Applications and limitations of hemapheresis.

Hemapheresis is the selective collection of any blood component. With the use of automated equipment, hemapheresis has become practical both for procuring specific components for transfusion and for removing specific components considered pathogenic factors in clinical disease. This review considers all aspects of hemapheresis, including its role in blood component procurement and its potential therapeutic applications. Attention is focused on the clinical indications for the use of apheresis-harvested components, and on the rationale for the effectiveness of therapeutic cytapheresis and plasma exchange.