When the NK cells were divided according to CD56 expression in NKbright (CD3-CD56++, immunoregulatory principally through cytokine production) and NKdim (CD3-CD56+, cytotoxic activity), we observed that COVID-19 patients presented lower median percentages of CD56bright NK and higher percentages of CD56dim NK cells compared to healthy controls: 0.4% (0.2–6) vs. 0.55% (0.4–0.8), p = 0.016 for CD56bright NK cells and 13.6% (8.2–19) vs. 8.7% (6.6–14.4), p = 0.039 for CD56dim NK cells (Table 1). The gene discussed is NCAM1; the disease is COVID-19.