Effect of aging on onset mechanism of bronchial asthma

Skin tests, serum total IgE levels, specific IgE antibodies against each allergen, bronchial reactions provoked by allergens and histamine release from basophils are well known as prameters of immediate allergic reactions. The incidence of positive immediate skin reaction to allergens such as house dust, ragweed, Aspergillus Alternaria, Cladosporium and Broncasma decreased with aging. On the other hand, the incidence of positive skin reaction to Candida albicans was higher in cases between the age of 41 and 50 and cases over the age of 61 compared to that in the other groups classified by age. Serum IgE levels was highest in cases aged between 0 and 30. The levels of serum IgE decreased with aging. The incidence of positive RAST scores (more than 2+) and positive bronchial reaction to house dust were highest in cases between 0 and 30, and decreased with aging. However, the positive ratio of these tests against C. albicans were highest in cases between 41 and 50. The degree of histamine release from basophils of asthmatics induced by anti-IgE was consistently high without any correlation to aging when their serum IgE levels were more than 501 IU/ml. In the cases with serum IgE levels of less than 300 IU/ml, basophil reactivity to anti-IgE decreasd with aging. Basophil reactivity to house dust was generally dependent on the levels of specific IgE antibodies against the allergen. Although basophil reactivity to C. albicans was also high in cases with positive RAST scores, some cases with a RAST score of 0+ or 1+ showed high or moderate basophil reactivity. Moderate or high reactivity of basophils was frequently observed in cases between 41 and 50 and cases over age 61.

気管支喘息の発症機序の一つとして,IgE抗体にmediateされる即時型アレルギー反応や好塩基球の反応性の関与が明らかにされている｡本論文では,即時型アレルギー反応や抗ヒトIgEや特異抗原に対する好塩基球の反応性が加齢によりどのような影響を受けるかについて検討を加えた｡ハウスダスト,ブタクサ,アスペルギルス,アルテルナリア,クラドスポリウム,ブロンカスマ などによる皮内反応の陽性率は,加齢とともに低下する傾向を示した｡一方カンジダによる皮内反応の陽性率は,41～50歳および61歳以上の年齢層で高度であった｡血清IgE値は加齢とともに低下する傾向がみられた｡ハウスダスト特異的IgE抗体,吸入誘発試験の陽性率は,加齢とともに低下する傾向を示した｡一方カンジダでは特異的IgE抗体,吸入誘発試験いずれも41～50歳および61歳以上の年齢層で比較的高い陽性率が観察された｡抗ヒトIgEに対する好塩基球の反応性は,血清IgEが高値(501IU/ml以上)の場合は年齢と関係なくIgE依存性であったが,血清IgE値の低い症例(301IU/ml以下)では年齢が高い群でその反応性が低い症例の比率が大きかった｡ハウスダストに対する好塩基球の反応性は,抗ヒトIgE同様年齢が高い群ほど反応性が低い症例の比率が大きかった｡カンジダに対する好塩基球の反応性は,41～50歳および61歳以上の年齢層の症例でより高度であった｡