NCAM1 and COVID-19: Although NKT cells are generally of low abundance in the PB, their percentages were also found increased in active COVID-19 patients; the CD3+ CD56+ CD16− compartment by ≈2-fold (4.22% vs. 1.80% of controls; p < 0.001) and the CD3+ CD56− CD16+ compartment by ≈3-fold (0.64% vs. 0.19% of controls).