The Effects Of SIL-2R And MicroRNAs On Regulator T Cells In Children With Acute Kawasaki Disease

PART ONE: THE EFFECTS OF PLASMA SIL-2R ONREGULATORY T CELLS IN CHILDREN WITH ACUTEKAWASAKI DISEASEObjective To investigate the effects of plasma sIL-2R onregulatory T cells (Treg) in children with Kawasaki disease (KD).Methods27children with KD and14age-matched healthychildren were enrolled in this study. The proportions ofCD4+CD25+Foxp3+regulatory T (Treg) and mean fluorescence intensity(MFI) for phosphorylated-STAT5(pSTAT5) protein in CD4+CD25+Tcells was were analyzed by flow cytometry; The concentrations ofsIL-2R、IL-2、IL-7、IL-15in plasma were measured by cytometric beadarray (CBA); Real-time PCR was performed to detect the levels ofFoxp3、GITR、CTLA4、IL-2Rα、IL-2Rβ、IL-2RγmRNA expression inCD4+CD25+T cells.Results①The proportions of CD4+CD25+Foxp3+Treg inperipheral blood from patients with KD,and levels of associating factors Foxp3、GITR、CTLA-4mRNA expression were significantly lower thanthose of health subjects（P<0.05), and recovered to some extent aftertreatment with IVIG （P<0.05）.②Levels of pSTAT5protein inCD4+CD25+T cells was significantly down-regulated during acute phaseof KD（P<0.05）, and significantly up-regulated after treatment with IVIG（P<0.05）.③plasma concentrations of sIL-2R were significantlyelevated during acute KD（P<0.05）,and decreased after treatment withIVIG（P<0.05）, and KD patients with coronary artery lesion(KD-CAL+)were found to be significantly higher than those of KD patients withoutcoronary artery lesion(KD-CAL-)（P<0.05）,while plasma concentrationsof IL-2、IL-7、IL-15were found to be no differen（tP>0.05）.④Comparedwith healthy subjects, the levels of IL-2Rα and IL-2RβmRNA expressionin CD4+CD25+T cells were significantly lower during acute phase of KD（P<0.05）, and higher to some extent after treatment with IVIG（P<0.05）, while transcription level of IL-2Rγ was found to be nodifferent （P>0.05）. There were significantly negative correlationsbetween plasma concentrations of sIL-2R and expression levels ofIL-2RβmRNA or pSTAT5（P<0.05, P<0.05）.Conclusion Aberrant IL-2/STAT5signaling pathway caused bysignificantly increased plasma concentration of sIL-2R might be one offactors leading to down-regulated of Treg cells in acute KD. IVIG therapycan decrease the plasma concentrations of sIL-2R and recover IL-2/IL-2Rβ/STAT5signaling pathway, which may be one of themechanisms that IVIG regulating inflammatory or autoimmune diseasesimmune dysfunction. PART TWO: THE EFFECTS OF MICRORNAS ONREGULATORY T CELLS IN CHILDREN WITH ACUTEKAWASAKI DISEASEObjective The study was designed to investigate the effects ofmicroRNA-155(miR-155)、 miR-21、miR-31on regulatory T cells (Treg)in children with Kawasaki disease (KD).Methods The proportions of CD4+CD25+Foxp3+regulatory T(Tregs) and mean fluorescence intensity (MFI) forphosphorylated-STAT5(pSTAT5) and phosphorylated-STAT3(pSTAT3)protein in CD4+CD25+T cells were analyzed by flow cytometry. Theconcentrations of IL-6in plasma were measured by cytometric bead array(CBA). Real-time polymerase chain reaction(PCR) was performed todetect the levels of miR-155, miR-21, miR-31and Foxp3, GITR, CTLA4,SOCS1mRNA expression in CD4+CD25+T cells. Results①Tregs proportions and mRNA expression levels ofassociating factors(Foxp3, GITR, CTLA-4) were significantly lower thanthose of health subjects(Ctrl)(P<0.05), and recovered to some extent aftertreatment with intravenous immune globulin(IVIG) in children with acuteKD(P<0.05).②Compared with healthy subjects, the levels of miR-155and miR-21expression were significantly down-regulated during acutephase of KD(P<0.05) and up-regulated after treatment withIVIG(P<0.05), while the levels of miR-31expression shew an oppositetrend.③The plasma IL-6concentrations, levels of pSTAT3protein andSOCS1mRNA expression were remarkably elevated, meanwhile levels ofpSTAT5protein were remarkably decreased during acute KD(P<0.05),which were reversed after IVIG treatment (P<0.05).④Main influencefactors of Foxp3mRNA expression were miR-155/SOCS1and miR-31signaling pathway（P<0.05）.Conclusion These results suggest that down-regulation of Tregcells might be associated with aberrant miR-155/SOCS1andpSTAT3/miR-21signaling pathway and over-expression of miR-31inpatients with acute KD. IVIG therapy can regulate Treg cell-relatedmiRNAs and the specific mechanism of action need to be further studied.