Pigeon fanciers' lung: effects of smoking on serum and salivary antibody responses to pigeon antigens

Diagnostic implications of positive avian serology in suspected hypersensitivity pneumonitis

BACKGROUND

The diagnostic evaluation of patients with interstitial lung disease (ILD) often involves serologic assessment for identifiable causes such as hypersensitivity pneumonitis (HP). While not on its own defining of HP, precipitin serologies are often obtained to support clinical suspicion if other findings are inconclusive. We studied the clinical relevance of positive avian serology in patients undergoing ILD evaluation.

MATERIAL AND METHODS

We identified individuals with positive avian serology (>53.3 mg/L) and undifferentiated ILD seen at our institution over a three-year period. Clinical, laboratory, pathologic, and radiologic findings were evaluated for consensus HP diagnosis by two expert pulmonologists, blinded to presenting serology levels.

RESULTS

Ninety-one ILD subjects with positive avian serology were identified; mean age was 62.7 ± 15.3 years with a slight male predominance (56%). Forty-nine (54%) received a consensus HP diagnosis. Those with HP had higher mean avian serology titer (95.0 ± 38.7 mg/L vs. 68.3 ± 16.7, (P < 0.0001). Never-smokers also had higher titers compared to prior or active smokers (P = 0.0008). Positive avian protein exposure (P < 0.0001, OR 21.3 (6.4-87)), DLCO% (P = 0.04, unit OR 0.96 (0.92-0.99)), and increasing serology titer (P < 0.015, unit OR 1.03 [1.01-1.06]) were independent predictors of HP diagnosis.

CONCLUSION

Among patients with positive avian serology, those with higher titers were more likely to have HP diagnosis. Nonsmokers also manifested higher titers compared to those with smoking history. These results may guide the usage and interpretation of avian serology screening in the initial assessment of suspected HP.

Utility of precipitating antibody testing in the diagnostic evaluation of chronic hypersensitivity pneumonia

Background: Chronic hypersensitivity pneumonitis (HP), in its progressive fibrotic form, is difficult to distinguish from other fibrosing interstitial lung diseases (ILD), particularly idiopathic pulmonary fibrosis (IPF) and non-specific interstitial pneumonia (NSIP). The role of serum precipitating antibodies in the diagnosis of fibrosing ILD has not been discussed in recent clinical practice guidelines. Objectives: The aim of this study is to assess the role of precipitins in the diagnosis of non pre-selected cases of fibrosing ILD. Methods: Clinical records of 108 consecutive patients referred for presumptive fibrosing ILD to our institution were retrospectively assessed for exposure history, serum precipitins, other diagnostic examinations, and multidisciplinary diagnosis (MDD). Their high resolution computed tomography (HRCT) images were blindly and prospectively re-assessed. We estimated sensitivity and specificity of precipitins against MDD and, to account for incorporation bias, we used two composite reference standards (CRSs), having exposure history and HRCT as component tests. Results: Definitive diagnosis achieved through MDD were chronic HP (17% of cases), NSIP (42%), IPF (18%) and others (23%). For serum precipitins, we estimated a sensitivity of 72% and a specificity of 68% using MDD as the reference standard. Sensitivity against the AND-CRS was 55%, while specificity against the OR-CRS was 61%. On the basis of this results, we can expect true sensitivity of precipitins lying between 55 and 72% and specificity between 61 and 68%. Conclusions:Serum precipitating antibodies did not result as having a relevant role in the diagnostic approach to chronic HP (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 149-155).

Hypersensitivity pneumonitis : a broader perspective

Hypersensitivity pneumonitis (HP) represents a group of lung disorders caused by the inhalation of a wide variety of organic particles by susceptible individuals. HP occurs mainly in nonsmokers, but smoking may promote an insidious and chronic disease. The prevalence of HP is difficult to estimate accurately since several antigens can produce the disease, but the range spans infancy to old age. Regardless of the causative antigen or its environmental setting, the clinical manifestations are essentially the same. Three different clinical presentations have been recognized: acute, subacute, and chronic. In the acute form, patients show flu-like symptomatology, followed by dyspnea and dry cough. Symptoms subside a few hours or days later. The subacute and chronic forms result from recurrent low-level antigen exposure and are characterized by progressive dyspnea and dry cough. Other constitutional symptoms such as fatigue, anorexia, and weight loss can be apparent. Fever may occur in the subacute form. Importantly, chronic HP may evolve insidiously or may result from repeated acute/subacute episodes. Recurrent acute, subacute, and chronic HP may progress to irreversible lung fibrosis or provoke emphysematous changes.HP can be difficult to identify, and precise diagnosis requires a history of exposure and a constellation of clinical, imaging, laboratory, bronchoalveolar lavage and pathologic findings. General laboratory tests show an increase of acute phase reactants. Specific precipitating antibodies, when present, are evidence of antigen exposure, and are a hallmark for diagnosis. Chest radiograph usually reveals widespread ground-glass attenuation, and nodular or reticulonodular shadowing. High-resolution CT features include diffuse or patchy ground-glass opacities with small poorly defined nodules and air trapping. Pulmonary function tests are characterized by a predominantly restrictive ventilatory defect with loss of lung volume and hypoxemia at rest that worsens with exercise. Bronchoalveolar lavage reveals a significant increase in lymphocytes, mostly over 40%. In the acute form there is also an increase in neutrophils. Antigen-induced lymphocyte proliferation, and environmental or laboratory-controlled inhalation challenge, may be used for diagnostic purposes and can help to establish a diagnosis of insidious forms of HP. In subacute or chronic cases, lung biopsy may be necessary. Typical findings include bronchiolitis, lymphocytic alveolitis, and loosely formed granulomas, although occasionally other morphologic patterns such as nonspecific interstitial pneumonia may exist. Treatment focuses on avoiding further exposure to the offending antigen(s). Corticosteroids are recommended in subacute and chronic forms. The usual regimen consists of initial high doses of systemic corticosteroid (e.g. prednisone 0.5-1.0 mg/kg/day), followed by gradual tapering.

