Abstract: There is virtually no information in the literature about the exposure levels needed to induce hypersensitivity pneumonitis (HP) by diisocyanates. The present study reports a case of occupational HP due to diisocyanates after low-level exposure. A 53-yr-old female never-smoker developed progressive shortness of breath on exertion, cough, fatigue and flu-like symptoms shortly after she began work as a secretary of a car body repair shop. A diagnosis of HP was made 2 yrs later, based on a restrictive ventilatory defect, a reticulonodular and discrete ground-glass pattern on high-resolution computed tomography, lymphocytosis in bronchoalveolar lavage and specific immunoglobulin G antibodies to diisocyanate human serum albumin conjugates in the patient's serum. The diagnosis was confirmed by recovery after exposure cessation and deterioration after re-exposure. Ambient monitoring revealed air concentrations of different diisocyanate monomers below the detection limit in both the patient's work station and in front of the paint spray booths, with the exception of one measurement that showed 4,4-methylenediphenyl diisocyanate concentrations of 3 microg x m(-3) in front of one booth (corresponding to a total reactive isocyanate group concentration of 1 microg x m(-3)). The present authors conclude that concentrations of diisocyanates far below current exposure limits may induce hypersensitivity pneumonitis in susceptible subjects.
Abstract: Lysozyme and alpha-1-antichymotrypsin depositions were recorded by means of the PAP technique from benign and malignant fibrohistiocytic tumours. These depositions were seen in relation to lesions with histiocytic reactions. The findings indicate that the detection of these markers support the solution of problems of differential diagnosis. An important role is particularly played by demonstration in fibroblastic elements within the neoplasm proper. The results also suggest the possible existence of an undifferentiated precursor cell.
Abstract: Focally aggregated epithelioid cells and granulomatous epithelioid cell reactions of different genesis were investigated immunohistochemically by means of PAP method according to Sternberger. We studied the presence of histiocytic markers lysozyme and alpha 1-antichymotrypsin, the content of albumin and of immunoglobulins and the question of immunophagocytosis and the presence of fibronectin. Various forms of activation of epithelioid cells as well as histiocytes and Langhans giant cells were found thereby. In the former, a phagocytosis could never be demonstrated, whereas this was true in histiocytes and giant cells. Fibronectin was not found in epithelioid cells. The findings suggest that epithelioid cells are a specific form of reaction of histiocytic elements. Thus they are a special reaction of MPS in a multiple causal genesis and a morphogenesis according to its own characteristics within a hypersensitivity reaction of a delayed type. Epithelioid cells modulate the immune response and in this way the tissue reaction.
