[Bird fancier's lung--an allergic alveolitis]

BACKGROUND

Bird fancier's lung is globally the second most frequent cause of extrinsic allergic alveolitis.

MATERIAL

For many years, the patient had influenza-like symptoms and developed progressing pulmonary fibrosis. Over a period of 10 years she had been exposed to up to 43 birds in the house at any one time and serum precipitates against avian proteins had been found. After sanitation of the house of birds and avian proteins, the pulmonary function has not deteriorated further in 5 years.

INTERPRETATION

A thorough environmental history is essential in the diagnosis of extrinsic allergic alveolitis; at an earlier stage it would have made us think about this possible etiological factor. This could have prevented the development of permanent pulmonary fibrosis if the patient had been advised to avoid further exposure to antigens. There should be greater awareness of this disease among general practitioners as well as among chest consultants in Norway.

Needs and Opportunities for Research in Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP) develops after inhalation of many different environmental antigens, causing variable clinical symptoms that often make diagnosis uncertain. The prevalence of HP is higher than recognized, especially its chronic form. Mechanisms of disease are still incompletely known. Strategies to improve detection and diagnosis are needed, and treatment options, principally avoidance, are limited. A workshop recommended: a population-based study to more accurately document the incidence and prevalence of HP; better classification of disease stages, including natural history; evaluation of diagnostic tests and biomarkers used to detect disease; better correlation of computerized tomography lung imaging and pathologic changes; more study of inflammatory and immune mechanisms; and improvement of animal models that are more relevant for human disease.

Hypersensitivity Pneumonitis Reaction to Mycobacterium avium in Household Water

BACKGROUND

Hypersensitivity pneumonitis has been described with exposure to aerosolized Mycobacterium avium complex (MAC) in indoor hot tubs (hot tub lung).

OBJECTIVES

To describe a case of MAC-associated hypersensitivity pneumonitis-like reaction possibly from showering and review previous hot tub lung reports.

METHODS

For the case report, we investigated a patient with histologically diagnosed hypersensitivity pneumonitis and MAC-positive sputum culture findings. Mycobacterial cultures were obtained from his home and workplace. Isolates were typed using pulsed-field gel electrophoresis. For the review, MEDLINE and EMBASE were searched for hot tub lung reports, which were reviewed and summarized.

RESULTS

A 50-year-old man had progressive dyspnea and episodic fever and myalgias. Pulmonary function testing results revealed obstruction and impaired diffusion; a chest CT scan found diffuse, centrilobular, ground-glass nodules, and air trapping, and a lymphocytic alveolitis with an elevated CD4/CD8 ratio. Transbronchial biopsy showed multiple well-formed nonnecrotizing granulomas. Multiple respiratory samples and shower and bathtub specimens grew MAC, with matching pulsed-field gel electrophoresis patterns. The patient changed from showering to tub bathing. Prednisone and antimycobacterial drugs were administered for approximately 1 year. His symptoms, pulmonary function abnormalities, and CT scan findings resolved. The literature review yielded 36 cases of hot tub lung. Clinical features included dyspnea (97%), cough (78%), and fever (58%). Pulmonary function testing showed obstruction (67%), restriction (55%), and impaired diffusion (75%). A chest CT scan showed ground-glass opacification (95%) and nodules (67%). Granulomas were well-formed in 95%. Treatments included discontinuation of hot tub use and prednisone, antimycobacterial drugs, or both. Outcomes were favorable.

CONCLUSIONS

A hypersensitivity pneumonitis-like reaction to mycobacteria can occur from exposures other than hot tubs. There are key differences between classic hypersensitivity pneumonitis and MAC-associated hypersensitivity pneumonitis. Antimycobacterial therapy may be required. The possibility of MAC hypersensitivity pneumonitis from showering raises potential implications in the investigation of patients with hypersensitivity pneumonitis.

[The role of pro- and antioxidant processes in the liver tissue of guinea pigs in pathogenesis of allergic alveolitis]

It was shown that allergic alveolitis development is accompanied by increase of superoxyddismutase and catalase activity as well as an increase of dien conjugates and malonic dialdehyde content in Guinea pig liver. The administration of alfa-tokoferol acetate, an antioxidant resulted in decrease of these indices in the liver tissue that testifies its correcting influence upon PLO and antioxidant system processes.

Extrinsic allergic alveolitis with IgA deficiency

Up to now only 3 cases of extrinsic allergic alveolitis (hypersensitivity pneumonitis) with IgA deficiency have been published worldwide. We had the opportunity to detect two additional cases which will be presented here. Summarizing all cases IgA deficiency is a risk factor for a severe course of the disease and an increased susceptibility to acquire allergic alveolitis by low dose antigen exposure.

Hypersensitivity pneumonitis: a multifaceted deceiving disorder

Hypersensitivity pneumonitis (HP) represents a group of immunologically mediated lung disorders provoked by recurrent exposure to various environmental agents. HP is multifaceted and may mimic almost any interstitial lung disease, some infectious diseases,and even bronchiolar disorders. In the absence of a diagnostic gold standard,diagnosis of HP requires a combination of clinical, environmental, radiologic, physiologic,and pathologic findings that represent a diagnostic challenge for clinicians and-in the chronic form-even for experienced pathologists. Therapeutic approach includes avoiding further exposure and, depending on the clinical form, the administration of a course of prednisone. New anti-inflammatory, immunoregulatory, and antifibrotic drugs are urgently needed for this and other interstitial lung diseases.