Correlation of macrophage inflammatory protein-1α single gene polymorphisms with the susceptibility to pigeon breeder's lung in chinese uygur population

OBJECTIVE

To investigate the correlation of macrophage inflammatory protein-1α (MIP-1α) gene single nucleotide polymorphisms (SNP) with the susceptibility to pigeon breeder's lung (PBL) in Chinese Uygur population.

METHODS

A total of 92 Uygur from Xinjiang, China were enrolled in the study. Among them, there were 32 patients with PBL, 30 negative controls with history of exposure to pigeons and 30 normal controls without pigeons contact. SNP genotyping for 24 SNPs of MIP-1α were performed.

RESULTS

Genotype distribution of MIP-1α SNPs rs1049191, rs1049195, rs3210166, rs1130374 and rs5029407 were significantly different among the three groups (P<0.05).

CONCLUSION

MIP-1α SNPs rs1049191, rs1049195, rs3210166, rs1130374 and rs5029407 might have correlation with the susceptibility to pigeon breeder's lung in Chinese Uygur population.

Lung biopsy-proved hypersensitivity pneumonitis without known offending antigen: characteristics and follow-up

INTRODUCTION

Hypersensitivity pneumonitis (HP) without known offending antigen is hard to diagnose.

OBJECTIVES

The purpose of this study was to identify and analyze the clinical features of lung biopsy-proved HP.

METHODS

A retrospective cohort study was performed using a database from a 900-bed specialty hospital. Twenty-eight patients with the diagnosis of HP through lung biopsy were enrolled. Demographic data and clinical characteristics, radiologic characteristics, serologic and pulmonary function results, histopathologic changes, treatment and follow-up were analyzed.

RESULTS

Of all the patients, serum interleukin-1β, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), eosinophil cationic protein and immunoglobulin E (IgE) were increased in over 50% patients, but decreased significantly after corticosteroid therapy (P < 0.05). An initially reduced diffusion lung capacity for carbon monoxide was noted in 92.9% patients, while 39.3% patients had hypoxemia. Ground-glass opacities on the basis of interlobular septa thickening were observed in 71.4% cases. Histopathological findings demonstrated peribronchiolar lymphocytic infiltrates, poorly formed non-caseating granulomas fibrosis in all acute and subacute HP patients' lungs. Ninety-two percent of patients got improvement after corticosteroid therapy when assessed by computer tomography scans and pulmonary function tests.

CONCLUSIONS

For suspected HP patients who without known offending antigens, earlier diagnosed by lung biopsy and followed by corticosteroid therapy showed promising. It might prevent the disease progression to lung fibrosis.

Nicotine treatment improves Toll-like receptor 2 and Toll-like receptor 9 responsiveness in active pulmonary sarcoidosis

BACKGROUND

New evidence links nicotine to the regulation of T cell-mediated inflammation via a 7 nicotinic cholinergic receptor activation, and chronic nicotine exposure (smoking) reduces the incidence of granulomatous diseases. We sought to determine whether nicotine treatment was well tolerated while effectively normalizing immune responses in patients with active pulmonary sarcoidosis.

METHODS

Consenting adults with symptomatic sarcoidosis (n 5 13) were randomly assigned to receive 12 weeks of nicotine treatment plus conventional therapy or conventional therapy alone. Obtained blood cells were evaluated for their responsiveness to selected Toll-like receptor (TLR) and nucleotide oligomerization domain-like receptor ligands and T cell surface marker expression before and after nicotine treatment. Asymptomatic patients (n 5 6) and disease-free subjects (n 5 6) served as comparative control subjects. Adverse events were monitored for the duration of the study.

RESULTS

Compared with the asymptomatic group, symptomatic patients had impaired peripheral responses to TLR2, TLR4, and TLR9 ligands (anergy) and reduced peripheral populations of CD4 1 FoxP3 1 regulatory T cells (Tregs). Nicotine treatment was associated with restoration of TLR2 and TLR9 responsiveness, and expansion of Tregs, including the CD4 1 CD25 2 FoxP3 1 phenotype. There were no serious adverse events or signs of nicotine dependency.

