ZFP36 as a Key Regulator of CD4+ T Cell Subset Balance in Immune Checkpoint Inhibitor-Induced Adverse Events in Lung Adenocarcinoma

Background: Immune checkpoint inhibitors (ICIs) have revolutionized lung adenocarcinoma (LUAD) treatment but are frequently accompanied by immune-related adverse events (irAEs). The zinc finger protein 36 (ZFP36), also known as tristetraprolin, serves as a critical post-transcriptional regulator of mRNA stability and has emerged as a key modulator of T cell function. However, its role in ICI-induced irAEs remains unexplored. Methods: We conducted single-cell RNA sequencing analysis of peripheral blood samples from 18 LUAD patients receiving ICI therapy, including 13 patients who developed irAEs and 5 irAE-free patients. Pan-cancer analysis of ZFP36 expression was performed using TCGA database across 33 cancer types. ZFP36 expression patterns in LUAD tissues were validated using quantitative PCR and immunofluorescence staining. The impact of ZFP36 on CD4+ T cell differentiation was functionally characterized through in vitro knockdown experiments and flow cytometry analysis. Results: Single-cell analysis revealed ZFP36 as a key differentially expressed gene in irAE-associated CD4+ T cells. ZFP36 expression was significantly lower in irAE patients compared to non-irAE patients (p < 0.001). Pan-cancer analysis demonstrated widespread ZFP36 downregulation across multiple cancer types, with significant reduction observed in LUAD tumor tissues compared to normal tissues (p < 0.0001). ZFP36 high expression was associated with enhanced immune infiltration, better immunotherapy response prediction (lower TIDE scores, p < 0.05), and increased expression of co-stimulatory immune checkpoint molecules. Functional validation revealed that ZFP36 knockdown significantly increased Th17 cell percentages (p < 0.001) while reducing Treg cell percentages (p < 0.001), demonstrating its critical role in maintaining Th17/Treg balance. Conclusions: ZFP36 downregulation promotes Th17/Treg imbalance, contributing to irAE susceptibility in LUAD patients receiving ICI therapy. ZFP36 expression serves as a dual biomarker for both irAE risk prediction and immunotherapy response assessment. These findings establish ZFP36 as a potential clinical tool for personalizing immunotherapy approaches in LUAD, enabling better patient stratification and management of immune-related complications.