TNF and chronic hepatitis B virus infection: Indeed, improving mitochondrial function by the anti-oxidant piperidine-nitroxide MitoTempo and IL-12 increased IFNγ release upon stimulation with HIV gag as well as CMV pp65, but did not affect the percentage of IFNγ, TNFα and IL-2 producing CD8 T cells as was observed in chronic hepatitis B [51, 52].