Despite the multitudes of cytokines in single reports, a smaller number have been implicated in meta-analyses, including IL6, IL12, IL18, IL1RA, CCL2/MCP1, TNF, CRP, IFNG, and sTNF2 in both dementia and MDD; TGFB, IL1B, IL2, IL8, MCP3, IP10/CXCL10, and sTNF1 in dementia; and IL3, IL10, IL13, and sIL2 in MDD [149, 151, 155, 156, 158, 162, 163, 167]. This evidence concerns the gene IL6 and major depressive disorder.