Cytokines are low-molecular-weight polypeptides exerting a wide variety of biologic effects at both local and systemic levels. Which of the following statement(s) is/are true concerning the production and actions of cytokines?

c. Cytokines may have both protective and deleterious effects on the host

Macrophages, endothelial cells, lymphocytes, and other cells secrete a large number of different compounds, termed cytokines, that are most probably evolved for the purpose of local intercellular and intracellular signaling. Cytokines frequently are secreted after initial lymphocyte or macrophage activation, and may act on the secreting cell itself (autocrine activation) or on other cells within the same local environment (paracrine activation) to cause increased secretion of the same cytokine or other cytokines, respectively. Some cytokines are produced by several cell types, and most produce a wide array of effects. The duality of the effects of the cytokine component of host defenses, exerting both salutatory and deleterious effects on the host, has become increasingly evident.