Longitudinal changes in serum immunoglobulin G testing in patients with fibrotic avian hypersensitivity pneumonitis

BACKGROUND

Evaluation of the antigen responsible for fibrotic hypersensitivity pneumonitis (HP) is challenging. Serum immunoglobulin (Ig) G testing against HP-associated antigens is performed. Although single-serum IgG testing has been investigated, multiple-serum IgG testing has not yet been studied.

METHODS

This study included patients who underwent histopathological examination and positive inhalation challenge test as well as those with moderate or high HP guideline confidence level. Serum IgG testing against pigeon serum was conducted twice using two methods: enzyme linked-immunosorbent assay (ELISA) and ImmunoCAP. The association between changes in serum IgG antibody titers and changes in forced vital capacity (FVC) and other parameters was investigated.

RESULTS

In this study, 28 patients (mean age, 64.5 years; mean FVC, 85.3%) with fibrotic avian HP were selected, of whom 20 and 8 underwent surgical lung biopsy and transbronchial lung cryobiopsy, respectively. Of the 28 patients, 19 had been keeping birds for more than 6 months. A correlation was observed between the annual changes in serum IgG antibody titers by ELISA and changes in relative FVC (r =  - 0.6221, p < 0.001). Furthermore, there was a correlation between the annual changes in serum IgG antibody titers by ImmunoCAP and changes in relative FVC (r =  - 0.4302, p = 0.022). Multiple regression analysis revealed that the change in serum IgG antibody titers by both ELISA and ImmunoCAP also influenced the relative FVC change (p = 0.012 and p = 0.015, respectively). Moreover, 13 patients were given additional treatments between the first and second blood test; however, the additional treatment group was not significantly different in relative FVC change compared to the group with no additional treatment (p = 0.982).

CONCLUSIONS

In patients with fibrotic avian HP, the annual changes in serum IgG testing were correlated with FVC changes, highlighting the importance of serum IgG testing over time.

Establishment of Rat Models of Different Pathological Types of Hypersensitivity Pneumonitis Using Pigeon Droppings

BACKGROUND

The pathogenesis and pulmonary histopathological characteristics of hypersensitivity pneumonitis (HP) are not yet fully understood. Therefore, we established animal models of HP of different stages, aiming to provide support for research on this disease.

METHODS

We established rat models of pigeon breeder's lung of different pathological types by creating freeze-dried allergen powder from fresh pigeon feathers, dander, and other droppings. Freeze-dried allergen powder suspensions of pigeon droppings were used to establish 2 rat models of HP, one by aerosol inhalation and one by airway instillation, and the rats were sacrificed after different lengths of time to observe the pathological changes in their lung tissues.

RESULTS

By the 40th week after allergen inhalation, granulomas were the main changes in the model, without fibrotic changes. When using airway instillation to establish the model, at the 20th week, group 1 (low dose + twice/week) and group 2 (medium dose + twice/week) showed granuloma changes, but no fibrosis; group 3 (high dose + once/week) and group 4 (high dose + twice/week) both showed obvious pulmonary fibrotic changes, but the death rate of rats in group 4 was greater.

CONCLUSIONS

Both aerosol inhalation and airway instillation of freeze-dried pigeon allergen powder can successfully establish an HP model. The airway instillation method can cause pulmonary fibrotic changes in a short time, and the pulmonary pathological changes of animal models manifest with an obvious time-dose effect.

Immunomodulatory effect of pigeon serum in an acute and chronic murine model of bird fanciers lung

INTRODUCTION

Since the immunopathological mechanisms of bird fancier's lung (BFL) are not well known, we created two models of the disease (acute and chronic BFL) to study and compare the pathways involved in its immunopathogenesis.

MATERIALS AND METHODS

C57BL/6 mice were used. Two intraperitoneal injections of 100 μL of commercial pigeon serum (PS) or saline (SAL) were administered with an interval of 48 h in between. Subsequently, intranasal instillations of 40 μL of PS or SAL were performed three days a week, for three weeks in the acute model (AC/PS) and for twelve weeks in the chronic model (CR/PS). Total lung capacity (TLC) was assessed. Pulmonary inflammation was evaluated in bronchoalveolar lavage (BAL), and total serum immunoglobulin (Ig) G was measured in serum samples 24 h, 7 days and 14 days after the last exposure. Histological studies of lungs were assessed.

RESULTS

A drop in TLC was observed in treated mice. This decrease was more marked in the CR/PS group (p < 0.001). Neutrophil and lymphocyte counts increased in both AC/PS and CR/PS groups (p < 0.01). The extent of airway inflammation was also examined in the histological analysis of the lungs, which showed predominant perivascular and peribronchiolar inflammation, with centrilobular oedema and subpleural inflammation in the AC/PS group. In the CR/PS group, the changes were greater, with increased levels of IL-5, IL-17F, IL-13 and IL-10 and decreased levels of IL-2.

CONCLUSIONS

Bronchial inflammation is present in acute and chronic models of HP following exposure to PS. Our results support the role of neutrophils and IL-17 in the development of the disease and an evolution towards a Th-2 immune response in chronic HP. These models may serve as a tool for future studies of the pathogenesis of HP.

Utility of immunological tests for bird-related hypersensitivity pneumonitis

BACKGROUND

The reaction of specific antibodies and sensitized lymphocytes to antigens is important in hypersensitivity pneumonitis (HP). However, there are no known studies evaluating the utility of the lymphocyte proliferation test (LPT) or specific antibodies to avian antigens in diagnosing bird-related HP. In this study, we examined the sensitivity and specificity of these two tests.

METHODS

Patients with acute bird-related HP (n=10), chronic bird-related HP (n=35), acute summer-type HP (n=14), and other interstitial pneumonia (IP) (n=76) were evaluated. The optimal cutoff values were determined by receiver operating curve (ROC) analyses of specific antibodies in serum and bronchoalveolar lavage fluid (BALF), and by conducting the LPT on mononuclear cells in peripheral blood and BALF.

