(A-B) Kidney needle biopsy, buffered 10 % formal paraffin process. (A) Fuchsinophilic “smudgy” appearance deposits on tubular basement membrane (Masson Trichrome stain; original magnification, ×40). (B) Electron microscopy shows mild tubular basement membrane deposits. (C-F) Kidney biopsy fixed in Michel’s solution. (C-D) Diffuse IgG deposits along Bowman capsule, tubular basement membrane, and segmental granular capillary wall (arrow). (E) Complement fraction C3 with weak stain along tubular membrane. (F) Indirect immunofluorescence microscopy from a separate patient’s normal kidney tissue. For the test, it was preincubated with serum from the studied patient and posteriorly incubated with IgG-FITC (fluorescein isothiocyanate). The staining along the brush border proves the presence of anti-brush border antibody in the serum.