CD40LG and COVID-19: We have previously demonstrated, with a study on ICU critically ill COVID-19 patients, that lymphocyte subpopulations such as CD3, CD4, CD8 or the level of serum immunoglobulins (subgroups IgA, IgM and IgG) obtained within 48 h of admission or over time, were not statistically different between survivors and nonsurvivors.