CONCLUSIONS

Nicotine treatment in active pulmonary sarcoidosis was well tolerated and restored peripheral immune responsiveness to TLR2 and TLR9 agonists and expansion of FoxP3 1 Tregs, including a specific “preactivated” (CD25 2 ) phenotype. The immune phenotype of patients with symptomatic sarcoidosis treated with nicotine closely resembled that of asymptomatic patients, supporting the notion that nicotine treatment may be beneficial in this patient population.

Mimics in chest disease: interstitial opacities

Septal, reticular, nodular, reticulonodular, ground-glass, crazy paving, cystic, ground-glass with reticular, cystic with ground-glass, decreased and mosaic attenuation pattern characterise interstitial lung diseases on high-resolution computed tomography (HRCT). Occasionally different entities mimic each other, either because they share identical HRCT findings or because of superimposition of patterns. Idiopathic pulmonary fibrosis (IPF), fibrosis associated with connective tissue disease, asbestosis, end-stage sarcoidosis or chronic hypersensitivity pneumonitis (HP) may present with lower zone, subpleural reticular pattern associated with honeycombing. Lymphangiomyomatosis may be indistinguishable from histiocytosis or extensive emphysema. Both pulmonary oedema and lymphangitic carcinomatosis may be characterised by septal pattern resulting from thickened interlobular septa. Ill-defined centrilobular nodular pattern may be identically present in HP and respiratory bronchiolitis–associated with interstitial lung disease (RBILD). Sarcoidosis may mimic miliary tuberculosis or haematogenous metastases presenting with miliary pattern, while endobronchial spread of tuberculosis may be indistinguishable from panbronchiolitis, both presenting with tree-in-bud pattern. Atypical infection presenting with ground-glass mimics haemorrhage. Ground-glass pattern with minimal reticulation is seen in desquamative interstitial pneumonia (DIP), RBILD and non-specific interstitial pneumonia (NSIP). Obliterative bronchiolitis and panlobular emphysema may present with decreased attenuation pattern, while obliterative bronchiolitis, chronic pulmonary embolism and HP may manifest with mosaic attenuation pattern. Various mimics in interstitial lung diseases exist. Differential diagnosis is narrowed based on integration of predominant HRCT pattern and clinical history.

Teaching Points

• To learn about the different HRCT patterns, which are related to interstitial lung diseases.

• To be familiar with the more “classical” entities presenting with each HRCT pattern.

• To discuss possible overlap of different HRCT patterns and the more common mimics in each case.

• To learn about some clues that help differentiate the various diagnostic mimics on HRCT.

Hypersensitivity Pneumonitis: Essential Radiologic and Pathologic Findings

Hypersensitivity pneumonitis is a diffuse, granulomatous interstitial lung disease caused by repeated exposure to a wide spectrum of environmental antigens. Clinical, radiologic, and histologic findings are quite variable and mimic many other diseases; therefore, diagnosis depends on a constellation of findings rather than a single defining feature. High-resolution computed tomography (HRCT) plays a critical role in this setting. The presence of centrilobular nodules, multifocal ground glass opacities, and evidence of air trapping in the expiratory phase of respiration is highly suggestive of hypersensitivity pneumonitis and can direct clinicians to the correct diagnosis. For the pathologist, typical HRCT findings not only corroborate the diagnosis of hypersensitivity pneumonitis when the characteristic triad of airway-centered chronic interstitial inflammation, interstitial poorly formed non-necrotizing granulomas, and organizing pneumonia is present on biopsy, but also improve diagnostic confidence in biopsies lacking components of the diagnostic histologic triad. Importantly, the presence of focal or unilateral imaging findings should prompt a careful search by the pathologist for an infectious etiology, thus avoiding errors in determining the significance of granulomas on biopsy. This article reviews the essential radiologic and pathologic findings in hypersensitivity pneumonitis, discusses the primary considerations in the differential diagnosis, and offers an approach to biopsy evaluation.

Imaging of Small Airway Disease (SAD)

This article comprehensively reviews and illustrates the imaging features of small airway diseases. The authors discuss the imaging findings of small airway diseases in general and how to differentiate them from other findings that can be confused with small airway diseases. The authors also discuss the features that aid in diagnosing specific diseases that affect the small airways.

Effect of smoking on gastric histology in Helicobacter pylori-positive gastritis

OBJECTIVE

Smoking and Helicobacter pylori are both deleterious to the gastric and duodenal mucosa. Smoking also seems to modify inflammation in H. pylori infection. The aim of this study was to investigate the relationship between smoking and H. pylori in the Finnish population.

MATERIAL AND METHODS

We analysed the effect of smoking on gastric inflammation, humoral response to H. pylori and peptic ulcer disease among 318 Finnish H. pylori-positive patients (age 18-75 years; 73 smokers). Gastric histology was evaluated according to the updated Sydney system.

