Urinary epidermal growth factor predicts renal prognosis in antineutrophil cytoplasmic antibody-associated vasculitis

Introduction The current study aimed to investigate the association between urinary epidermal growth factor (uEGF) and renal disease severity and outcomes in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Methods Intrarenal EGF mRNA expression was extracted from transcriptomic data of microdissected tubulointerstitial compartments of kidney biopsies of patients with AAV. uEGF was measured in 173 patients with AAV in active stage and 143 in remission, and normalised to urine creatinine excretion (uEGF/Cr). The association between uEGF/Cr (or EGF mRNA) and clinical–pathological parameters was tested using linear regression analysis. The ability of uEGF/Cr to predict renal outcomes was analysed using Cox’s regression analysis. Results In patients with AAV, intrarenal EGF mRNA expression was significantly associated with estimated glomerular filtration rate (eGFR)(log 2 ) at time of biopsy (β=0.63, p 2 ) at time of sampling in both active and remission stage (β=0.60, p Conclusion Lower uEGF/Cr levels are associated with more severe renal disease, renal resistance to treatment and higher risk of progression to composite outcome in patients with AAV.