Recombinant human soluble CD40 ligand, also named CD145 or gp 39, is a 16.3 kD glycoprotein containing 149 aa residues comprising the receptor binding TNF-like domain of CD40 ligand. It is expressed on antigen-presenting cells such as B cells, macrophages, dendritic cells and thymic epithelial cells and it constitutes the nexus between the inflammatory system and the vascular thrombotic processes. Its gene is located in the long arm of the human X chromosome. Prognostic evaluation of the residual fixed atherosclerotic plaque is insufficient to predict clinical course. Currently, studies have been done that demonstrate the participation of the immunoinflammatory system in the genesis and complications of the atherosclerotic condition. In the future, the most specific biomarkers of vulnerability will be very useful in the daily practice (interleukins, CD40, etc.). The soluble CD40 ligand together with its CD40 receptor are overexpressed in experimental and human atherosclerotic lesions. This leads to an increase of mediators for the development of atherosclerosis. Both significantly contribute to the inflammatory processes that leads to atherosclerosis and thrombosis.