Plasma endothelin-1, cytokine, and prostaglandin E2 levels in sickle cell disease and acute vaso-occlusive sickle crisis.

The relative contributions of microvascular inflammation and vasomotor dysregulation to the development of acute vaso-occlusive crisis in sickle cell disease have been intensely studied. The present observational study was designed to examine the levels of circulating proinflammatory cytokines, anti-inflammatory cytokines, and vasoactive mediators during and after acute painful crisis. In symptomatic sickle cell patients, plasma levels of endothelin-1 and prostaglandin E2 were elevated during crises compared with healthy African-American controls. These levels had decreased, but not normalized, when patients were seen 1 to 3 weeks after discharge from hospital. Other mediators (tumor necrosis factor alpha [TNFalpha], interleukin-1beta [IL-1beta], IL-6, IL-8, and IL-10) were neither elevated in asymptomatic sickle cell disease nor in acute vaso-occlusive crisis. As a potent long-acting mediator of vasoconstriction and inflammation, endothelin-1 may play a key role in the cycle of ischemia and inflammation that initiates and sustains pain of crisis. The downregulatory effects of prostaglandin E2 on immune cell function may contribute to the increased susceptibility to infection observed in patients with sickle cell disease.