Integrated bioinformatics analysis and clinical validation identifies TNFSF14 and CD40 as novel biomarkers for chronic kidney disease progression and tubulointerstitial injury

BACKGROUND: Chronic kidney disease (CKD) is a global public health burden characterized by irreversible renal function loss and progressive fibrosis. Non-invasive biomarkers reflecting intra-renal inflammation and early tubulointerstitial injury remain an unmet clinical need. We combined bioinformatics analysis with clinical validation to characterize two immune-related genes, TNFSF14 and CD40, in CKD progression. METHODS: Two independent CKD transcriptomic datasets (GSE66494, n = 61; GSE97709, n = 48) were retrieved from the GEO database. Differentially Expressed Genes (DEGs) were screened with FDR adjustment. Clinical validation was performed in 140 CKD patients (KDIGO Stages I-V) and 60 healthy controls. TNFSF14 and CD40 levels were quantified in serum/urine via ELISA, with intra-renal expression assessed via immunofluorescence in 80 biopsy specimens. Multivariable regression was used to evaluate independent predictive value. RESULTS: TNFSF14 and CD40 were identified as core hub genes enriched in the TNF signaling pathway. Both markers were significantly elevated in serum/urine of CKD patients (Adjusted P < 0.05), with upregulation localized to renal tubular epithelial cells. Urinary levels increased in a CKD stage-dependent manner, positively correlating with serum creatinine/BUN and inversely with eGFR. Urinary TNFSF14 and CD40 were independent predictors of advanced CKD, with a combined diagnostic model achieving an AUC of 0.892 (95% CI: 0.851-0.933). CONCLUSIONS: TNFSF14 and CD40 are robust molecular signatures of tubulointerstitial injury, and their urinary levels serve as non-invasive biomarkers for CKD detection and risk stratification.