A possible explanation for this discrepancy is that the meta-analysis by Ng et al. included far fewer studies than that by Lai et al. Still, Nesham et al. reported the opposite trend in a study of 60 subjects, in which mRNA levels of IFN-γ and TNF-α in PBMCs of AD subjects were, instead, decreased compared with non-demented controls [117]. This evidence concerns the gene IFNG and Alzheimer disease.