Homocysteine (Hcy) is a sulfur-containing non-constitutive amino acid derived from the essential amino acid methionine.Numerous clinical studies have established hyperhomocysteinemia (HHcy) as an independent risk factor for cardiovascular diseases in human.We and others have demonstrated that HHcy accelerates atherosclerosis by affecting the immuno-inflammatory response,stimulating chemokine/cytokine secretion in monocytes and T lymphocytes and repressing regulatory T-cell function.