RESULTS

The sensitivity and specificity of the antibodies were 80-100% and 92-100% in acute bird-related HP, and 26-79% and 73-93% in chronic bird-related HP, respectively. The sensitivity and specificity of the LPT were 50-100% and 100% in acute bird-related HP, and 46% and 91% in chronic bird-related HP, respectively.

CONCLUSIONS

Specific antibodies and the LPT are quite useful for diagnosing acute bird-related HP. The presence of specific antibodies in BALF and the results of LPT with peripheral blood mononuclear cells are particularly useful for diagnosing chronic bird-related HP.

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

Bird fancier's lung (BFL) is a disease produced by exposure to avian proteins present in droppings, blooms, and serum of a variety of birds. Although serological test results are currently used to confirm clinical diagnosis of the disease, bird species specificity is poorly understood. This study aimed to contribute to a better understanding of the specificity of immunogenic proteins revealed from the droppings of three bird species. Sera from four patients with BFL and two controls without exposure were analyzed by Western blotting with antigens from droppings of two pigeon and budgerigar strains and two hen species. When the antigens from the droppings of the three bird species were compared, the profile of immunogenic proteins was different and there were similarities between strains of the same species. Only one 68-kD protein was common to pigeon and budgerigar droppings, while proteins of 200, 175, 140, 100, and 35 kD were detected as specific in one bird species. These results provide insight to further characterize these proteins, and to design new serological tests specific to different bird species. These tests may help to refine strategies of antigenic exclusion and also to allow a patient compensation in case of BFL of occupational origin.

Environmental triggers of autoimmunity in anti-synthetase syndrome: the lungs under the spot light

The prevalence of interstitial lung involvement in anti-synthetase syndrome (anti-SS) may be as high as 70% and is a major contributor to morbidity and mortality. Histidyl-tRNA synthetase (Jo-1) is the most common autoantigenic target among the aminoacyl-tRNA synthetases. We report two well documented anti-SS cases where it was observed significant exposure to a known inhaled offending antigen, development of a lymphocytic interstitial lung disease (ILD) and negative auto-antibodies, interpreted at first as hypersensitivity pneumonitis. Only after 14 and 30 months, respectively, the development of systemic symptoms compatible with anti-SS and anti-Jo-1 was observed. A growing body of evidence suggests that the lungs are the environment in which Jo-1 autoimmunity may be initiated and propagated. The description of the clinical and laboratorial evolution of these patients together with accumulated evidence of biological plausibility support the hypothesis that anti-SS can follow an episode of lung inflammation secondary to inhaled antigen exposure.

[Measurement of bird specific antibody in bird-related hypersensitivity pneumonitis]

Since the avian antigen is one of the important causative antigens in hypersensitivity pneumonitis, measurement of bird-specific antibody should be readily available. We measured IgG and IgA antibodies against pigeons and budgerigars by the ImmunoCap system in bird-related hypersensitivity pneumonitis (BRHP) to evaluate their diagnostic utility. In acute BRHP, antibodies markedly increased and showed high sensitivity and specificity ranging from 75-100% based on the cut-off values determined by ROC analysis. In chronic BRHP, antibody reactivity slightly increased, showing a sensitivity of 27-73% and specificity of 45-100%. Pigeon antibodies evaluated by the ImmunoCap system showed a good correlation with anti-pigeon dropping extract antibodies measured by ELISA. In conclusion, measurement of antibodies against pigeons and budgerigars are helpful for the diagnosis of BRHP.

[Case of bird-related hypersensitivity pneumonitis in a farmer]

A 48-year-old female farmer presented to our hospital with shortness of breath and cough. Her partial pressure of arterial oxygen (PaO2) level on room air was 58.4Torr, and chest computed tomography (CT) showed centrilobular ground-glass micronodules. She was admitted for further evaluation. After admission, symptoms, PaO2, and radiological findings improved without any treatment; however, her symptoms recurred when she returned to work. Exposure to her house did not elicit any symptomatic response. We initially suspected farmer's lung, but inhalation provocation tests with hay showed no significant change in symptoms, laboratory data or radiological findings. Antibody tests for Thermoactinomyces vulgaris or Saccharopolyspora rectivirgula were negative. Because many pigeons were found roosting on her farm, we suspected bird-related hypersensitivity pneumonitis. Precipitating antibodies testing against pigeon serum and IgG and IgA antibodies testing against pigeon dropping extracts were all positive, and bird-related hypersensitivity pneumonitis was diagnosed. Because typically, many birds roost on farms, not only farmer's lung, but also bird-related hypersensitivity pneumonitis, should be included in a differential diagnosis when a farmer clinically suspected to have hypersensitivity pneumonitis is encountered.

[The sequential changes of the serum levels of KL-6, SP-D, and DLCO were followed for a long term in a case of acute bird fancier's lung]

The sequential changes of the serum levels of KL-6, SP-D, and DLco were followed for a long term in a case of acute bird fancier's lung, A 52 years-old-male was admitted to our hospital because of cough, dyspnea on exertion and fever. He has been breeding 12 pigeons in home for the last five years. HRCT of the chest demonstrated diffuse centrilobular nodules and ground-glass opacities with mosaic pattern in bilateral lung fields. Bronchoalveolar lavage (BAL) showed an increased number of lymphocytes with a increased CD4/CD8 ratio, and transbronchial lung biopsy (TBLB) specimen revealed alveolitis with infiltration of lymphoid cells and Masson body in the air spaces. He was diagnosed as having bird fancier's lung because of the elevated antibodies against pigeon dropping extracts (PDE) in the serum and BALF. Respiratory failure continued after complete avoidance of contact with pigeons for a week. Clinical symptoms and chest X-ray findings improved markedly after administration of steroid, and he left the hospital to move into a new house. The serum levels of KL-6 and SP-D were unchanged by antigen avoidance, although those were returning to normal gradually after treatment of steroid. SP-D and KL-6 returned to normal in 8 months and 18 months respectively and DLco was also improved slowly in parallel with a decrease of these markers. These results suggest that the serum KL-6 level and DLco reflect the disease activity showing gradual recovery of alveolitis in such a long period.

