ABSTRACT
This chapter discusses the issue of eosinophil, mast cell and basophil differentiation as it relates to the process of cell recruitment. It shows that both these cell types namely fibroblasts and epithelial cells produce cytokines, including granulocyte-macrophage colony-stimulating factor, interleukin (IL)-6 and IL-8, which play roles in perpetuating the inflammatory process. In light microscopic sections, activated eosinophils can be demonstrated by immuno-staining for eosinophil cationic protein in nasal polyps. Polyps represent a very interesting and convenient model to study the recruitment of eosinophils to airway tissues. Micro-environmental molecular control of the inflammatory process is complex. Hemopoietic progenitors may be of key importance in this process, but a series of cell interactions also takes place, leading to accumulation of mature cells such as eosinophils. Eosinophils and other inflammatory cells, even at terminal stages of differentiation or activation, are capable of feeding back and enhancing the inflammatory process.
