The phagocytes: neutrophils and monocytes

Abstract

The production and deployment of phagocytes are central functions of the hematopoietic system. In the 1950s, radioisotopic studies demonstrated the high prodution rate and short lifespan of neutrophils and allowed researchers to follow the monocytes as they moved from the marrow through the blood to become tissue macrophages, histiocytes, and dendritic cells. Subsequently, the discovery of the colony-stimulating factors greatly improved understanding the regulation of phagocyte production.

Lipid metabolism modulation by the P2X7 receptor in the immune system and during the course of infection: new insights into the old view

“…The lumen becomes highly acidic and can increase the production of superoxide anions, as well as oxygen, nitrogen, and other degradative molecules [96,97]. Additionally, other substances associated with cell killing, such as thiols, metal centers, protein tyrosine residues, nucleic acids, and lipids, are produced [98].…”

Measurement of the Unfolded Protein Response (UPR) in Monocytes

“…Monocytes and their macrophage progeny act as immunological orchestrators and serve three major functions, antigen presentation, phagocytosis, and immunomodulation (Dale et al, 2008). Upon activation, monocytes and macrophages produce large amounts of cytokines and chemokines that recruit other immune cells such as neutrophils to sites of infection and inflammation.…”

Clinical significance of hemophagocytosis in BM clot sections during the peri-engraftment period following allogeneic hematopoietic SCT

“…[4][5][6][7] Although the role of macrophages in these complications is undetermined, macrophages have an ability to secrete significant amounts of pro-inflammatory cytokines. 2 Furthermore, fatal outcomes of hemophagocytic syndrome after allo-HSCT have been described in case reports. 8 This evidence suggests that activation of macrophages has a significant impact on post-transplantation outcome.…”

“…9 Measuring the levels of cytokines or chemokines produced by activated macrophages, such as IL-1, IL-6, IL-12, TNF-a and macrophage inflammatory protein-1, may be a possible method to evaluate the activation of macrophages. 1,2,10 However, as these cytokines and chemokines are produced by many cell types, their elevated levels are not specific to macrophage activation. 1,[10][11][12] An alternative method for evaluating the activation of macrophages is to assess the morphological change associated with macrophage activation, namely phagocytosis.…”

“…1,2 Following allogeneic hematopoietic SCT (allo-HSCT), macrophages contribute to the development of acute GVHD by producing pro-inflammatory cytokines. 3 In addition to aGVHD, pro-inflammatory cytokine release is implicated in the pathogenesis of various early complications after allo-HSCT, such as sinusoidal obstruction syndrome, engraftment syndrome (ES) and capillary leakage syndrome.…”