目的 探讨辅助性T细胞9 （Th9） 及其细胞因子白细胞介素-9 （IL-9） 在川崎病 （KD） 患儿急性期外周血的表达及临床意义。方法 选取2014年4月至2015年7月45例急性期川崎病患儿进行研究，并且对其进行恢复期随访；另取健康体检儿童45例作为对照组。采用流式细胞术检测外周血Th9水平及酶联免疫吸附试验 （ELISA） 检测血清IL-9水平。结果 KD患儿急性期Th9及IL-9水平明显高于恢复期和对照组 （P < 0.05）；而恢复期患儿与对照组的Th9、IL-9水平差异均无统计学意义 （P > 0.05）。急性期的Th9与CRP、PCT、ESR、PLT及球蛋白水平呈正相关 （r=0.324、0.402、0.382、0.467、0.386，均P < 0.05），与血清白蛋白呈负相关 （r=-0.306； P < 0.05）；IL-9水平与CRP、PCT、ESR、PLT、球蛋白水平呈正相关 （r=0.365、0.456、0.403、0.423、0.453，均P < 0.05），与血清白蛋白呈负相关 （r=-0.343；P < 0.05）。结论 KD患儿急性期外周血Th9细胞及其细胞因子IL-9水平明显升高，恢复期降至正常；且Th9表达及IL-9水平与急性期指标密切相关。推测Th9细胞与IL-9在KD的发病及转归过程起重要作用。

Objective To investigate the changes in the expression levels of peripheral blood T helper 9 (Th9) cells and cytokine interleukin-9 (IL-9) in children in the acute stage of Kawasaki disease (KD) and their clinical significance. Methods A total of 45 children in the acute stage of KD who were treated from April 2014 to July 2015 were enrolled, and the children were followed up in the recovery stage. Another 45 healthy children who underwent physical examination were enrolled as the control group. Flow cytometry was used to measure the percentage of peripheral blood Th9 cells, and ELISA was used to measure the serum level of IL-9. Results The children in the acute stage of KD showed a significantly higher percentage of Th9 cells and a significantly higher serum level of IL-9 compared with those in the recovery stage and the control group (P < 0.05). The percentage of Th9 cells and serum level of IL-9 showed no significant differences between the children in the recovery stage and those in the control group (P > 0.05). In the acute stage, the percentage of Th9 cells was positively correlated with the levels of IL-9, C-reactive protein (CRP), procalcitonin (PCT), erythrocyte sedimentation rate (ESR), platelet count (PLT), and globulin (r=0.624, 0.324, 0.402, 0.382, 0.467, and 0.386 respectively, all P < 0.05), but negatively correlated with serum albumin (r=-0.306, P < 0.05). The serum level of IL-9 was positively correlated with the levels of CRP, PCT, ESR, PLT, and globulin (r=0.365, 0.456, 0.403, 0.423, and 0.453 respectively, all P < 0.05), but negatively correlated with serum albumin (r=-0.343, P < 0.05). Conclusions The children in the acute stage of KD show significant increases in the percentage of peripheral Th9 cells and serum cytokine IL-9 level, which return to normal in the recovery stage. In the acute stage of KD, the expression levels of Th9 and IL-9 are closely correlated with laboratory markers. The results suggest that Th9 cells and IL-9 play important roles in the pathogenesis and outcome of KD.