Correlations between lichen planus and autoimmune diseases: a Mendelian randomization study

Area of Science:

• Immunology
• Genetics
• Epidemiology

Background:

• Observational studies suggest a link between lichen planus (LP) and autoimmune diseases.
• Mendelian randomization (MR) is a robust method for inferring causality using genetic variants.

Purpose of the Study:

• To investigate the potential causal associations between genetic predisposition to lichen planus (LP) and 15 other autoimmune diseases.
• To leverage a two-sample Mendelian randomization approach for enhanced causal inference in autoimmune disease research.

Main Methods:

• Utilized genome-wide association study (GWAS) data from the IEU Open GWAS database.
• Employed genetic variants strongly associated with LP (P < 5×10⁻⁶) in a European population as instrumental variables (IVs).
• Calculated causal effects using odds ratios (ORs) with 95% confidence intervals (CIs), assessing for horizontal pleiotropy and result stability via leave-one-out analysis.

Main Results:

• The genetic risk for psoriasis showed a significant positive association with atopic dermatitis (OR [95%CI]=0.964[0.936, 0.992], P=0.013).
• A significant positive association was also observed between psoriasis and ankylosing spondylitis (OR [95%CI]=0.879[0.774, 0.999], P=0.047).
• Furthermore, genetic risk for psoriasis was linked to an increased risk of Type 1 diabetes (OR [95%CI]=1.074[1.008, 1.145], P=0.027).

Conclusions:

• The Mendelian randomization study provides evidence for a causal relationship between genetic factors influencing psoriasis and the development of atopic dermatitis, ankylosing spondylitis, and Type 1 diabetes in European individuals.
• The findings highlight potential shared genetic underpinnings or causal pathways among these autoimmune conditions.
• Further research is warranted to elucidate the specific biological mechanisms driving these observed causal associations.