TNF and Alzheimer disease: Firstly, AD patients and psoriatic patients share an increase in several inflammatory and cardiovascular risk markers in their blood serum, including T helper (Th)1 (interferon gamma (IFN-γ), tumour necrosis factor alpha (TNF-α), and Th17 (C-C motif chemokine ligand 20 (CCL20)) (Figure 2) [28].