花粉症患者外周血CD4＋CD25＋调节性T细胞数量和功能变化研究

Changes in percentage and function of CD4＋CD25＋regulatory T cells in peripheral blood of patients with hay fever

目的 检测花粉症患者在发作期外周血中CD4＋CD25＋调节性T细胞（regulatory T cells,Treg）数量和功能变化,探讨Tregs在花粉症患者病情发生、发展中的作用.方法 收集20例确诊为花粉症患者（花粉症组）,20例尘螨过敏哮喘患者（尘螨过敏哮喘组）和20例健康儿童（健康对照组）外周血,流式细胞术检测外周血中单个核细胞（PBMC）中的CD4＋CD25＋Treg数量.采用磁珠分选技术分选花粉症组患者和健康对照组儿童的CD4＋CD25＋Treg和CD4＋CD25-T细胞（Teff）,采用MTT法检测CD4＋CD25＋Treg对自身CD4＋CD25-T细胞增殖的抑制作用;提取各组PBMCs的总RNA,RT-PCR法检测TGF-β1、Foxp3 mRNA的表达水平.结果 本研究共入组花粉症患者20例,男9例,女11例,平均年龄（10.3±4.3）岁;尘螨过敏哮喘患者20例,男10例,女10例,平均年龄（11.5±3.8）岁;健康对照组儿童20例,男12例,女8例,平均年龄（12.1±4.6）岁.在季节发作期内,花粉症患者外周血Treg数量[（1.82±0.82）％]显著低于尘螨过敏哮喘组[（2.96±1.34）％]以及健康对照组[（5.78±2.29）％],差异均有统计学意义（P均〈0.05）.花粉症组外周血Foxp3 mRNA基因表达水平为（0.46±0.25）,均低于尘螨过敏哮喘组（0.64±0.31）和健康对照组（1.04±0.21）,差异均有统计学意义.花粉症组、尘螨过敏哮喘组患者外周血TGF-β1 mRNA基因表达水平分别为0.34±0.27和0.43±0.31,与健康对照组（0.99±0.34）相比均显著降低.花粉症组外周血CD4＋CD25＋Treg对自身Teff增殖的抑制率为（17.1±8.4）％,显著性低于尘螨过敏哮喘组[（21.4±9.1）％]和健康对照组[（36.0±13.9）％],差异具有统计学意义（P均〈0.05）.结论 花粉季节发作期内Tregs数量降低和功能缺陷可能是花粉症患者病情发生发展的重要诱因之一.

Objective To investigate the changes in percentage and function of CD4＋CD25＋regu-latory T cells （ Tregs） in peripheral blood of patients with hay fever. Methods A total of 20 patients with hay fever, 20 patients with house dust mite-induced allergic asthma and 20 healthy subjects were enrolled in this study. Peripheral blood samples were collected from all subjects to isolate PBMCs. Percentages of Tregs in PBMCs were measured by flow cytometry. CD4＋CD25＋ Tregs and CD4＋CD25-T cells （ Teffs） were isola-ted by immunomagnetic cell sorting. Effects of CD4＋CD25＋Tregs on the proliferation of Teffs were evaluated by MTT assay. Expression of Foxp3 and TGF-β1 at mRNA level was analyzed by RT-PCR. Results During the pollen season, the percentage of circulating Tregs in patients with hay fever [（1. 82＋0. 82）%] was sig-nificantly lower than that in patients with house dust mite-induced allergic asthma [（2. 96±1. 34）%] and health subjects [（5. 78±2. 29）%] （both P〈0. 05）. Expression of Foxp3 at mRNA level was significantly reduced in patients with hay fever （0. 46±0. 25） as compared with that of the house dust mite-induced aller-gic asthma （0. 64±0. 31） and healthy control （1. 04±0. 21） groups （both P〈0. 05）. Expression of TGF-β1 at mRNA level in both hay fever （0. 34±0. 27） and house dust mite-induced allergic asthma （0. 43±0. 31） groups was lower than that of the healthy control group （0. 99±0. 34）. Treg-mediated suppression of Teff proliferation was significantly decreased in patients with hay fever [（17. 1±8. 4）%] as compared with that in patients with house dust mite-induced allergic asthma [（21. 4±9. 1）%]） and healthy subjects [（36. 0± 13. 9）%] （P〈0. 05）. Conclusion Decreased percentage and defective function of Tregs might be one of the major causes for the occurrence and development of hay fever in children during the pollen season.