IFNG and Alzheimer disease: On the other hand, the mRNA levels were reduced in Bifidobacteria-treated AD mice compared with the AD mice (IL-1 β, P = 0.0395; TNF-α, P = 0.0498; IL-4, P = 0.0099; IL-6, P = 0.0353; IFN-γ, P = 0.0212; Fig. 5).