(A) Flow cytometry dot plots showing CD40 expression on gated C, T, and NC Mo from representative non–COVID-19 controls and mild (G1), severe (G2), and critical (G3) COVID-19 patients. Fluorescence minus one (FMO) controls (blue) for each cell subset are included for comparison purposes. (B) Box-and-whisker plots representing CD40 MFI on the indicated myeloid cell populations present in the blood of healthy individuals versus either total COVID-19 patients included in the study or patients stratified into groups according to mild (G1; n = 19), severe (G2; n = 21),and critical (G3; n = 24) clinical characteristics specified in Supplemental Table 1. Median is highlighted. Error bars represent maximum and minimum values. Statistical differences between patient groups were calculated using a Kruskal-Wallis test followed by Dunn′s post hoc test for multiple comparisons. TOT, total. *P < 0.05.