An increase in exhaled nitric oxide is not associated with activity in pulmonary sarcoidosis

Extended Exhaled Nitric Oxide Analysis in Interstitial Lung Diseases: A Systematic Review

Fractional exhaled nitric oxide (FeNO) is a well-known and widely accepted biomarker of airways inflammation that can be useful in the therapeutic management, and adherence to inhalation therapy control, in asthmatic patients. However, the multiple-flows assessment of FeNO can provide a reliable measurement of bronchial and alveolar production of NO, supporting its potential value as biomarker also in peripheral lung diseases, such as interstitial lung diseases (ILD). In this review, we first discuss the role of NO in the pathobiology of lung fibrosis and the technique currently approved for the measurement of maximum bronchial flux of NO (J'awNO) and alveolar concentration of NO (CaNO). We systematically report the published evidence regarding extended FeNO analysis in the management of patients with different ILDs, focusing on its potential role in differential diagnosis, prognostic evaluation and severity assessment of disease. The few available data concerning extended FeNO analysis, and the most common comorbidities of ILD, are explored too. In conclusion, multiple-flows FeNO analysis, and CaNO in particular, appears to be a promising tool to be implemented in the diagnostic and prognostic pathways of patients affected with ILDs.

Distinguishing asthma from sarcoidosis: an approach to a problem that is not always solvable

BACKGROUND

Because pulmonary sarcoidosis often affects the airway, it is commonly confused with asthma.

METHODS

This article reviews the mechanisms of airflow obstruction in sarcoidosis, the symptoms associated with this phenomenon, and the approach to distinguish sarcoidosis from asthma.

DISCUSSION

Because asthma is highly likely in a patient with wheeze, cough, and chest tightness, sarcoidosis is usually not considered unless the patient has extrapulmonary manifestations of sarcoidosis or a family history of the disease. When pulmonary sarcoidosis is a consideration, a chest radiograph should be performed. A chest radiograph should also be performed in an asthmatic patient when the presentation is atypical, or fails to respond to standard asthma treatment; chest radiography should be performed in this situation to consider not only pulmonary sarcoidosis but also other possible cardiopulmonary disorders. In a patient with confirmed pulmonary sarcoidosis, the diagnosis of concomitant asthma is problematic. The symptoms associated with the two disorders are often identical. Airflow obstruction is common in sarcoidosis so that pulmonary function testing is unlikely to differentiate these two diseases. Demonstration of airway hyperreactivity may fail to distinguish these disorders as this is common in sarcoidosis. Serum IgE, serum angiotensin-converting enzyme levels, sputum eosinophilia, and exhaled nitric oxide measurements show promise as distinguishing tests, although they have not been studied specifically. Pulmonary imaging is probably of limited value unless baseline studies are available for comparison. We suspect that historical information will be more useful in distinguishing these two diseases. Not infrequently, it may be impossible to exclude or confirm an asthmatic component in a confirmed pulmonary sarcoidosis patient. Fortunately, exacerbations of both these diseases are often treated with systemic corticosteroids initially. Significant variability in pulmonary symptoms and airflow obstruction suggest that an asthma component is present, and inhaled corticosteroids and bronchodilators should be considered in these cases,

CONCLUSIONS

Asthma and sarcoidosis share many of the same symptoms, as sarcoidosis commonly affects the airways. Therefore, it is problematic to distinguish these two diseases. In this article, we have outlined an approach to assess the presence of each of these diseases and an approach to therapy.

Is mycobacterial heat shock protein 16 kDa, a marker of the dormant stage of Mycobacterium tuberculosis, a sarcoid antigen?

We demonstrated opposite presence of mycobacterial heat shock proteins (Mtb-hsp) 70 kDa, 65 kDa, 16 kDa in sera and lymph nodes in sarcoidosis (SA). Higher occurrence of serum Mtb-hsp70 than Mtb-hsp 65 and Mtb-hsp 16 could be caused by sequestration of Mtb-hsp 65 and Mtb-hsp 16 in circulating immune complexes (CIs). It is possible that in genetically different predisposed hosts, Mtb-hsp 16 induced by dose-dependent nitrate/nitrite (NOx) may be involved in latent tuberculosis (TB), active TB, or SA development. We evaluated Mtb-hsp 70, Mtb-hsp 65, Mtb-hsp 16 presence in precipitated CIs and serum NOx level in 20 SA patients, 19 TB patients, and 21 healthy volunteers using PEG precipitation, Western Blot, and Griess methods. We revealed higher NOx concentrations in SA and TB than in controls, but lower in SA than TB. Mtb-hsp 16, Mtb-hsp 65, and Mtb-hsp70 concentrations in precipitated CIs were higher in SA than in TB and controls. In all tested groups, Mtb-hsp 16 concentration was higher than Mtb-hsp70 and Mtb-hsp 65. We suggest that lower levels of NOx may induce a M. tuberculosis genetic dormancy program via higher Mtb-hsp 16 expression in SA. It seems that Mtb-hsp 16 may be more important than Mtb-hsp70 and Mtb-hsp 65 in CIs formation and initiate an autoimmune response in SA related to mycobacteria's stationary-phase.

Breath biomarkers in diagnosis of pulmonary diseases

Breath analysis provides a convenient and simple alternative to traditional specimen testing in clinical laboratory diagnosis. As such, substantial research has been devoted to the analysis and identification of breath biomarkers. Development of new analytes enhances the desirability of breath analysis especially for patients who monitor daily biochemical parameters. Elucidating the physiologic significance of volatile substances in breath is essential for clinical use. This review describes the use of breath biomarkers in diagnosis of asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), lung cancer, as well as other pulmonary diseases. A number of breath biomarkers in lung pathophysiology will be described including nitric oxide (NO), carbon monoxide (CO), hydrogen peroxide (H₂O₂) and other hydrocarbons.

