TLR4 and dry eye syndrome: Additionally, heat shock proteins (HSPs), such as HSP27, HSP60, HSP70, and HSP90, are overexpressed in KCs of psoriasis patients, and these HSPs can function as autoantigens to activate antigen-presenting cells (APC) through TLR4 to promote APC maturation and secretion of TNFα and IL12 [67–69].