Are single nucleotide polymorphisms of the immunoglobulin A Fc receptor gene associated with allergic asthma?

Background: Eosinophils are important components of allergic inflammation. The immunoglobulin A (IgA) Fc receptor (FcalphaRI), encoded by the FCAR gene, is a possible candidate for eosinophil activation at mucosal surfaces, where IgA is abundant. Both elevated cell surface expression of FcalphaRI and increased avidity for IgA were described on eosinophils from allergic subjects. The aim of our study was to examine the possible association of FCAR gene polymorphisms with allergic asthma.

Methods: We screened three regions of the FCAR gene: (1) the promoter region, (2) exon 3, encoding the first extracellular domain (EC1), and (3) exon 5, coding for the transmembrane and cytoplasmic domain, for new and published polymorphisms using a sensitive temperature gradient gel electrophoresis technique and compared their frequencies in 112 patients diagnosed with allergic asthma and 100 healthy controls.

Results: Six polymorphisms, including two novel ones, were detected. No differences between patients and controls were found in the distribution of any of these polymorphisms.

Conclusion: FcalphaRI polymorphism does not seem to be a risk factor in allergic asthma. Nevertheless, this is the first report on the distribution of 6 single nucleotide polymorphisms of the FCAR gene in a human population and the first study on FCAR polymorphism in allergic asthma.