CD40LG and COVID-19: In mild and moderate COVID-19, the increase in basic-FGF levels can be probably attributed to platelet, epithelial and endothelial cell dysfunctions caused by the SARS-CoV-2 virus because other researchers found that the levels of this GF were correlated with the levels of P-selectin (in the endothelium) and sCD40L in platelets (54–56).