Chronic hypersensitivity pneumonitis caused by Aspergillus complicated with pulmonary aspergilloma

A 57-year-old man consulted our hospital with a history of the gradual onset of dyspnea and a productive cough. Chest computed tomographic (CT) scans showed a nodular shadow in a cavity lesion, and reticulonodular, cystic, and ground-grass opacities in the bilateral lung fields with honeycombing. He was diagnosed as having pulmonary aspergilloma and idiopathic pulmonary fibrosis (IPF). As an outpatient, he suffered from dyspnea upon physical exertion with exacerbation of the high-resolution CT (HRCT) opacities. An inhalation provocation test for Aspergillosis fumigatus was positive and chronic hypersensitivity pneumonitis (CHP) caused by Aspergillus was finally diagnosed. Insidious CHP is sometimes misdiagnosed as IPF. The diagnosis of insidious CHP should be made on the basis of a detailed history, specific HRCT findings, and lymphocyte-dominant bronchoalveolar lavage fluid cell findings.

Working Group report 1: tools for the diagnosis of organic dusts-induced disease

This paper describes the outcomes of the discussion of Working Group 1. The tasks of the workgroup were to: i) review current methods for the clinical diagnosis of organic dust induced disease, and ii) suggest how further research in this field should proceed. The working group proceeded on the paradigm that for diagnosis specific and precise tests are needed, where outcomes can be related to the risk for disease. The different methods available for the investigation of individuals and groups exposed to organic dusts are summed and graded according to scientific or diagnostic values. Many of the tools should be used in experimental research only, but can be used diagnostically for evaluation during follow up of patients when treated or removed from exposure. These techniques may also be employed for investigations of outbreaks, however, only after comparison with a proper control group. Future research should focus on associations between markers of inflammation and symptoms or clinical outcomes and dose-response relationships both for short-term and long-term health effects.

New aspects of hypersensitivity pneumonitis

PURPOSE OF REVIEW

Hypersensitivity pneumonitis (HP) represents a complex pulmonary disorder of varying intensity and clinical presentation, which is characterized by a diffuse Tc1 immune response of lung parenchyma and airways in patients previously sensitized to one of more than 300 etiologic agents that may favor the HP reaction. This review describes recent data that have clarified some of the events that govern the development of the hypersensitivity reaction following exposure to the causative agents involved in this disease.

RECENT FINDINGS

A number of recent data clearly demonstrate that several cytokines and chemokines, which are secreted at sites of disease activity, participate in the pulmonary inflammatory responses taking place in the lung of patients with HP.

SUMMARY

The past few years have seen outstanding advances in the understanding of immunologic and molecular events involved in the pathogenesis of HP. It is possible that these data could allow the discovery of therapeutic targets in individuals chronically exposed to HP antigens and evolving towards pulmonary fibrosis.

Hypersensitivity pneumonitis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Hypersensitivity Pneumonitis Caused by Esparto Dust in a Young Plaster Worker:A Case R eport and Review of the Literature

We report a case of a 25-year-old, white, male plaster worker who started developing fever, severe dyspnea and cough during the manipulation of esparto fibers. The functional lung study showed restrictive lung disease and decreased single-breath carbon monoxide transfer lung capacity. High-resolution computed tomography revealed a diffuse 'ground-glass' pattern. The histopathological findings were interstitial inflammation with a marked predominance of lymphocytes and microgranulomas. Bronchoalveolar lavage showed a significant predominance of lymphocytes, with an increase in the level of CD8. Serum precipitins against fungal antigens confirmed that Aspergillus fumigatus was the cause of the patient's hypersensitivity pneumonitis.

Studies on the role of fungi in Sick Building Syndrome

Sick Building Syndrome is a term used to describe symptoms in humans which result from problems with indoor air quality. Common complaints include dyspnea, flu-like symptoms, watering eyes, and allergic rhinitis. Although there is likely no single cause for Sick Building Syndrome, fungal contamination in buildings has increasingly been associated with this spectrum of symptoms. The authors describe 2 case studies, and other experimentation, that have investigated the role of fungi in the occurrence of Sick Building Syndrome.

