Burgers J A, Bruynzeel P L, Mengelers H J, Kreukniet J, Akkerman J W
Department of Hematology, University Hospital Utrecht, The Netherlands.
J Lipid Mediat. 1993 Jun;7(2):135-49.
The administration of platelet-activating factor (PAF) to human subjects triggers asthma-like responses. We investigated whether a bronchoconstrictive reaction was accompanied by the release of PAF in the circulation of allergic asthmatics. The appearance of PAF was assessed by measuring the number of freely accessible PAF-receptors on platelets in vitro, assuming that the contact between platelets and PAF in vivo would reduce the receptor binding of [3H]PAF in vitro. 16 asthmatics were challenged twice, first with buffer and the next day with allergen. A comparison between receptor binding after provocation with the data of the same patients after allergen challenge revealed a significant difference in PAF binding (P = 0.034), with an average decrease of 14% immediately after allergen challenge followed by a return to control values after about 4 h and a transient increase of 9% at 7 h after provocation. The decrease in accessible PAF receptors was accompanied by a slight decrease in platelet count in peripheral blood between 30 min and 4 h after allergen challenge. The platelet counts recovered to the original values afterwards. These data support the concept that in patients with allergic asthma PAF is secreted in the circulation. The contact between PAF and the platelets may trigger the transient sequestration of platelets, possibly in the lung. Thus, PAF and platelets may contribute to the pathogenesis of allergic asthma.
给人类受试者注射血小板活化因子（PAF）会引发类似哮喘的反应。我们研究了变应性哮喘患者循环中PAF的释放是否伴随着支气管收缩反应。通过体外测量血小板上可自由结合的PAF受体数量来评估PAF的出现情况，假定体内血小板与PAF的接触会减少体外[3H]PAF与受体的结合。16名哮喘患者接受两次激发试验，第一次用缓冲液，第二天用变应原。将激发试验后受体结合情况与同一患者变应原激发后的数据进行比较，发现PAF结合存在显著差异（P = 0.034），变应原激发后立即平均下降14%，约4小时后恢复到对照值，激发后7小时短暂升高9%。变应原激发后30分钟至4小时外周血血小板计数略有下降，可结合PAF受体减少与之相伴。之后血小板计数恢复到原始值。这些数据支持变应性哮喘患者循环中分泌PAF这一概念。PAF与血小板的接触可能触发血小板的短暂隔离，可能发生在肺部。因此，PAF和血小板可能参与变应性哮喘的发病机制。
