Immunohistochemistry for IgG subclasses on renal biopsy sections from patients with anti-GBM disease (×400). A. The weakly segmental deposition of IgG1 along GBM; B. The strong linear deposition of IgG2 along GBM; C. The strong linear deposition of IgG3 along GBM; D. The weakly linear deposition of IgG4 along GBM; E. Negative control. F. IgG3 partially deposits along TBM and inflammatory cell infiltration in the interstitium near TBM.