METHACHOLINE CHALLENGE DOES NOT AFFECT BRONCHOALVEOLAR FLUID CELL NUMBER AND MANY INDEXES OF CELL-FUNCTION IN ASTHMA

Methacholine (MCh) challenge testing is often incorporated into clini cal studies prior to performing bronchoscopy as a measure of bronchial hyperresponsiveness (BHR). However, the effect of methacholine on man y aspects of bronchoalveolar lavage (BAL) fluid cell count and functio n have not been fully evaluated,Ten patients with asthma, maintained o n inhaled beta(2)-agonists, were studied, Each subject underwent two b ronchoscopies in a random order, one preceded by methacholine challeng e within 30 min of the BAL, The investigators were blinded to the regi men, Several markers of BAL fluid cell number and function were studie d: cell count and differential, histamine, eosinophil products, includ ing eosinophil cationic protein and Charcot-Leyden crystal protein, ma crophage production of thromboxane B-2 and leukotriene B-4, neutrophil lysozyme and lactoferrin, lymphocyte typing and activation markers me asured via flow cytometry,No significant differences were noted in any of these markers of cell number or function which could be ascribed t o methacholine challenge, Thus, methacholine challenge does not appear to affect these markers of fell number and function, These findings i ndicate that a methacholine challenge can be used as a measure of bron chial hyperresponsiveness within 30 min prior to bronchoscopy without altering bronchoalveolar lavage fluid characteristics.