IgM, IgG, and IgA rheumatoid factors in pigeon hypersensitivity pneumonitis

The association of rheumatoid factor (RF) and lung disease in several immunologically mediated conditions has suggested that it may be physiopathologically relevant. Since previous reports in hypersensitivity pneumonitis (HP) have dealt mainly with the immunoglobulin M (IgM) RF measurement, we studied such antibody activity in other immunoglobulins, to determine the IgG and IgA RF levels in pigeon-HP, and in asymptomatic breeders (AB) and rheumatoid arthritis (RA) as controls. RFs were measured in 35 HP patients, 41 AB, 31 RA controls, and 55 healthy donors by enzyme-linked immunosorbent assay (ELISA) using human or rabbit immunoglobulin G (IgG), anti-IgM, F(ab')2 of IgG, and IgA F(ab')2 conjugates. An affinity chromatography, fragment crystallizable (Fc) preparations of IgG, pepsin digestion, and Western blots were used to confirm RF specificity. We also evaluated anti-avian antibodies (AA) and cross-reacting antibodies. The HP group revealed positive IgM (51.4%), IgG (31.4%), and immunoglobulin A (IgA) (34.2%) RF tests, and these antibody values exceeded the AB reference levels (P<0.02). HP and RA showed a similar frequency and distribution of RFs. Possible immunoassay interferences were excluded. As in other immunologically mediated diseases, IgG and IgA RFs may play a pathogenic role in HP, amplifying the inflammatory reaction, immune-complex formation, and complement activation. IgM-RF producing cells that have been implicated in the presentation of self and foreign antigens, and T-cell activation might induce the isotype switching of RFs.

Pigeon hypersensitivity pneumonitis: immunohistochemical demonstration of the causative antigen in the lung

A number of clinicopathological manifestations may define the presence of hypersensitivity pneumonitis. Histological study is used to establish the diagnosis and to differentiate the disease from other respiratory disorders. This case report suggests that immunohistological demonstration of the causative antigen in the lung may be a useful diagnostic approach in cases of pigeon hypersensitivity pneumonitis. A 52 year-old woman was studied. She had a prior history of pigeon exposure, and lived in an area with a high prevalence of tuberculosis. Her clinical presentation, respiratory function tests and imaging studies revealed a predominant interstitial lung disease. The results of antiavian antibodies, bronchoalveolar analysis, and other laboratory parameters were non-diagnostic. A lung biopsy showed a prominent granulomatous reaction with a sarcoid-like appearance in some areas, and an interstitial infiltration constituted by lymphocytes, plasma cells and foamy macrophages. Although the disease manifestations were compatible with hypersensitivity pneumonitis, we decided to study the causal antigen by immunohistochemistry. The use of a polyclonal antibody raised against pigeon serum showed a predominant cytoplasmic immunostaining in multinucleated giant cells and histiocytes from lung granulomas. Other respiratory disorders were reasonably excluded. Previous exposure to a known antigen may support the diagnosis of hypersensitivity pneumonitis. Although the inhalation of organic dusts may be clinically evident, the aetiology is commonly evaluated by different challenge tests or immunological methods. We propose that the study of pigeon antigen by immunohistochemistry may be used as part of the diagnostic approach for hypersensitivity pneumonitis.

Effect of cigarette smoking on the development of murine chronic pigeon breeder's lung. The difference between a short-term and a long-term exposure

Previous reports suggested that cigarette smoke had a protective effect of on the development of hypersensitivity pneumonitis (HP). However, smoking rate in chronic pigeon breeder's lung (PBL) seemed to be high in our clinical experiences. We developed a murine model of PBL by intranasal instillation with pigeon dropping extracts (PDE) for 4 weeks (short-term exposure) and 17 weeks (long-term exposure) to investigate the effect of cigarette smoke on disease processes. In this model, lung inflammation associated with the production of anti-PDE antibodies and antigen dependent lymphocyte proliferation was induced. Long-term exposure to PDE without cigarette smoking resulted in an increase in lung weight/body weight ratio, total cell number in bronchoalveolar lavage (BAL) fluid, and content of hydroxyproline in the lung compared to shortterm exposure. After a short-term exposure, cigarette smoke lessened the lymphocytosis in BAL fluid, and lymphocyte proliferation. On the other hand, after a long-term exposure cigarette smoke increased lung hydroxyproline. These results suggest that a short-term cigarette smoking attenuates lung inflammation, but a long-term cigarette smoking enhances lung inflammation with fibrosis.

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.

A clinical study of hypersensitivity pneumonitis presumably caused by feather duvets

BACKGROUND

Bird fancier's lung (BFL) is a type of hypersensitivity pneumonitis induced by the inhalation of bird-related antigens. The BFL induced by feathers is difficult to diagnose because feathers are generally unrecognized as a causative antigen.

OBJECTIVE

To determine the clinical features of BFL presumably induced by feather duvets (feather duvet lung) to provide clues for diagnosis.

METHODS

We performed a retrospective review of the medical records of patients with feather duvet lung evaluated between April 1, 2000, and June 30, 2003, at the Tokyo Medical and Dental University Hospital in Japan.

