Enhanced basophil histamine release and neutrophil chemotactic activity predispose grain dust-induced airway obstruction.
BACKGROUND
The pathogenic mechanism of grain dust (GD)-induced occupational asthma (OA) remains unclear.


OBJECTIVE
To understand further the mechanism of GD-induced OA.


METHODS
Fifteen employees working in a same GD industry, complaining of work-related respiratory symptoms, were enrolled and were divided into two groups according to the GD-bronchoprovocation test (BPT) result: six positive responders were grouped as group III, nine negative responders as group II and five healthy controls as group I. Serum GD-specific immunoglobulin (Ig)E (sIgE), specific IgG (sIgG) and specific IgG4 (sIgG4) antibodies were detected by enzyme-linked immunosorbent assay. Basophil histamine release was measured by the autofluorometric method, and changes of serum neutrophil chemotactic activity were observed by the Boyden chamber method.


RESULTS
For clinical parameters such as degree of airway hyperresponsiveness to methacholine, duration of respiratory symptoms, exposure duration, and prevalences of serum sIgE, sIgG and sIgG4 antibodies, there were no significant differences between group II and III (P > 0.05, respectively). Serum neutrophil chemotactic activity increased significantly at 30 min and decreased at 240 min after the GD-BPT in group III subjects (P < 0.05, respectively), while no significant changes were noted in group II subjects (P > 0.05). Basophil histamine release induced by GD was significantly higher in group III than those of group I or group II (P < 0.05, respectively), while minimal release of anti-IgG4 antibodies was noted in all three groups.


CONCLUSIONS
These results suggest that enhanced basophil histamine release and serum neutrophil chemotactic activity might contribute to the development of GD-induced occupational asthma.
Park
H
H
Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.
Jung
K
K
Kang
K
K
Nahm
D
D
Cho
S
S
Kim
Y
Y
D000328:Adult; D001249:Asthma / Q000209:etiology*; D001491:Basophils / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte; D004391:Dust / Q000009:adverse effects*; D002523:Edible Grain / Q000276:immunology*; D006636:Histamine Release; D006801:Humans; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology*; D009784:Occupational Diseases / Q000209:etiology*
D004391:Dust