Lemière C, Cartier A, Dolovich J, Chan-Yeung M, Grammer L, Ghezzo H, L'Archevêque J, Malo J L
Department of Chest Medicine, Sacré-Coeur Hospital, Montréal, Canada.
Am J Respir Crit Care Med. 1996 Aug;154(2 Pt 1):329-33. doi: 10.1164/ajrccm.154.2.8756802.
A decrease in specific bronchial responsiveness (SBR) could occur after removal from exposure to an agent causing occupational asthma as a result of loss of immunologic and/or nonspecific bronchial reactivity (NSBR). We studied 15 subjects with occupational asthma (eight to a high- and seven to a low-molecular-weight agent, isocyanate in all instances), proved by specific inhalation challenges (SIC) done 2 yr or more before. Subjects were reexposed in the same way as in the initial SIC: for subjects who did not react, the exposure was increased until either an asthmatic reaction occurred or a maximum of 2 h was reached. NSBR was assessed before and after SIC. Subjects had a decrease in their SBR if the total dose of agent necessary to induce asthmatic reaction was greater by twofold compared with the initial SIC. There was a significant improvement in NSBR in seven of 15 subjects. Nine of 15 subjects (60%) had a decrease in their SBR. Only one had a complete loss of SBR. Changes in NSBR, molecular weight of the offending agent, decrease of antibody level against offending agents, or duration of exposure at work did not explain the decrease in SBR. We conclude that after removal from exposure to the offending agent a majority of subjects (60%) show a decrease but a persistence of SBR to high- and low-molecular-weight agents.
脱离导致职业性哮喘的致病因子接触后，由于免疫性和/或非特异性支气管反应性（NSBR）丧失，特异性支气管反应性（SBR）可能会降低。我们研究了15名职业性哮喘患者（8名接触高分子量致病因子，7名接触低分子量致病因子，所有病例均为异氰酸酯），这些患者在2年或更早之前通过特异性吸入激发试验（SIC）得到确诊。患者以与初始SIC相同的方式再次接触：对于无反应的患者，增加接触剂量，直至发生哮喘反应或最长达到2小时。在SIC前后评估NSBR。如果诱发哮喘反应所需的致病因子总剂量比初始SIC时增加两倍，则患者的SBR降低。15名患者中有7名的NSBR有显著改善。15名患者中有9名（60%）的SBR降低。只有1名患者的SBR完全丧失。NSBR的变化、致病因子的分子量、针对致病因子的抗体水平降低或工作接触时长均无法解释SBR的降低。我们得出结论，脱离致病因子接触后，大多数患者（60%）的SBR会降低，但对高分子量和低分子量致病因子仍持续存在。
