# The roles of serum Th1, Th2, and Th17 cytokines in patients with chronic urticaria: a systematic review and meta-analysis

## TL;DR

This study identifies elevated TNF-α and IL-17 cytokine levels in chronic urticaria patients, suggesting their potential use in diagnosing and assessing disease activity.

## Contribution

The study is the first to systematically review and meta-analyze Th1, Th2, and Th17 cytokines in chronic urticaria, identifying TNF-α and IL-17 as significant biomarkers.

## Key findings

- Serum TNF-α and IL-17 levels are significantly higher in chronic urticaria patients compared to healthy controls.
- The meta-analysis included 50 studies reporting 22 cytokines related to Th1, Th2, and Th17 pathways.

## Abstract

To conduct a systematic review and meta-analysis to identify Th1-, Th2, and Th17 related serum biomarkers that reflect disease activity in chronic urticaria (CU), thereby enhancing the assessment of disease activity in both trials and clinical practice.

Systematic searches of PubMed, EMBASE, and Web of Science were conducted through November 2024 to identify articles reporting the associations between CU and serum biomarkers. Serum Th1, Th2, and Th17 related biomarkers were identified in CU patients and correlated with disease severity and patient characteristics (ex. Age, sex, and comorbidities). The study quality was assessed using the National Heart, Lung, and Blood Institute Quality Assessment Tool for case-control studies. Meta-analysis was performed using the random-effects model with Hedges' g to pool standardized mean differences (SMDs). For meta-analysis, data were included for biomarkers reported in at least four studies with available means and standard deviations (SDs). Data reported as medians with ranges or interquartile ranges (IQRs) were evaluated for skewness. If the data were found to be significantly skewed, the means and SDs were not calculated. Conversely, if the data were not skewed, the means and SDs were estimated using validated methods.

A total of 6,013 studies were screened, of which 50 were included, reporting 22 serum Th1, Th2, and Th17 related cytokines. Meta-analyses revealed significant pooled standardized mean differences (SMDs) for serum TNF-α and IL-17.

Serum TNF-α and IL-17 levels are significantly increased in patients with CU compared to healthy age- and sex-matched controls. These findings have the potential to influence clinical guidelines for the diagnostic workup of CU to include testing the serum levels of TNF-α and IL-17.