RESULTS

Seven patients with feather duvet lung were included in this study; 4 patients had acute disease and 3 had chronic BFL. Duration of contact with feather duvets was 1 month to 10 years. Serum KL-6 and surfactant protein D levels were elevated in all the patients. Specific antibodies against avian antigens were positive in acute BFL but negative in chronic BFL. Antigen-induced lymphocyte proliferation in peripheral blood or bronchoalveolar lavage cells was positive in all the patients. The diagnosis was confirmed by an environmental or inhalation provocation test.

CONCLUSIONS

Feather duvets can induce acute and chronic BFL. Physicians should be aware of feather duvets as a cause of BFL because feather duvets are becoming more prevalent.

Analysis of KL-6 and SP-D as disease markers in bird fancier's lung

BACKGROUND AND AIM

KL-6 and SP-D are potential serum markers in interstitial lung diseases. Their discriminative value, and ability to reflect pulmonary disease activity and prognosis in bird fancier's lung were analyzed.

METHODS

We studied 49 patients, 38 unexposed and 9 exposed controls. Serum KL-6 and SP-D concentrations were measured at presentation and a second sample, taken after antigen avoidance, was available in 17 patients. Pulmonary function tests were analyzed at presentation and 2-year follow-up.

RESULTS

KL-6 and SP-D were significantly elevated in patients compared to controls (p < 0.0001). ROC curve analysis revealed that both are equally useful in discriminating patients from controls. Analysis of their value as activity markers showed that both correlated with pulmonary function impairment; however, KL-6 correlated best with diffusing capacity. Evaluation of their predictive value showed that higher levels at onset were associated with improvement of diffusing capacity during follow-up. Further, it was noted that KL-6 and SP-D levels decreased after more than one month of allergen avoidance.

CONCLUSIONS

KL-6 and SP-D appear useful serum markers in bird fancier's lung. Since higher levels are associated with more severe lung function impairment at presentation, and better recovery over time, we postulate that in this disease they are especially markers of disease activity.

Qualitative and Quantitative Evaluation of Bird-Specific IgG Antibodies

BACKGROUND

Exposure to organic dust produced by birds often gives rise to an immune response, e.g. IgG antibodies, but intense exposure can lead to high concentrations of IgG antibodies and the development of allergic alveolitis, often known as "bird fancier's lung". The aim of this study was to establish the distribution of bird-specific IgG antibodies in exposed and nonexposed individuals and compare a nonquantitative and quantitative method in evaluating raised levels of IgG antibodies.

METHODS

Sera were collected in Sweden and South Africa and levels of IgG antibodies specific to pigeon, budgerigar and parrot antigens were quantified using the UniCAP system. Results were compared to the precipitation in gel assay. The IgG antibody values of symptomatic patients without precipitating antibodies (non-PP group; n = 51) and patients with precipitating antibodies (PP group; n = 34) were analyzed and compared to nonexposed asymptomatic blood donors (BD group; n = 73) and environmentally exposed pigeon breeders (n = 11).

RESULTS

The IgG antibody response of the analyzed groups in Sweden and South Africa did not vary significantly from each other. IgG antibody responses were the strongest to pigeon antigens with clear increased IgG antibody levels in the PP group [geometric mean (GM) 603 mg/l] compared to the non-PP (GM 6.9 mg/l) and BD group (GM 5.0 mg/l). Threshold values, calculated as the GM value from the BD group plus 3 standard deviations (99% confidence interval), were 9.8, 10.8 and 10.0 mg/l for pigeons, budgerigars and parrots, respectively. Comparison of the two methods resulted in a good concordance with a level of agreement of 94.1% (kappa statistic = 0.83).

CONCLUSIONS

The UniCAP system for the detection of bird-specific IgG antibodies is a highly reproducible, generally available, quantitative method for routine diagnostic testing and monitoring of exposed subjects with a very high level of agreement to the precipitating gel assay.

[Pulmonary fibrosis in young patients with hypersensitivity pneumonitis]

Hypersensitivity pneumonitis (HP) is more common in middle-aged individuals but has been also diagnosed in patients of all ages including infants and children. Host risk factors are poorly characterized. The aim of this paper is presentation of 6 young patients in whom HP was diagnosed at the stage of lung fibrosis. There were 5 females at the age of 16-35 years and 1 male at the age of 28 years. All of them were exposed to organic dust for many years. Three of them were asthenic with scoliosis, 5 had clubbing. All patients were released from sport exercises in school due to fatigue but the diagnostic procedures were started at that time only in 2 patients. One woman had been ill from early childhood (recurrent pneumonia was recognised). In the another girl (16 years old) the spontaneous pneumothorax was the cause of the first chest X-ray examination. In the next woman (21 years old) marked dyspnea was connected with pregnancy and massive fibrotic lesions were recognised after delivery of her child. The only man was diagnosed before change of his job; he had no complaints. Two oldest women (34 and 35 years old) were diagnosed in childhood but avoidance of antigen exposure and corticotherapy were not effective. In all patients precipitins against farmer's lung and pigeon fancier's lung antigens were found. In all patients chest X-ray showed features of advanced lung fibrosis. All patients were treated with steroids without improvement. Two patients died during corticotherapy.

CONCLUSIONS

1) HP could be taken into consideration during differential diagnosis of interstitial lung diseases, 2) Cough and dyspnea on exertion could be the first symptoms of chronic HP in children also.

Feather duvet lung

BACKGROUND

Bird fancier's lung (BFL) is a type of hypersensitivity pneumonitis, which is induced by inhalation of bird related antigens. The diagnosis of BFL induced by feathers is difficult because feathers are generally not recognized as a causative antigen of BFL. We report a female case of chronic BFL presumably due to a feather duvet, which presents as pulmonary fibrosis.

