Elevated bronchoalveolar lavage fluid histamine levels in allergic asthmatics are associated with increased airway obstruction.

Bronchoalveolar lavage (BAL) fluid was evaluated for histamine and tryptase levels in 61 samples (46 samples from 24 atopic asthmatics, seven samples from seven patients with allergic rhinitis, and eight samples from eight normal volunteers). Asthmatics and patients with allergic rhinitis had significantly higher BAL histamine than did normal subjects (169 +/- 22, 141 +/- 23, 42 +/- 6 pg/ml, respectively; p less than 0.05, both comparisons). BAL fluid tryptase levels were also higher in asthmatics and patients with allergic rhinitis than in normal subjects (0.36 +/- 0.03, 0.38 +/- 0.05, 0.23 +/- 0.04 ng/ml, respectively; p less than 0.05, both comparisons); however, levels of tryptase and histamine in BAL were not correlated (r = -0.03 in the group as a whole, r = -0.12 in the asthmatic group). BAL concentration of histamine correlated inversely with FEV1 percent predicted in the asthmatic group (r = -0.44, p less than 0.005). Asthmatics with high BAL fluid histamine (greater than or equal to 100 pg/ml, n = 23) had lower FEV1 percent predicted (80 +/- 3% versus 96 +/- 3%, p = 0.0005), lower FEV1/FVC ratio (72 +/- 1% versus 77 +/- 2%, p less than 0.05), higher percentage of BAL eosinophils (2.2 +/- 0.4% versus 0.6 +/- 0.1%, p less than 0.002), and greater airway responsiveness (lower PD20 [13.1 +/- 3.4 versus 41.5 +/- 13.7 cumulative breath units, p less than 0.05]) compared with asthmatics with low BAL fluid histamine (less than 100 pg/ml, n = 23).(ABSTRACT TRUNCATED AT 250 WORDS)