应用放射免疫分析法对２０例正常儿、２７例毛细支气管炎、７例肺炎和６例上感进行血浆血栓素Ｂ＿２（ＴＸＢ＿２），６－酮－前列素Ｆ＿（１α）（６－Ｋｅｔｏ－ＰＧＦ＿（１α））测定，动态观察其变化。结果显示：（１）毛细支气管炎急性期ＴＸＢ＿２、ＴＸＢ＿２／６－Ｋｅｔｏ－ＰＧＦ＿（１α）（Ｔ／Ｋ）比值明显升高，病情重者较高，恢复期则下降至正常，而６－Ｋｅｔｏ－ＰＧＦ＿（１α）无显著变化；（２）肺炎或上感上述指标均无显著变化。提示ＴＸＡ＿２－ＰＧＩ＿２之间平衡失调可能是毛细支气管炎发病的重要因素之一。 The plasma levels of TXB_2, 6-Keto-PGF_ (1α) and T-lymphocyte were measured by radioimmunoassay in 20 normal children, 27 bronchiolitis patients, 7 pneumonia and 6 superficial sensations. (1α)), dynamic observation of its changes. The results showed that: (1) The ratios of TXB_2, TXB_2 / 6-Keto-PGF_ (1α) (T / K) in patients with bronchiolitis were significantly increased in acute phase of bronchiolitis, -PGF_ (1α) no significant change; (2) pneumonia or the above indicators were no significant changes. It is suggested that the imbalance between TXA_2 and PGI_2 may be one of the important factors in the pathogenesis of bronchiolitis.