IFNG and infection: Both iNOS−/− and L-NMMA treated mice indicated only moderate effect of NO on ALA development within the first three days after intrahepatic infection and argues that the effect seen in the double knock-out mice used by Seydel et al. might primarily be due to the lack of the ability to activate immune cells via IFNγ, a cytokine that is crucial in the control of ALA [9], [36], [49].