ISSN 2147-9720 | E-ISSN 2148-4279
Original Article
IL-1A gene variation in relation to cytokine levels and clinical characteristics in ankylosing spondylitis
1 Department of Rheumatology, University of Western Australia, Sir Charles Gairdner Hospital, Perth, Australia  
2 Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway  
3 Department of Rheumatology, University Hospital North Norway, Tromsø, Norway  
Eur J Rheumatol 2019; 6: 67-70
DOI: 10.5152/eurjrheum.2018.18150
Key Words: Ankylosing spondylitis, IL1A, SNP, spinal function, cytokines

Objective: Variations in the IL-1 alpha (IL-A) gene increase the risk for ankylosing spondylitis (AS), but the pathway underlying this association is not fully understood. As IL-1A is primarily a regulatory cytokine, we investigated the influence of IL-1A gene variation on disease severity and cytokine expression in AS.


Methods: This was a cross sectional study of tumor necrosis factor inhibitors (TNFi)-naïve AS patients (n=334, 90% B27 +, age 45 years) fulfilling the modified New York criteria. We recorded demographics, clinical findings, spinal mobility, Bath AS Functional Index (BASFI), and routine lab findings. IL-1A genotyping for three AS-associated single nucleotide polymorphism (SNP; rs2856836, rs17561 and rs1894399) was performed using Taqman RT-PCR, with TNF, IL-6, IL-17A, and IL-23 levels measured using ELISA. Genotypic associations included logistic regression analysis for genotype (codominant model) and global haplotype (threshold 5%) associations with cytokine levels and clinical features.


Results: The three variants were in near complete linkage disequilibrium and formed two only common haplotypes (ACC 67%, GAT 33%). The levels for TNF, IL-6, IL-17A, IL-23, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were similar across genotypes and haplotypes (all p-values >0.4) as were the measures for spinal mobility and BASFI. The TAQ haplotype showed a borderline significant trend with reduced heart disease and mortality during follow-up.


Conclusion: IL-1A gene cluster variations do not have an impact on the clinical disease measures or cytokine levels in AS, suggesting that IL-1A has no direct role in AS.


Cite this article as: Nossent JC, Sagen-Johnsen S, Bakland G. IL-1A gene variation in relation to cytokine levels and clinical characteristics in ankylosing spondylitis. Eur J Rheumatol 2019; 6(2): 64-7.

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