CCL2 and immune system disorder: Patients who advance to develop severe immune dysfunction exhibit a delayed interferon reaction, and a surge in pro-inflammatory cytokines and chemokines such as IL-1-ß, tumor necrosis factor (TNF)-a, C-X-C motif chemokine 10 (CXCL-10), IL-10, IL-18, IL-8, monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1ß (MIP-1ß) [26]. A study found that individuals who developed COVID-19 pneumonia and dengue hemorrhagic fever (DHF) had considerably greater levels of cytokines than those with minor symptoms [26].