RESULTS

Smoking affected neither antral inflammation nor atrophy. In the gastric body, smokers showed milder chronic and neutrophilic inflammation and less atrophy (4% versus 17%, p=0.004). In smokers, H. pylori infiltration was denser in the atrium (mean 2.14 versus 1.87, p=0.02) but less dense in the body (mean 1.55 versus 1.84, p=0.003). Smoking thus seems to decrease inflammation in the gastric body and to delay atrophic changes in the gastric body. Subsequently, the prevalence of duodenal ulcers increased (32% versus 11%, p<0.001), but not the prevalence of gastric ulcers. Smoking also reduced serum IgG antibody titres against H. pylori (mean 8535 versus 5587, p=0.002) and their percentage decrease after successful eradication, possibly affecting serological diagnostic efficacy. Smokers were younger than non-smokers, but when age was taken into account, the differences remained the same.

CONCLUSIONS

In H. pylori-positive gastritis, smoking reduced inflammation and atrophy in the gastric body as well as humoral response to H. pylori.

High-dose but not low-dose mainstream cigarette smoke suppresses allergic airway inflammation by inhibiting T cell function

Epidemiological studies have identified childhood exposure to environmental tobacco smoke as a significant risk factor for the onset and exacerbation of asthma, but studies of smoking in adults are less conclusive, and mainstream cigarette smoke (MCS) has been reported to both enhance and attenuate allergic airway inflammation in animal models. We sensitized mice to ovalbumin (OVA) and exposed them to MCS in a well-characterized exposure system. Exposure to MCS (600 mg/m(3) total suspended particulates, TSP) for 1 h/day suppresses the allergic airway response, with reductions in eosinophilia, tissue inflammation, goblet cell metaplasia, IL-4 and IL-5 in bronchoalveolar lavage (BAL) fluid, and OVA-specific antibodies. Suppression is associated with a loss of antigen-specific proliferation and cytokine production by T cells. However, exposure to a lower dose of MCS (77 mg/m(3) TSP) had no effect on the number of BAL eosinophils or OVA-specific antibodies. This is the first report to demonstrate, using identical smoking methodologies, that MCS inhibits immune responses in a dose-dependent manner and may explain the observation that, although smoking provokes a systemic inflammatory response, it also inhibits T cell-mediated responses involved in a number of diseases.

Bird fancier's lung: a series of 86 patients

Bird fancier's lung (BFL) is one of the most common types of hypersensitivity pneumonitis. Nevertheless, the criteria for diagnosing this condition are not standardized. The current study is an in-depth investigation into the clinical characteristics of BFL in the largest series examined for this purpose by a single group, to our knowledge, taking into account the acute, subacute, or chronic clinical presentation. From 1977 to 2003, BFL was diagnosed in 86 patients using a homogeneous protocol. Data from the clinical history and physical examination were analyzed, as well as the results from the following complementary examinations: laboratory analyses, specific serum IgG antibodies determination, chest X-ray, chest computed tomography (CT), pulmonary function testing, immediate hypersensitivity skin testing, delayed cutaneous hypersensitivity testing, bronchofibroscopy with bronchoalveolar lavage (BAL) and/or transbronchial biopsy, bronchial challenge testing, and surgical lung biopsy. In addition, clinical and epidemiologic characteristics were determined in a control group of 60 pigeon breeders who did not meet the diagnostic criteria of BFL. Eighty-six patients (21 men and 65 women) with a mean age of 47 years were studied. Seven (8%) patients were younger than 15 years of age at the time of the diagnosis. In 3 cases, the disease was caused by exposure to feather-filled bedding. Nearly 1 in 5 patients was diagnosed in the chronic phase of the disease. The mean diagnostic delay was 1.6 years overall, and 3.2 years in patients diagnosed in the chronic phase of the disease. Among the 17% of patients with chronic disease, the mean interval from initiation of exposure to diagnosis was 16 years, a higher value than in the acute or subacute presentation forms. Dyspnea and cough were the most common clinical symptoms (98% and 82%, respectively), and nearly 25% had grade III or IV dyspnea at diagnosis. Only 18% of patients experienced chest tightness, a symptom classically considered to be frequent in this condition. Erythrocyte sedimentation rate was elevated (>30 mm/h) in 44% of patients. Urinary calcium was elevated in 20% of patients. Angiotensin-converting enzyme was not elevated in any of the patients in which it was measured. Lactate dehydrogenase increases were found in 51% of patients. Specific IgG antibodies to avian antigens were documented in 92% of BFL patients, but also in 87% of pigeon breeder controls. The most frequent radiologic finding was an interstitial pattern in 79% of patients. Common chest CT features were ground glass areas (68%) and a mosaic pattern (61%); areas of emphysema were found in 7/41 (17%) patients, 5 of whom had never smoked. Two patients had a CT pattern of pulmonary fibrosis indistinguishable from idiopathic pulmonary fibrosis. Immediate hypersensitivity skin testing with bird sera and pigeon bloom was positive in 78% and 100% of BFL patients, respectively, and in 64% and 88% of control pigeon breeders, respectively. Almost one-third of the patients (29%) presented an anergic response on delayed cutaneous hypersensitivity testing. Restrictive ventilatory impairment was the most frequent functional pattern (77%), although 9% and 4% showed a pure obstructive and mixed pattern, respectively. The carbon monoxide diffusing capacity was decreased (<80% of the predicted value) in 85% of cases. Forty-one percent of patients had PaO2 <60 mm Hg at diagnosis when blood gas analysis was performed. Lymphocytosis (>20% lymphocytes) was documented in 83% of patients who underwent BAL, with a similar frequency in the 3 presentation forms: 70% acute, 89% subacute, and 85% chronic. In addition, inversion of the CD4/CD8 ratio (<1) was observed in 62% of the patients, but 38% of cases showed a CD4 predominance. The characteristic triad of histopathologic findings in hypersensitivity pneumonitis was found in only 9% of patients undergoing transbronchial biopsy, but at least 1 of these findings was seen in 69%. Surgical lung biopsy was undertaken in 14/86 (16%) patients; the complete triad was observed in 50% and at least 1 finding in 100%. In 54/86 (63%) patients, the diagnosis was confirmed by bronchial challenge testing, a test with a sensitivity of 92% and specificity of 100%. BFL is a potentially severe disease that can progress to respiratory failure secondary to pulmonary fibrosis or chronic obstructive pulmonary disease, as a form of chronic occupational respiratory disease. Respiratory symptoms in exposed patients, including children and adults who have only 1 pet bird at home, should raise the suspicion of BFL. Diagnosis in the chronic phase is frequent, and the delay to diagnosis was greatest in these cases. Elevated urinary calcium, lactate dehydrogenase, and erythrocyte sedimentation rate in a bird fancier may constitute a combined marker for suspected BFL. Chest CT frequently discloses emphysema and a pattern of idiopathic pulmonary fibrosis in some patients. An anergic response on delayed cutaneous hypersensitivity testing is not infrequent. The presentation with respiratory failure and the predominance of CD4 T lymphocytes in some patients' BAL are both remarkable. Lymphocytosis on BAL also persists in the chronic phase of the disease. Bronchial challenge testing has a high diagnostic yield, and surgical lung biopsy is not needed to reach the final diagnosis in the vast majority of cases.

