Superoxide anion release from blood monocytes and alveolar macrophages in patients with diffuse lung fibrosis

Bronchoalveolar Lavage Lymphocytes in the Diagnosis of Hypersensitivity Pneumonitis among Patients with Interstitial Lung Disease

Rationale: Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) characterized by inflammation and/or fibrosis in response to an inhalational exposure.Objectives: To determine the value of bronchoalveolar lavage (BAL) fluid lymphocyte cellular analysis in the detection of HP among patients with newly detected ILD.Methods: This systematic review was undertaken in the context of development of an American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax clinical practice guideline. The clinical question was, "should patients with newly detected ILD undergo BAL fluid lymphocyte analysis to diagnose HP?" MEDLINE, EMBASE, and the gray literature were searched through October 2019. Studies that reported the percentage of BAL fluid lymphocytes for various ILDs were selected for inclusion. Meta-analyses compared the mean percentage of BAL fluid lymphocytes among patients with HP with that among patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis. The sensitivity and specificity by which various percentages of BAL fluid lymphocytes distinguish HP from IPF and sarcoidosis were also evaluated.Results: Eighty-four articles were selected. No randomized trials or observational studies were identified that compared BAL fluid lymphocyte analysis with no BAL fluid lymphocyte analysis in patients with ILD. Included studies were case series describing BAL fluid cell differentials in patients with various ILDs. The percentage of BAL fluid lymphocytes was significantly higher in both fibrotic and nonfibrotic HP compared with IPF. Similarly, the percentage of BAL fluid lymphocytes was significantly higher in both fibrotic and nonfibrotic HP compared with sarcoidosis. A threshold of 20% BAL fluid lymphocytes distinguished fibrotic HP from IPF with a sensitivity and specificity of 69% and 61%, respectively, and nonfibrotic HP from IPF with a sensitivity and specificity of 95% and 61%, respectively. It distinguished fibrotic HP from sarcoidosis with a sensitivity and specificity of 69% and 26%, respectively, and nonfibrotic HP from sarcoidosis with a sensitivity and specificity of 95% and 26%, respectively.Conclusions: The percentage of BAL fluid lymphocytes is higher in HP than IPF or sarcoidosis. However, a threshold that distinguishes HP from IPF or sarcoidosis with both high sensitivity and high specificity was not identified.

Diagnosis of Hypersensitivity Pneumonitis in Adults. An Official ATS/JRS/ALAT Clinical Practice Guideline

Background: This guideline addresses the diagnosis of hypersensitivity pneumonitis (HP). It represents a collaborative effort among the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax.Methods: Systematic reviews were performed for six questions. The evidence was discussed, and then recommendations were formulated by a multidisciplinary committee of experts in the field of interstitial lung disease and HP using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.Results: The guideline committee defined HP, and clinical, radiographic, and pathological features were described. HP was classified into nonfibrotic and fibrotic phenotypes. There was limited evidence that was directly applicable to all questions. The need for a thorough history and a validated questionnaire to identify potential exposures was agreed on. Serum IgG testing against potential antigens associated with HP was suggested to identify potential exposures. For patients with nonfibrotic HP, a recommendation was made in favor of obtaining bronchoalveolar lavage (BAL) fluid for lymphocyte cellular analysis, and suggestions for transbronchial lung biopsy and surgical lung biopsy were also made. For patients with fibrotic HP, suggestions were made in favor of obtaining BAL for lymphocyte cellular analysis, transbronchial lung cryobiopsy, and surgical lung biopsy. Diagnostic criteria were established, and a diagnostic algorithm was created by expert consensus. Knowledge gaps were identified as future research directions.Conclusions: The guideline committee developed a systematic approach to the diagnosis of HP. The approach should be reevaluated as new evidence accumulates.

