Since disturbances in the T cell compartment characterize COVID-19 patients [28] and different subpopulations are proposed to predict the clinical course of the disease [29, 30], we focused on two factors related to T cell function in our study, namely sCD25/ IL-2Rα (activation) and sPD-L1 (immune-checkpoint). The gene discussed is SPDL1; the disease is COVID-19.