目的：探讨幼年类风湿关节炎(JRA)患儿血清白介素15变化及其TH细胞亚群CD4+CD45RA+，CD4+CD45RO+的表达变化。方法：采用ELISA方法检测39例JRA患儿的血清IL15的水平，并同期选择26例年龄、性别无差异的健康儿童为对照。对其中24例JRA患儿采用免疫荧光标记技术和流式细胞仪检测外周血CD4+T淋巴细胞亚群CD4+CD45RA+，CD4+CD45RO+的表达。结果：JRA患儿组血清IL15水平显著高于正常对照组(P<0.05)；JRA常见亚型中全身型患儿血清IL15水平明显升高，与对照组比较差异有显著性(P<0.01)，而少关节型、多关节型患儿IL15水平与对照组比较差异无显著性(P>0.05)；治疗后IL15水平较治疗前明显下降(P<0.01)；JRA患儿血清IL15水平与外周血白细胞计数呈正相关(r=0.347,P<0.05)，与血沉无相关(r=0.307，P>0.05)，与C反应蛋白呈显著正相关(r=0.452，P<0.01)；IL15高表达组患儿外周血CD4+CD45RO+T淋巴细胞数明显高于IL15低表达组患儿(P<0.05),CD4+CD45RA+T淋巴细胞数、CD4+CD45RA+T/CD4+CD45RO+T比值略低于IL15低表达组患儿，差异无显著性(P>0.05)。结论：JRA患儿血清IL15的水平显著升高；IL15升高使JRA患儿外周血CD4+T细胞表面CD45RA分子向CD45RO分子转换，促使T淋巴细胞大量激活，进而介导组织免疫病理损伤；在临床上可通过检测IL15以判断JRA的病情状况，为JRA治疗提供理论依据。

OBJECTIVE: To study the changes of serum interleukin-15 (IL-15) levels and the expression of CD4+T (T-helper lymphocyte) subsets CD4+CD45RA+ and CD+CD45RO+ in peripheral blood of children with juvenile rheumatoid arthritis (JRA). METHODS: The serum concentration of IL-15 was detected using ELISA in 39 children with JRA. The expressions of CD4+CD45RA+T and CD4+CD45RO+ T in peripheral blood were detected by flow cytometry in 24 out of the 39 patients with JRA. Twenty-six age and sex-matched healthy children were used as the Control group. RESULTS: The mean serum IL-15 level in JRA patients was significantly higher than that in controls (1.37±0.98 pg/mL vs 0.96±0.41 pg/mL, P<0.05). Among the 39 JRA patients, the serum IL-15 level in 17 patients with systemic JRA increased remarkably (P<0.01), but not in patients with the other two types of JRA, the oligoarthritis and polyarthritis (n=13, n=9, respectively), compared with that in controls. The mean serum IL-15 level of the JRA patients was significantly reduced after conventional treatment (P<0.01). The serum IL-15 level in JRA patients positively correlated with white blood cell count (r=0.347, P<0.05) and C reactive protein (r=0.452, P<0.01), but not with the erythrocyte sedimentation rate. The patients with high serum IL-15 levels (≥medium level 1.73 ρg/mL) had higher expression of CD4+CD45RO+T than those with low serum IL-15 levels