Variation in IL7R predisposes to sarcoid inflammation

Area of Science:

• Immunogenetics
• Pulmonary Medicine
• Genetic Epidemiology

Background:

• Sarcoidosis is a chronic granulomatous disease driven by Th1 lymphocyte infiltration.
• Interleukin 7 Receptor Alpha (IL7R), crucial for T cell function, is highly expressed on both naive and memory T cells.

Purpose of the Study:

• To investigate the association between the IL7R gene region and susceptibility to sarcoidosis.
• To explore the role of IL7R genetic variations in the risk of developing granulomatous lung disease.

Main Methods:

• Genotyping of six single-nucleotide polymorphisms (SNPs) within the IL7R gene in sarcoidosis patients and healthy controls.
• Statistical analysis of SNP associations, including replication in an independent cohort and patients with Löfgren's disease.
• In silico analysis to assess linkage disequilibrium between identified SNPs and functional variants.

Main Results:

• The rs10213865 SNP in the IL7R gene showed a significant association with sarcoidosis risk (P=0.008).
• This SNP is in complete linkage disequilibrium with a functional coding SNP (rs6897932, T244I).
• Combined analysis of 663 sarcoidosis patients and 586 controls confirmed a strong association (P=5 x 10(-4), OR=1.49), indicating IL7R variation increases sarcoidosis risk.

Conclusions:

• Genetic variations in the IL7R gene are significantly associated with an increased risk of sarcoidosis.
• The findings suggest that IL7R gene variations may contribute to the general risk of developing granulomatous lung diseases, including sarcoidosis and potentially Löfgren's disease.