AUTHOR=Liu Qi , Du Jingli , An Huiru , Li Xianan , Guo Donglin , Li Jiebai , Gong Wenping , Liang Jianqin 

TITLE=Clinical characteristics of patients with non-tuberculous mycobacterial pulmonary disease: a seven-year follow-up study conducted in a certain tertiary hospital in Beijing

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2023.1205225

DOI=10.3389/fcimb.2023.1205225

ISSN=2235-2988

ABSTRACT=<sec><title>Background</title><p>The incidence of non-tuberculous mycobacterial pulmonary disease (NTM-PD) has increased in recent years. However, the clinical and immunologic characteristics of NTM-PD patients have received little attention.</p></sec><sec><title>Methods</title><p>NTM strains, clinical symptoms, underlying diseases, lung CT findings, lymphocyte subsets, and drug susceptibility tests (DSTs) of NTM-PD patients were investigated. Then, the counts of immune cells of NTM-PD patients and their correlation were evaluated using principal component analysis (PCA) and correlation analysis.</p></sec><sec><title>Results</title><p>135 NTM-PD patients and 30 healthy controls (HCs) were enrolled from 2015 to 2021 in a certain tertiary hospital in Beijing. The number of NTM-PD patients increased every year, and <italic>Mycobacterium intracellulare</italic> (<italic>M. intracellulare</italic>), <italic>M. abscessus</italic>, <italic>M. avium</italic>, and <italic>M. kansasii</italic> were the major pathogens of NTM-PD. The main clinical symptoms of NTM-PD patients were cough and sputum production, and the primary lung CT findings were thin-walled cavity, bronchiectasis, and nodules. In addition, we identified 23 clinical isolates from 87 NTM-PD patients with strain records. The DST showed that almost all of <italic>M. abscessus</italic> and <italic>M. avium and</italic> more than half of the <italic>M. intracellulare</italic> and <italic>M. avium</italic> complex groups were resistant to anti-tuberculosis drugs tested in this study. <italic>M. xenopi</italic> was resistant to all aminoglycosides. <italic>M. kansasii</italic> was 100% resistant to kanamycin, capreomycin, amikacin, and para-aminosalicylic acid, and sensitive to streptomycin, ethambutol, levofloxacin, azithromycin, and rifamycin. Compared to other drugs, low resistance to rifabutin and azithromycin was observed among NTM-PD isolates. Furthermore, the absolute counts of innate and adaptive immune cells in NTM-PD patients were significantly lower than those in HCs. PCA and correlation analysis revealed that total T, CD4<sup>+</sup>, and CD8<sup>+</sup> T lymphocytes played an essential role in the protective immunity of NTM-PD patients, and there was a robust positive correlation between them.</p></sec><sec><title>Conclusion</title><p>The incidence of NTM-PD increased annually in Beijing. Individuals with bronchiectasis and COPD have been shown to be highly susceptible to NTM-PD. NTM-PD patients is characterized by compromised immune function, non-specific clinical symptoms, high drug resistance, thin-walled cavity damage on imaging, as well as significantly reduced numbers of both innate and adaptive immune cells.</p></sec>