To help define the relationships among inflammation, Alzheimer disease, and depression, the Texas Alzheimer's Research Consortium analyzed an array of inflammatory biomarkers in a cohort of patients with Alzheimer disease and in controls. Inflammation severity was highly correlated with earlier age at onset of Alzheimer disease and was also associated with cognitive decline. The relationship between inflammation and depression was not as clear, and it varied with aspects of depression, gender, and the presence of Alzheimer disease.