Cytokine‐regulated accumulation of eosinophils in inflammatory disease

Abstract

The role of cytokines in the accumulation of eosinophil granulocytes in inflamed tissue has been studied extensively during recent years, and these molecules have been found to participate throughout the whole process of eosinophil recruitment. Haematopoietic cytokines such as IL‐3, IL‐5 and GM‐CSF stimulate the proliferation and differentiation of eosinophils in the bone marrow, and the release of mature eosinophils from the bone marrow into the blood is probably promoted by IL‐5. Priming of eosinophils in the blood following, for example, allergen challenge is performed mainly by IL‐3, IL‐5 and GM‐CSF. An important step in the extravasation of eosinophils is their adhesion to the vascular endothelium. Adhesion molecules are upregulated by, e.g. IL‐1, IL‐4, TNF‐α and IFN‐γ and the same cytokines may also increase the affinity of adhesion molecules both on eosinophils and endothelial cells. Finally, a number of cytokines have been shown to act as eosinophil chemotactic factors, attracting the cells to the inflammatory focus in the tissue. Some of the most important eosinophil chemoattractant cytokines are IL‐5, IL‐8, RANTES, eotaxin, eotaxin‐2, eotaxin‐3, MCP‐3, MCP‐4 and TNF‐α. Th2 cells, mast cells and epithelial cells are important sources of proinflammatory cytokines, but in recent years, the eosinophils have also been recognized as cytokine‐producing and thereby immunoregulatory cells. The aim of this paper is to review the role of cytokines in the process of eosinophil recruitment in asthma, allergy and ulcerative colitis.

A water extract of Samchulkunbi-tang attenuates airway inflammation by inhibiting inos and MMP-9 activities in an ovalbumin-induced murine asthma model

“…TNF-α is also an important chemoattractant for the recruitment of eosinophils into the lungs [30] and is a potent modulator of the immune and inflammatory responses. Inflammatory cells contribute to the generation of Th2 cytokines (IL-4, IL-5, and IL-13), chemokines (eotaxin and RANTES), and TNF-α, whose levels increase in the asthmatic lung [31].…”

EGF receptor activation during allergic sensitization affects IL‐6‐induced T‐cell influx to airways in a rat model of asthma

“…The eosinophil number in BAL was not reduced by AG1478 treatment although this inhibitor significantly reduced the eotaxin expression in BAL supernatant, suggesting that airway eosinophilia in this rat model of acute asthma is not eotaxindependent. The recruitment of eosinophils may be mediated by many different mediators including RANTES, IL-5, IL-8 and leukotriene B4 [36,37].…”

“…The recruitment of eosinophils may be mediated by many different mediators including RANTES, IL-5, IL-8 and leukotriene B4 [36,37].…”

“…The eosinophil number in BAL was not reduced by AG1478 treatment although this inhibitor significantly reduced the eotaxin expression in BAL supernatant, suggesting that airway eosinophilia in this rat model of acute asthma is not eotaxindependent. The recruitment of eosinophils may be mediated by many different mediators including RANTES, IL-5, IL-8 and leukotriene B4 [36,37].IL-6 is a pleiotropic cytokine expressed by a variety of cell types and has an important role in immune responses, acute-phase reactions and hematopoiesis. IL-6 levels increase in blood [38], BAL [39] and lung tissues [40] of asthmatic patients and this cytokine may play an important role in the immunopathogenesis of asthma.…”

Detection and quantitation of eosinophils in the murine respiratory tract by flow cytometry

“…Studies have shown that CD4 + T cells polarized toward a Th2 type phenotype secrete cytokines (e.g. IL-4 and IL-5) which serve as potent eosinophil chemoattractants (Lampinen et al 2004). As a result, eosinophils constitute a prominent cell type observed during a Th2 type response and the presence of an eosinophil infiltrate at the site of inflammation is one of the most frequently used indicators for the development of such an immune response.…”