Clinical significance of sCD163 and its possible role in asthma

Abstract

Macrophages exert important functions in the balance and efficiency of immune responses, and participate in innate and adaptive immunity. The proinflammatory actions of macrophages are implicated in autoimmune diseases. Unlike classically activated M1 macrophages, the alternatively activated cluster of differentiation (CD)163+ and CD206+ M2 macrophages are involved in tissue repair and wound healing, and use oxidative metabolism to support their long-term functions. CD163 is a member of the scavenger receptor superfamily, categorized into class B, and its soluble(s) form, sCD163, is a marker of activated M2 macrophages. CD163 is selectively expressed in cells of the monocyte and macrophage lineages; however, its biological role has yet to be elucidated. The expression of sCD163 is markedly induced by anti-inflammatory mediators, such as glucocorticoids and interleukin-10, whereas it is inhibited by proinflammatory mediators, such as interferon-γ. These findings suggest that CD163 may serve as a potential target for the therapeutic modulation of inflammatory responses. The concentration of sCD163 in blood is associated with acute and chronic inflammatory processes in autoimmune disorders of connective tissue, fat metabolism and cardiovascular diseases, and it can be used for the assessment of cancer prognosis. A role for sCD163 in the pathogenesis of asthma has also been proposed. The present review serves to present the available knowledge concerning the implication of sCD163 in the pathophysiological mechanisms of asthma, and evaluate its potential as a biomarker and possible therapeutic target for asthma.

Systemic corticosteroid therapy augments ex vivo release of sCD163 by peripheral blood monocytes of asthmatic patients

“…Our study is consistent with previously published studies which demonstrate the increase in the serum sCD163 concentration in chronic inflammatory diseases such as asthma and rheumatoid arthritis [26,27]. In ad-dition, it demonstrates that inflammation associated with asthma exacerbations leads to a systemic increase in sCD163, which is consistent with previous reports in pneumonia or chronic inflammatory diseases [28].…”

“…A mouse model of allergic asthma provided further evidence for an important role of CD163 in regulation of inflammatory response in the airways [25]. Genetically modified mice, which do not express CD163, were characterized by a greater airway inflammation in response to a house dust mite allergen challenge [26]. The beneficial effect of CD163 was dependent on its direct binding to a major house dust mite allergen Der p 1, which led to attenuated production of CCL24 [26].…”

“…Genetically modified mice, which do not express CD163, were characterized by a greater airway inflammation in response to a house dust mite allergen challenge [26]. The beneficial effect of CD163 was dependent on its direct binding to a major house dust mite allergen Der p 1, which led to attenuated production of CCL24 [26]. Exogenous sCD163 enhance Dermatophagoides pteronyssinus allergen extract induced IL-10 release by peripheral blood mononuclear cells [17].…”

Pigs Lacking the Scavenger Receptor Cysteine-Rich Domain 5 of CD163 Are Resistant to Porcine Reproductive and Respiratory Syndrome Virus 1 Infection

“…The extracellular portion of CD163 forms a pearl-on-a-string structure of nine scavenger receptor cysteine-rich (SRCR) domains and is anchored by a single transmembrane segment and a short cytoplasmic domain ( 17 ). A proteolytically cleaved, soluble form of the protein ectodomain is found in the bloodstream and is involved in the inflammation and ischemic repair response ( 18 , 19 ). Transmembrane anchoring and interaction with SRCR domain 5 (SRCR5) of CD163 were found to be essential for successful infection with PRRSV ( 20 , 21 ).…”

Hepatitis C Virus E2 Envelope Glycoprotein Induces an Immunoregulatory Phenotype in Macrophages

“…CD163 is a class B member of the scavenger receptor superfamily, and its soluble form, sCD163, is a marker of activated M2 macrophages . Culture supernatants from HCV E2‐stimulated macrophages enhanced release of sCD163 by ELISA in five of seven samples tested (Fig.…”