CASE REPORT

A 73 year-old woman presented with exertional dyspnea for the last three years. She had raised two pigeons for three years (1971-1973) in her forties and had been using a feather duvet for the last eight years (1992-2000). A chest X-ray showed reticular infiltrates in the both peripheral lung field and an HRCT scan showed scattered consolidation, micronodules, and peribronchial ground-glass opacities. Lymphocyte proliferation to the feather antigen was positive and inhalation provocation test using a bird antigen was also positive. Thoracoscopic biopsy specimens showed organization, cholesterol clefts, alveolitis around terminal and respiratory bronchioles--all of which are consistent with chronic hypersensitivity pneumonitis. Clinical findings have spontaneously improved after she stopped using her feather duvet.

CONCLUSIONS

Feather beds including duvets, pillows, and cushions are now popular all over the world. Physicians should be aware of feathers as a cause of BFL since this induction seems to be more prevalent.

Anti-avian antibodies and rheumatoid factor in pigeon hypersensitivity pneumonitis

BACKGROUND

Although several immunological abnormalities may be present in pigeon hypersensitivity pneumonitis (HP), few specific hallmarks have been described.

OBJECTIVE

To determine whether the presence of rheumatoid factor (RF) could be useful to discriminate pigeon HP from asymptomatic breeders (AB) and other interstitial lung diseases.

METHODS

Fifty-three patients with pigeon HP, 47 AB, 31 idiopathic pulmonary fibrosis (IPF) patients and a rheumatoid arthritis (RA) group were studied. IgM RF was determined through enzyme-linked immunosorbent assay (ELISA) and western blot using human IgG and IgG Fc fragment as antigens. IgG and IgA anti-avian antibodies (AA) against pigeon serum antigen were also measured. The use of F(ab')2 fraction of peroxidase-labelled anti-human immunoglobulins prevented endogenous interferences. Possible cross-binding of RF with avian antigens and the reactivity against human IgG by AA were studied.

RESULTS

RF tests were frequently positive in HP (52.8%) in comparison to AB (4.2%) and IPF (12.9%; P = 2.6 x 10-10 and 4.1 x 10-5). Therefore, the presence of RF in pigeon HP showed a sensitivity of 52% and was highly specific considering the results of AB and IPF (95 and 87%, respectively). The RA group revealed positive RF but negative AA tests. RF activity was confirmed through western blot using purified IgG Fc fragment. Overlapping levels of IgG and IgA AA were found in HP and AB. The frequency of AA was low in IPF. The cross-reaction of RF with avian antigens was excluded, and no reactivity against human IgG by AA was detected. Other endogenous interferences were ruled out.

CONCLUSION

No single immunological test may definitively distinguish pigeon HP from AB and other interstitial lung disorders; however, positive RF, together with high AA levels, seems to be useful in differentiating the diagnosis.

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.

Interference by rheumatoid factor activity in the detection of antiavian antibodies in pigeon breeders disease

The assessment of antiavian antibodies is relevant for the study of pigeon breeder's disease; nevertheless, different factors may hamper their accurate detection. The objective of this study was to determine whether an endogenous interfering effect in pigeon breeder's disease might explain the simultaneous presence of IgM, IgG, and IgA antiavian antibodies in high titers as assessed by ELISA. Fifty-nine patients with pigeon breeder's disease, 80 healthy controls, and 47 asymptomatic breeders were studied. To assess possible interfering effects by endogenous immunoglobulins, serum IgG was separated through protein A-Sepharose CL-4B chromatography. Antiavian antibodies were measured in whole and separated samples by ELISA. Since a decline of IgM antiavian antibodies following IgG removal was consistent with a false-positive effect, the causes were studied. High values of IgM, IgG, and IgA antiavian antibodies were found in 47.4% [corrected] of patients with pigeon breeder's disease. An IgM rheumatoid factor activity against IgG was found through ELISA in sera with false-positive IgM antiavian antibodies. Rheumatoid factor binding was confirmed by Western blot. Experimental addition of purified rheumatoid factor to sera with IgG antiavian antibodies replicated the interfering effect. A control group of rheumatoid arthritis with high rheumatoid factor values did not show positive antiavian antibodies tests. No IgG with anti-IgM or anti-IgA activity was found, and the detection of IgA against IgM and IgG was negative. In conclusion, the study of antiavian antibodies might be affected by different immunoassay conditions. An endogenous rheumatoid factor activity produced false-positive IgM results. Other similar interferences warrant a careful evaluation during the serological assessment of pigeon breeder's disease.

IgM antiavian antibodies in sera from patients with pigeon breeder's disease

The authors' objective was to study the presence of IgM antiavian antibodies in sera from patients with pigeon breeder's disease. We studied 93 patients with interstitial lung disease admitted for the assessment of pigeon breeder's disease. Eighty sera from healthy donors with no history of bird contact and 47 asymptomatic pigeon breeders were included as controls. The presence of IgM, IgG, and IgA antiavian antibodies was detected by ELISA and Western blot using avian-pooled serum antigen. Fifty-three patients were classified as having definite pigeon breeder's disease, whereas 40 did not fulfill these diagnostic criteria. The levels of IgM antiavian-antibodies in pigeon breeder's disease by ELISA exceeded both the values of healthy subjects with no history of avian contact (P = 2.5 x 10(-8)) and the results of asymptomatic breeders (P = 0. 03). Positive IgA antiavian antibodies were the most frequent abnormalities in pigeon breeder's disease showing values over the reference levels of control groups that reach significant statistical differences. Both precipitin-positive and -negative samples demonstrated IgM reactivity. IgM antiavian antibodies were confirmed by Western blot. A relationship of IgM positive tests with a recent history of avian antigen exposure and acute disease was found. Additionally, the positive IgM group included patients having subacute and chronic lung disease. Antiavian antibodies have previously been considered of minor significance in hypersensitivity pneumonitis; nevertheless, recent studies support their use in clinical diagnosis. Although no specific laboratory tests can confirm the diagnosis in pigeon breeder's disease, IgM antiavian antibodies may be useful for detecting recent antigen exposure and the acute stage of the disease.

