AluyMICB dimorphism within the class I region of the major histocompatibility complex is associated with asthma and airflow obstruction in the Busselton population.
OBJECTIVE
To examine the association between the Alu dimorphism within the first intron of the MICB gene and asthma and airflow obstruction. Background The highly polymorphic non-classical MHC class I polypeptide-related (MIC) genes, MICA and MICB, encode stress inducible glycoproteins, which are expressed on a variety of epithelial cells, including those of the lungs.


METHODS
AluyMICB genotyping was performed on 1109 subjects from the Busselton Health Study. From a standard questionnaire, 359 individuals indicated that they had been diagnosed by a doctor with asthma. Lung function was assessed by the forced expired volume in 1 second (FEV1) and expressed as a percent of the predicted value. Airflow obstruction was defined as FEV1<80% predicted.


RESULTS
In men, a dominant relationship was found between the AluyMICB DD genotype and asthma (P=0.006; chi2(2)=7.65). Furthermore, multivariate analysis adjusted for age, height, weight and body mass index (BMI) showed a relationship between DD genotype and asthma in men in a dominant model (odds ratio (OR)=1.97; 95% confidence interval (CI)=1.11-3.51; P=0.021). In women, an association was found between the AluyMICB II genotype and FEV1 percent predicted as a continuous variable (P=0.001). When adjusted for age and BMI, it showed a significant relationship between AluyMICB and airflow obstruction in a dominant model (OR=14.11%, 95% CI 3.29-60.57, P<0.001). However, no association was found between the AluyMICB II genotypes and airflow obstruction in men.


CONCLUSIONS
These findings suggest the possible involvement of a MHC class I gene in abnormal airway structure in women and airway function in men.
Hui
J
J
UWA Centre for Medical Research, Western Australian Institute for Medical Research, The University of Western Australia, and Western Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Western Australia. jhui@cyllene.uwa.edu.au
Palmer
L J
LJ
James
A L
AL
Musk
A W
AW
Beilby
J P
JP
D000328:Adult; D000368:Aged; D001249:Asthma / Q000235:genetics* / Q000276:immunology*; D001483:Base Sequence; D016022:Case-Control Studies; D005060:Europe / Q000208:ethnology; D005260:Female; D005541:Forced Expiratory Volume; D005838:Genotype; D006306:Health Surveys; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008173:Lung Diseases, Obstructive / Q000235:genetics* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D015999:Multivariate Analysis; D011110:Polymorphism, Genetic; D012737:Sex Factors; D012882:Skin Tests; D014904:Western Australia
D015395:Histocompatibility Antigens Class I; C098080:MICB antigen