Other studies have used direct ex vivo markers of T cell or B cell activation (e.g., KI67) (Mathew et al., 2020), polyclonally stimulated T cells (Lucas et al., 2020; Remy et al., 2020), measurements of common leukocyte types, or inflammatory proteins in blood (Giamarellos-Bourboulis et al., 2020; Laing et al., 2020; Mathew et al., 2020; Meckiff et al., 2020; Ou et al., 2020; Sekine et al., 2020) to obtain powerful information about the status of COVID-19 patients. The gene discussed is MKI67; the disease is COVID-19.