Subacute hypersensitivity pneumonitis in an HIV infected patient receiving antiretroviral therapy

Abnormal pulmonary immune response to various antigens can lead to hypersensitivity pneumonitis. This disease has not previously been reported in HIV infected patients. This case report describes an HIV infected woman who developed subacute hypersensitivity pneumonitis in response to bird exposure. The disease manifested itself only after the patient experienced an improvement in her CD4 positive T lymphocyte count secondary to antiretroviral therapy. This case emphasises the need to consider non-HIV associated diseases in patients with HIV and suggests that diseases in which host immune response plays an essential role in pathogenesis may become more prevalent in HIV infected patients receiving effective antiretroviral therapy.

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.

[Asthmatic child without asthma]

Two boys aged 13 and 7 years, displayed chronic coughing, dyspnoea on exertion, anorexia, weight loss, and fatigue. At first a diagnosis of asthma was made. However, a correct interpretation of anamnestic and clinical features, laboratory findings and radiographic results led to the diagnosis of 'pigeon breeder's disease' in both cases. Both patients recovered after drug treatment and avoidance of re-exposure to pigeon antigen.

B-lymphocyte aggregates in alveoli from a child with hypersensitivity pneumonitis (bird breeders lung)

BACKGROUND

Hypersensitivity pneumonitis is an interstitial lung disease mediated through a patient's immunologic response to a variety of inhaled organic dusts. Studies of the cellular components of lavage fluid from patients with this disease show marked increases of CD8+ suppressor/cytotoxic T-lymphocytes.

OBJECTIVE

In this study, we identified, in addition to the expected suppressor T-cells and natural killer cells, follicle-like aggregates of B-cells in the lung interstitium of an affected patient.

METHODS

The patient was an 11-year-old non-asthmatic, Caucasian male who presented with a 4-month history of progressive dyspnea, cough, and fever. The home contained nine cockatiel and two doves. Admission pulmonary functions revealed a restrictive pattern with diminished diffusion capacity. Prior to a diagnosis, the patient underwent bronchoalveolar lavage and transbronchial biopsy. Serum precipitins were eventually positive to pigeon (which cross-reacts with dove) droppings. The symptoms resolved after a prolonged course of prednisone.

RESULTS

Analysis of bronchoalveolar lavage lymphocyte population revealed a predominance of CD8+ cells (50%) with 85% expressing the activation marker HLA-DR. The percentage of CD4+ and CD56+ were 32% and 16%, respectively. The transbronchial biopsy revealed CD20+ follicle-like aggregates within the lung interstitium.

CONCLUSIONS

The histopathologic findings confirm that in hypersensitivity pneumonitis, the predominant immune response is an infiltrate of CD8+ T cells. The presence of B cell aggregates, however, may indicate that the local synthesis of antibody may be involved in an antibody-dependent cellular cytotoxic mechanism.

Sequential changes in bronchoalveolar lavage cells and cytokines in a patient progressing from acute to chronic bird Fancier's lung disease

A 65-year-old pigeon breeder who presented with acute hypersensitivity pneumonitis refused to give up contact with pigeons and her lung disease, which had initially improved in hospital in response to removal from pigeons, progressed to chronic interstitial fibrosis. Bronchoalveolar lavage lymphocytes fell from 50.0% of total cells in December 1986 to 27.1% in February 1990. The ratio of CD4+/CD8+ lymphocytes shifted from 0.43 to 1.47. Furthermore, IL-6 and TNF-alpha were elevated initially and were much higher at the second time point. These data pointed to the importance of CD4+ lymphocytes, IL-6 and TNF-alpha in the development of pulmonary fibrosis.

Pigeon fanciers' lung: identification of disease-associated carbohydrate epitopes on pigeon intestinal mucin

Pigeon intestinal mucin, a complex high molecular weight glycoprotein, is a key antigen in the development of pigeon fanciers' lung (PFL). We have studied the specificity of antibodies to mucin in patients with PFL and asymptomatic antibody-positive individuals. Extensive papain digestion, which removes the non-glycosylated regions of the mucin leaving the heavily glycosylated 'bottle brush' regions, resulted in a 600-fold decrease in IgG3 antibody titres with little effect on IgG1 and IgG2 titres. This suggests that IgG1 and IgG2 are directed against the region rich in O-linked sugar chains whilst the majority of the IgG3 is directed against epitopes which are proteinase-sensitive. Lectin mapping of the carbohydrates present on pigeon intestinal mucin demonstrated high levels of exposed N-acetyl neuraminic acid, N-acetyl galactosamine and N-acetyl glucosamine, with lower levels of fucose and some galactose. Sera from pigeon fanciers inhibited binding of lectins specific for N-acetyl neuraminic acid, N-acetyl galactosamine, internal N-acetyl glucosamine and fucose. Sera from people with PFL, compared with sera from asymptomatic antibody-positive fanciers, had significantly higher titres of antibody that inhibited binding of four lectins specific for N-acetyl galactosamine and one fucose-specific lectin, suggesting that these sugars may play a dominant role in disease-associated epitopes. The results suggest that different IgG subclasses recognize different epitopes on mucin and that the epitopes recognized by the major subclasses are present on the O-linked oligosaccharides. Further, the carbohydrate-specific anti-mucin antibodies produced by PFL patients may differ in their specificity from those found in asymptomatic individuals.

Mucosal immunity in extrinsic allergic alveolitis: salivary immunoglobulins and antibody against inhaled avian antigens among pigeon breeders

BACKGROUND

Inhaled antigens from pigeons can cause extrinsic allergic alveolitis (EAA); a model disease of pulmonary inflammation. Among pigeon breeders, serum antibody and sensitized lymphocytes specific for these antigens have been described primarily, but not always, with disease. Antibody activity within the lung may have a closer association with disease, however, sampling by alveolar lavage at bronchoscopy is impractical for screening, therefore we used saliva to quantify the mucosal antibody response.

