Figure 2: Characteristic histopathologic manifestations of diffuse proliferative lupus nephritis (Class IV-G/A by the International Society of Nephrology/Renal Pathology Society Classification). Glomeruli (left column) are diffusely hyper-cellular. Peripheral capillary loop lumens are compromised due to endocapillary proliferation (arrow). Large immune complex deposits are observed between layers of basement membrane material (silver stain, middle, arrow) giving rise to the characteristic “tram track” or double contour appearance of the capillary loops. Immunofluorescence studies demonstrate the characteristic “full house” pattern of positive staining for all immune reactants (IgG, IgA, IgM, C1q, C3, kappa and lambda light chain) in glomeruli.