Compared with the control group, the LC group was found to have a significantly reduced percentage of CD4+CD25+FOXP3+ Treg cells (p < 0.01, Fig. 1a and b), markedly increased CD4+IL-17+ Th17 cells (p < 0.001, Fig. 1c and d), and a significantly lower Treg/Th17 ratio (p < 0.001, Fig. 1e). This evidence concerns the gene IL17A and laryngotracheoesophageal cleft.