Characteristics of alveolar macrophages in bronchioalveolar lavage fluids from active tuberculosis patients identified by single-cell RNA sequencing

Tuberculosis(TB),is an infectious disease caused by Mycobacterium tuberculosis(M.tuberculosis),and presents with high morbidity and mortality.Alveolar macrophages play an important role in TB pathogenesis although there is heterogeneity and functional plasticity.This study aimed to show the characteristics of alveolar macrophages from bronchioalveolar lavage fluid(BALF)in active TB patients.Single-cell RNA sequencing(scRNA-seq)was performed on BALF cells from three patients with active TB and additional scRNA-seq data from three healthy adults were established as controls.Transcriptional profiles were analyzed and compared by differential gene expression and functional enrichment analysis.We applied pseudo-temporal trajectory analysis to investigate correlations and heterogeneity within alveolar macrophage subclusters.Alveolar macrophages from active TB patients at the single-cell resolution are described.We found that TB patients have higher cellular percentages in five macrophage subclusters.Alveolar macrophage subclusters with increased percentages were involved in inflammatory signaling pathways as well as the basic macrophage functions.The TB-increased alveolar macrophage subclusters might be derived from M1-like polarization state,before switching to an M2-like polarization state with the development of M.tuberculosis infection.Cell-cell communications of alveolar macrophages also increased and enhanced in active TB patients.Overall,our study demonstrated the characteristics of alveolar macrophages from BALF in active TB patients by using scRNA-seq.

A clinical comparative study of polymerase chain reaction assay for diagnosis of pneumocystis pneumonia in non-AIDS patients

Background Pneumocystis jirovecii pneumonia （PCP） is one of the most common and fatal infections in non-AIDS immunocompromised patients, which is difficult to diagnose by traditional morphologic methods. This study evaluated polymerase chain reaction （PCR） assays of Pneumocystis jirovecii mitochondrial large subunits ribosomal RNA in sputum and bronchioalveolar lavage fluid （BALF） for diagnosing PCP. Methods Sputum and BALF specimens from two groups were collected： one group （PCP group） included 20 patients definitely diagnosed of PCP by Gomori methenamine silver （GMS） stains of BALF; the other group （non-PCP group） included 40 patients. Each specimen was examined by GMS stains and PCR assays. Results GMS stains of BALF in PCP group were 100% positive （20/20）, GMS stains of sputum in PCP group were 35% positive （7/20）; GMS stains of BALF in non-PCP group were 100% negative （40/40）, GMS stains of sputum in non-PCP group were 100% negative （40/40）. PCR assays of BALF in PCP group were 100% positive （20/20）, PCR assays of sputum in PCP group were 100% positive （20/20）; PCR assays of BALF in non-PCP group were 100% negative （40/40）, PCR assays of sputum in non-PCP group were 100% negative （40/40）. Sensitivity and specificity of PCR assays of sputum and BALF were both 100%; positive and negative predictive values were also both 100%. Conclusion The diagnostic value of PCR assays of Pneumocystisjirovecii mitochondrial large subunits ribosomal RNA on sputum and BALF for pneumocystis pneumonia are both high and equivalent.