Associations between polymorphisms of the high-affinity immunoglobulin E receptor and late-onset airflow obstruction in older populations.

OBJECTIVES

To test the hypothesis that genetic polymorphisms in the beta subunit of the high-affinity immunoglobulin E (IgE) receptor are associated with late-onset airflow obstruction.

DESIGN

Case-control candidate gene association study.

SETTING

Department of Medicine for the Elderly and Respiratory Medicine in three teaching hospitals in Leicester and Manchester, United Kingdom.

PARTICIPANTS

Cases with late-onset airflow obstruction with age-, sex-, and geographically matched controls.

MEASUREMENTS

Subjects were genotyped for two polymorphisms of the beta subunit of the high-affinity IgE receptor (RsaI intron 2 and RsaI exon 7). The association between the polymorphisms and phenotypes was examined using contingency tables and linear regression models.

RESULTS

Two hundred eighty-three cases and 144 controls were genotyped. RsaI exon 7 AA was associated with eczema (odds ratio (OR)=2.27, 95% confidence interval (CI)=1.17-4.38, P=.015). No other associations were found. Total serum IgE levels were significantly higher in cases than controls (adjusted OR for high/low IgE=2.56, 95% CI=1.53-4.28, P<.001).

CONCLUSION

Serum IgE levels, but not the high-affinity IgE receptor polymorphisms, were associated with late-onset airflow obstruction, suggesting that interaction between environmental and genetic factors controlling serum IgE levels and disease pathogenesis may differ between early- and late-onset airflow obstruction phenotypes.