Intracrine actions: intracellular action by regulation of intracellular events within the cytoplasm and/or nucleus.Autocrine: action produced within the cell through surface cell receptors.Intercrine: communication between cells. This type of cell interaction can be classified into:Paracrine: signaling produced by soluble mediators through neighboring cells.Matricrine: CYTOKINES are immobilized in the extracellular matrix (ECM) by its binding to proteoglycans, and they are then stored in an inactive form. These cytokines will be released by the action of proteases such as Metalloproteinases (MMPs) by a mechanism know as Protease-triggered matricrine (PTM). Glycocalyx, which is made of GLYCOPROTEIN carbohydrate-motifs with proteoglycan on its surface, could play the same role.Cytokine secretion by exchange of membrane fragments between cells through mechanisms such as trogocytosis, formation of tunneling nanotubes (TNTs) and release, secretion, and transportation of microvesicles (MVs)/Exosomes.Juxtacrine: neighboring ADJACENT cells send signals through membrane-anchored mediators. The classic example is the action of the endothelium on smooth muscle of the tunica media of certain vessels. Some cytokines have the ability to bind to extracellular matrix soluble proteoglycans or to proteoglycan-cell surfaces (for example, CD44, Glypicans, Syndecans, Betaglycan/TGFBR3, inter alia), where this mechanism serves as a reservoir, or as an enabler of these mediators to act on specific receptors in a juxtracrine manner.Endocrine: this refers to the distal or systemic action which depends on secreted cytokine and its transportation within the blood.Note that the autocrine, paracrine, juxtacrine, and endocrine actions are exerted by the binding to transducing signals (second messenger cascade) through specific cell surface receptors. Cytokines have limited biological half-lives and they act locally for the most part. Furthermore, they have overlapping actions characterized by a very broad range of functions, e.g., HEMATOPOIESIS, cell growth and differentiation, angiogenesis, tissue remodeling, wound healing, effector immune cell activity, and life/death decissions. Moreover, cytokines with endocrine action circulate in picomolar concentrations, but under the influence of strong immune activation circumstances, they can surge up to 1,000-fold (cytokinemia).In immunological JARGON, terms such as interleukins (IL’s), monokines, lymphokines, haematopoietins, lymphopoietins, myelopoietins, leucopoietins, basophilopoietins, chalones, leucokines, macrophage-activator factors (MAF), macrophage inhibitor factors (MIF), histamine-releasing factors (HRF), endogenous pyrogens, tumor necrosis factors, and interferons were originally used to identify the cellular source, the target cell and/or their action-type. However, at present, it is cleared understood that these substances are produced by a multiplicity of cell populations, depending on whether the cell is in a physiological resting state, activated state,