In vitro responses to antigen stimulation: comparison between human lung parenchyma resected from asthmatic patients and non-asthmatic patients

Background: The airway of asthmatic patients is hyperresponsive to various stimuli in vivo. There are, however, only a few reports that compared the i n vivo responsiveness of asthmatic patients and non-asthmatic subjects to t hose of lung parenchyma in vitro. Objectives: To compare the contractile response, release of various chemica l mediators, and responsiveness to drugs in samples of lung parenchyma exci sed from asthma patients with those of non-asthmatic subjects. Methods: Human lung parenchymal strips were subjected to passive sensitizat ion with sera of 5+ RAST titer to mites. The strip was suspended in a magnu s bath containing a buffer solution. Parenchymal contraction was induced by PGF(2)alpha. After washing, the baseline concentrations of thromboxane B-2 (TXB2), leukotriene (LT), and histamine were measured in each bath and the n contraction was induced by the addition of a mite antigen. The concentrat ions of TXB2, LT, and histamine were measured after contraction. The inhibi tory effects of TXA(2) synthetase inhibitor (DP-1904) and TXA(2) receptor a ntagonist (AA-2414) were also evaluated in both tissue samples. Results: There were no significant differences between lung parenchymal tis sues of asthmatic and non-asthmatic patients with regard to PGF(2)alpha-ind uced contraction, antigen-induced contraction, release of chemical mediator s, and the response to drugs. Conclusion: Unlike the response in vivo, there are no differences in the re sponse to stimuli in vitro between lung parenchymal tissues of asthmatic an d non-asthmatic patients.