Eosinophils in repair and remodelling

Abstract

SummarySeveral studies in man suggest a role for the eosinophil in repair in remodelling. Skin biopsies taken at time intervals after allergen injection into human skin indicate that the formation of myofibroblast‐like cells and activation of fibroblasts, as shown by tenascin and procollagen‐1 production, may be partly under the control of infiltrating TGF‐β1+/IL‐13+ eosinophils. Studies involving the infusion of an anti‐IL‐5 monoclonal antibody to atopic subjects indicate that eosinophils are unlikely to be essential for the redness, swelling and induration characteristic of late‐phase allergic response but may play a role in repair/remodelling processes as shown by inhibition of tenascin deposition. Selective reduction of eosinophils by anti‐IL‐5 was also associated with a significant reduction in the up‐regulated expression of ECM proteins in the reticular basement membrane of asthmatics. Furthermore, this reduction in the expression of matrix proteins occurred over a relatively short time period and despite only partial eosinophil depletion. Taken together these data provide direct evidence of a causal association between eosinophils and ECM protein deposition in mild atopic asthma.