In parallel, the increased release of cytokines (IL-6 and IL-10) in COVID-19 patients could exacerbate this immune cell disproportion, eliciting an upregulation of NKG2A expression, with a subsequent increment of its inhibitory action on the lymphocyte component, thus compromising the balance between lymphocytes and neutrophils (Fig. 1). Here, KLRC1 is linked to COVID-19.