From total blood exchange to erythrocytapheresis and back to treat complications of sickle cell disease

Erythrocytapheresis is an important procedure in the management of certain complications of sickle cell disease, including acute stroke, stroke prevention, acute chest syndrome, and multiorgan failure. Erythrocytapheresis in sickle cell disease simply entails the removal of the patient's red blood cells containing the abnormal sickle hemoglobin and replacing them with normal red blood cells carrying normal hemoglobin. In these procedures, the patient's plasma is not exchanged but is returned to the patient. Several studies have demonstrated that the plasma of patients with sickle cell disease contains several components that increase blood viscosity and initiate or promote vaso-occlusion. These factors include increased levels of globulins, especially immunoglobulin G, acute-phase reactants, fibrinogen, coagulation factors, inflammatory mediators, and heme in the steady state and increase further during painful crises. This may explain why, in certain complications of sickle cell disease, such as acute chest syndrome, hepatic crisis, and priapism, erythrocytapheresis by itself may not be effective despite repetitive cycles of red blood cell exchange. The use of therapeutic plasma exchange in addition to erythrocytapheresis in these situations seems to be useful in resolving them more efficiently. The role of therapeutic plasma exchange in the management of certain complications of sickle cell disease needs further evaluation. This commentary addresses the role of therapeutic plasma exchange in the management of complications of sickle cell disease.