Significance of M2 macrophages in glomerulonephritis with crescents.

OBJECTIVES: CD163 and CD206, markers of M2 macrophages, possesses anti-inflammatory properties. This study aims to investigate the clinicopathologic significance of M2 macrophages in patients of glomerulonephritis with crescents.

METHODS: Renal tissue samples from patients of glomerulonephritis with more than 30% cell or cell-fibrous crescents, including lupus nephritis (LN, n=14), anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV, n=14), IgA nephropathy(IgAN) (n=11), Henoch Schonlein purpura glomerulonephritis(HSPGN)(n=8)were included in this study. The expression of CD163, CD206 and CD68 in renal tissues was detected by immunohistochemistry or immunofluorescence.

RESULTS: (1) CD163 was mainly expressed in cell or cell-fibrous crescents, proliferative glomerular lesions and acute tubulointerstitial injury. There were numerous CD163-positive cells in LN and AAV in comparison with IgAN and HSPGN. (2) CD206-positive cells were mainly observed in acute tubulointerstitial injury, and proliferative glomerular lesions, especially in LN. Patients with LN had numerous CD206-positive cells in glomerular than other groups. The number of CD163-positive cells and CD206-positive cells in acute tubulointerstitial lesions of LN and AAV were more than IgAN and HSPGN. (3) Both the number of CD163-positive cells and CD206-positive cells in acute tubulointerstitial lesions negatively correlated to estimated glomerular filtration rate. (4) In LN, activity index (AI) positively correlated with the number of CD206-positive cells and CD163-positive cells. Dual staining showed that CD163-positive cells and CD206-positive cells also expressed CD68.

CONCLUSIONS: CD163-positive cells and CD206-positive cells, subpopulation of macrophages, which were involved in the pathogenesis of active crescentic glomerulonephritis, especially in LN and AAV.