CCL2 and Alzheimer disease: From our cell experiments with the human keratinocyte cell line HaCaT cells, we also found that melatonin treatment could reduce the cytokine-stimulated secretion of AD-related cytokines, including TNF-α and IFN-γ induced MCP-1 production, and IL-4, IL-13, and IFN-γ induced IP-10 secretion.