Notably, monocyte–NK interactions in these samples were also predicted to upregulate several genes involved in cell cycle regulation [CCNG2 (68), ING1 (69), PDCD4 (70), TENT5C (71)] (Fig. 2D), which contrasts with the genes involved in proliferation and apoptosis upregulated in severe COVID-19 patient NK cells (Fig. 2C). The gene discussed is PDCD4; the disease is COVID-19.