The glycocalyx is an important anti-inflammatory and anti-adhesive barrier at the luminal side of endothelial cells. Glycocalyx volume was significantly reduced in sickle cell patients (HbSS/HbSbeta(0)-thalassemia median 0.47L, IQR 0.27-0.66, HbSC/HbSbeta(+)-thalassemia 0.23L, 0.0-0.58) compared with controls (1 x 10(9)L, 0.52-1.77) (p=0.03). Reduced glycocalyx may be a new factor in the pathophysiology of sickle cell disease.