Abstract: Recent studies have demonstrated that lymphocyte-derived microparticles (LMPs) impair endothelial cell function. The present invention concerns the use of LMPs in the regulation of angiogenesis or diseases such as cancer or retinopathy of prematurity (ROP). Having long been considered as cellular debris, microparticles constitute reliable markers of vascular damage. Released into biological fluids, microparticles are involved in the modulation of key functions including immunity, inflammation, vascular remodeling and angiogenesis. The present data demonstrates that LMPs have considerable impact on angiogenesis in vitro and in vivo. In view of this, LMPs may be important contributors to the pathogenesis of diseases that are accompanied by impaired angiogenesis and could thus influence vascular function (microvascular angiogenesis and vasopermeability of ischemic tissue, alerting the body for special attention and the need for emergency repair procedures.