Although clinical data were inconsistent for individual cytokines and across studies, a meta-analysis published in 2010 included 40 studies and demonstrated that patients with AD had elevated peripheral blood levels for tumor necrosis factor (TNF)-alpha, interleukin (IL)-1β, IL-6, IL-12, IL-18, and transforming growth factor (TGF)-β, whereas blood IL-4, IL-8 and IL-10 did not show significant differences between AD patients and controls (22). Here, IL4 is linked to Alzheimer disease.