The proportions of cells in bronchoalveolar lavage (BAL) fluid, the release of histamine, leukotrienes C(4) and B(4) from leucocytes and BAL cells, and bronchial reactivity to methacholine were examined in 40 patients with asthma in relation to patient age. 1. The proportions of lymphocytes and neutrophils in BAL fluid were higher in older patients over age 60 than in younger patients between 20 and 49. The proportions of eosinophils and basophilic cells in BAL fluid were higher in younger patients than in older patients, and the difference in the proportion of BAL basophilic cells was significant between the two groups (p<0.05). 2. The release of histamine from BAL cells was significantly higher in younger patients
than in older patients (p<0.001). The release of LTC(4) from BAL cells was higher in older patients compared to younger patients. 3. Bronchial reactivity to methacholine was higher in younger patients than in older patients. The number of patients reactive to low concentration of methacholine (390μg/mℓ or less) was larger in younger patients (12/16 ; 75.0%) than in older patients (5/14 ; 35.7%). These results suggest that bronchial hyperresponsiveness changes with aging, accompanied by changes in the release of chemical mediators from BAL cells and in the proportion of BAL cells.気管支喘息を対象に,気管支肺胞洗浄(BAL)液中の細胞の出現頻度,末梢血白血球およびBAL細胞からのヒスタミン,ロイコトリエンC(4),B(4)遊離,気道過敏性などについて,患者年齢との関連のもとに検討を加えた｡1.BAL液中のリンパ球および好中球頻度は,60才以上の老齢症例で,20-49才の若青年症例に比べやや高い傾向が見られたが,推計学的には有意の差は見られなかった｡BAL液中の好酸球,好塩基細胞の頻度は,若青年症例で,老年症例に比べて高く,特に好塩基性細胞の頻度には両症例群間に有意の差が見られ(P<0.05)｡
2.BAL細胞からのヒスタミン遊離は,若青年症例で,老年症例に比べ有意に多い傾向が見られた(P<0.001)｡一方,BAL細胞からのロイコトリエンC(4)遊離は,若青年症例に比べ,老年症例で多い傾向が見られたが,両症例群間に有意の差は見られなかった｡3.メサコリンに対する気道の反応性は,全般的に若青年症例で,老年症例に比べより強い傾向を示した｡そして,390μg/mℓまたはそれ以下の低濃度のメサコリンに反応を示す症例は,若青年症例では16例中12例(75.0%),老年症例では14例中5例(35.7%)であった｡以上の結果より,気道過敏性は,BAL細胞からの化学伝達物質遊離の変化やBAL細胞の頻度の変化とともに,加齢の影響を受けることが明らかとなった
