Application of metagenomic next-generation sequencing technology for difficult lung lesions in patients with haematological diseases

BACKGROUND: The purpose of this study was to evaluate the diagnostic value of combined virtual bronchoscopic navigation (Direct Path), radial endobronchial ultrasound with guide-sheath (EBUS), ultrathin bronchoscopy, rapid on-site evaluation of cytology (ROSE), and metagenomic next-generation sequencing (mNGS) for difficult lung lesions in patients with haematological diseases. METHODS: In this study, lung specimens were obtained from patients with haematological diseases by transbronchial lung biopsy (TBLB) and bronchoalveolar lavage (BAL). The specimens were subjected to mNGS for sequencing of pathogenic microorganisms and sent to the laboratory for examination and pathological analysis. Additionally, the clinical data and pathogenic characteristics of the patients were analysed. The sensitivity and specificity of mNGS for sequencing pathogenic microorganisms were compared between TBLB and BAL specimens. RESULTS: In this study, the diagnosis of infectious pneumonia mainly included cytomegalovirus pneumonia, Pneumocystis jirovecii pneumonia (PCP), pulmonary aspergillosis, and tuberculosis. Some patients had non-infectious pulmonary complications, and the clinical and therapeutic outcomes were diagnosed as graft-versus-host disease (GVHD), idiopathic pneumonia syndrome (IPS), and delayed pulmonary toxicity syndrome (DPTS). The sensitivity of mNGS for pathogenic microbes in lung tissue is better than that of alveolar lavage fluid, whereas compared with alveolar lavage fluid, its specificity is reduced. CONCLUSIONS: The results of this study indicate that combined virtual bronchoscopic navigation (Direct Path), radial EBUS, ultrathin bronchoscopy, and ROSE of target control specimens reduce the risk of bleeding, and their combination with mNGS has high diagnostic value for difficult lung lesions in patients with haematological diseases, especially in the field of infection diagnosis. TBLB and BAL specimens have respective advantages in specificity and sensitivity for mNGS analysis.