TLR4 and Alzheimer disease: AD risk is associated with genetic polymorphisms in several key sensors of innate immunity such as NLRP1 (NACHT, LRR and PYD domains-containing protein 1) and TLR4 (toll-like receptor 4), and over a dozen of immune mediators, which include pro-inflammatory cytokines IL-1, TNF-alpha, and IL-6, adhesion molecules such as ICAM-1 (intercellular adhesion molecule 1), chemokines IL-8 (interleukin 8) and MCP-1 (monocyte chemotactic protein 1), and chemokine receptors, such as CCR2 and CCR5 [75, 77].