Cellular collection by apheresis.

Cellular collection is an important and increasingly used apheresis procedure. These collections are performed by leukocytapheresis, a procedure involving the removal of a patient's or donor's white blood cells, and are used to collect hematopoietic progenitor cells, specific cell populations (such as T-lymphocytes), and granulocytes. Hematopoietic progenitor cell apheresis and T-lymphocyte collection are performed by procedures that enrich for mononuclear cells. Hematopoietic progenitor cells are used for autologous and allogeneic hematopoietic stem cell transplantation, whereas T-cell collection is being used increasingly in novel cellular therapy approaches and for donor lymphocyte infusions to induce graft-versus-leukemia effect. Granulocytes are collected from healthy donors to treat severe sepsis in patients who are refractory to antimicrobial therapies. Less frequently, cellular depletion of leukocytes may be indicated in leukemic patients who have severe hyperleukocytosis resulting in leukoaggregation and decreased tissue perfusion. In these procedures, establishing and maintaining adequate vascular access are critical prerequisites to ensuring a successful procedure. For most types of leukocytapheresis procedures, efforts should be made to ensure that they are performed using peripheral veins, and the use of an intravascular access device should be considered only after it is determined that peripheral access is not feasible or desirable. However, in some settings (such as in patients undergoing autologous hematopoietic stem cell transplantation), intravascular access devices are often used to facilitate both the leukocytapheresis procedure and the subsequent transplant. Here, different types of vascular access approaches used in cellular collections are discussed, and this information is supplemented by the author's experience and practice in areas where published information is limited.