Acrolein inhibits cytokine gene expression by alkylating cysteine and arginine residues in the NF-kappaB1 DNA binding domain

Cigarette smoke is a potent inhibitor of pulmonary T cell responses, resulting in decreased immune surveillance and an increased incidence of respiratory tract infections. The alpha,beta-unsaturated aldehydes in cigarette smoke (acrolein and crotonaldehyde) inhibited production of interleukin-2 (IL-2), IL-10, granulocyte-macrophage colony-stimulating factor, interferon-gamma, and tumor necrosis factor-alpha by human T cells but did not inhibit production of IL-8. The saturated aldehydes (acetaldehyde, propionaldehyde, and butyraldehyde) in cigarette smoke were inactive. Acrolein inhibited induction of NF-kappaB DNA binding activity after mitogenic stimulation of T cells but had no effect on induction of NFAT or AP-1. Acrolein inhibited NF-kappaB1 (p50) binding to the IL-2 promoter in a chromatin immunoprecipitation assay by >99%. Using purified recombinant p50 in an electrophoretic mobility shift assay, we demonstrated that acrolein was 2000-fold more potent than crotonaldehyde in blocking DNA binding to an NF-kappaB consensus sequence. Matrix-assisted laser desorption/ionization time-of-flight and tandem mass spectrometry demonstrated that acrolein alkylated two amino acids (Cys-61 and Arg-307) in the DNA binding domain. Crotonaldehyde reacted with Cys-61, but not Arg-307, whereas the saturated aldehydes in cigarette smoke did not react with p50. These experiments demonstrate that aldehydes in cigarette smoke can regulate gene expression by direct modification of a transcription factor.

Avian circoviruses of the genus Circovirus: A potential trigger in Pigeon breeder’s lung (PBL)/Bird fancier’s lung (BFL)

Pigeon breeder's lung (PBL) or Bird fancier's lung (BFL) is one of the most common extrinsic allergic alveolitis or hypersensitivity pneumonitis. It is caused after prolonged inhalation of avian antigens and provokes a hypersensitivity reaction in the lungs of sensitised people. Although the pathogenic mechanism is unclear, the epidemiology of BFL shows that it occurs worldwide, and has been described in adults keeping birds and also in their children. Laboratory findings associated with the disease classified as a type III immunologic reaction that produces blood precipitin antibodies against birds' serum, feathers, intestinal mucin and/or faeces. In particular, the fine dust from pigeon feathers has strong antigenic properties. There is an interaction between host and antigen that seems to be influenced by both genetic and environmental factors. Avian circoviruses (ACV) of the genus Circovirus, has been detected in free-ranging and captive birds worldwide, such as pigeons, canaries, psittacines, Senegal doves, finches, gulls, Australian ravens and geese. T lymphocytes are the main target cells of the ACV and in the above avian species circovirus-like particles were detected in blood, macrophages, feathers, crop secretions, intestinal contents and/or faeces. Most of the ACV was demonstrated that are pantropic and viral antigen in pigeon tissues was most commonly detected in respiratory organs, including the trachea, pharynx and lung. The transmission of the circovirus between the birds usually occurs through inhalation of feathers dust. There is evidence that animal circoviruses may originate when vertebrates become "infected" with DNA from a plant nanovirus. So, it seems that further investigation for the avian circoviruses is needed to determine if they are host specific or not. This study attempts to demonstrate ACV or ACV-like particles as potential triggers in the BFL aetiology, and the possible involvement in BFL's pathogenic mechanism.

