IL6 and depressive symptom measurement: C-reactive protein is an acute phase reactant which promotes phagocytosis and macrophage proliferation.67 During an inflammatory response, CRP is induced by inflammatory cytokines such as IL-6, TNF-α and IL-1β, which promote its production in the liver and secretion into plasma.68 CRP is elevated in people with HIV69,70 and people with depression,54 although the role of CRP in depression is unresolved due to contradictory findings.