glucocorticoid-induced tumour necrosis factor-receptor (GITR), cytotoxic T lymphocyte antigen (CTLA)-4)] were significantly lower in KD patients (P < 0·05). MiR-155 and miR-21 levelswere significantly down-regulated and miR-31 expression was higher in KD patients (P < 0·05). Plasma interleukin (IL)-6 concentrations, pSTAT-3 protein levels and suppressors of cytokine signalling (SOCS)-1 mRNA expression were remarkably elevated in acute KD (P < 0·05), while pSTAT-5 protein levels were remarkably decreased in acute KD (P < 0·05). These findings were reversed after intravenous immunoglobulin treatment (P < 0·05). Our results demonstrate that FoxP3 mRNA levels were primarily affected by the miR-155/SOCS1 and the miR-31 signalling pathways. These results suggest that the decrease in FoxP3 + Treg might be associated with decreased expression of miR-155, leading to aberrant SOCS1/STAT-5 signalling and overexpression of miR-31 in patients with acute KD.