Interleukin-13 and Its Receptors in Idiopathic Interstitial Pneumonia: Clinical Implications for Lung Function

Idiopathic interstitial pneumonia (IIP) is characterized by varying degrees of interstitial fibrosis. IL-13 and IL-4 are strong inducers of tissue fibrosis, whereas IFN-gamma has antifibrotic potential. However, the roles of these substances in IIP remain unknown. IL-13, IL-4, and IFN-gamma were measured in the BAL fluid of 16 idiopathic pulmonary fibrosis (IPF) patients, 10 nonspecific interstitial pneumonia (NSIP) patients, and 8 normal controls. The expression of IL-13 and IL-13Ralpha1/alpha2 in lung tissues was analyzed using ELISA and immunohistochemistry. IL-13 levels were significantly higher in IPF patients than the others (P<0.05). IL-4 levels were higher in both IPF and NSIP patients than in normal controls (P<0.05), and IFN-gamma levels were lower in NSIP patients than in normal controls (P=0.047). IL-13 levels correlated inversely with FVC% (r=-0.47, P=0.043) and DLCO% (r=-0.58, P=0.014) in IPF and NSIP patients. IL-13 was strongly expressed in the smooth muscle, bronchial epithelium, alveolar macrophages and endothelium of IPF patients. IL-13Ralpha1, rather than IL-13Ralpha2, was strongly expressed in the smooth muscle, bronchial epithelium, and endothelium of IPF patients. IL-13 and its receptors may contribute to the pathogenesis of fibrosis in IIP and appear to be related to the severity of the disease.

Impact of Circulating TGF-beta and IL-10 on T Cell Cytokines in Patients with Asthma and Tuberculosis

Regulatory T cells, which stimulate or inhibit the effector functions of distinct T cell subsets, are critical in the control of the immune response. We investigated the effect of TGF-beta and IL-10 on T cell subsets according to the Th1/Th2 immune status. Sixty-two patients with asthma and 38 patients with pulmonary tuberculosis were included. Allergy skin tests, tuberculin tests, and chest radiography were performed. The levels of circulating IL-4, IFN-gamma, TGF-beta1, and IL-10 were measured using ELISA. The level of TGF-beta1 was higher in patients with asthma than in those with tuberculosis, but the IL-10 levels were the same between the asthma and tuberculosis groups. Atopy was unrelated to the tuberculin response. The IFN-gamma level was correlated with the IL-10 level, and the level of IL-4 was unrelated to the IL-10 or TGF-beta1 level. The level of IL-10 was higher in the negative tuberculin reactors than in the positive tuberculin reactors among patients with asthma, and TGF-beta1 was higher in the positive tuberculin reactors than in the negative tuberculin reactors among patients with tuberculosis. These results demonstrate that the regulatory effects of circulating TGF-beta and IL-10 on T cell cytokines may be different between Th2-type asthma and Th1 tuberculosis.

Proteomic Analysis of Differently Expressed Proteins in a Mouse Model for Allergic Asthma

Allergic asthma is associated with persistent functional and structural changes in the airways and involves many different cell types. Many proteins involved in allergic asthma have been identified individually, but complete protein profiles (proteome) have not yet been reported. Here we have used a differential proteome mapping strategy to identify tissue proteins that are differentially expressed in mice with allergic asthma and in normal mice. Mouse lung tissue proteins were separated using two-dimensional gel electrophoresis over a pH range between 4 and 7, digested, and then analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MS). The proteins were identified using automated MS data acquisition. The resulting data were searched against a protein database using an internal Mascot search routine. This approach identified 15 proteins that were differentially expressed in the lungs of mice with allergic asthma and normal mice. All 15 proteins were identified by MS, and 9 could be linked to asthma-related symptoms, oxidation, or tissue remodeling. Our data suggest that these proteins may prove useful as surrogate biomarkers for quantitatively monitoring disease state progression or response to therapy.