Fig. 1

a Light microscopy of the kidneys showing mesangial cells and matrix proliferation in the glomeruli (H&E stain, 400 ×). b Light microscopy showing the disappearance of brush margins and the dilation of lumen in partial renal tubules. Renal interstitial edema and inflammatory cell infiltration were also observed (H&E, 400 ×). c Immunofluorescence staining of the kidneys showing bright granular deposition of IgA (400 ×). d Silver staining of the kidneys showing shedding of tubule bristles and enhanced interstitial edema (400 ×)