CD40LG and endothelial dysfunction: The presence of IgM specific to Sip1 only in the sera from patients with primary vascular disease as well as the positive correlation of serum IgM specific to Sip1 C-ter with the serum levels of soluble E-selectin, a typical marker of endothelial activation and inflammation, suggests the potential role of these antibodies as immunological markers of endothelial dysfunction [24].