Clinicopathological significance of CD206-positive macrophages in patients with acute tubulointerstitial disease.

OBJECTIVE To investigate the clinicopathological significance of CD206-positive macrophage expression in patients with acute tubulointerstitial disease, including acute tubular necrosis (ATN) and acute interstitial nephritis (AIN). METHODS Renal tissue samples from patients with ATN (n=10), AIN (n=10), and minimal change disease (MCD, as disease control, n=8) as well as tissue from normal control kidneys (negative control, n=3) were included in this study. The expression of CD206 and CD68 in renal tissues was detected by immunohistochemistry or immunofluorescence. RESULTS CD206-positive cells accumulated in areas around damaged tubular cells and regenerating tubules. Compared with AIN patients, ATN patients had lower serum albumin, lower proteinuria, lower urinary osmolality and higher plasma hemoglobin, (P=0.002; P=0.01; P<0.001; P=0.002, respectively). CD206-positive cells could also be observed in the tubular basement membrane and tubule lumen. Some CD206-positive cells infiltrated into the tubular cells in patients with AIN. Compared to patients with ATN, patients with AIN had more CD206-positive cells (P=0.005). In the ATN patients, there were more CD206-positive cells in ischemic tissue. CD206-positive cells were negatively correlated with hemoglobin (r=-0.565, P=0.009) and positively correlated with serum albumin (r=0.496, P=0.026), urinary osmolality (r=0.567, P=0.009) and proteinuria (r=0.460, P=0.041). There was no correlation between CD206-positive cells and eGFR. CONCLUSION CD206-positive macrophages are involved in the pathogenesis of acute tubular necrosis and acute interstitial nephritis.