CCL2 and COVID-19: They also appeared to exhibit an immunophenotype that is reminiscent of more severe COVID-19 patients, reflected in the decreased naïve—but increased effector T cells, the accumulation of CD28- senescent T cells, and a cytokine profile of increased MCP-1(CCL2)/ reduced concentration of MIP-1β (CCL4), even though characterization by their symptoms using the WHO classification suggested otherwise.