleles that govern antigen presentation and similar autologous viruses.
To ascertain whether single nucleotide polymorphisms (SNPs) regulating the expression of interferon-gamma (IFN-gamma), IFN-gamma receptor-1 (IFNGR-1), interleukin-6 (IL-6), IL-10, IL-18, and tumor necrosis factor-alpha (TNF-alpha) may be associated with early fibrosis progression of recurrent hepatitis C, 50 liver transplantation recipients (32 men, 18 women, median age 56 years) with a median histologic follow-up time of 54 months were studied; 98 healthy blood donors served as controls.
Interferon-gamma-inducible protein 10 (IP-10), a chemokine that recruits activated T lymphocytes, has recently been shown by in situ hybridization to be expressed in the liver during chronic HCV infection.
More importantly, NK cells in co-infection displayed a highly impaired functional activity with significantly lower IFN-γ production and degranulation than in healthy donors as well as HIV and HCV mono-infection, suggesting a synergistic effect of both viruses.
However, no significant association was observed between the cytokines (IL-10 and IFN-γ) genotypes profile and HCV-liver cirrhosis risk in the studied population, except for the high frequency of IFN-γ +874 T allele in cirrhotic patients.
This study suggests that strong IFN-gamma responses associated with efficient viral clearance primarily result from Ag-driven selection/survival of HCV-specific T cells expressing high-avidity TCR.
The rgFLU-HCV<sub>CE1E2</sub> virus also stimulated IFN-γ production by virus-specific peripheral blood mononuclear cells in patients with chronic HCV infection.
Furthermore, a genetic tendency to produce higher levels of IFN-gamma was noted among LTx recipients with nonrecurrent hepatitis C than among those with recurrent hepatitis C.
Interferon-gamma mRNA was increased in both haemochromatosis (0.29+/-0.08%, P=0.01) and hepatitis C patients (1.02+/-0.32%, P=0.03) compared to controls (0.04+/-0.01%).