OBJECTIVE

To establish: (a) if antibody activity against inhaled avian antigens was detectable in the saliva of pigeon breeders, (b) if the distribution of saliva antibody and total immunoglobulin levels were quantitatively or qualitatively different from serum, and (c) whether the hypersensitivity symptoms of EAA were associated more with the mucosal or the systemic humoral immune response.

MEASURES

Saliva and serum total and avian antigen-specific IgG, IgA (IgA1 and IgA2) antibody activity in 87 pigeon breeders and 24 control subjects with no avian exposure. Albumin levels were used as a protein reference and cotinine levels confirmed smoking status. Specific hypersensitivity symptoms and various exposure indices to pigeons were established by interview.

RESULTS

Absolute levels and relative proportions (vs albumin) of IgG, IgA and IgA1 in saliva, and IgG in serum, were significantly higher in pigeon breeders compared with controls, suggesting mucosal inflammation. Avian antigen-specific antibody of all isotypes was readily demonstrable in saliva (predominantly IgA) and serum (predominantly IgG) from pigeon breeders, and there were no significant titres in controls. The levels of IgG antibody in saliva and in serum correlated significantly (r = 0.52, P < 0.001), and both correlated with the raised immunoglobulin levels. In both saliva and serum the IgG rather than the IgA antibody activity was associated with symptoms of EAA.

CONCLUSIONS

Antibody activity in saliva and serum, representing the mucosal and systemic responses, respectively, were both strongly stimulated by inhaled antigens. The IgG antibody titres of saliva and serum correlated significantly and were a useful index of inflammation, as measured by the raised total immunoglobulin levels, and symptoms. This suggests that IgG antibody in serum may reflect clinical and immunological sensitization of the lung mucosa. Collecting saliva is noninvasive, and saliva antibody measurement is a convenient method for monitoring EAA, especially in children, and will facilitate sampling for example in epidemiological studies of antibody prevalence.

Purification of the antigenic components of pigeon dropping extract, the responsible agent for cellular immunity in pigeon breeder's disease

BACKGROUND

Pigeon breeder's disease (PBD) is a lung disease caused by inhalation of antigens derived from pigeons.

OBJECTIVE

This study was undertaken to characterize the responsible component of pigeon dropping extract (PDE) for PBD.

METHODS

First, crude PDE was applied to SDS-PAGE followed by immunoblotting by using antibodies in bronchoalveolar lavage (BAL) fluid. Second, 9 bands of PDE were separated by SDS-PAGE and used for antigen-induced PBMCs. Finally, amino-terminal sequencing was conducted on an isolated 21-kd protein by 2-dimensional electrophoresis.

RESULTS

Immunoblots with BAL fluid from patients with PBD identified 9 bands. Similar patterns were observed by using BAL fluid from 10 control patients (9 with summer-type hypersensitivity pneumonitis or idiopathic pulmonary fibrosis and 1 asymptomatic breeder), except for the 21-kd protein, which was detected in 10 patients with PBD and 1 asymptomatic breeder. The stimulation indices of PBMCs determined by using proteins electroeluted from the 9 bands were higher in patients with PBD than in the 10 control patients. The 21-kd protein was separated into 5 spots by 2-dimensional electrophoresis; these spots were all reactive with BAL fluid from patients with PBD as determined by immunoblotting. The sequence of the 21-kd protein had 57% identity to a Saccharomyces cerevisiae chromosome X reading frame. A synthetic peptide, derived from the amino acid sequence of the N-terminal of the native protein, induced significant proliferation of PBMCs obtained from 5 patients with PBD, but not with PBMCs obtained from control patients.

CONCLUSION

The 21-kd protein is the only protein that identified individuals exposed to pigeons by immunoblotting. Only PBMCs from patients with PBD showed significant proliferation to the 21-kd protein and to the synthetic peptide on the basis of the N-terminal sequence of the native peptide. The 21-kd protein will be an important antigen for studies on the epidemiology, diagnosis, and pathogenesis of PBD.

Pigeon fanciers' lung: the mucin antigen is present in pigeon droppings and pigeon bloom

BACKGROUND

Pigeon intestinal mucin has been implicated as an important antigen pigeon fanciers' lung. This study investigated whether mucin is detectable in pigeon droppings and bloom, the likely antigenic sources in disease.

METHODS

Soluble extracts of a number of materials found in a pigeon loft were prepared and specific IgG subclass antibodies to these antigens were measured in 14 antibody-positive pigeon fanciers. Cross-reactivity between these materials and purified pigeon intestinal mucin was investigated by inhibition of anti-mucin ELISA. Mucin was purified from the soluble extracts of these crude antigen mixtures by CsCl density gradient centrifugation.

RESULTS

The patterns of IgG subclass responses to purified pigeon intestinal mucin and to the four materials collected from the pigeon loft were similar. Subclass differences between symptomatic and asymptomatic individuals, demonstrable against purified mucin, were similarly seen against pigeon droppings and pigeon bloom. Both pigeon droppings and pigeon bloom were capable of inhibiting IgG binding to purified pigeon mucin, and mucin inhibited substantially the binding of IgG to these materials. Glycoprotein with a density similar to that described for pigeon intestinal mucin was purified from each source.

CONCLUSION

Pigeon intestinal mucin is present in a variety of materials found in the environment of the pigeon loft in a form capable of reacting with anti-mucin antibodies in the sera of exposed individuals. Reduction in exposure to these materials may decrease the likelihood of developing pigeon fanciers' lung and minimise reactions in sensitised individuals.

