Kuo M L, Huang J L, Yeh K W, Li P S, Hsieh K H
Health Research Division, Chang Gung Children's Hospital, Taoyuan, Taiwan, Republic of China.
Ann Allergy Asthma Immunol. 2001 Mar;86(3):272-6. doi: 10.1016/S1081-1206(10)63297-8.
Th2-type cytokines, such as IL-4 and IL-5, are generally believed to play an important role in the pathogenesis of allergic asthma. In contrast, Th1-type cytokine, especially interferon (IFN)-gamma, is thought to have a downregulatory effect on Th2 immune response cells. Thus, the imbalance of Th1 and Th2 cells may be a key factor in relation to disease severity.
The aim of this study is to examine the changes in the Th1/Th2 ratios and cytokine production profiles of asthmatic children at acute attacks and convalescent stages.
Twelve asthmatic patients were included in this study. The percentages of IFN-gamma- or IL-4-producing cells were determined with a flow-cytometric method of intracellular protein detection. Fresh whole blood obtained from normal controls and patients at two stages was stimulated with brefeldin A, phorbol myristate acetate, and ionomycin for 4 hours. Cells were fixed and stained intracellularly with fluorescein isothiocyanate- or phycoerythrin-conjugated antibody specific to each cytokine in combination with anti-CD4. ELISA assays were applied to measure cytokine concentrations of supernatant from peripheral blood mononuclear cells (PBMC) activated with phorbol myristate acetate and ionomycin for 24 hours.
Among CD4+ cells, the percentage of IL-4+ cells decreased significantly from 8.18 +/- 4.77% at acute attacks to 4.18 +/- 1.26% (P < .020) at convalescence. The percentage of IFN-gamma+ cells also decreased from 13.49 +/- 4.21% to 9.03 +/- 5.42% (P < .052). The Th1/Th2 ratios of patients at the two stages were similar, and both were lower than the normal controls. Significantly higher IL-5 and lower IFN-gamma production were detected from activated PBMC of asthmatic patients than normal controls.
The decrease of IFN-gamma+ and IL-4+ cells detected at the single-cell level may explain the potential mechanism of convalescence from acute asthma attacks. High Th1/Th2 ratio and low IL-5 production from the PBMC of normal controls support the idea of a biased Th2 immune response in asthmatic patients.
一般认为，白细胞介素-4（IL-4）和白细胞介素-5（IL-5）等Th2型细胞因子在过敏性哮喘的发病机制中起重要作用。相比之下，Th1型细胞因子，尤其是干扰素（IFN）-γ，被认为对Th2免疫反应细胞具有下调作用。因此，Th1和Th2细胞的失衡可能是与疾病严重程度相关的关键因素。
本研究旨在检测哮喘患儿急性发作期和恢复期Th1/Th2比值及细胞因子产生情况的变化。
本研究纳入12例哮喘患者。采用细胞内蛋白检测的流式细胞术方法测定产生IFN-γ或IL-4的细胞百分比。用布雷菲德菌素A、佛波酯肉豆蔻酸酯和离子霉素刺激从正常对照和两个阶段的患者获取的新鲜全血4小时。细胞固定后，用异硫氰酸荧光素或藻红蛋白偶联的针对每种细胞因子的特异性抗体与抗CD4联合进行细胞内染色。采用酶联免疫吸附测定法（ELISA）检测用佛波酯肉豆蔻酸酯和离子霉素激活外周血单个核细胞（PBMC）24小时后的上清液中细胞因子浓度。
在CD4+细胞中，IL-4+细胞百分比从急性发作期的8.18±4.77%显著降至恢复期的4.18±1.26%（P<0.020）。IFN-γ+细胞百分比也从13.49±4.21%降至9.03±5.42%（P<0.052）。两个阶段患者的Th1/Th2比值相似，且均低于正常对照。哮喘患者激活的PBMC中检测到的IL-5产生显著高于正常对照，而IFN-γ产生低于正常对照。
在单细胞水平检测到的IFN-γ+和IL-4+细胞减少可能解释了急性哮喘发作恢复期的潜在机制。正常对照PBMC的高Th1/Th2比值和低IL-5产生支持哮喘患者存在偏向性Th2免疫反应的观点。
