Bronchoalveolar Lavage: Quantitative Mass Spectrometry-Based Proteomics Analysis in Lung Diseases

A role for the terminal C5-C9 complement pathway in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease characterized by damage to the alveolar epithelium, leading to fibrosis and excessive accumulation of extracellular matrix in the interstitium of the lung. In the present study we performed high-resolution proteomic profiling of bronchoalveolar lavage (BAL) from IPF patients and controls, and found that the complement pathway was highly upregulated in IPF. The proteins C5, C6, C7, C8, and C9, all of which are part of the complement end product, TCC, were all upregulated. We also found that TCC levels were increased in plasma among IPF patients compared to controls, after adjustment for age, sex and BMI [mean (SD) 0.62 (0.24) vs. 0.33 (0.10), p = 0.031]. These findings suggest a role for the complement system in the pathogenesis of IPF.

Proteomic characteristics and diagnostic potential of exhaled breath particles in patients with COVID-19

BACKGROUND

SARS-CoV-2 has been shown to predominantly infect the airways and the respiratory tract and too often have an unpredictable and different pathologic pattern compared to other respiratory diseases. Current clinical diagnostical tools in pulmonary medicine expose patients to harmful radiation, are too unspecific or even invasive. Proteomic analysis of exhaled breath particles (EBPs) in contrast, are non-invasive, sample directly from the pathological source and presents as a novel explorative and diagnostical tool.

METHODS

Patients with PCR-verified COVID-19 infection (COV-POS, n = 20), and patients with respiratory symptoms but with > 2 negative polymerase chain reaction (PCR) tests (COV-NEG, n = 16) and healthy controls (HCO, n = 12) were prospectively recruited. EBPs were collected using a "particles in exhaled air" (PExA 2.0) device. Particle per exhaled volume (PEV) and size distribution profiles were compared. Proteins were analyzed using liquid chromatography-mass spectrometry. A random forest machine learning classification model was then trained and validated on EBP data achieving an accuracy of 0.92.

RESULTS

Significant increases in PEV and changes in size distribution profiles of EBPs was seen in COV-POS and COV-NEG compared to healthy controls. We achieved a deep proteome profiling of EBP across the three groups with proteins involved in immune activation, acute phase response, cell adhesion, blood coagulation, and known components of the respiratory tract lining fluid, among others. We demonstrated promising results for the use of an integrated EBP biomarker panel together with particle concentration for diagnosis of COVID-19 as well as a robust method for protein identification in EBPs.

CONCLUSION

Our results demonstrate the promising potential for the use of EBP fingerprints in biomarker discovery and for diagnosing pulmonary diseases, rapidly and non-invasively with minimal patient discomfort.

Special Staining of the Liquid-Based Cytopathology Test in Bronchoalveolar Lavage Fluid for Diagnosis of Invasive Pulmonary Aspergillosis with Nonneutropenic Patients

In recent years, various biomarkers have been gradually applied on bronchoalveolar lavage (BAL) fluid for the diagnosis of invasive pulmonary aspergillosis (IPA). The objective of this study is to assess the value of the liquid-based cytopathology test (LCT) for improving the identification of IPA in BAL fluid from possible IPA patients, following special staining with periodic acid-Schiff staining (PAS) or Grocott's methenamine silver (GMS). A total of 47 consecutive possible IPA patients who underwent bronchoscopy with BAL fluid from January 2017 to December 2018 were included. 45 people had a pair of BAL fluid specimens and 2 patients had two BAL fluid specimens. The 49 pairs of BAL fluid specimens were processed for culture, tuberculosis acid fast staining smear, direct microbial smear, and LCT with special staining (PAS and GMS), respectively. Then, we compared the sensitivity and specificity of PAS and GMS in BAL fluid in high-risk patients. Among 47 possible IPA patients, 25 patients had proven/probable IPA, and 11 patients had other invasive fungal diseases. The sensitivity of GMS was higher than that of PAS (92.11% versus 81.58%; P = 0.175). The specificity of GMS was 81.82%, which was higher than that of PAS (81.82% versus 72.73%; P = 0.611). The negative predictive value (NPV) for PAS and GMS were 53.33% and 75.00%, respectively. The positive predictive value (PPV) for PAS and GMS were 91.18% and 94.59%, respectively. This study showed that special staining of LCT in BAL fluid may be a novel method for the diagnosis of IPA, and the GMS of LCT had higher sensitivity and specificity, which was superior to PAS.

Is Induced Sputum A Useful Noninvasive Tool in the Diagnosis of Pulmonary Sarcoidosis?

OBJECTIVES

In patients with pulmonary sarcoidosis, the provocation of sputum expectoration through the inhalation of hypertonic saline has been investigated as an alternative diagnostic tool for invasive procedures. We aimed to assess the diagnostic value of induced sputum (IS) by observing its cell distribution in patients with a confirmed histopathological diagnosis of sarcoidosis.

MATERIALS AND METHODS

In this prospective, cross-sectional study, we compared the IS results of 20 patients with a histopathologically confirmed pulmonary sarcoidosis diagnosis and 24 healthy volunteers. The percentages of macrophages, lymphocytes, neutrophils, and eosinophils in IS and the CD4/CD8 ratio were compared.

RESULTS

The percentage of lymphocytes in IS was significantly higher in the pulmonary sarcoidosis patients compared to the control group (41.6% vs 8.9%, p<0.001). There were no significant differences in the other IS cell percentages and CD4+/CD8+ ratio between the groups. Sputum induction was well tolerated.

CONCLUSION

Sputum induced by the inhalation of hypertonic saline is a safe, inexpensive, less invasive, and easily repeated method and can be a valuable alternative to other invasive methods in the diagnosis of pulmonary sarcoidosis.

Exploiting the human peptidome for novel antimicrobial and anticancer agents

Infectious diseases and cancers are leading causes of death and pose major challenges to public health. The human peptidome encompasses millions of compounds that display an enormous structural and functional diversity and represents an excellent source for the discovery of endogenous agents with antimicrobial and/or anticancer activity. Here, we discuss how to exploit the human peptidome for novel antimicrobial and anticancer agents through the generation of peptide libraries from human body fluids and tissues and stepwise purification of bioactive compounds.