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    This chapter describes the myeloid cells of the peripheral blood: neutrophils, eosinophils, basophils, and monocytes. It describes their basic physiology and important disease states associated with defects of each of these entities. Each of these cells arise from a common bone marrow myeloid progenitor to differentiate into their unique types.
    Myelopoiesis
    The tumor microenvironment (TME) of diverse cancer types is often characterized by high levels of infiltrating myeloid cells including monocytes, macrophages, dendritic cells, and granulocytes. These cells perform a variety of functions in the TME, varying from of immune suppressive to immune stimulatory roles. In this review, we summarize the different myeloid cell populations in the TME and the intratumoral myeloid targeting approaches that are being clinically investigated, and discuss strategies that identify new myeloid subpopulations within the TME. The TME therapies include agents that modulate the functional activities of myeloid populations, that impact recruitment and survival of myeloid subpopulations, and that functionally reprogram or activate myeloid populations. We discuss the benefits, limitations and potential side effects of these therapeutic approaches.
    Citations (107)
    Abstract Aging, and age-related physiological changes, have been heavily implicated in declining immune functions. Many of these changes to the immune system include changes to the myeloid subsets, which have been poorly studied so far. Myeloid cells play crucial roles in acute infection and are involved in antigen presentation to cells of the adaptive immune system. Consequently, deciphering these age-related mechanisms holds great potential for targeting age-related changes in immunity. Here, we developed a model to map age related phenotypic changes in the myeloid compartment in all immunologically relevant murine organs. Using mass cytometry analysis (CyTOF), we assessed over 35 cell surface parameters on myeloid cells using a geriatric healthy mouse model. Results indicates age-related changes affecting the frequency and cell surface density of lineage markers on myeloid cells. Concretely, we see significant changes to cellular frequencies and marker expression within various resident myeloid populations, and exemplar organs will be presented here. Such age-related patterns may contribute to the impaired immune decline observed in aging. We are currently continually expanding this study and will validate the implications of these findings using spectral flow cytometry analysis.
    Mass cytometry
    Immunosenescence
    Compartment (ship)
    CD14 is a pattern recognition receptor; its important role in innate immunity is reviewed here. Since its discovery and subsequent classification at the first leucocyte typing workshop in 1982, CD14 has been thought of as a leucocyte differentiation antigen. However, it has become clear that CD14 is also expressed by many non‐myeloid cells, and the evidence for this is presented. The possible role of the presence of low copy number CD14 on non‐myeloid cells is discussed. It is time to acknowledge CD14 as an ubiquitous molecule and abandon the position that it is expressed by myeloid cells alone.
    Lineage (genetic)
    Recent evidence suggests that myeloid cells are critical in cancer development and therapy resistance processes. Pharmacological targeting of tumor-associated myeloid cells is an emerging approach among upcoming immune therapies. Surprisingly, myeloid cells are heterogeneous, including a subset of the myeloid cell displaying angiogenic properties in solid tumors. There is an urgent need to delineate angiogenic myeloid cell populations in order to facilitate specific targeting of protumor myeloid cells among heterogeneous pool. This review article is intended to compile all the relevant information in the literature for improved understanding of angiogenic myeloid cells and their role in tumor refractoriness to cancer therapy.
    Citations (13)