ABSTRACT
<p><b>OBJECTIVE</b>To determine the frequencies and significance of myeloid-derived suppressor cells (MDSCs) and T-helper 17 (Th17) cells in peripheral blood of young children with recurrent wheezing.</p><p><b>METHODS</b>Thirty young children with an acute exacerbation of recurrent wheezing were randomly enrolled. Twenty age-matched children with bronchopneumonia (pneumonia group) and 23 age-matched preoperative children with non-infectious or non-neoplastic diseases (hernia or renal calculus) (control group) were selected. The frequencies of MDSCs and Th17 cells in the peripheral blood were measured using flow cytometry and their correlation was determined by the Spearman's correlation coefficient.</p><p><b>RESULTS</b>The percentage of MDSCs in nucleated cells was significantly higher in the wheezing group than in the pneumonia and control groups (P<0.05), and it was significantly higher in the pneumonia group than in the control group (P<0.05). The percentage of Th17 cells in mononuclear cells was significantly higher in the wheezing group than in the pneumonia and control groups (P<0.05), but it showed no significant difference between the pneumonia and control groups (P>0.05). The frequency of MDSCs was positively correlated with the frequency of Th17 cells in the wheezing group (r=0.645, P<0.01).</p><p><b>CONCLUSIONS</b>MDSCs and Th17 cells may contribute to the pathogenesis of recurrent wheezing in young children.</p>