Vitamins and respiratory disease: antioxidant micronutrients in pulmonary health and disease

The lungs are continually exposed to relatively-high O(2) tensions, and as such, in comparison with other organs, they represent a unique tissue for the damaging effects of oxidant attack. At particular times during a lifetime this every day challenge may increase exponentially. The first oxidative insult occurs at birth, when cells are exposed to a sudden 5-fold increase in O(2) concentration. Thereafter, the human lung, from infancy through to old age, can be subjected to deleterious oxidative events as a consequence of inhaling environmental pollutants or irritants, succumbing to several pulmonary diseases (including infant and adult respiratory distress syndromes, asthma, chronic obstructive pulmonary disease, cystic fibrosis and cancer) and receiving treatment for these diseases. The present paper will review the concept that consumption of a healthy diet and the consequent ability to establish and then maintain adequate micronutrient antioxidant concentrations in the lung throughout life, and following various oxidative insults, could prevent or reduce the incidence of oxidant-mediated respiratory diseases. Furthermore, the rationale, practicalities and complexities of boosting the antioxidant pool of the respiratory-tract lining fluid in diseases in which oxidative stress is actively involved, by direct application to the lung v. dietary modification, in order to achieve a therapeutic effect will be discussed.

Superoxide dismutases in the lung and human lung diseases

The lungs are directly exposed to higher oxygen concentrations than most other tissues. Increased oxidative stress is a significant part of the pathogenesis of obstructive lung diseases such as asthma and chronic obstructive pulmonary disease, parenchymal lung diseases (e.g., idiopathic pulmonary fibrosis and lung granulomatous diseases), and lung malignancies. Lung tissue is protected against these oxidants by a variety of antioxidant mechanisms among which the superoxide dismutases (SODs) are the only ones converting superoxide radicals to hydrogen peroxide. There are three SODs: cytosolic copper-zinc, mitochondrial manganese, and extracellular SODs. These enzymes have specific distributions and functions. Their importance in protecting lung tissue has been confirmed in transgenic and knockout animal studies. Relatively few studies have been conducted on these enzymes in the normal human lung or in human lung diseases. Most human studies suggest that there is induction of manganese SOD and, possibly, extracellular SOD during inflammatory, but not fibrotic, phases of parenchymal lung diseases and that both copper-zinc SOD and manganese SOD may be downregulated in asthmatic airways. Many previous antioxidant therapies have been disappointing, but newly characterized SOD mimetics are being shown to protect against oxidant-related lung disorders in animal models.

Tachykinin activation of human monocytes from patients with interstitial lung disease, healthy smokers or healthy volunteers

Three types of tachykinin receptors, NK(1), NK(2)and NK(3), have been described to preferentially interact with substance P (SP), neurokinin A (NKA) and neurokinin B (NKB) respectively. Experimental evidence indicates that SP and NKA modulate the activity of inflammatory and immune cells, including mononuclear ones, and points to their involvement in lung pathophysiology. We previously reported that NK(1)and NK(2)receptors are present on monocytes (MO) isolated from healthy donors or rheumatoid patients - a greater sensitivity to NK(2)receptor stimulation was observed in the latter condition. This study evaluated the effects of SP and NKA, as well as NK(1)and NK(2)selective agonists and antagonists, on MO obtained from healthy volunteers, healthy smokers or patients with interstitial lung diseases (e.g. sarcoidosis and idiopathic pulmonary fibrosis). Superoxide anion (O(2)(-)) production was chosen as a parameter of cell activation. SP and NKA dose-dependently evoked O(2)(-)production from MO in all the conditions evaluated, their effects being competitively antagonized by selective antagonists (CP 96 345 and MEN 10 627, respectively). When selective NK(1)and NK(2)agonists were used, [Sar(9)Met(O(2))(11)]SP, a selective NK(1)agonist, induced a more than doubled O(2)production in MO obtained from patients with interstitial lung diseases as compared to healthy volunteers, whereas MO isolated from healthy volunteers were more sensitive to NK(2)receptor stimulation.