Cigarette tar phenols impede T cell cycle progression by inhibiting cyclin-dependent kinases

Cigarette smoking causes profound suppression of pulmonary T cell responses, which is associated with increased susceptibility to respiratory tract infections and decreased tumor surveillance. We previously demonstrated that the phenolic compounds in cigarette tar inhibit blastogenesis and interfere with human T cell cycle progression. To identify the mechanism by which cell cycle arrest occurs, we examined the effects of these compounds on cyclin-dependent kinases (Cdk) that control the G0/G1 transition. We found that hydroquinone inhibited induction of Cdk4 and Cdk6 kinase activities by >80%, while catechol and phenol were markedly less potent. HQ did not affect mitogenic induction of the Cdk6 protein, but inhibited expression of cyclin D3 by >90% resulting in a dramatic reduction in proper Cdk6/Cyclin D3 complex formation.

Hypersensitivity pneumonitis in children: clinical features, diagnosis, and treatment

Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, is a form of immune-mediated inflammatory lung disease involving the distal portions of the lungs associated with intense or repeated exposure to a variety of finely dispersed environmental antigens. Although once believed to be a disease of adults because of its frequent association with the occupational setting, HP exists in the pediatric population and often goes unrecognized. Childhood HP is often associated with exposure to antigens in the home environment as well as with certain hobbies. Patients present in any one of the three disease stages: acute, subacute, and chronic, all with unique clinical presentations. Histopathologic findings depend on the disease stage at the time of evaluation. The immuno-pathogenesis is complex, but immune-complex (type III hypersensitivity) and cell-mediated (type IV hypersensitivity) immune responses appear to be the primary immune mechanisms involved in the pathogenesis of HP. Diagnosis can be very challenging. Although no single diagnostic or clinical laboratory test is available to diagnose HP, the most significant diagnostic tool is a detailed environmental exposure history. Avoidance of the inciting antigen is the most important form of treatment. Acute HP is responsive to antigen removal alone. However, a short course of prednisone for 2-3 weeks can be useful in patients with severe attacks. Subacute and chronic HP may require higher doses of corticosteroids for a longer duration (i.e. months); however, the long-term efficacy of using corticosteroids is still not well defined. As with most hypersensitivity diseases, early diagnosis provides the best prognosis.

Acrolein in cigarette smoke inhibits T-cell responses

BACKGROUND

Cigarette smoking inhibits T-cell responses in the lungs, but the immunosuppressive compounds have not been fully identified. Cigarette smoke extracts inhibit IL-2, IFN-gamma, and TNF-alpha production in stimulated lymphocytes obtained from peripheral blood, even when the extracts were diluted 100-fold to 1000-fold.

OBJECTIVE

The objective of these studies was to identify the immunosuppressive compounds found in cigarette smoke.

METHODS

Gas chromatography/mass spectroscopy and HPLC were used to identify and quantitate volatile compounds found in cigarette smoke extracts. Bioactivity was measured by viability and production of cytokine mRNA and protein levels in treated human lymphocytes.

RESULTS

The vapor phase of the cigarette smoke extract inhibited cytokine production, indicating that the immunosuppressive compounds were volatile. Among the volatile compounds identified in cigarette smoke extracts, only the alpha,beta-unsaturated aldehydes, acrolein (inhibitory concentration of 50% [IC50] = 3 micromol/L) and crotonaldehyde (IC50 = 6 micromol/L), exhibited significant inhibition of cytokine production. Although the levels of aldehydes varied 10-fold between high-tar (Camel) and ultralow-tar (Carlton) extracts, even ultralow-tar cigarettes produced sufficient levels of acrolein (34 micromol/L) to suppress cytokine production by >95%. We determined that the cigarette smoke extract inhibited transcription of cytokine genes. The inhibitory effects of acrolein could be blocked with the thiol compound N-acetylcysteine.

CONCLUSION

The vapor phase from cigarette smoke extracts potently suppresses cytokine production. The compound responsible for this inhibition appears to be acrolein.

Hypersensitivity pneumonitis

PURPOSE OF REVIEW

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is a granulomatous, inflammatory disease of the lungs caused by the inhalation of antigenic organic particles or fumes. The disease may present as an acute, subacute, or chronic illness. Episodes of acute and subacute HP usually resolve following cessation of antigen exposure. Chronic HP may be progressive, irreversible, and result in debilitating fibrotic lung disease. This review discusses current concepts regarding the diagnosis, pathogenesis, and treatment of HP.

