Background: Previous results demonstrated that sensitization to specific olive pollen allergens could be related with a different clinical pattern (asthma and/or rhinitis), and that specific patterns of sensitization are regulated by different HLA class II antigens. The authors analyze the possible implication of 7 genetic polymorphisms described as asthma susceptibility genes: IL13 (C-1112T and R130Q), IL4RA (I50V, Q551R), IL5 (C-746T) and ADRB2 (Q27E and R16G) in specific olive pollen allergic sensitization.
Methods: The authors genotyped seven polymorphisms of the IL13, IL4RA, IL5 and ADRB2 genes in 146 patients allergic to olive pollen with seasonal rhinitis/asthma and 50 controls using the polymerase chain reaction-restriction fragment length polymorphism and real-time polymerase chain reaction techniques.
Results: Two polymorphisms of IL13 were associated with allergy to olive pollen: the TT genotype of IL13 C-1112T was decreased (odds ratio, OR = 0.35, p = 0.006) whereas the RQ heterozygous genotype of IL13 R130Q increased in patients allergic to olive pollen (OR = 3.12, p = 0.009). The combined analysis of two IL4RA single nucleotide polymorphisms (SNPs) (I50V and Q551R) showed an association with asthma: IL4RA V50/Q551 was associated with risk (OR = 2.48, p = 0.007) whereas the IL4RA V50R551 haplotype was associated with protection (OR = 0.31, p = 0.003).
Conclusions: The IL13 polymorphisms under study were associated with specific allergy to olive pollen: the IL13 C-1112T polymorphism as a protective factor and the IL13 R130Q polymorphism as a risk factor. Interestingly, although single polymorphisms of IL4RA are not associated with any phenotype analyzed, the interaction between IL4RA I50V/Q551R was strongly associated with the asthma phenotype. IL13 and IL4RA could be relevant markers for allergy to olive pollen and asthma development.
(c) 2008 S. Karger AG, Basel.