Leukocytapheresis: A procedure gaining ground?

Abstract

In the hemato-oncologic practice, leukocytapheresis is known both for therapeutic procedures like blastapheresis but also for preparative purposes. Examples of the latter are a. patient and donor stem cell apheresis after G-CSF mobilization and b. procurement of donor lymphocytes that in the post allogeneic stem cell transplantation can help the transplanted patient to attain full donor chimerism or to eradicate his/her (minimal) residual disease. Leukocytapheresis can also be adapted to collect therapeutic quantities of donor granulocytes. Although, not yet evidence based, donor granulocytes have been described to be of help in preventing reactivation of or cure severe -often fungalinfections in granulocytopenic patients. Much broader use of leukocytapheresis-isolated leukocytes (subsets) from the peripheral blood, however, seems heralded by the promise of immunomodulatory cell therapy to attenuate autoimmunity, to generate tolerance for organ and hematopoietic stem cell transplants and to induce new or stronger immunity against cancer or pathogens. In this respect, leukocytapheresis using closed system tubing sets is the most practical method to isolate GMP-grade buffy coats. These buffy coats namely are the raw material for subsequent elutriation or immunoadsorption (CliniMacs) mediated enrichment or depletion to prepare cell products such as regulatory T-cells (via CD25 and CD4 positivity), natural killer cells (via CD56 positivity and CD3 a/o CD19 negativity) and monocytes (via CD14 positivity). Leukocytapheresis, elutriation and immunoadsorp-