Pigeon fancier's lung

Not all children with nodular interstitial lung patterns in South Africa have TB-A rare case of paediatric "Bird Fanciers' disease"

Bird Fancier's disease is an allergic alveolitis that is rare in children. We describe the relevance of adequate history for making the diagnosis in children and the difficulty distinguishing this entity on chest radiographs and CT from imaging patterns caused by infections such as tuberculosis and HIV in developing countries. Pediatr. Pulmonol. 2011; 46:1134-1136. © 2011 Wiley Periodicals, Inc.

A new application of Streptavidin ImmunoCAP for measuring IgG antibodies against non-available commercial antigens

BACKGROUND

Enzyme immunoassay has been successfully used for the diagnosis of hypersensitivity pneumonitis (HP), but there are difficulties in standardising this method because of the difficulty in obtaining stable solid phases from a huge variety of heterogeneous antigenic sources. With this in mind, the aim of this work was to demonstrate the usefulness of the standard available fluoro-enzyme-immuno-assay (FEIA) to measure specific IgG to uncommon, commercially unavailable HP-causing antigens.

METHODS

Serum samples from patients suffering from HP caused by canary and pigeon protein exposure with positive immunoprecipitation values, as well as cystic fibrosis patients, patients with respiratory allergies, asymptomatic subjects exposed to canary proteins (canary breeders) and healthy unexposed individuals were evaluated by FEIA using biotinylated serum proteins coupled to streptavidin-activated solid phases. Statistical analyses were performed to compare the different groups and to evaluate the performance of this technique.

RESULTS

The group of patients with hypersensitivity pneumonitis caused by exposure to canary proteins showed the highest value of specific IgG (35.70 mg IgG/mL). ROC analysis demonstrated an optimal cut-off value of 8.44 mg IgG/mL with a sensitivity of 100% and a specificity of 91.76%. Comparisons with other groups revealed statistically significant differences. Comparison between ELISA and FEIA results revealed a strong positive relationship between values obtained in both assays.

CONCLUSION

The results demonstrate that Streptavidin ImmunoCAP is a sensitive, specific and efficient laboratory method for routine diagnostic testing of HP caused by protein antigens that are not commercially available.

Hypersensitivity pneumonitis: clinical perspectives

CONTEXT

The clinical course of hypersensitivity pneumonitis (HSP) is highly variable and its diagnosis clinically challenging.

OBJECTIVE

To provide a concise review of major clinical, radiographic, and laboratory findings that permits diagnosis of HSP from the standpoint of a clinician/pulmonologist.

DATA SOURCES

Review of major contemporary and historical literature in combination with the author's experience and viewpoints.

CONCLUSIONS

The approach to the diagnosis of HSP is multidisciplinary. For patients being evaluated for unexplained dyspnea and cough and an unknown interstitial disease process, the initial evaluation should include detailed environmental and occupational histories with ancillary testing such as serology, chest imaging, inhalation challenges, and bronchoalveolar lavage, as indicated. In uncertain cases, lung biopsy is recommended.

[Hypersensitivity pneumonitis in a chicory worker]

INTRODUCTION

We report a case of occupational hypersensitivity pneumonitis in a patient handling chicory leaves.

CASE REPORT

The diagnosis was based symptoms of broncho-alveolitis with pyrexia, positive precipitins to moulds present on chicory, especially Fusarium, and the disappearance of the clinical and radiological manifestations following cessation of exposure to chicory.

CONCLUSION

"Chicory worker's lung" is an occupational disease which should be considered in cases of respiratory symptoms suggestive of hypersensitivity pneumonitis and chronic exposure to chicory leaves.

Interstitial lung disease: progress and problems

Interstitial lung disease involves all areas of medicine as it often occurs in patients with comorbidities or as a consequence of systemic diseases and their treatment. Typically the physician is faced with a breathless patient, a diffusely abnormal chest radiograph, and a wide differential diagnosis. Progress has been made in using high resolution computed tomography as the key investigation in characterising the pattern and extent of the disease. Bronchoalveolar lavage is particularly important in excluding infection as a cause of diffuse lung infiltrates. Surgical lung biopsies have led to a new classification system for the range of histopathological patterns of disease that were previously known by the collective term cryptogenic fibrosing alveolitis. Problems persist in deciding when a surgical lung biopsy is clinically justified, in understanding the pathogenesis of these diseases, and in finding more effective treatments.

Quantifying serum antibody in bird fanciers' hypersensitivity pneumonitis

Background

Detecting serum antibody against inhaled antigens is an important diagnostic adjunct for hypersensitivity pneumonitis (HP). We sought to validate a quantitative fluorimetric assay testing serum from bird fanciers.

Methods

Antibody activity was assessed in bird fanciers and control subjects using various avian antigens and serological methods, and the titer was compared with symptoms of HP.

Results

IgG antibody against pigeon serum antigens, quantified by fluorimetry, provided a good discriminator of disease. Levels below 10 mg/L were insignificant, and increasing titers were associated with disease. The assay was unaffected by total IgG, autoantibodies and antibody to dietary hen's egg antigens. Antigens from pigeon serum seem sufficient to recognize immune sensitivity to most common pet avian species. Decreasing antibody titers confirmed antigen avoidance.

