Sensitivity to the house dust mite and airway hyperresponsiveness in a young adult population.
BACKGROUND
The pathogenic mechanisms of airway hyperresponsiveness (AHR) in asthma are unknown and only a few studies have examined the importance of sensitivity to antigens in AHR in young adults.


OBJECTIVE
We investigated the correlation between AHR and sensitivity to specific antigens, atopy, history of childhood asthma and spirometry in a young adult population.


METHODS
Based on the results of interviews with 447 students at our university, 308 non-smoker students were classified into six groups. Group 1 comprised subjects with intermittent mild bronchial asthma; group 2, subjects with history of childhood asthma; group 3, subjects with atopic disease, and a RAST score for Dermatophagoides farinae (Def) of > or = 2; group 4, normal subjects with a RAST score for Def of > or = 2; group 5, subjects with cedar pollinosis; and group 6, normal subjects. We measured AHR to methacholine (MCh), spirometry, immunoglobulin E-radioimmunosorbent test (IgE-RIST), IgE-radioallergosorbent test to six common antigens, eosinophil cationic protein (ECP), and eosinophil count in peripheral blood in each subject.


RESULTS
Airway hyperresponsiveness to MCh did not correlate with IgE-RIST, eosinophil count, or ECP. The highest AHR to MCh was present in groups 1 and 2 and lowest in groups 5 and 6. Multiple regression analysis showed that sensitivity to Def was the only factor that significantly influenced AHR to MCh. Airway hyperresponsiveness to MCh of groups with a RAST score for Def of 0/1 was lower than groups with a RAST score of 2 to 6. Airway hyperresponsiveness to MCh did not correlate with the degree of positivity to Def antigen among positive sensitized groups (RAST score 2 to 6).


CONCLUSIONS
Sensitivity to mite antigen may be important in the pathogenesis of AHR and Def is a major contributing antigen in young adults in Japan. Once asthma occurs, AHR remains positive for a long time even after the disappearance of asthma-related symptoms.
Obase
Y
Y
The Second Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
Shimoda
T
T
Mitsuta
K
K
Matsuo
N
N
Matsuse
H
H
Kohno
S
S
D000328:Adult; D000485:Allergens / Q000276:immunology; D000818:Animals; D039741:Antigens, Dermatophagoides; D001232:Aspergillus fumigatus / Q000276:immunology; D001249:Asthma / Q000453:epidemiology / Q000209:etiology; D001798:Blood Proteins / Q000276:immunology; D016535:Bronchial Hyperreactivity / Q000453:epidemiology / Q000209:etiology*; D001985:Bronchial Provocation Tests; D002415:Cats; D004285:Dogs; D004391:Dust / Q000009:adverse effects*; D047091:Eosinophil Granule Proteins; D004802:Eosinophilia / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005541:Forced Expiratory Volume; D006023:Glycoproteins / Q000276:immunology; D006197:Hair / Q000276:immunology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007564:Japan / Q000453:epidemiology; D008297:Male; D016210:Methacholine Chloride; D008925:Mites / Q000276:immunology*; D011058:Pollen / Q000276:immunology; D011852:Radioallergosorbent Test; D012260:Ribonucleases; D013147:Spirometry
D000485:Allergens; D039741:Antigens, Dermatophagoides; D001798:Blood Proteins; D004391:Dust; D047091:Eosinophil Granule Proteins; D006023:Glycoproteins; D016210:Methacholine Chloride; D007073:Immunoglobulin E; D012260:Ribonucleases