Immunogenic proteins specific to different bird species in bird fancier's lung

A rapid test for the environmental detection of pigeon antigen

INTRODUCTION

Avoidance of inhaled bird antigens is essential to prevent hypersensitivity pneumonitis disease progression. The aim of the present study was to develop a sandwich enzyme link immunoassay (ELISA) and an immunochromatographic test (ICT) and compare their ability to detect pigeon antigens in environmental samples.

METHODS

An amplified sandwich ELISA using pigeon serum as a calibration standard and a ICT using gold-labeled anti-pigeon serum antibodies for the rapid detection of pigeon antigens in environmental samples were developed. Twenty-two different airborne samples were collected and analysed using both methods. Strip density values obtained with ICT were calculated and compared with the concentrations determined by the ELISA method for pigeon antigens. Strips results were also visually analysed by five independent evaluators.

RESULTS

The ELISA method to quantify pigeon antigen had a broader range (58.4 and 10,112.2 ng/ml), compared to the ICT assay (420 to 3360 ng/ml). A kappa index of 0.736 (p < 0.0001) was obtained between the observers evaluating the ICT strips. The results of the ELISA and the relative density of the ICT showed a highly significant correlation (rs:0.935; p < 0.0001). Bland-Altman plot also confirmed excellent agreement between the two methods (mean difference: -1.626; p < 0.0001).

CONCLUSIONS

Since there was a good correlation between both assays, we can conclude that the rapid and simple ICT assay is a good and valid alternative, which does not require expensive equipment, for the validated ELISA technique.

Pilot Study Using Recombinant Antigens r-PROE and r-IGLL1 for the Serodiagnosis of Feather Duvet Lung

BACKGROUND

Feather duvet lung (FDL) is an underestimated form of acute and chronic hypersensitivity pneumonitis. Serological tests for FDL need to be validated. We investigated the ability of recombinant pigeon Proproteinase E (r-PROE) and Immunoglobulin-lambda-like-polypeptide-1 (r-IGLL1) proteins to support the serological diagnosis of FDL, and propose them as a serological tool for clinicians to differentiate cases from FDL and Bird fancier's lung (BFL).

METHODS

Specific IgG antibodies against r-PROE and r-IGLL1, analyzed with ELISA, were measured in patients diagnosed with FDL (n=31), BFL (n=15) controls exposed (n=15) and unexposed to feathers (n=15).

RESULTS

The sensitivity and specificity of the r-PROE ELISA for the serological diagnosis of FDL cases versus exposed and unexposed controls were 74.2% and 86.7% respectively, with an index threshold of 0.5 (AUC: 0.89). In addition, this serological test was effective to support the serological diagnosis of FDL and BFL cases with significantly different thresholds. The r-IGLL1 ELISA was only effective for the serological diagnosis of BFL. Also, these two serological tests were useful for the diagnosis of both chronic and acute forms.

CONCLUSIONS

The new diagnostic test for FDL using r-PROE protein should help to detect overt and hidden cases of FDL. The combination of both test will help the clinician in distinguish between the etiology of birds or feathers duvet.

Hypersensitivity pneumonitis: A new strategy for serodiagnosis and environmental surveys

We propose a strategy for serodiagnosis of hypersensitivity pneumonitis (HP): 1) question patients about their private or occupational activity, or visit him on site; 2) select panels of six somatic specific antigens appropriate for each type of exposure; 3) and use ELISA to test concomitantly two recombinant antigens highly specific to Farmer's lung, Metalworking-fluid HP, and for Bird fancier's lung. The serodiagnosis provides an immunological argument that may complete radiological, functional lung exploration and clinical features; 4) If the serodiagnosis is negative but the suspicion of HP is strong, a microbial analysis of the patient's specific exposure is conducted; 5) "A la carte" antigens are produced from the microorganisms isolated in the patient's environment sample and tested; 6) Finally, the patient may be asked to undergo a specific inhalation challenge with the offending antigens in a safety cabin, or to avoid his usual environment for a few days.