RECENT FINDINGS

The pathogenesis of HP involves both type III and type IV hypersensitivity reactions that are mediated by immune complexes and Th1 T cells, respectively. Proinflammatory cytokines and chemokines activate alveolar macrophages, cause an influx of CD8+ lymphocytes into the lungs, facilitate granuloma formation, and promote the development of pulmonary fibrosis. IFN-gamma is essential for the development of HP and IL-10 appears to modulate the severity of disease. TNF-alpha and TGF-beta have been implicated in development of the pulmonary fibrosis that is seen in chronic HP. It has been shown that pigeon fanciers with HP have an increase in the frequency of HLA-DRB1*1305 and HLA-DQB1*0501 alleles, a decrease in the frequency of the HLA-BRB1*0802 allele, and an increased frequency of the TNF-2 (-308) polymorphism of the TNF-alpha promoter gene.

SUMMARY

A careful environmental and occupational history and establishment of exposure to a known inciting antigen are key factors in making the diagnosis of HP. Serum precipitating antibodies, bronchoalveolar lavage, and lung biopsy may be helpful in making the diagnosis. Avoidance of organic antigen exposure is the most important factor in the management of HP. Corticosteroids are indicated for the treatment of severe acute and subacute HP and for chronic HP that is severe or progressive. Long-term corticosteroid therapy for the treatment of chronic HP should be considered only if objective improvement in clinical signs, pulmonary function, or radiographic abnormalities is documented.

Effects of cigarette smoking on diagnostic tests for work-related hypersensitivity pneumonitis: data from an outbreak of lung disease in metalworkers

BACKGROUND

It is widely believed that development of hypersensitivity pneumonitis (HP) is forestalled in cigarette smokers. We encountered the largest outbreak of HP in metalworkers yet reported [Hodgson et al. (2001): Am J Ind Med 39:616-628] and subsequently did a chart review of the 61 patients seen in connection with the outbreak [Dangman et al. (2002a): Am J Resp Crit Care Med 165(8):A528; Dangman et al. (2002b): Am J Ind Med 42:150-162], developing a diagnostic index for this disease.

METHODS

A re-examination of data from the chart review was carried out to explore possible effects of cigarette smoking on the clinical tests used to diagnose HP [Hodgson et al. (2001): Am J Ind Med 39:616-628].

RESULTS

Cigarette smokers with HP were less likely than non-smokers with HP to develop crackles in the lungs, elevated erythrocyte sedimentation rates (ESRs), and restrictive spirometry. Smoking habits had little effect on diffusion capacity and alveolar-arterial oxygen gradients in the patients with HP. Smokers were more likely to have abnormal gallium scans than non-smokers.

CONCLUSIONS

It appears that cigarette smoking can affect the physical examination findings, spirometry, and ESR changes associated with HP, making these tests less sensitive and specific, and potentially obscuring the diagnosis. Such changes may contribute to the apparent "protective" effect of smoking on the development of HP.

Hydroquinone and catechol interfere with T cell cycle entry and progression through the G1 phase

Cigarette smoking causes profound suppression of pulmonary T cell responses, which is associated with increased susceptibility to respiratory tract infections and decreased tumor surveillance. Hydroquinone (HQ) and catechol, at concentrations comparable to those found in cigarette smoke, are potent inhibitors of T cell activation and proliferation. We have previously shown that HQ and catechol inhibit ribonucleotide reductase, the rate-limiting enzyme in DNA synthesis. In this report we demonstrate that HQ and catechol also inhibit blastogenesis by interfering with T cell cycle entry and progression through the G(1) phase. In an attempt to localize the point in the cell cycle where arrest occurred, a set of key markers of activation and cell cycle progression were examined, including induction of c-Myc, up regulation of RNA synthesis, surface expression of CD71, and induction of E2F-dependent gene expression. Addition of HQ or catechol prior to stimulation inhibited each of these events without decreasing cell viability. However, production of IL-2 and surface expression of CD69 and CD25 were not affected, indicating that HQ and catechol inhibit only certain cell cycle events. These studies provide further indication of the regulatory pathways by which cigarette smoke inhibits T cell responses in the lungs of smokers.

Clinical and radiologic manifestations of hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is an inflammatory interstitial lung disease caused by recurring exposure to a variety of occupational and environmental antigens. It features widely variable clinical, radiologic, and histopathologic findings. Because the clinical findings of HP mimic multiple other diseases, a high degree of clinical suspicion and a thorough occupational and environmental history are essential for accurate diagnosis. There is no single pathognomonic feature for HP; rather, diagnosis relies on a constellation of clinical, radiologic, and pathologic findings. The radiologic manifestations, particularly the high-resolution computed tomography (HRCT) pattern, provide important clues and frequently point clinicians towards the correct diagnosis. The HRCT findings in HP may include ground-glass opacification, centrilobular nodules, air trapping (mosaic pattern), fibrosis, emphysema, or more frequently a combination of these. The combination of a mosaic pattern with ground-glass opacification and centrilobular nodules is particularly suggestive of the diagnosis. The best long-term prognosis is achieved with early diagnosis and removal from exposure.

The long-term outcome in acute, subacute, and chronic forms of pigeon breeder's disease hypersensitivity pneumonitis

BACKGROUND

Pigeon breeder's disease (PBD) is an avian-induced hypersensitivity pneumonitis. The limited data that exist on the long-term outcome for the disease are conflicting.

