# Causal association between B cell count and psoriasis using two‐sample Mendelian randomization

## TL;DR

This study finds that higher memory B cell counts are linked to a lower risk of psoriasis, suggesting a potential new treatment approach.

## Contribution

The study identifies a causal link between memory B cell counts and reduced psoriasis risk using Mendelian randomization.

## Key findings

- Genetically predicted memory B cell counts are associated with lower psoriasis risk.
- MR-Egger analysis confirmed no horizontal pleiotropy affecting the results.
- Transitional B cell counts also showed a significant association with reduced psoriasis risk.

## Abstract

To investigate the causality between B cell count and psoriasis by Mendelian randomization (MR). Collected B cell count and psoriasis data from IEU Open GWAS Project. Employed inverse variance weighting (IVW), MR‐Egger, WM, weighted mode for analysis, ensuring result robustness. Assessed horizontal pleiotropy with MR‐Egger, detected outliers using MR‐PRESSO and examined instrumental variables heterogeneity with Cochran's Q‐test. The IVW method suggested an association between a genetically predicted memory B cell count and the risk of psoriasis vulgaris. IVW results also showed no causality between other exposure factors and the corresponding outcomes. Also, the global test of MR‐PRESSO analysis showed a significant association between a genetically predicted transitional absolute B cell count and the lower risk of psoriasis vulgaris. MR‐Egger regression showed that horizontal pleiotropy did not influence the analysis results. We found that memory B cell absolute counts are associated with a lower risk of psoriasis. These data further elucidate the role of memory B cells in psoriasis and provide new options for psoriasis treatment.