Acute hypersensitivity pneumonitis in woodworkers caused by inhalation of birch dust contaminated with and .

Case Description: Five workers (2 males and 3 females) employed in a furniture factory located in eastern Poland developed hypersensitivity pneumonitis (HP) after the pine wood used for furniture production was replaced by birch wood. All of them reported onset of respiratory and general symptoms (cough, shortness of breath, general malaise) after inhalation exposure to birch dust, showed crackles at auscultation, ground-glass attenuations in HRCT examination, and lymphocytosis in the BAL examination. The diagnosis of acute HP was set in 4 persons and the diagnosis of subacute HP in one.

Identification Of Specific Allergen: Samples of birch wood associated with evoking disease symptoms were subjected to microbiological analysis with the conventional and molecular methods. Two bacterial isolates were found to occur in large quantities (of the order 10 CFU/g) in examined samples: Gram-negative bacterium of the species and a non-filamentous Gram-positive actinobacterium of the species . In the test for inhibition of leukocyte migration, 4 out of 5 examined patients showed a positive reaction in the presence of and 2 in the presence of . Only one person showed the presence of precipitins to and none to . In the inhalation challenge, which is the most relevant allergological test in the HP diagnostics, all patients reacted positively to and only one to . The results indicate that developing in birch wood was the main agent causing HP in the workers exposed to the inhalation of dust from this wood, while the etiologic role of is probably secondary.

Conclusion: The results demonstrate that apart from fungi and filamentous actinobacteria, regarded until recently as causative agents of HP in woodworkers, Gram-negative bacteria and non-filamentous actinobacteria may also elicit disease symptoms in the workers processing wood infected with large amounts of these microorganisms. The results obtained also seem to indicate that cellular-mediated reactions are more significant for causing disease symptoms compared to those that are precipitin-mediated.