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We investigated the secretion of interleukin (IL)-13 into the airways in 10 mild allergic asthmatics by employing local allergen challenge, and compared the data both to IL-4 levels and eosinophil numbers obtained by bronchoalveolar lavage (BAL).Appropriate allergen or saline were endoscopically instilled into different airway segments, which were lavaged 10 min and 18 h after allergen or sham challenge. IL-4 and IL-13 were measured in unconcentrated BAL fluid using a double sandwich enzymes-linked immunosorbent assay (ELISA).Endobronchial allergen challenge induced a highly significant increase in the numbers of eosinophils after 18 h in the allergen exposed segment. Ten minutes following allergen exposure, low levels of IL-4 and IL-13 could be detected, whilst concentrations of both cytokines were significantly raised 18 h following local allergen exposure. In contrast to IL-4, the concentration of IL-13 strongly correlated with the eosinophil numbers found 18 h post-allergen challenge.The results suggest that interleukin-13 is actively secreted during the late asthmatic response in mild asthmatic subjects. In view of its action on eosinophils and other cell types, we conclude that interleukin-13, in addition to interleukin-4, may play an important role in the pathogenesis of eosinophil-related inflammation, such as bronchial asthma. Eur Respir J., 1996, 9, 899-904

SUMMARYThe pathogenesis of pulmonary sarcoidosis has been related to an increased production of Th1-like cytokines. However, cytokine expression in sarcoidosis has not been systematically studied at a singlecell level. We therefore investigated the expression of IL-2, IL-4, IL-13, tumour necrosis factor-alpha (TNF-a ) and interferon-gamma (IFN-g) intracellularly in bronchoalveolar lavage (BAL) and peripheral blood CD31 T lymphocytes from patients with pulmonary sarcoidosis (radiologic stage II±III, n 8) and normal controls (n 9) by flow cytometry. In contrast to IL-4 and IL-13, the percentage of T lymphocytes expressing intracellular IL-2 (49´3^21´3% versus 14´5^15´6%), IFN-g (75´5^14´9% versus 32´6^18´7%) and TNF-a (68´3^18´7% versus 36´8^20´8%) was significantly higher in patients with sarcoidosis than in normal controls (each P , 0´005). In contrast to BAL lymphocytes, expression of these cytokines in peripheral blood lymphocytes did not differ between patients with sarcoidosis and normal controls. Close correlations were observed between the percentages of BAL lymphocytes expressing intracellular IL-2, IFN-g and TNF-a , but not for IL-4 or IL-13. Analysis of the expression of these cytokines in T lymphocyte subsets revealed IL-2, IFN-g, and TNF-a in CD41 as well as CD8 1 T lymphocytes, suggesting a contribution of TC1 cells to the production of proinflammatory cytokines in sarcoidosis. We conclude that a Th1-like cytokine pattern can be observed in CD41 as well as in CD8 1 BAL T lymphocytes in patients with pulmonary sarcoidosis.

Cystic fibrosis (CF) is the most common inherited fatal disorder among Caucasians. Bronchial mucus in CF contains more potassium and less sodium, which may be due to increased sodium absorption, resulting in a reduced airway water content. We studied 23 patients with CF after inhalation of normal saline or amiloride (10(-3) M), a sodium transport blocker. Mucociliary clearance (MC) and cough clearance (CC) were determined with a gamma camera that traced the movement of 99mTc-labeled, hardened erythrocytes over a 1-h period after the patients inhaled these particles as an aerosol. Before and after each investigation pulmonary function tests (PFT) and blood pressure (BP) were measured. Sputum thread formation was measured by means of a filancemeter. Six of the patients also completed a 3-wk trial of amiloride inhalation therapy. MC increased significantly (p less than 0.001) after acute amiloride inhalation (bronchial deposition, 0.07 mg amiloride) compared with that in the saline control. CC also increased, but not as much as MC. After 3 wk of amiloride inhalation (2 times a day) clearance values (both MC and CC) were markedly enhanced (p less than 0.01); after a similar period of saline inhalation, clearance values were not different from baseline. Sputum filance values also decreased significantly after amiloride inhalation. There were no adverse effects of the amiloride inhalation compared with saline. We conclude that amiloride inhalation administered as a single dose or as long-term therapy is able to increase MC and CC in CF airways and that the effect of 10(-3) M amiloride inhalation on MC lasts at least 40 min. (ABSTRACT TRUNCATED AT 250 WORDS)