When analysing the IFN-γ response in subgroups of CMV seropositive and negative AD and ND patients, our data suggest that the increased Th1/Tc1-like proinflammatory response in the AD group is only due to the strong reactivity in the CMV seropositive AD individuals, something not seen in CMV seropositive ND or CMV seronegative AD subjects. The gene discussed is IFNG; the disease is Alzheimer disease.