Cigarette smoking in interstitial lung disease: concepts for the internist

Pulmonary fibrosis and emphysema: Is the emphysema type associated with the pattern of fibrosis?

AIM: To investigate whether the predominant emphysema type is associated with the high resolution computed tomography (HRCT) pattern of fibrosis in combined pulmonary fibrosis and emphysema (CPFE).

METHODS: Fifty-three smokers with upper lobe emphysema and lower lobe pulmonary fibrosis on - HRCT - were retrospectively evaluated. Patients were stratified into 3 groups according to the predominant type of emphysema: Centrilobular (CLE), paraseptal (PSE), CLE = PSE. Patients were also stratified into 3 other groups according to the predominant type of fibrosis on HRCT: Typical usual interstitial pneumonia (UIP), probable UIP and nonspecific interstitial pneumonia (NSIP). HRCTs were scored at 5 predetermined levels for the coarseness of fibrosis (Coarseness), extent of emphysema (emphysema), extent of interstitial lung disease (TotExtILD), extent of reticular pattern not otherwise specified (RetNOS), extent of ground glass opacity with traction bronchiectasis (extGGOBx), extent of pure ground glass opacity and extent of honeycombing. HRCT mean scores, pulmonary function tests, diffusion capacity (DLCO) and systolic pulmonary arterial pressure were compared among the groups.

RESULTS: The predominant type of emphysema was strongly correlated with the predominant type of fibrosis. The centrilobular emphysema group exhibited a significantly higher extent of emphysema (P < 0.001) and a lower extent of interstitial lung disease (P < 0.002), reticular pattern not otherwise specified (P < 0.023), extent of ground glass opacity with traction bronchiectasis (P < 0.002), extent of honeycombing (P < 0.001) and coarseness of fibrosis (P < 0.001) than the paraseptal group. The NSIP group exhibited a significantly higher extent of emphysema (P < 0.05), total lung capacity (P < 0.01) and diffusion capacity (DLCO) (P < 0.05) than the typical UIP group. The typical UIP group exhibited a significantly higher extent of interstitial lung disease, extent of reticular pattern not otherwise specified, extent of ground glass opacity with traction bronchiectasis, extent of honeycombing and coarseness of fibrosis (0.039 > P > 0.000). Although the pulmonary arterial pressure was higher in typical UIP group relative to the NSIP group, the difference was not statistically significant.

CONCLUSION: In CPFE patients, paraseptal emphysema is associated more with UIP-HRCT pattern and higher extent of fibrosis than centrilobular emphysema.

Cell recovery in bronchoalveolar lavage fluid in smokers is dependent on cumulative smoking history

Background

Smoking is a risk factor for various lung diseases in which BAL may be used as a part of a clinical investigation. Interpretation of BAL fluid cellularity is however difficult due to high variability, in particular among smokers. In this study we aimed to evaluate the effect of smoking on BAL cellular components in asymptomatic smokers. The effects of smoking cessation, age and gender were also investigated in groups of smokers and exsmokers.

Methods

We performed a retrospective review of BAL findings, to our knowledge the largest single center investigation, in our department from 1999 to 2009. One hundred thirty two current smokers (48 males and 84 females) and 44 ex-smokers (16 males and 28 females) were included. A group of 295 (132 males and 163 females) never-smokers served as reference.

Result

The median [5–95 pctl] total number of cells and cell concentration in current smokers were 63.4 [28.6–132.1]×10⁶ and 382.1 [189.7–864.3]×10⁶/L respectively and correlated positively to the cumulative smoking history. Macrophages were the predominant cell type (96.7% [90.4–99.0]) followed by lymphocytes (2% [0.8–7.7]) and neutrophils (0.6% [0–2.9]). The concentration of all inflammatory cells was increased in smokers compared to never smokers and ex-smokers. BAL fluid recovery was negatively correlated with age (p<0.001). Smoking men had a lower BAL fluid recovery than smoking women.

Conclusion

Smoking has a profound effect on BAL fluid cellularity, which is dependent on smoking history. Our results performed on a large group of current smokers and ex-smokers in a well standardized way, can contribute to better interpretation of BAL fluid cellularity in clinical context.

BAL in the diagnosis of smoking-related interstitial lung diseases: review of literature and analysis of our experience

The group of interstitial lung diseases (ILDs) is formed by respiratory tract disorders, whose aetiology is unknown in the majority of cases, the clinical course differs and the prognosis is generally serious. Some of the ILDs have a potential relation to tobacco smoking and are known as smoking-related ILDs (sr-ILD). Bronchoalveolar lavage fluid (BALF) examination is one of the initial procedures in the diagnosis of ILD. Despite the fact that histological confirmation is the gold standard in ILD diagnosis in many studies, the number of reported biopsies was low. In this review we present the results of BALF examinations of patients with sr-ILD and discuss their value in the differential diagnosis with other types of ILD. An extremely high total cell count (about 50 x 10(6) cells) with significant predominance of pigmented alveolar macrophages is a characteristic pattern of BALF in sr-ILD. The greatest challenge in BALF cytology interpretation is to distinguish sr-ILD and idiopathic pulmonary fibrosis (IPF). IPF is characterised by an elevated proportion and absolute count of lymphocytes and neutrophils; in addition, BALF lymphocytosis is higher in non-specific interstitial pneumonia than in usual interstitial pneumonia (UIP). The population of alveolar macrophage of patients with sr-ILD differs markedly from the foamy and vacuolated cells that predominate in IPF/UIP. Thus, the absence of pigmented cells rather excludes sr-ILD and indicates other types of ILD. To summarise, the place of BALF in the diagnosis of sr-ILD seems to be established.

Morphological and molecular markers in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a progressive, lethal, interstitial lung disease with no proven effective therapy other than lung transplantation. A definitive diagnosis of the disease requires surgical lung biopsy to show a histological appearance of usual interstitial pneumonia. The main histological features include temporal and spatial heterogeneity, fibroblastic foci, extracellular matrix deposition with vessel remodeling and honeycomb changes. There are some morphological aspects that have recently been taken into account as possible prognostic markers for disease progression. Although the cellular and molecular pathways driving disease pathogenesis are complex and not fully delineated, increasing evidence suggests that a key event is ongoing alveolar epithelial injury in association with an abnormal host repair response. Inflammation seems to play a less important role and remains largely debated while increased attention has been on the role of noninflammatory structural cells, such as fibroblasts, epithelial cells and endothelial cells. The modifications and interactions among these cells are complex and regulated by various molecular factors. This article reviews the morphology of the disease, focusing on some new facets and on the principal molecular factors involved in the different aspects of parenchymal remodeling.