[A case of hypersensitivity pneumonitis showing acute respiratory distress syndrome due to exposure to dust containing diphenylmethane diisocyanate]

The patient was a 61-year-old man who reported coughing and fever that occurred immediately after the work of breaking up a large refrigerator containing diphenylmethane diisocyanate (MDI). He was brought to our medical center with respiratory distress ten days after onset. Acute respiratory distress syndrome was diagnosed on the basis of a P/F oxygen ratio of less than 200 and chest CT findings of extended consolidation in both lung fields. He was intubated and ventilated mechanically. Steroid pulse therapy was started because of an elevated lymphocyte count found through bronchoalveolar lavage (BAL). After that, arterial blood gas and chest radiography findings improved gradually, and high-resolution chest findings on the 4th day of hospitalization showed centrilobular and uncleared shadows of marginated acini in both lung fields. The patient was extubated ten days after admission, the steroid therapy was withdrawn, and he was discharged from the intensive care unit on the 22nd day of hospitalization. Transbronchial lung biopsy on admission revealed alveolitis, Masson bodies and activated macrophages in the air spaces. The dismantled refrigerator was known to contain MDI, and because of the IgE and the IgG to MDI present in the serum, and of the IgG to MDI in the BAL fluid, we diagnosed hypersensitivity pneumonitis with acute respiratory distress syndrome due to exposure to dust containing MDI. There are many reports of painters with hypersensitivity pneumonitis following exposure to isocyanates, but care should be taken to avoid the possibility of acute respiratory distress syndrome arising because of the inhalation of dust mixed with isocyanates.

Pathogenesis of hypersensitivity pneumonitis

PURPOSE OF REVIEW

Hypersensitivity pneumonitis is a group of immunologically mediated diseases caused by an abnormal response to a wide variety of inhaled antigens. Its pathogenesis is complex and involves many immunological concepts. This review discusses recent advances in our understanding of the pathogenesis of hypersensitivity pneumonitis.

RECENT FINDINGS

Over the last 3 years, several studies on the pathogenesis of hypersensitivity pneumonitis have been published. New antigens have been identified. We now have a better understanding of the role of inflammatory cells and mediators, and promoting and protective factors have been suggested.

SUMMARY

Most of the mechanisms involved in the pathogenesis of hypersensitivity pneumonitis remain incompletely understood. Current and future findings will not only help our understanding of the disease and its prevention, but also improve its treatment.

T cells in the lung of patients with hypersensitivity pneumonitis accumulate in a clonal manner

Hypersensitivity pneumonitis (HP) is characterized by an alveolitis sustained by CD8(+) T lymphocytes showing a limited expression of the T cell receptor (TCR). We previously demonstrated that a bias in T cell selection occurs in the lower respiratory tract of patients with HP, with a compartmentalization in the lung of CD8(+) T cells bearing (TCR)-beta variable (TCRBV) #2, 3, 5, 6, 8, and 13 gene segments. We herein characterized the clonal T cell populations present in the lung and in the blood of patients with HP. Heteroduplex analyses, cloning, and sequencing T cells bearing TCR indicate oligoclonal expansions of T cells expressing homologous or identical complementary-determining region 3. Furthermore, T cell clones isolated from the two compartments expressed similar, sometimes identical, junctional regions. Removal from antigenic exposure led to the disappearance of T cell clones. Our findings indicate that expansions of T lymphocytes bearing clonal TCRBV region gene segments take place in the lung of patients with HP during exposure. The evidence that identical T cell clones are present in the lung and the blood of the same patient suggests that the immune reaction occurring at lung level gives rise to a systemic reaction.

Familial presentation of occupational hypersensitivity pneumonitis caused by aspergillus-contaminated esparto dust

Esparto grass (Stipa tenacissima), which is commonly found in the Mediterranean area, has a wide variety of uses. Five plaster workers from the same family developed cough, dyspnea, malaise, and fever after exposure to the esparto fiber used in their work for the previous few years. They showed a significant decrease in symptoms when away from work. Precipitating antibodies against an esparto extract were found in the sera of all patients. Specific IgG antibodies against Aspergillus fumigatus were detected. A. fumigatus was identified after microbiologic evaluation of esparto fiber samples. The dust derived from fungi-contaminated esparto fibers can cause hypersensitivity pneumonitis in exposed subjects. The causative antigen is A. fumigatus. When esparto fibers were strongly contaminated by fungi, all the workers developed a clinical picture compatible with hypersensitivity pneumonitis. The coincidental finding of an occupational and a familiar condition is unusual.

Clinical diagnosis of hypersensitivity pneumonitis

The diagnosis of hypersensitivity pneumonitis (HP) is difficult and often relies on histopathology. Our objective was to identify diagnostic criteria and to develop a clinical prediction rule for this disease. Consecutive patients presenting a condition for which HP was considered in the differential diagnosis underwent a program of simple standardized diagnostic procedures. High-resolution computed tomography scan and bronchoalveolar lavage (BAL) defined the presence or absence of HP. Patients underwent surgical lung biopsy when the computed tomography scan, BAL, and other diagnostic procedures failed to yield a diagnosis. A cohort of 400 patients (116 with HP, 284 control subjects) provided data for the rule derivation. Six significant predictors of HP were identified: (1) exposure to a known offending antigen, (2) positive precipitating antibodies to the offending antigen, (3) recurrent episodes of symptoms, (4) inspiratory crackles on physical examination, (5) symptoms occurring 4 to 8 hours after exposure, (6) and weight loss. The area under the receiver operating characteristic curve was 0.93 (95% confidence interval: 0.90-0.95). The rule retained its accuracy when validated in a separate cohort of 261 patients. The diagnosis of HP can often be made or rejected with confidence, especially in areas of high or low prevalence, respectively, without BAL or biopsy.