Review of Nonfoodborne Zoonotic and Potentially Zoonotic Poultry Diseases

Emerging and re-emerging diseases are continuously diagnosed in poultry species. A few of these diseases are known to cross the species barrier, thus posing a public health risk and an economic burden. We identified and synthesized global evidence for poultry nonfoodborne zoonoses to better understand these diseases in people who were exposed to different poultry-related characteristics (e.g., occupational or nonoccupational, operational types, poultry species, outbreak conditions, health status of flocks). This review builds on current knowledge on poultry zoonoses/potentially zoonotic agents transmitted via the nonfoodborne route. It also identifies research gaps and potential intervention points within the poultry industry to reduce zoonotic transmission by using various knowledge synthesis tools such as systematic review (SR) and qualitative (descriptive) and quantitative synthesis methods (i.e., meta-analysis). Overall, 1663 abstracts were screened and 156 relevant articles were selected for further review. Full articles (in English) were retrieved and critically appraised using routine SR methods. In total, eight known zoonotic diseases were reviewed: avian influenza (AI) virus (n = 85 articles), Newcastle disease virus (n = 8), West Nile virus (WNV, n = 2), avian Chlamydia (n = 24), Erysipelothrix rhusiopathiae (n = 3), methicillin-resistant Staphylococcus aureus (MRSA, n = 15), Ornithonyssus sylvarium (n = 4), and Microsporum gallinae (n = 3). In addition, articles on other viral poultry pathogens (n = 5) and poultry respiratory allergens derived from mites and fungi (n = 7) were reviewed. The level of investigations (e.g., exposure history, risk factor, clinical disease in epidemiologically linked poultry, molecular studies) to establish zoonotic linkages varied across disease agents and across studies. Based on the multiple outcome measures captured in this review, AI virus seems to be the poultry zoonotic pathogen that may have considerable and significant public health consequences; however, epidemiologic reports have only documented severe human cases clustered in Asia and not in North America. In contrast, avian Chlamydia and MRSA reports clustered mainly in Europe and less so in North America and other regions. Knowledge gaps in other zoonoses or other agents were identified, including potential direct (i.e., nonmosquito-borne) transmission of WNV from flocks to poultry workers, the public health and clinical significance of poultry-derived (livestock-associated) MRSA, the zoonotic significance of other viruses, and the role of poultry allergens in the pathophysiology of respiratory diseases of poultry workers. Across all pathogens reviewed, the use of personal protective equipment was commonly cited as the most important preventive measure to reduce the zoonotic spread of these diseases and the use of biosecurity measures to reduce horizontal transmission in flock populations. The studies also emphasized the need for flock monitoring and an integrated approach to prevention (i.e., veterinary-public health coordination with regard to diagnosis, and knowledge translation and education in the general population) to reduce zoonotic transmission.

Allergen component analysis as a tool in the diagnosis of occupational allergy

PURPOSE OF REVIEW

Rapid developments have been seen in molecular allergy diagnosis, based on the detection and quantification of specific IgE to single allergens. This review summarizes and discusses studies on allergen component analysis as a tool in the diagnosis of occupational allergy.

RECENT FINDINGS

More than 400 agents are identified as sensitizers of occupational asthma, but only very few are characterized on the molecular level and available for routine diagnosis. Baker's asthma is one of the most frequently occurring forms of occupational asthma caused by workplace-related inhalation of cereal flour mainly wheat. Wheat sensitization profiles of bakers show great interindividual variability and no wheat allergen could be classified as the major allergen. Component-resolved diagnosis is a useful tool for diagnosing natural rubber latex (NRL) allergy. In cases with unexpected high-latex IgE but without clinical symptoms application of crossreactive carbohydrate determinants are helpful to clarify the cause of IgE binding.

SUMMARY

Latex is an excellent model for component-resolved diagnosis and demonstrates well how to improve the diagnosis by using single allergens. For diagnosis of baker's asthma, a whole wheat extract is still the best option for specific IgE determination, but single wheat allergens might help to discriminate between wheat-induced food allergy, grass-pollen allergy, and baker's asthma. New diagnostic tools and platforms are promising, but further knowledge of molecules relevant for occupational asthma (as in wood dust allergens, enzymes, laboratory animal allergens, etc.) and for occupational hypersensitivity pneumonitis is necessary to improve and standardize the diagnostic tools.

Western blotting as a tool for the serodiagnosis of farmer's lung disease: validation with Lichtheimia corymbifera protein extracts

Electrosyneresis and double diffusion are immunoprecipitation techniques commonly used in the serological diagnosis of Farmer's lung disease (FLD). These techniques are reliable but lack standardization. The aim of this study was to evaluate Western blotting for the serodiagnosis of FLD. We carried out Western blotting with an antigenic extract of Lichtheimia corymbifera, an important aetiological agent of the disease. The membranes were probed with sera from 21 patients with FLD and 21 healthy exposed controls to examine the IgG antibody responses against purified somatic antigens. Given the low prevalence of the disease, 21 patients could be considered as a relevant series. Four bands were significantly more frequently represented in membranes probed with FLD sera (bands at 27.7, 40.5, 44.0 and 50.5 kDa) than those probed with control sera. We assessed the diagnostic value of different criteria alone or in combination. The diagnostic accuracy of the test was highest with the inclusion of at least two of the following criteria: at least five bands on the strip and the presence of one band at 40.5 or 44.0 kDa. Sensitivity, specificity and positive and negative predictive values were all 81%, and the odds ratio was 18.06. Inclusion of bands of high intensity diminished rather than improved the diagnostic value of the test. We concluded that Western blotting is a valuable technique for the serodiagnosis of FLD. The industrial production of ready-to-use membranes would enable the routine use of this technique in laboratories, and provide reliable and standardized diagnostic results within a few hours.