# Causal role of immune cells in allergic rhinitis: A bidirectional Mendelian randomization study

## TL;DR

This study finds a causal link between immune cells and allergic rhinitis using genetic data, suggesting new therapeutic strategies.

## Contribution

The study uses bidirectional Mendelian randomization to establish causality between immune cells and allergic rhinitis.

## Key findings

- 38 immune cell types were found to influence allergic rhinitis.
- Allergic rhinitis was linked to changes in 20 immune cell types.
- Results were stable across multiple statistical methods and sensitivity analyses.

## Abstract

•Immune cells causally affect allergic rhinitis, guiding therapy and clinical study.•The study used two independent samples to avoid overfitting caused by duplication.•Bidirectional Mendelian randomization analysis effectively excluded reverse causality.•Multiple immune cells were evaluated for AR association, preventing single-marker bias.

Immune cells causally affect allergic rhinitis, guiding therapy and clinical study.

The study used two independent samples to avoid overfitting caused by duplication.

Bidirectional Mendelian randomization analysis effectively excluded reverse causality.

Multiple immune cells were evaluated for AR association, preventing single-marker bias.

Previous observational studies have indicated an association between various immune cells and allergic rhinitis; however, the causal relationship remains uncertain. This study seeks to further investigate the causal link between immune cells and allergic rhinitis through bidirectional two-sample Mendelian randomization analysis.

Allergic rhinitis related data were obtained from the MRC-IEU database, while data for 731 immune cells were sourced from the GWAS catalog. The causal association between immune cells and allergic rhinitis was assessed using inverse variance weighting, MR-Egger, weighted median, simple mode, and weighted mode methods. Stability and reliability of the findings were evaluated through Cochran's Q test, MR-Egger intercept p-value, and leave-one-out analysis.

Primarily based on IVW methods, 38 distinct immunocyte phenotypes were identified as potentially influencing allergic rhinitis (p < 0.05), while allergic rhinitis was found to potentially impact 20 different immunocyte phenotypes (p < 0.05). The results for heterogeneity, horizontal pleiotropy, and sensitivity analyses demonstrated stability.

This study establishes a strong genetic correlation between immune cells and allergic rhinitis, enhances current knowledge regarding the role of immune cells in AR, and offers potential targets for the development of novel immune-based therapeutic strategies.

Level 5.