Microglia are involved in first line defensein response to HSV-1infection and are a major source of iNOS where these immune cellsincrease NO production to avoid cell death during viral infection.43,42 Microgliosis has also been found associated with upregulation ofiNOS and decreased Arg1 expression in response to prion infectionwithin mouse models.44 This mirrors theaction of microglia observed in AD pathogenesis where their iNOS productionis upregulated in response to Aβ-associated inflammation suggestinga harmful cycle of neuroinflammation in response to increased iNOSlevels.38 The gene discussed is NOS2; the disease is viral infectious disease.