TGFB1 and chronic kidney disease: In a case-control study that compared 10 healthy subjects to 11 AS pediatric patients with normal values of albuminuria and proteinuria without CKD, AS patients presented higher levels of serum and urinary HMGB1 and TGF-β1, suggesting that subclinical pro-fibrotic and inflammatory processes are triggered before the appearance of proteinuria [33].