[Pneumonitis caused by hypersensitivity to the antigen(s) of pigeons. I. Clinical study]

We studied twenty six patients with hypersensitivity pneumonitis due to pigeon antigens (pigeon breeder's disease). This insidious illness, causes an interstitial lung disease, with restrictive pattern and also pulmonary hypertension. Most of the cases showed circulating antibodies against pigeon serum proteins, polyclonal hypergammaglobulinemia and rheumatoid factor. Treatment based on avoidance of pigeon droppings and glucocorticoids gave good results.

Canary fancier's lung

A 54-year-old man presented with features consistent with extrinsic allergic alveolitis occurring after contact with his pet birds. Screening of the serum for avian precipitating antibody was negative but canary precipitins were present. Extrinsic allergic alveolitis to his pet canaries was confirmed by inhalation challenge.

Antibody measurement in extrinsic allergic alveolitis

Serum IgG antibody against purified avian antigens was quantified by radioimmunoassay in 507 active pigeon fanciers, of whom 110 had documented Pigeon Breeders Disease (PBD). The incidence of PBD increased from 3.7% in the antibody-negative group to 78% of those with IgG antibody greater than 30 micrograms/ml. The highest levels of antibody tended to occur in subjects with relatively short avian exposure, and a significant correlation between decreasing antibody levels and increasing years of avian contact was demonstrated, which was unrelated to age or smoking history. The antibody -positive subjects had lower daily hours of avian contact and this group which contained most of the PBD subjects demonstrated some self-regulation of antigen exposure.

A rabbit model for hypersensitivity pneumonitis

A rabbit model of acute hypersensitivity pneumonitis was produced by immunization and subsequent inhalation of pigeon serum. The pathological features, consisting of alveolitis and interstitial granulomas, were similar to those reported previously in the experimental models. Repeated inhalation challenge of pigeon serum, however, did not develop chronic alveolitis but led to the fading of the disease. It was suggested that desensitization defined as the suppression of delayed hypersensitivity contributed to the mechanism of the fading of the disease. Repeated pigeon serum inhalation without previous immunization by the same antigen could produce a moderate interstitial pneumonitis but did not demonstrate a typical granulomatous histological change in lungs. It was necessary to use adjuvant for producing a complete animal model of hypersensitivity pneumonitis. Antigen-specific antibody response did not directly correlate with the development of the animal model of hypersensitivity pneumonitis.

Lung T cells in hypersensitivity pneumonitis

Monoclonal antibodies OKT3 (all T cells), OKT4 (T-helper/inducer), and OKT8 (T-suppressor/cytotoxic) were used to determine surface phenotypes of bronchoalveolar lavage and peripheral blood lymphocytes in patients with chronic hypersensitivity pneumonitis. Similar studies were done in asymptomatic pigeon breeders, patients with sarcoidosis, and nonsmoking controls. Increased numbers of lavage T cells were found in patients with hypersensitivity pneumonitis and sarcoidosis and in asymptomatic pigeon breeders. The predominant T-cell subset in patients with hypersensitivity pneumonitis and in asymptomatic pigeon breeders was T8 +; in contrast, the predominant subset in those with sarcoidosis was T4 +. Peripheral blood T-cell subsets were normal in all groups. Thus, most lung T lymphocytes in chronic hypersensitivity pneumonitis belong to the T8 + subset; the local cellular immune response in hypersensitivity pneumonitis and sarcoidosis are different; and the pattern of alveolitis, as determined by bronchoalveolar lavage, is not the sole determinant of lung impairment after exposure to hypersensitivity pneumonitis antigens.

Detection of precipitating and complement consuming antibodies by enzyme linked immune sorbent assay in pigeon breeders' disease

The sera of patients with pigeon breeders' disease usually contain both precipitating and complement-fixing antibodies to antigens in pigeon droppings or pigeon serum. These antibodies are not equivalent. Both types of antibody could be detected by means of an ELISA technique, using either pigeon serum or pigeon dropping antigens in the solid phase. The good correlation between the ELISA results and the complement consumption assay indicates that the ELISA technique may represent a one-step assay for assessing both precipitating and complement-consuming IgG-class antibodies, thereby identifying both symptomatic patients and breeders potentially at risk. IgM antibodies appeared to be of minor significance in the serology of pigeon breeders' disease.

