Causal association between systemic lupus erythematosus and primary biliary cholangitis: A bidirectional Mendelian...

Area of Science:

• Immunology
• Genetics
• Hepatology

Background:

• Observational studies suggest an association between systemic lupus erythematosus (SLE) and primary biliary cholangitis (PBC).
• The precise causal relationship between these two autoimmune diseases remains undetermined.
• Understanding the link is crucial for clinical management and research.

Purpose of the Study:

• To investigate the potential bidirectional causal associations between SLE and PBC.
• To utilize Mendelian randomization (MR) to assess genetic links between the two conditions.
• To provide evidence for etiological pathways connecting SLE and PBC.

Main Methods:

• Bidirectional Mendelian randomization (MR) analysis using single-nucleotide polymorphisms (SNPs) from large genome-wide association studies (GWAS).
• Data sourced from European populations for PBC (24,510 samples) and SLE (14,267 samples).
• Inverse variance weighted (IVW) method as primary analysis, with MR-Egger and Cochran's Q for pleiotropy and heterogeneity assessment.

Main Results:

• Genetically predicted SLE was associated with an increased risk of PBC (OR 1.324, P < .001).
• Genetically predicted PBC was associated with an increased risk of SLE (OR 1.414, P < .001).
• No significant horizontal pleiotropy or heterogeneity was detected, supporting the robustness of the findings.

Conclusions:

• This study provides strong evidence for bidirectional causal relationships between SLE and PBC.
• The findings suggest that genetic predispositions to one disease may influence the risk of developing the other.
• These insights contribute to understanding the complex interplay between SLE and PBC, informing future research and clinical strategies.