CD4 and aneurysm: It is secreted mainly by monocytes and the Th2-subset of CD4+ T-cells and is capable of polarizing the inflammatory response towards a Th2 type; this latter property might play a role in aneurysm since it has been reported that a Th2-type inflammation and blockade of the Th1 cytokine IFN-gamma induce aneurysms in allografted aorta in mice [38].