Abstract
Background: Asthma is a multifactorial disorder, and both genetic and environmental factors contribute to its development. We investigated the possible association between asthma and 5 single-nucleotide polymorphisms (SNPs) in the interleukin 17 (IL17) gene-rs17880588 (G/A) and rs17878530 (C/T) in IL17A and rs763780 (TIC), rs11465553 (TIC), and rs2397084 (G/A) in IL17F-and compared levels of the proteins IL17A and IL17F in asthma patients with those of controls.
Patients and Methods: The study group included 100 asthma patients and 102 ethnically matched controls. Genotyping was performed on purified DNA using reverse transcriptase-polymerase chain reaction with specific primers and probes. Levels of IL17A and IL17F were measured in plasma using enzyme-linked immunosorbent assay.
Results: Genotyping showed that AG heterozygotes of rs17880588 in IL17A were significantly more common in the control group than among the asthma patients (P<.05); no significant associations were observed for any of the other SNPs examined. Levels of IL17A and IL17F were both higher in asthma patients (IL17A, 2.242 [0.099] vs 2.752 [0.287] pg/mL; IL17F, 236.01 [38.28] vs 700 [201.078] pg/mL). The difference was statistically significant for IL17F (P=.025, t test). Levels of IL17A and IL17F were positively and significantly correlated in the asthma patients
Conclusion: Of all the SNPs analyzed, only rs17880588 showed a significant association with asthma in the Saudi population we studied. Levels of IL17A and IL17F were significantly upregulated in the asthma patients. The morphology of IL17Fappeared to affect expression levels.