The study aims to investigate the relationship between the small molecule metabolite sphingolipids and asthma clinical features and explore its involvement in asthma pathogenesis.

Inclusion Criteria:

• 1. clinical diagnosis of asthma

Exclusion Criteria:

• 1. Combined with chronic obstructive pulmonary disease, bronchiectasis, pneumonia, obstructive sleep apnea hypopnea syndrome, malignant tumor 2. Combined with acute and chronic respiratory failure 3. Combined with severe cardiovascular disease 4. Pregnant woman.

Patients with asthma who visited or were hospitalized in the Department of Respiratory and Critical Care Medicine of Peking University Third Hospital, who met the asthma diagnostic criteria proposed in the Bronchial Asthma Prevention and Treatment Guidelines and healthy controls without history or symptoms of chronic respiratory disease, allergic status or other conditions that could affect the outcome.