[Bird-breeder's lung. Apropos of a fatal case. Immunohistochemical and anatomo-pathological study]

The authors report the case of a female bird breeder who presented with severe pneumopathy from which she died within two weeks. An autopsy was performed. The case is compared with others taken from the literature and the danger of a severe outcome under certain circumstances is emphasized. The authors advocate recourse to immunohistochemical detection of specific markers.

Skin testing and extrinsic allergic alveolitis

Skin testing with six common allergens, tuberculin and a sterile avian antigen preparation from pigeon serum was performed on 102 pigeon fanciers. The incidence of positive prick tests to common allergens was no different for subjects with extrinsic allergic alveolitis. EAA, caused by avian exposure than the whole group. Positive immediate weal and flare reactions following skin prick testing with avian antigen occurred in 22 subjects and was closely correlated with atopy. However, when the same antigen was administered intradermally, 69 subjects developed an immediate (15 min) weal and flare reaction which did not correlate with atopy, instead, the weal diameter correlated significantly with the serum IgG antibody titre against pigeon serum gamma-globulin antigen, and furthermore, the higher grades of reaction were highly selective for subjects with EAA. Ten subjects, all with strong early intradermal skin reactions, developed a late (4-6 h) skin reaction; this was again highly selective for EAA. The subjects with cutaneous anergy to tuberculin had markedly higher IgG antibody titres to avian antigens, and these included the majority of the subjects with alveolitis.

Precipitins to inhaled avian antigens: results of an inter-laboratory study

Precipitins against avian antigens in sera from patients with extrinsic allergic alveolitis, asymptomatic pigeon and chicken breeders and from control individuals were tested with different antigen extracts in six laboratories by a variety of different methods. Eighty percent of the results coincided in identifying the positive sera from patients and 90% in identifying the controls. It seems possible therefore to exchange results among experienced laboratories with fair confidence.

[Bird breeder's lung with conversion to fatal fibrosing alveolitis]

An 11-year-old girl developed typical symptoms of bird breeder's lung after several years of contact with budgerigars and other birds. The clinical diagnosis was confirmed by immunological and lung-function tests. Despite exclusion of exposure to allergens and treatment with steroids and D-penicillamine no improvement occurred, the exogenous allergic alveolitis progressing to fibrosing alveolitis of which the girl died.

Seasonal variation of antibody levels among pigeon fanciers

IgG antibody against avian antigens was measured by quantitative radioimmunoassay in serum samples obtained regularly from twenty pigeon fanciers over a 1-year period. A seasonal variation was seen in nine antibody-positive subjects; eight of whom had symptoms of pigeon breeder's disease (PBD), and a clear peak of antibody production occurred during late summer, corresponding with the period of maximum avian contact in the sporting season. All subjects with insignificant specific IgG levels were asymptomatic and displayed minimal changes throughout the year despite a similar exposure pattern to antigen for all individuals. Raised total IgG was a feature of six symptomatic subjects, two of whom had raised total IgA. Three of these six subjects had maximum hypergamma-globulinaemia coinciding with peak specific-antibody levels, but in general the total immunoglobulin levels tended to remain high throughout the year with only marginal fluctuations. The total immunoglobulin levels in the other individuals were within normal limits and displayed no remarkable changes during the year. The subjects with pigeon breeder's disease had a more active immune responsiveness to avian contact, and the association of the highest levels with periods of maximal contact with antigen may have an important bearing on the dynamic nature of this condition.

The late bronchus-obstructive response to bronchial challenge with pigeon faeces and its correlation with precipitating antibodies (IgG) in the serum of patients having long-term contact with pigeons

From a total of 160 patients with allergic bronchial asthma or chronic asthmatic bronchitis, eighteen (11.3%) patients reported being regularly exposed to pigeons. In these eighteen patients, bronchial provocation tests with pigeon faeces were performed and the precipitating antibodies (IgG) in their serum against pigeon faeces and serum were estimated. Of the eighteen patients, seven (39%) demonstrated a 'late bronchus-obstructive response' to pigeon faeces. Three patients developed only an 'isolated late response' and in the other four patients the late response occurred as a part of the 'dual response'. In the seven patients with the positive late bronchial response, the precipitating antibodies in their serum to pigeon faeces were positive in five (71%) and to pigeon serum in two (28%) of them. The late skin responses to pigeon faeces were positive in five (71%) patients, the blood eosinophilia increased in six (86%) of them, a slight pyrexia occurred in two (28%) and general malaise symptoms appeared in six (86%) of them. None of these patients developed changes on the chest X-ray during the late response. The remaining eleven patients did not develop any bronchial response to pigeon faeces challenge, although in six (55%) of them the late skin responses were positive, and two (18%) had precipitating antibodies in the serum to pigeon faeces and one (9%) to pigeon serum. It is concluded that positive precipitating antibodies in the serum to pigeon faeces and serum are important parameters for detection of pigeon breeder's disease in exposed individuals, however confirmation of this diagnosis should be provided by the bronchial provocation tests.

