Fig. 5.

Evaluation of the cytotoxic response in PBMCs of hospitalized patients with COVID-19 who received each dose of vitamin D. (A) Cytotoxicity of PBMCs from patients with COVID-19 who received 2000 IU/day and 10,000IU/day of cholecalciferol at baseline, 7 and 14 days was analyzed by quantifying early apoptosis in K562 cells as unspecific target after co-culture (1:1) for 1 h. (B) Direct antiviral cytotoxicity against SARS-CoV-2 infected cells was evaluated in the same PBMCs by quantifying caspase-3 activity in a monolayer of Vero E6 cells infected with pseudotyped SARS-CoV-2 virus G614 that were co-cultured with PBMCs (1:1) for 1 h. Both NK (C) and NKT (D) cell populations were analyzed by evaluating the expression of the activation marker CD56 and the degranulation marker CD107a. (D) The expression of the inhibitory marker CD158f/KIR2DL5 was evaluated in the same cells. Each dot corresponds to one sample. Statistical significance was calculated using Mann–Whitney U-test.