Immunohistochemistry on renal biopsies. Single labeling for CD68 (A,C,E) and for CX₃CR1 (B,D,F). Immunohistochemistry was performed on kidney sections from HC (A, B), children with postdiarrheal HUS (C, D), and children with atypical HUS due to factor H deficiency (E, F). The figure shows (arrows) CD68⁺ and CX₃CR1⁺ cells within glomeruli of children with either form of HUS. Original magnification, × 400 (A-C, E); × 200 (D, F); and × 1000, panel E inset (which shows magnified CD68⁺ macrophages). Images were acquired using a Leica microscope equipped with a 40 ×/0.65 NA (A-C, E) or 20 ×/0.50 NA (D, F) objective, or a 100 ×/1.30 NA oil-immersion objective lens (E inset). The camera and software (IM 50, V4.0 R11) were also from Leica (Heidelberg, Germany).