慢性閉塞性肺疾患患者における一過性運動負荷強度の違いが唾液中分泌型免疫グロブリンAに及ぼす影響

外来通院中の慢性閉塞性肺疾患(COPD)患者5名を対象に, 運動負荷強度の違いが唾液中分泌型免疫グロブリンA(唾液中SIgA)に与える影響について検討した. 運動負荷は, 漸増シャトルウォーキングテスト(ISWT)を実施し, 最大歩行速度の40%および80%に相当する運動強度を算出し, 20分間のトレッドミル歩行をそれぞれ実施した(40% ISWT, 80% ISWT). 各運動負荷の実施前後に唾液採取を行い, 酵素標識免疫測定法を用いて, 唾液中SIgA濃度を測定し, 唾液中SIgA分泌速度を算出した. その結果, 40% ISWT後には5例中3例において唾液中SIgA分泌速度が低下し, 残りの2例において増加した. 一方, 80% ISWT後には5例中4例において唾液中SIgA分泌速度が低下し, 残りの1例において増加した. 健常者でも免疫機能が低下することが報告されている高強度の運動負荷に加え, COPD患者では低強度の運動負荷後でも免疫機能が低下する可能性が示唆された.

The present study was designed to examine the effects of exercise intensity on local immunity of the upper respiratory tract. We measured salivary levels of secretory immunoglobulin A (SIgA) in five outpatients with chronic obstructive pulmonary disease (COPD). Maximum walking speed for each subject was determined by incremental shuttle walking test (ISWT). Exercise was 20 min walking on a treadmill at speeds of 40% or 80% of ISWT (40% or 80% ISWT). Saliva samples were collected before and after exercise. Salivary SIgA concentrations were measured by enzyme-linked immunosorbent assay and secretion rates (μg/min) were calculated by multiplying the salivary SIgA concentration by saliva flow rate (ml/min) for each subject. After 40% ISWT, the salivary SIgA secretion rate of three patients decreased but that of the other two increased. After 80% ISWT, the salivary SIgA secretion rate of four patients decreased while that of the remaining one increased. It was suggested that in addition to the decline in local immunity after high intensity exercise like that seen in a normal healthy subject, the local immunity of the upper respiratory tract for COPD patients deceased after even low intensity exercise.