Different roles of histamine and leukotriene C₄ in the airways between patients with atopic and nonatopic asthma

The release of histamine and leukotriene C₄ (LTC₄) from bronchoalveolar lavage (BAL) cells and peripheral blood stimulated with Ca ionophore A23187 was compared between atopic and nonatopic asthma. The proportion of basophilic cells in BAL fluid was significantly higher in atopic than in nonatopic asthma (p < 0.01); however, no significant differences were present in the other BAL cells between the two asthma types. The concentration of histamine in BAL fluid was significantly higher in younger patients (20-59 years) with atopic than in nonatopic asthma (p < 0.01). In contrast, the concentration of LTC₄ was significantly higher in nonatopic than in younger patients with atopic asthma (p < 0.01). The release of histamine from BAL cells (p < 0.001) and peripheral blood (p < 0.01) was significantly larger in younger patients with atopic than in nonatopic asthma. The generation of LTC₄ by BAL cells was significantly larger in nonatopic than in younger (p < 0.01) and older patients with atopic asthma (60+ years) (p < 0.05). These results suggest that both histamine and LTC₄ participate in the onset mechanism of atopic asthma, and only LTC₄ participates in that of nonatopic asthma.