Comparison of renal survival according to α-SMA expression in crescentic and mixed classes. (A) Tissue section showing absence of α-SMA staining in a normal glomerulus, except in the glomerular vascular pole and thickened Bowman’s capsule. (B) Tissue section showing marked α-SMA expression in a normal glomerulus, suggesting activation of a mesangial cell. (C) Higher α-SMA positivity tended to be associated with poor renal survival. Abbreviation: SMA, smooth muscle actin.