OBJECTIVE

We sought to determine the long-term outcome of patients with PBD to evaluate the course of the disease.

METHODS

Review a case series of 18 pigeon breeders that were followed from 4 to 26 years after initial diagnosis.

RESULTS

Fourteen breeders reduced their bird contact significantly; four kept their birds. In eight patients with the acute form of the disease, pulmonary function either did not change from normal or improved to normal. Of five patients with subacute disease, four had persistent symptoms. All had mildly abnormal spirometry with either restrictive or obstructive changes which persisted. Five patients with chronic disease exhibited daily dyspnea. They had severe abnormalities of lung function at diagnosis. Of these patients, three improved and two deteriorated. Chest radiographs were of little value in predicting outcome.

CONCLUSIONS

Patients with the acute form of PBD have the best prognosis, compared with those with subacute and chronic forms. Although some improvement could be seen in most individuals, recovery may still not be complete. Those with the chronic form are at particular risk for morbidity.

Adult endomysial antibody-negative coeliac disease and cigarette smoking

OBJECTIVE

To determine the relative incidence and characteristics of endomysial antibody (EMA)-negative coeliac disease in adults.

DESIGN

Retrospective analysis of prospectively collected data on adults with newly diagnosed coeliac disease, with determination of EMA status before gluten withdrawal.

SETTING

District general hospital (secondary care institution).

PARTICIPANTS

Sixty consecutive incident cases.

MAIN OUTCOME MEASURES

(i) Proportion of cases who were EMA-negative; (ii) comparison of clinical and laboratory variables at diagnosis for EMA-positive and EMA-negative subjects.

RESULTS

Fifteen subjects (25%, 95% CI 15-38%) were EMA negative, of whom only two were IgA deficient. There was clinical evidence in all 15 patients and histological evidence in 13 patients of a response to gluten withdrawal. No significant differences were found between EMA-positive and EMA-negative subjects with respect to histological features, age, gender, clinical manifestations, concurrent autoimmune disorders, family history of coeliac disease, or haemoglobin and albumin concentrations at diagnosis. However, EMA-negative status at diagnosis was associated strongly with current or recent cigarette smoking (OR 7.0, 95% CI 1.7-31.5, P= 0.003).

CONCLUSIONS

A substantial minority of patients with otherwise typical coeliac disease are EMA negative, and most of these are IgA replete. The value of EMA as a screening tool is therefore limited. EMA status in untreated coeliac disease correlates strongly with cigarette smoking history: this may be of pathogenic significance, given the previously demonstrated association between smoking and the risk of coeliac disease.

Exposure to cigarette tar inhibits ribonucleotide reductase and blocks lymphocyte proliferation

Cigarette smoking causes profound suppression of pulmonary T cell responses, which has been associated with increased susceptibility to respiratory tract infections and decreased tumor surveillance. Exposure of human T cells to cigarette tar or its major phenolic components, hydroquinone and catechol, causes an immediate cessation of DNA synthesis without cytotoxicity. However, little is known of the mechanisms by which this phenomenon occurs. In this report we demonstrate that hydroquinone and catechol inhibit lymphocyte proliferation by quenching the essential tyrosyl radical in the M2 subunit of ribonucleotide reductase.

Detection of specific antibodies to pigeon serum and bloom antigens by enzyme linked immunosorbent assay in pigeon breeder's disease

BACKGROUND

Pigeon breeder's disease is an extrinsic allergic alveolitis in the lungs of sensitised people, caused by hypersensitivity reactions to inhaled pigeon antigens. Antigens from different sources of the animal are used for diagnostic purposes, with serum being the most widely used. Bloom is rarely used; very little is known of its antigenicity and diagnostic performance, particularly when used with the enzyme linked immunosorbent assay (ELISA) method, which is the most popular test as it permits measurement of the antibody response.

METHODS

To (a) standardise an ELISA for the measurement of specific IgG against pigeon serum and pigeon bloom extract; (b) to establish reference values for specific IgG in 73 non-exposed controls, (c) to show the presence of specific IgG against pigeon serum and bloom in serum samples of 17 patients with bird fancier's lung and 11 asymptomatic fanciers, and (d) to study the similarity of the two antigen sources by cross reactivity experiments.

RESULTS

Reference values of specific IgG were defined with the 97.5 percentile (367.9 U/ml for pigeon serum and 953.7 U/ml for pigeon bloom extract). Of symptomatic patients 100% had values higher than the cut off for both antigens. In asymptomatic fanciers values were higher than the cut off for pigeon serum in 45% and bloom extract in 54%. Cross reactivity experiments showed that the two antigens differed in antigenic content although some components may be common to both.

CONCLUSION

The ELISA methods used proved to be useful tools for evaluating specific IgG antibody responses against both antigens. The diagnostic performance of both ELISA methods performed with these antigen sources was similar, showing very high sensitivity but moderate specificity. Although some antigenic similarity was found between pigeon serum and bloom extract, cross reactivity studies showed that various antigens seemed to be specific to the bloom extract. However, the antigens responsible for pigeon breeder's disease seem to be present in both antigenic sources.