Background: CD163, a marker of M2 macrophages, express anti-inflammatory properties. This study aims to investigate the difference of CD163 positive macrophages expression between IgA nephropathy patients with and without crescents.
Methods: Renal tissues from IgAN patients (n = 24), including IgAN with crescents (n = 10), IgAN without crescents (n = 14), minimal change disease (MCD, as disease control, n = 8) and normal control kidneys (negative control, n = 3), were included in this study. Expressions of CD163 and CD68 in renal tissues were detected by immunohistochemistry or immunofluorescence.
Results: Compared with IgAN without crescent, IgAN patients with crescents have lower serum albumin and poor renal function. CD163 was mainly expressed in acute tubulointerstitial lesions. CD163 positive cells accumulate in areas around tubules with RBC casts. CD163 positive cells can also be seen in tubular lumen. CD163 positive cells can be seen in glomerular lesions, including endocapillary hypercellularity, cellular crescent and fibrous-cellular crescent. There were more CD163 positive cells in tubulointerstitial and glomerular lesions in IgAN patients with crescents. CD163 positive cells number in tubulointerstitial tissue was positive correlated with percentage of crescents, proteinuria, and negative correlated with serum albumin, eGFR. CD163 positive cells number in glomeruli was positive correlated with percentage of crescents, and was negative correlated with eGFR. Percentage of crescents was negative correlated with serum albumin, eGFR, and positive correlated with proteinuria. Dual staining showed that CD163 positive cells also expressed CD68.
Conclusions: CD163 positive macrophages were involved in active crescent disease, acute tubular injury and glomerular lesions of IgAN with crescents.
Keywords: CD163; IgA nephropathy; acute tubular injury; macrophage.