Budgerigar fancier's lung. The persistence of budgerigar precipitins and the recovery of lung function after cessation of avian exposure

Forty-eight budgerigar fanciers have been studied and twenty-five (52%) of these lost their serum budgerigar precipitins after cessation of avian exposure. Twenty (80%) subjects lost their precipitins within 2 years. The lung function was assessed serially in seventeen patients with allergic alveolitis and correlated with the persistence of their serum precipitins. There was no difference in the lung function at presentation or in the incidence of complete recovery between the ten subjects, whose precipitins persisted for longer than 2 years, and the seven individuals in whom the precipitins had disappeared within this time. These observations suggest that budgerigar precipitins do not have a major role to play in the continuing pathogenesis of allergic alveolitis.

Diagnosis of pigeon breeder's disease by indirect immunofluorescence on sections of pigeon oviduct

A new technique by indirect immunofluorescence on sections of pigeon oviduct, is described as an aid to diagnosis of pigeon breeder's disease. It is easy to do, inexpensive, and permits distinction between affected patients and exposed but unaffected persons. The main allergen, pigeon IgA, participates in the fluorescent responses of the mucous membrane and associated secretions. It has been possible to relate changes in antibody titre with improvement following treatment.

Experimental murine hypersensitivity pneumonitis: multigenic control and influence by genes within the I-B subregion of the H-2 complex

An animal model of hypersensitivity pneumonitis was developed in the mouse by immunization with pigeon dropping extract (PDE) in complete Freund's adjuvant, followed by daily aerosol challenge with soluble specific antigen. C3H/He (H-2k) mice developed intense diffuse interstitial lung disease and were classified as high responders. On the other hand C57BL/10 (H-2b) mice developed only mild perivascular infiltration. Moreover, although high-responder C3H/He mice developed delayed hypersensitivity to PDE, low-responder C57BL/10 mice failed to develop this reactivity. Breeding studies in F1 and F2 progeny of C3H/He high responders and C57BL/10 low responders showed that responsiveness was multigenic. B10.BR (H-2k) mice also developed intense PDE-induced diffuse interstitial lung disease, suggesting that genes within the H-2 complex influence the development of pulmonary inflammation. On the other hand, C3H.SW (H-2b) mice were also high responders, possibly because of non-H-2 genes in the C3H/He background that influenced responsiveness. Studies in H-2 recombinant strains with C57BL/10 backgrounds mapped the H-2-linked genes that influence responsiveness within the I-B subregion.

The antigens of pigeon breeder's disease. VII. Isoelectric focusing studies on unfractionated pigeon dropping extract

Isoelectric focusing (IEF) studies on pigeon dropping extracts (PDE) revealed that it is a complex mixture of components that are acidic in nature. Chromatographically purified antigens PDEB, PDE1, and PDE3 showed multiple bands in IEF, indicating a microheterogeneity of these components, with peak concentrations focusing at pH 6.1, 4.6, and 3.8, respectively. The isoelectric points are compatible with the chromatographic behavior of these antigens on DEAE-cellulose. Crossed immunoelectrofocusing (CRIF) resolved PDE into seven precipitin lines with rabbit antiserum in a pH gradient from 3.5 to 9.5, and into nine precipitable components in a pH gradient from 2.5 to 7.0. The complexity of this antigen source appears to reside in the heterogeneity of immunologically related antigens. A comparison of pigeon breeder's sera by CRIF of PDE revealed a qualitative difference in precipitation patterns obtained with symptomatic and asymptomatic individuals. Sera from all (eight out of eight) of the symptomatic breeders tested precipitated an unidentified component of PDE, whereas none (zero out of four) of the sera from asymptomatic breeders detected this antigen. These results suggest that CRIF of PDE is useful as a diagnostic tool and that some specific component of PDE may be involved in the pathogenesis of the disease.