High level of prevotella melanogenic in the lower respiratory microbiota of checkpoint inhibitor pneumonitis and radiation pneumonitis

Background: Checkpoint inhibitor pneumonitis (CIP) and radiation pneumonitis (RP) lead to anti-cancer therapy discontinuation and poor diagnosis. The human microbiome is related to various respiratory diseases. However, the role of the lung microbiome in CIP and RP remains unknown. Our study aimed to explore the lower respiratory tract (LRT) microbiome in the CIP/RP patients.

Methods: The study enrolled 61 patients who had pneumonitis or pneumonia, including 23 with CIP/RP, and 38 with lung cancer with pneumonia (LC-P). Metagenomic next-generation sequencing (mNGS) was performed to identify the microbiota in bronchoalveolar lavage fluid (BALF), and bioinformatics methods were used to compare the microbial differences between the CIP/RP and LC-P groups. Correlation analysis was conducted to explore the relationship between the LRT microbiota and clinical features.

Results: The Prevotella was the dominant genus in both groups. The Prevotella melaninogenica, which belongs to the Prevotella genus, was the dominant species in the CIP/RP group and second most abundant species in the LC-P group. Compared to the LC-P group, the CIP/RP group had significantly high levels of the Prevotella melaninogenica species and lymphocytes(L) in BALF (BALF-L) but significantly low levels of the lymphocytes , eosinophiles (EOS) and albumin (ALB) in peripheral blood. In addition, the Prevotella melaninogenica species had a negative correlation with peripheral blood L.

Conclusion: The enrichment of Prevotella melaninogenica species in lower respiratory tract (LRT) and a decreased level of peripheral blood L are associated with CIP/RP.

To be updated shortly..