Use of granulocyte/monocytapheresis in ulcerative colitis: A practical review from a European perspective

Table 1 Main drivers of the mechanism of action of granulocyte/monocytapheresis

Within the apheresis filter	In the patient’s bloodstream
(1) Absorption of circulating IgG and immunocomplexes by cellulose beads; (2) Activation of complement fragments (C3a, C5a); (3) Granulocyte and monocyte absorption via Fc𝛾 receptors (IgG and immunocomplexes), and binding sites of leukocyte complement receptors (not in lymphocytes); and (4) Generation of apoptotic cells	(1) Reduction of activated neutrophils and pro-inflammatory monocytes (CD14+CD16+); (2) Apoptotic cells interact with regulatory B-cells, producing IL-10 and mature regulatory B-cells; and (3) Return of substances released by adsorbed cells: IL-1ra and HGF

IgG: Immunoglobulin G; IL: Interleukin; HGF: Hepatocyte growth factor.