摘要目的 探讨SOCS1和SOCS3低甲基化对川崎病Th1/Th2细胞失衡的影响.方法 急性期川崎病患儿36例,健康同年龄对照组16名.酶联免疫吸附试验(ELISA)检测血浆白细胞介素(IL)-6蛋白浓度;实时荧光定量聚合酶链反应(PCR)检测CD4+T细胞SOCS1、SOCS3、T-bet、干扰素(IFN)-γ、GATA3、IL-4基因mRNA表达;流式细胞术检测外周血Th1/Th2细胞比例和CD4+T细胞磷酸化STAT3(pSTAT3)蛋白平均荧光强度(MFI);甲基化特异性定量PCR(MethySYBR PCR)检测CD4+T细胞SOCSl基因外显子2、SOCS3基因5'端非翻译区(5'-UTR)3个可能的STAT3结合位点CpG岛甲基化水平.采用t检验进行统计分析.结果 ①急性期川崎病患儿血浆IL-6浓度[分别为(51.8±16.3)pg/ml和(8.6±2.0)pg/ml]、CD4+T细胞pSTAT3 MH水平[分别为(52±14)和(10±4)]显著上调(P＜0.05).其中川崎病合并冠状动脉损伤组(川崎病-CAL+)IL-6和pSTAT3 MFI水平均明显高于无冠状动脉损伤组[IL-6为(87.2±27.4)pg/ml与(36.2±12.8)pg/ml,P＜0.05;pSTAT3 MFI为(75±15)和(42±11),P＜0.05].②急性期川崎病患儿Th1、Th2细胞比例及相关因子(T-bet、IFN-γ、GATA3和IL-4)表达明显增高(P＜0.05),Th1/Th2比值低于健康对照组(P＜0.05).其中川崎病-CAL+组Th1、Th2细胞比例及相关因子表达水平高于川崎病-GAL-组(P＜0.05),而Th1/Th2比值则略低于后者(P＜0.05).③急性期川崎病患儿CD4+T细胞SOCS1和SOCS3 mRNA水平显著高于同年龄对照组(P＜0.05),其中川崎病-CAL+组 SOCS1和SOCS3 mRNA表达低于川崎病-CAL-组(P＜0.05);健康对照组SOCS1基因外显子2、SOCS3基因5'-UTR区第3个STAT3结合位点的CpG岛完全去甲基化,急性期川崎病患儿呈低甲基化状态(P＜0.05),其中川崎病-CAL+组去甲基化水平明显低于川崎病-CAL组(P＜0.05);各组SOCS3基因5'-UTR区第1、2个STAT3结合位点CpG岛均处于完全去甲基化状态(P＞0.05).结论 SOCS1和SOCS3基因低甲基化所致表达相对不足可能是川崎病Th1/Th2细胞失衡的因素之一.

abstractsObjective To investigate the effect of SOCS1 and SOCS3 hypomethylation on homeostasis of Th1/Th2 in Kawasaki disease(KD). Methods Thirty-six children with KD and sixteen age-matched healthy children consented to participate in this study. Protein concentration of IL-6 in plasma was measured by ELISA. Transcriptional levels of SOCS1, SOCS3, T-bet, IFN-γ, GATA3 and IL-4 were assessed by realtime PCR. The proportion of Th1 and Th2 cells, and mean fluorescence intensity(MFI)for phosphorylated STAT3(pSTAT3)protein in CD4+ T cells was analyzed by flow cytometry. A quantitative methylation specific PCR based on SYBR Green was used to evaluate methylation status of CpG islands in SOCSl exon2, and three potential binding sites for STAT3 in 5'-untraslated region(5'-UTR)of SOCS3 in CD4+T cells. Comparisons between groups were performed with t-test. Results ①Compared with healthy volunteers, plasma IL-6 concentration[(51.8±16.3)pg/ml vs(8.6±2.0)pg/ml, respectively]and MFI for pSTAT3[(52±14)vs(10±4), respectively]in CD4+ T cells were elevated significantly during acute phase of KD(P＜0.05), and the two items in KD patients with coronary artery lesion(KD-CAL+)were found to be higher than those in KD patients without coronary artery lesion(KD-CAL-)[IL-6:(87.2±27.4)pg/ml vs(36.2±12.8)pg/ml, P＜0.05; pSTAT3 MFI:(75±15)vs(42±11), P＜0.05]. ② The proportions of Th1 and Th2 cells and transcription levels of Th-associating factors(T-bet, IFN-γ, GATA3 and IL-4)in CD4+ T cells increased significantly in acute KD(P＜0.05), while the rate of Thl div Th2 in KD patients was found to be lower than that in normal controls(P＜0.05). In addition, the proportions of Th1 and Th2 cells and expressions levels of Th-associating factors in KD-CAL+ group were higher than those in KD-CAL-group, as well as the rate of Thl div Th2 cells in KD -CAL+ group were lower than that in KD-CAL- group(P＜0.05). ③ The mRNA levels of SOCSl and SOCS3 in CD4+ T cells increased significantly during acute phase of KD(P＜0.05), while the two items in KDCAL+ group were lower than those in KD-CAL- group(P＜0.05). Furthermore, CpG islands in SOCSl exon2 and the third potential binding site for STAT3 in SOCS3 5'-UTR were hypomethylated in acute KD, while those in healthy volunteers were fully demethylated(P＜0.05). Demethylation levels of the two items mentioned above in the KD-CAL+ group were lower than those in the KD-CAL-group(P＜0.05). CpG islands in the other two binding sites for STAT3 in SOCS3 5'-UTR were fully demethylated among all the groups(P＞0.05).Conclusion Relative insufficiency of SOCS1 and SOCS3 expression caused by hypomethylation may be one contributing factor for the imbalance of Th1/Th2 in KD.