Conclusion

Increasing antibody titer reflected the likelihood of HP, and decreasing titers confirmed antigen avoidance. Quantifying antibody was rapid and the increased sensitivity will improve the rate of false-negative reporting and obviate the need for invasive diagnostic procedures. Automated fluorimetry provides a method for the international standardization of HP serology thereby improving quality control and improving its suitability as a diagnostic adjunct.

Treatment of interstitial lung disease in children

The treatment of interstitial lung disease in children depends on the nature of the underlying pathology. In approximately 50% of cases a specific aetiology can be found such as: chronic viral infection, an auto-immune process, sarcoidosis or alveolar proteinosis. In the remainder, the process is idiopathic and the pathological findings are based on the descriptive morphological features seen in the diagnostic lung biopsy. If a specific cause is found then targeted treatment with antivirals, steroids or other immunosuppressive agents is available. Alveolar proteinosis can be treated by bronchial lavage and GM-CSF. Idiopathic cases are treated primarily with intravenous pulsed methylprednisolone or oral prednisolone backed up hydroxychloroquine. Other immunosuppressive agents such as azathioprine, methotrexate or ciclosporin have been used successfully in individual patients. The prognosis is very variable and includes no response to any therapy, partial response with chronic long term morbidity, to virtually complete recovery. The overall mortality rate is 15%. There are no controlled therapeutic trials available because of the rarity of these conditions in childhood. Unlike in adult practice, no correlation has as yet been demonstrated between the initial pattern of chest x-ray change or the degree of pathological change on the lung biopsy and the clinical outcome. The recurrence rate within families is 1 in 8.

Use of co-immunoelectrodiffusion to detect presumed disease-associated precipitating antibodies, and time-course value of specific isotypes in bird-breeder's disease

BACKGROUND AND OBJECTIVE

The practical value of immunological diagnosis of bird-breeder's disease (BBD) is controversial, because of difficulties in distinguishing active disease patients from simple contact subjects. The aim of this study was to determine the diagnostic and prognostic value of (a) presumed disease-associated antibodies precipitating pigeon antigens (immunoglobulin A (IgAp) and P2 component), (b) characterization of specific isotypes (IgG, IgM, and IgA), and (c) antibody kinetics after antigen eradication.

METHODS

405 subjects (775 sera) in contact with birds were studied [by means of co-immunoelectrodiffusion (Co-IED) and enzyme-linked immunofiltration (ELIFA)] with soluble extracts of pigeon droppings and squab crop milk. These patients were divided into two groups based on the final clinical evaluation of the patients' physicians, which was taken as the gold standard (positive in 90 and negative in 315 cases).

RESULTS

On the basis of this gold standard, the detection of presumed disease-associated precipitating antibodies by Co-IED had a specificity of 95.5%, a sensitivity of 98.7%, an accuracy of 98%, and positive and negative predictive values of 95.5% and 98.7%, respectively. Most of the patients with a final positive diagnosis of BBD had specific IgG, IgM, and IgA antibodies by ELIFA. After antigen eradication, anti IgAp and/or P2 antibodies disappeared more rapidly than other precipitating systems.

CONCLUSION

Identification by Co-IED of precipitating immune complexes IgAp and/or P2 significantly reinforces the intrinsic credibility of immunological diagnosis of BBD. Compared to these presumed disease-associated precipitating antibodies, detection and time course of specific IgM, IgA antibodies, provided no additional diagnostic value or prognostic arguments to judge disease activity after antigen eradication.

Takes your breath away--the immunology of allergic alveolitis

Extrinsic allergic alveolitis (synonym: hypersensitivity pneumonitis) is caused by inhaling antigenic aerosols which induce hypersensitivity responses in susceptible individuals. It is an interstitial inflammatory disease affecting the distal, gas-exchanging parts of the lung, in contrast to allergic asthma where the inflammation is more proximal, affecting the conducting airways. The aims of this review are to describe current concepts of the immunology of this model of lung inflammation, to describe some of the constitutional and environmental characteristics which affect disease susceptibility and development, and to describe topics for prospective study.

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

A reduced prevalence of pigeon fanciers' lung has been reported in pigeon breeders who smoke cigarettes. Serum and salivary antibodies to pigeon intestinal mucin and pigeon serum proteins were investigated in 227 pigeon fanciers, subdivided according to smoking habit and clinical status. Smokers had a lower incidence of precipitating antibodies to pigeon antigens and lower titres of serum IgG and IgA antibodies to mucin and to pigeon serum proteins in ELISA compared with non-smokers and ex-smokers. In contrast, IgG antibody titres to tetanus toxoid were similar in smoking and non-smoking groups. In contrast to serum antibodies, salivary IgA antibody titres to pigeon antigens were similar in smokers and non- or ex-smokers. Approximately one third of the smokers reported symptoms consistent with pigeon fanciers' lung but did not have precipitating antibodies. Only some individuals with precipitating antibodies had disease symptoms, and IgG antibody titres in these individuals were not significantly higher than in many asymptomatic individuals. Salivary IgA titres against pigeon mucin were significantly higher in asymptomatic individuals, consistent with a protective role for these antibodies. The results confirm that smoking is associated with a decreased serum antibody response to inhaled pigeon antigens, affecting IgG1, IgG2 and IgA responses, but this impairment does not extend to salivary IgA or to antibody responses to a parenterally administered protein antigen. The fact that responses to pigeon serum proteins and to pigeon intestinal mucin were similarly affected suggests that cigarette smoking depresses both T-independent and T-dependent responses to inhaled antigens.