TNF and Alzheimer disease: Moreover, pro-inflammatory cytokine levels (such as IL-6 and TNFα) have been found to be elevated in patients with dementia [22,23,24,25] However, many reports on cytokine levels in MCI or AD patients are controversial or inconclusive, particularly those which provide data on frequently investigated cytokines such as tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6) [26,27,28,29].