Background: Penicillium frequentans is considered to be the causal agent of suberosis, hypersensitivity pneumonitis due to cork dust inhalation. Nevertheless, other fungi can colonize cork during its storage period in humid conditions. The aims of the study" were to assess the etiologic role of several fungi and cork itself in the genesis of suberosis, and to review the clinical characteristics of patients with this disease.
Methods: Eight patients with suberosis were studied. Chest radiography, high-resolution chest CT, pulmonary function testing, bronchofibroscopy with BAL, and transbronchial biopsy, and delayed cutaneous hypersensitivity tests were performed. Fungal and suberin (cork that is culture negative for fungi) antigens were used for serum determination of specific IgC antibodies, immediate hypersensitivity specific skin tests, and specific bronchial challenge tests.
Results: Serum specific IgG antibody determinations and specific skin tests against Aspergillus fumigatus and suberin demonstrated the capacity of both these antigenic extracts to induce an immunologic response. Positive specific bronchial challenge tests performed not only with P frequentans but also with A fumigatus, and cork itself were recorded in some patients for the first time in this disease. Dyspnea and cough were the most frequent symptoms. Clinical and functional improvement occurred after antigen avoidance.
Conclusions: In addition to P frequentans, A fumigatus and cork dust itself may contribute to the development of suberosis.
Key words: Aspergillus fumigatus: hypersensitivity pneumonitis; suberosis
Abbreviations: DLCO = diffusion capacity of the lung for carbon monoxide; ELISA = enzyme-linked immunosorbent assay: TBB = transbronchial biopsy
Cork is a light, porous, impermeable material extracted from the bark of some trees. The most widely used cork is obtained from the cork tree (Quercus suber), owing to its greater thickness. The processes used in the manufacture of cork depend on the end product to be obtained. "Natural" stoppers (wine bottle corks) are made from bark that is boiled, stored under dark humid conditions until moldy, sliced, punched, and polished. Cork compounds made from ground bark are used as parquet flooring, wallpaper, wall coverings, shoe soles, life belts, champagne corks, and panels for industrial soundproofing, etc. During the manufacturing process, workers are exposed to an environment that is heavily contaminated with cork dust. The world production of cork is centered in the south of Europe, with Spain being the second most important producer after Portugal.
Suberosis was first described in 1955 by Cancella d' Abreu. (1) In any event, different respiratory and occupational diseases ranging from bronchial asthma to chronic bronchitis (2-4) have been related to cork dust exposure and associated microbial contaminants. Suberosis is the term applied to hypersensitivity pneumonitis due to cork dust inhalation. It is the most well-known respiratory disease attributable to cork exposure in Spain. Despite the importance of the Spanish cork industry, there are few epidemiologic (5) or sporadic studies (6,7) on this subject, particularly as compared to those published by Portuguese authors. (3)
In early works, researchers (2-8) detected precipitins to cork dust and later to Penicillium frequentans in serum of cork workers. Since that time, this micro-organism has...
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