Alternative activation genes in Alzheimer's disease. mRNA expression was determined for NOS2, TNFα, IL-1β, AGI, MRC1, CHI3L1, CHI3L2, AG2, CD45, CAT 2 and CAT3 in frontal lobe cortical extracts from AD patients and age-matched, cognitively normal controls. The real-time PCR results are expressed as the average (± SEM) fraction of control where age-matched, cognitively normal brain served as the comparator control. The data show significant elevations in mRNA expression levels for AG1 (* = p < 0.04), CHI3L1 (** = p < 0.006), and CHI3L2 (* = p < 0.04). NOS2 and IL-1β mRNA did not change but TNFα mRNA increased significantly (* = p < 0.04) in AD. CAT2 mRNA, which encodes the inducible arginine transporter, also significantly increased (# = p < 0.02) in AD compared to control. AG2, MRC1, CD45 and CAT 3 mRNA expression levels were equivalent between the AD and control brains.