Koh Y Y, Park Y, Lee H J, Kim C K
Department of Pediatrics and Clinical Research Institute, Seoul National University Hospital, Seoul, Korea.
Pediatrics. 2001 Mar;107(3):E39. doi: 10.1542/peds.107.3.e39.
In connection with the possible relationship between Mycoplasma infection and the onset of asthma, several studies have shown not only a high level of serum total immunoglobulin E (IgE) but also the production of IgE specific to Mycoplasma or common allergens during the course of Mycoplasma infection. It has been suggested that the balance of T helper type 1 (TH1)/T helper type 2 (TH2) immune response may regulate the synthesis of IgE. The objective of this study was to investigate the pattern of cytokine response (TH1 or TH2) during an episode of acute lower respiratory tract infection caused by Mycoplasma pneumoniae.
Using a bronchoalveolar lavage (BAL) with flexible bronchoscopy procedure, this study determined the levels of interleukin (IL)-2, interferon (IFN)-gamma (TH1), and IL-4 (TH2) in the supernatant of BAL fluid as well as the BAL cellular profiles of patients with Mycoplasma pneumonia (n = 14). These results were compared with those of patients with pneumococcal pneumonia (n = 12) or those of children with no identifiable airway infections (control group: n = 8).
The BAL cellular profile in the Mycoplasma pneumonia group was characterized by a high percentage of neutrophils and lymphocytes. A significantly increased level of IL-2 was found in both pneumonia groups, compared with the control group. In contrast, the IFN-gamma level was not different for the 3 groups. The level of IL-4 and ratio of IL-4/IFN-gamma were significantly elevated in the Mycoplasma pneumonia group, but not in the pneumococcal pneumonia group, compared with the controls.
IL-4 levels and IL-4/IFN-gamma ratios in BAL fluid are significantly higher in patients with Mycoplasma pneumonia than in patients with pneumococcal pneumonia or control participants. The BAL cytokine data suggest a predominant TH2-like cytokine response in Mycoplasma pneumonia, thus representing a favorable condition for IgE production.
关于支原体感染与哮喘发病之间的可能关系，多项研究表明，在支原体感染过程中，不仅血清总免疫球蛋白E（IgE）水平较高，而且还会产生针对支原体或常见过敏原的特异性IgE。有人提出，1型辅助性T细胞（TH1）/2型辅助性T细胞（TH2）免疫反应的平衡可能调节IgE的合成。本研究的目的是调查肺炎支原体引起的急性下呼吸道感染发作期间细胞因子反应（TH1或TH2）的模式。
本研究采用可弯曲支气管镜进行支气管肺泡灌洗（BAL），测定了14例支原体肺炎患者BAL液上清液中白细胞介素（IL）-2、干扰素（IFN）-γ（TH1）和IL-4（TH2）的水平以及BAL细胞谱。将这些结果与12例肺炎球菌肺炎患者或无明确气道感染的儿童（对照组：8例）的结果进行比较。
支原体肺炎组的BAL细胞谱特征为中性粒细胞和淋巴细胞百分比高。与对照组相比，两个肺炎组的IL-2水平均显著升高。相比之下，3组的IFN-γ水平没有差异。与对照组相比，支原体肺炎组的IL-4水平和IL-4/IFN-γ比值显著升高，但肺炎球菌肺炎组未升高。
支原体肺炎患者BAL液中的IL-4水平和IL-4/IFN-γ比值显著高于肺炎球菌肺炎患者或对照组参与者。BAL细胞因子数据表明，支原体肺炎中存在主要的类似TH2的细胞因子反应，因此为IgE的产生创造了有利条件。
