Cranial and extracranial giant cell arteritis do not exhibit differences in the IL6 -174 G/C gene polymorphism

Area of Science:

• Immunology
• Genetics
• Rheumatology

Background:

• Interleukin-6 (IL-6) is a key proinflammatory cytokine in giant cell arteritis (GCA) pathogenesis.
• Genetic variations in the IL-6 gene promoter, specifically the -174 G/C polymorphism, are investigated for their role in GCA susceptibility and clinical presentation.

Purpose of the Study:

• To investigate the association between the IL6 -174 G/C polymorphism and the risk of developing GCA.
• To determine if this polymorphism influences the clinical spectrum of GCA, differentiating between cranial and extracranial large vessel vasculitis (LVV-GCA).

Main Methods:

• Genotyping of the IL6 -174 G/C polymorphism (rs1800795) in 191 GCA patients, 109 LVV-GCA patients, and 877 controls.
• Comparative analysis of genotype and allele frequencies between patient groups and controls.
• Stratification of GCA patients based on clinical features like polymyalgia rheumatica, ischemic manifestations, and HLA status.

Main Results:

• No significant differences in IL6 -174 G/C genotype or allele frequencies were observed between GCA patients and healthy controls.
• Comparisons between cranial and extracranial LVV-GCA subgroups and controls also showed no significant associations.
• Stratification by clinical phenotypes, including visual loss and HLA-DRB1*04:01 status, revealed no influence of the IL6 -174 G/C polymorphism.

Conclusions:

• The IL6 -174 G/C polymorphism is not a significant genetic factor in the susceptibility to giant cell arteritis.
• This polymorphism does not appear to influence the phenotypic expression or clinical characteristics of GCA.