CCL2 and COVID-19: The cytokine profiles of late-stage COVID-19 patients are similar to patients with secondary haemophagocytic lymphohistocytosis, a type of cytokine storm that can be triggered by systemic viral infection, including increased levels of interleukin (IL)-2, IL-6, IL-7, C-reactive protein (CRP), granulocyte-colony stimulating factor (GCSF), interferon-γ inducible protein 10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein 1-α (MIP1-α) and tumor necrosis factor-α (TNF-α) [45, 63, 64].