Exhaled nitric oxide in diagnosis and management of respiratory diseases

The analysis of biomarkers in exhaled breath constituents has recently become of great interest in the diagnosis, treatment and monitoring of many respiratory conditions. Of particular interest is the measurement of fractional exhaled nitric oxide (FENO) in breath. Its measurement is noninvasive, easy and reproducible. The technique has recently been standardized by both American Thoracic Society and European Respiratory Society. The availability of cheap, portable and reliable equipment has made the assay possible in clinics by general physicians and, in the near future, at home by patients. The concentration of exhaled nitric oxide is markedly elevated in bronchial asthma and is positively related to the degree of esinophilic inflammation. Its measurement can be used in the diagnosis of bronchial asthma and titration of dose of steroids as well as to identify steroid responsive patients in chronic obstructive pulmonary disease. In primary ciliary dyskinesia, nasal NO is diagnostically low and of considerable value in diagnosis. Among lung transplant recipients, FENO can be of great value in the early detection of infection, bronchioloitis obliterans syndrome and rejection. This review discusses the biology, factors affecting measurement, and clinical application of FENO in the diagnosis and management of respiratory diseases.

Atopic disease and exhaled nitric oxide in an unselected population of young adults

BACKGROUND

Several studies have reported elevated levels of fractional exhaled nitric oxide (FeNO) in atopic patients, particularly in asthmatic patients, suggesting that FeNO is a marker of bronchial inflammation. However, the independent influence of different atopic entities (eczema, allergic rhinitis, and asthma) on FeNO has never been studied in the general population.

OBJECTIVE

To study the influence of a questionnaire-based diagnosis of atopic diseases and IgE and lung function measurements on FeNO levels.

METHODS

This study was part of a follow-up on otitis media of a birth cohort of 1,328 children born in Nijmegen, the Netherlands, between September 1, 1982, and August 31, 1983. Within the birth cohort, the incidence of asthma, allergic rhinitis, and eczema was determined, and off-line FeNO, spirometry, and IgE measurements were performed at the age of 21 years.

RESULTS

FeNO measurements were successfully performed in 361 participants. Median FeNO levels were significantly higher in those with vs without eczema (23.6 vs 18.0 ppb; P < .0001), those with vs without allergic rhinitis (20.7 vs 17.8 ppb; P = .0001), and those with vs without atopic asthma (23.3 vs 18.1 ppb; P = .02) but not in those with vs without asthma (20.8 vs 18.3 ppb; P = .24). Eczema, allergic rhinitis, smoking, sex, and atopic sensitization appeared to be independently associated with log FeNO in this population sample, whereas (atopic) asthma was not. No effect on FeNO levels was observed for lung function parameters.

CONCLUSION

Eczema, allergic rhinitis, and atopic status were all independently associated with elevated FeNO levels, whereas (atopic) asthma was not. This finding implies that future studies into the role of FeNO in asthma should consider the influence of atopic disease outside the lungs.

Hydrogen peroxide in exhaled breath condensate (EBC) vs eosinophil count in induced sputum (IS) in parenchymal vs airways lung diseases

We compared exhaled breath condensate (EBC) and induced sputum (IS) for assessing inflammation in pulmonary diseases in patients with obstructive lung disease (n = 20), persistent cough >6 months (n = 20), interstitial lung disease (n = 25) and controls (n = 10). EBC was collected by suspending a Teflon perfluoroalkoxy tube installed in an ice-filled container and connected to a polypropylene test tube. IS was recovered after 20' inhalation of 3% saline with an ultrasonic nebulizer, and 300 cells were differentially counted in cytospin Giemsa-stained slides. H(2)0(2) was measured by a method based on oxidation of phenolsulfonphthalein (phenol red) mediated by horseradish peroxidases and H(2)0(2). Pulmonary function tests were performed by conventional methods. H(2)0(2) levels in EBC and % eosinophils in IS were significantly different between groups. A positive and significant correlation was found between % eosinophils in IS and the levels of H(2)0(2) in EBC for each group and for all patients combined.

Paediatric sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown aetiology, most commonly affecting young adults. Divergent prevalence rates and clinical appearances in different races indicate the existence of predisposing genes, with probably a major effect of the major histocompatibility complex. The diagnosis is relatively rare in children. Lesions can occur in almost any tissue or organ but the lungs, lymph nodes, eyes, skin and liver are the most commonly involved. Clinical symptoms are non-specific and often minor. The diagnosis can only be supported by typical histopathological findings with non-caseating epithelioid-cell granulomas. The prognosis seems to be more severe in younger children and in cases of multi-organ involvement. Corticosteroids are the therapeutic agents most commonly used and are indicated in cases of significant lung or eye lesions, cardiac, neurological, or multiorgan involvement. Close monitoring is mandatory during and after treatment because relapses are common.

[Update on sarcoidosis]

Since the first description more than a century ago, intensive research continues to focus on sarcoidosis. Based on our current knowledge, sarcoidosis can be considered as an immune syndrome resulting from a variable combination of predisposing genetic, ethnic, and environmental factors. Over the last few years, several teams have proposed a link between certain genetic polymorphisms, particularly of the HLA system, and the risk of development or progression of sarcoidosis. Other pathogenic mechanisms involved in the formation of the sarcoid granuloma are becoming more clear and have led to the development of new therapeutic approaches such as anti-TNF currently being evaluated in multicentric trials.