The etiology of cryptogenic organizing pneumonia (COP)was not clear, but previous studies have shown that in some patients, some pathogen could be detected in bronchoalveolar lavage fluid (BALF), and may be one of the causes of COP. This study aimed to screen the pathogenic microorganisms in BALF and lung puncture fluid of the patients with COP through the next-generation sequencing to further clarify the correlation between the incidence of COP and pathogenic microorganisms.

The cause of cryptogenic organizing pneumonia (COP) was unknown, but studies had shown that certain bacteria, viruses, or specific pathogens could be detected in bronchoalveolar lavage fluid (BALF) in some patients, and these pathogenic microorganisms may be the cause of COP. Specimens were obtained by conventional methods (sputum, blood, BALF or lung puncture fluid) for microbiological detection. Due to the influence of the quality of acquired specimens, specimen preservation and transportation which were influenced by external factors, many patients did not get good test results, which affected the diagnosis and subsequent treatment of patients. Next-generation sequencing (NGS) which could determine hundreds of thousands to millions of DNA molecules in parallel at one time, and efficiently sequence or fragment of pathogenic microorganisms. NGS had greatly improved the detection rate of pathogenic microorganisms. This study aimed to screen pathogenic microorganisms in BALF and lung puncture fluid of COP patients by NGS, and further clarify the correlation between occurrence of COP and pathogenic microorganisms.

Inclusion Criteria:

1. The patient was older than 18 years old.
2. The patient was organizing pneumonia (OP) through pathology.
3. The patient was diagnosed as OP from clear cause through routine detection.
4. Chest CT shows consolidation or ground glass

Exclusion Criteria:

1. The patient has specific characteristics of connective tissue disease or autoimmune disease.
2. The patient has a clear other cause of OP.
3. The patient has severe systemic diseases of heart, brain, liver, kidney and so on, and cannot tolerate invasive examination
4. The patient disapproves of invasive testing

The patients with cryptogenic organizing pneumonia