CD4 and idiopathic pulmonary fibrosis: In contrast, our study found that high expression of CXCL14 is significantly associated with the infiltration of CD4 + T cells and regulatory Treg (SHAP value = 0.43, p < 0.001), which resonates with the “chemokine-immune cell axis” theory proposed (33), but for the first time establishes a direct link between CXCL14 and adaptive immunity in IPF.