To study the expression level of biomarkers such as GITRL in peripheral blood of children with asthma and analyze their correlation with the severity of asthma. To study the predictive value of biomarkers level for the occurrence and development of asthma. And to provide supplementary detection means and predictive indicators for the diagnosis of asthma and the severity of asthma.

Recruit 30 children with asthma and 30 healthy children based on the consent of the children and their parents or their guardian. Collect and record general information such as name, age, time of first diagnosis, allergens or triggers, daily dosage and frequency of asthma control drugs, home address and contact information. Collect 5 ml of blood sample for the detect of the biomarkers. Asthma severity was assessed using pulmonary function by spirometry and score of C-CAT. Finally study the correlation between the level of biomarkers and asthma severity and the role of biomarkers in the occurrence and development of asthma.

Inclusion Criteria:

• In line with the diagnostic criteria in the Guidelines for the Diagnosis and Prevention of Bronchial Asthma in Children (2016 Edition)
• Age: 4-12 years old for new diagnosis or recurrent episodes
• Typical clinical manifestations and complete clinical data
• Family members or guardians of children with informed research and signed consent
• All healthy control subjects had no history of lung disease, allergic rhinitis or any other atopic disease

Exclusion Criteria:

• Suffering from other respiratory diseases (such as bronchiectasis, allergic rhinitis, respiratory failure, tuberculosis, obstructive airway disease) or other inflammatory diseases.
• Abnormal development of congenital airway and lung tissue
• History of immunosuppressant or glucocorticoid use in the first 4 weeks
• Suffering from other endocrine system and immune system diseases
• Incomplete clinical data or examinations.

Children with typical asthma symptoms, such as cough, wheezing, chest tightness, dyspnea and abnormal lung function tests, were diagnosed with asthma by a respiratory doctor