The appearance and distribution of inflammatory, anti-inflammatory and regulatory interleukins in relatively healthy lung tissue

Abstract

Background: Various cytokines expressed by immune cells, as well as epithelial and connective tissue cells initiate, suppress and regulate the local immune response, providing wide intercellular communication networks. Aims: The aim of this study was to determine the appearance and distribution of inflammatory, anti-inflammatory and regulatory cytokines in relatively healthy lung tissue samples. Methods: We evaluated lung tissue specimens obtained from 49 patients aged from 9 to 95 years in relatively healthy study subjects. Tissue samples were examined by hematoxylin and eosin staining and immunohistochemistry for interleukin (IL)-1, IL-4, IL-6, IL-7, and IL-10. The number of positive structures was graded semi-quantitatively. Results: IL-1-positive cells were found mostly in bronchial cartilage and alveolar epithelium. Immunoreactive lung macrophages also were seen. The number of IL-4, IL-6, IL-7, IL-10-containing cells were found in addition to previously listed, also in bronchial epithelium. The number of positive structures varied from occasional to moderate, graded higher in cartilage. Almost no positive structures for cytokines were found in connective tissue and bronchial glands. Overall less IL-1-positive cells and more IL-10-positive cells were found. Conclusions: Relatively healthy lung tissue shows the local anti-inflammatory response, as well as suggests the persistent stimulation of cytokine expression in lung tissue and indicates the local regulatory and modulating patterns. Pronounced cytokine distribution in bronchial cartilage suggests the involvement of compensatory local immune response in supporting tissue.