Expression and Clinical Significance of IL-33 and its Receptor ST2 in Children with Obstructive Sleep Apnea Syndrome

Abstract Background To detect the expression of interleukin-33 (IL-33) and its receptor ST2 in adenoids of children with obstructive sleep apnea syndrome (OSAS) as well as to explore the significance of IL-33/ST2 in the disorder. Methods 40 children undergoing adenoidectomy due to OSAS in the Otolaryngology of Tianjin Children’s Hospital were selected as the study subjects. The number of IL-33 and ST2 positive cells in adenoids was detected by immunohistochemical SP method. Results IL-33 positive cells were mainly distributed in the submucosa epithelium and vascular endothelium, and expressed in the nucleus and cytoplasm. While ST2 positive cells were primarily observed in the mucosa and expressed in the nucleus and cytoplasm, a little expression of intercellular substance. There was a positive correlation between the proportion of adenoids in the posterior nostril diameter and the number of IL-33 positive cells. The expression of IL-33 in adenoids was positively correlated with the level of ST2 (r = 0.809, P = 0.000). The expression of IL-33 in adenoids was positively correlated with the level of eosinophil granulocyte (r = 0.859, P = 0.000). Moreover, the expression of ST2 in adenoids was positively correlated with the level of eosinophil granulocyte (r = 0.814, P = 0.000). The number of IL-33 positive cells was significantly higher in moderate hypoxemia group than that in mild hypoxemia group (P < 0.05). There was no significant difference in the number of ST2 positive cells between moderate hypoxemia group and mild hypoxemia group (P > 0.05). Conclusions Both IL-33 and its receptor ST2 were expressed in adenoids of OSAS children. The severity of airway obstruction caused by adenoid hypertrophy was positively correlated with the expression of IL-33.