RESUMEN
<p><b>OBJECTIVE</b>To investigate the changes in the levels of interleukin-17 (IL-17) and transforming growth factor beta 1 (TGF-β1) in serum and bronchoalveolar lavage fluid (BALF) and their clinical significance among children with asthma.</p><p><b>METHODS</b>Fifty-six children with asthma were divided into moderate or severe asthma (n=37) and mild asthma groups (n=19) and 18 children without asthma were selected as the control group. Cells in BALF were counted under a microscope. The levels of IL-17 and TGF-β1 in serum and BALF were measured using ELISA.</p><p><b>RESULTS</b>were no significant differences in total cell count and percentage of macrophages between the two asthma groups and the control group (P>0.05). The percentages of neutrophils, eosinophils and epithelial cells in BALF were significantly higher in the two asthma groups than in the control group (P<0.05). The two asthma groups had significantly higher levels of IL-17 and TGF-β1 in serum and BALF than the control group (P<0.05), and the moderate or severe asthma group had significantly higher levels of IL-17 and TGF-β1 in serum and BALF than the mild asthma group (P<0.05). Levels of IL-17 and TGF-β1 in serum were significantly positively correlated with those in BALF (r=0.935 and 0.943, P<0.05 for both). In children with asthma, serum IL-17 level was significantly positively correlated with the percentage of neutrophils, eosinophils and epithelial cells in BALF (r=0.802, 0.799, and 0.674, P<0.05 for all), and a significant positive correlation was also seen between serum levels of IL-17 and TGF-β1 (r=0.878, P<0.05).</p><p><b>CONCLUSIONS</b>Levels of IL-17 and TGF-β1 in serum and BALF are elevated in children with asthma. IL-17 and TGF-β1 may be involved in the occurrence and development of asthma, and they play important roles in asthma attack and aggravation.</p>