Inhaled methacholine does not influence the cellular composition of bronchoalveolar lavage fluid.

A methacholine or a histamine test is often used to quantitate bronchial responsiveness, in studies investigating the influence of various inhaled stimuli on the responsiveness and composition of bronchoalveolar lavage (BAL) fluid. Histamine has been shown to evoke an inflammatory cell response in BAL fluid. In order to test the influence of the methacholine test on the cellular composition of BAL fluid, we investigated 14 healthy, nonsmoking volunteers with a methacholine test 24 h before performing a BAL. The results showed no significant changes in the cellular composition of BAL fluid, as compared with control BAL in the same persons.