Utility of a provocation test for diagnosis of chronic pigeon Breeder's disease

Chronic hypersensitivity pneumonitis (CHP) can be difficult to differentiate from other interstitial lung diseases (ILD). To determine the diagnostic usefulness of a provocation test (PT), 17 patients with CHP induced by avian antigens, 17 with other ILD, and five healthy control subjects were challenged with pigeon serum. After PT, an increase in body temperature (BT) and a decrease in FVC, PaO2 and SaO2% were observed in all patients with CHP and in three with ILD. No reaction was noticed in healthy subjects. ROC curves showed that for FVC the best cut point was a drop of 16% displaying sensitivity (S): 76%, specificity (SP): 81%, positive predictive value (PPV): 81%, and negative predictive value (NPV): 83%. For a drop of 3 mm Hg in PaO2 or 3% SaO2, S was 88% for both, SP was 82 and 86%, PPV was 81 and 82%, and NPV was 82 and 86%, respectively. An increase of BT > 0.5(o) C showed S, 100%; SP, 82%; PPV, 100%; NPV, 86%. A univariate regression analysis confirmed that changes in BT and FVC are predicting values of CHP: RR, 82.5 (CI, 10.43 to 651.76) and 1.21 (CI, 1.06 to 1.36). There were no challenge test complications. These findings suggest that PT is a useful tool for diagnosis of CHP.

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.

IgG subclass responses to pigeon intestinal mucin are related to development of pigeon fanciers' lung

BACKGROUND

Pigeon fanciers' lung (PFL) is a form of extrinsic allergic alveolitis. Affected individuals produce antibodies to various pigeon antigens, and the resulting immune complexes are thought to initiate the disease. However, high antibody titres also occur in some asymptomatic individuals. Previously attention has focused on protein antigens, but we have recently identified pigeon intestinal mucin as a novel antigen in PFL.

OBJECTIVE

To determine the relationship between IgG subclass antibodies to pigeon intestinal mucin and the development of pigeon fanciers' lung.

METHODS

Sera were collected from 250 pigeon fanciers, who also completed a clinical questionnaire. Sera were screened for precipitating antibodies to pigeon serum and droppings. Individuals with symptoms and precipitating antibodies were considered to have classical PFL. Serum IgG and IgG subclass antibodies to pigeon intestinal mucin and pigeon serum proteins were investigated by quantitative enzyme-linked immunosorbent assay (ELISA).

RESULTS

Very high titres of IgG antibodies against pigeon mucin were found in all precipitin-positive individuals. A strong positive correlation was seen between titres of antibodies to mucin and to serum proteins, but this was not due to crossreactivity. No significant differences in IgG titres to either mucin or pigeon serum proteins were found between individuals with PFL and asymptomatic precipitin positive fanciers. IgG1 and IgG2 were the major subclasses of anti-mucin, with lower titres of IgG3. Patients with PFL had significantly higher titres of IgG1 to mucin than asymptomatic, precipitin-positive individuals. In contrast, no significant differences were seen between PFL and asymptomatic precipitin-positive sera with respect to the subclass titres against pigeon serum proteins.

CONCLUSION

The high titres of anti-mucin IgG in sera of all individuals with PFL, together with the finding that high IgG1 titres to mucin are associated with the development of disease confirm pigeon intestinal mucin as an important antigen in PFL.

On the correct determination of reference values for serum antibodies against pigeon serum antigen using a group of healthy blood donors

An enzymatic immunoassay was developed in order to evaluate the statistical distribution of IgG serum antibodies against pooled pigeon sera antigen in 102 healthy blood donors (HBD). A non-normal distribution was obtained as demonstrated by abnormal values of skewness (2.02) and kurtosis (6.50). A cut-off point (0.120) was determined from the mean plus 2 standard deviations of the optical density values obtained in the HBD group. This value was able to segregate 94% of subjects. However, when calculation of the mean less 2 SD was performed to delimit 95% of the samples, an aberrant negative value was obtained. In contrast, when the nonparametric method of percentile calculation was applied, an optical density value of 0.130 discriminated 97.5% of samples. In addition, the interval between p97.5 and p2.5 delimited 95% of samples. We conclude that when reference values and cut-off point are determined from an enzymatic immunoassay, careful analysis of the statistical distribution of reference values is necessary in order to avoid the inappropriate application of parametric procedures as demonstrated in this study for antibodies against pigeon serum antigens.

Feather mites are potentially an important source of allergens for pigeon and budgerigar keepers

BACKGROUND

Previous studies on allergy to feathers have not addressed whether organisms living on feathers (mites, lice, moulds) are a source of allergens.

OBJECTIVE

To investigate whether feather mites produced allergens of clinical relevance to bird keepers.

METHODS

We examined serum IgE responses of 96 pigeon breeders to an extract of feather mites from pigeons (predominantly Diplaegidia columbae), using Western blotting, specific IgE assay using AlaSTAT EIA and RAST inhibition.

RESULTS

Feather mites are a major source of soluble proteins derived from feathers, accounting for up to 10% of the total weight of the feather. Forty-three sera had a negative score (0) for anti-feather mite IgE, 27 were weakly positive (1-2) and 26 had strongly positive scores (3-4). Fewer pigeon breeders with scores > or = 3 were asymptomatic than those with negative scores (12 versus 40%), more had late onset symptoms (with or without early onset symptoms: 77% versus 44%) and had IgE antibody against house dust mite (89% versus 23%). Western blotting of eight sera against the extract of Diplaegidia columbae revealed 20 IgE-binding components ranging from 22 to 200 kDa. A high diversity of components was recognized by each serum: arithmetic mean 7 (range 2-14). RAST inhibition indicated feather mites had species-specific epitopes as well as ones that cross-reacted with Dermatophagoides pteronyssinus.

CONCLUSION

Strongly-positive AlaSTAT scores to pigeon feather mite were associated with allergic symptoms of late onset in pigeon breeders. We conclude that feather mites are a major source of clinically-relevant allergens for pigeon breeders.