CCL21 and type 2 diabetes mellitus: Notably, DN patients with normal eGFR (eGFR  >  90 ml/min/1.73m2, n  =  6) showed remarkable elevation of urinary small EVs derived CCL21 mRNA compared with T2DM patients and healthy controls, indicating the earlier enhanced secretion of small EVs derived CCL21 mRNA than renal dysfunction (Fig. 2C).