Further, we found that cytokine–receptor interaction axes (e.g. CCL2-CCR2, CCL3-CCR1, CCL3-CCR5, CCL4-CCR5, CCL4L2-VSIR, and CCL3L1-CCR1) observed in severe COVID-19 were significantly correlated with TEX. The gene discussed is CCL3; the disease is COVID-19.