Causal relationship between multiple sclerosis and primary Sjögren's syndrome: a two-sample mendelian randomization...

Area of Science:

• Autoimmune Diseases
• Neuroimmunology
• Genetics

Background:

• Primary Sjögren's syndrome (SS) and multiple sclerosis (MS) are distinct autoimmune diseases.
• Understanding potential shared genetic mechanisms and causal links is crucial for therapeutic strategies.
• Previous research suggests possible overlaps but lacks robust causal evidence.

Purpose of the Study:

• To investigate the bidirectional causal relationship between primary SS and MS.
• To explore common underlying mechanisms using genetic data.
• To identify potential therapeutic targets based on genetic associations.

Main Methods:

• Two-sample Mendelian randomization (MR) analysis utilizing GWAS data for primary SS and MS in European ancestry populations.
• Selection of genetic variants as instrumental variables (IVs) for primary SS and MS.
• Application of various MR methods (IVW, MR Egger, Weighted Median) and sensitivity analyses (MR-PRESSO, leave-one-out) to ensure result robustness.

Main Results:

• A significant protective effect of multiple sclerosis (MS) on primary Sjögren's syndrome (SS) was identified (OR: 0.896, P=0.001).
• No significant evidence of heterogeneity or horizontal pleiotropy was found, supporting the causal inference.
• 42 and 5 single nucleotide polymorphisms (SNPs) were identified as robust IVs for primary SS and MS, respectively.

Conclusions:

• The study provides strong genetic evidence for a negative causal association, suggesting MS has a protective effect against primary SS.
• This finding highlights a potential shared pathway or immune regulation between these two autoimmune conditions.
• The results open new avenues for research into the complex interplay of autoimmune diseases and potential cross-disease therapeutic interventions.