Fig. 1

Histological examination of renal biopsy specimens before (a, c, e, g, i, and k) and after (b, d, f, h, j, and l) bortezomib/dexamethasone therapy. In the first biopsy, glomeruli show lobular configuration with nodular formation and endocapillary hypercellularity (a, c, e, and g). The second biopsy reveals moderate mesangial cell proliferation and matrix increase without nodules (b, d, f, and h). A significant reduction in deposits is seen in all samples after treatment. Staining for C3 (j) is decreased after treatment. a and b. Masson trichrome staining at low magnification (×200). The scale bar represents 100 μm. c and d. Periodic acid-Schiff staining of glomeruli (×400). The scale bar represents 50 μm. e and f. Periodic acid–methenamine silver staining of glomeruli (×400). The scale bar represents 50 μm. g and h. Masson trichrome staining of glomeruli (×400). The scale bar represents 50 μm. i and j. Immunofluorescent images of frozen sections stained for immunoglobulins and complement. The staining for immunoglobulin was negative. The staining for C3 was strongly positive before BD therapy but negative after treatment. k and l. Electron microscopic findings. Before BD therapy (k), band-like areas of dense deposits along the basement membrane are clearly noticeable. Large deposits are also observed in the mesangial matrix. Deposits are less prominent after treatment (l). The scale bars at the bottom of the images represent respective numerical values