Fig. 2

Parvovirus Capsid Protein Staining. Immunohistochemistry results on patient’s initial renal biopsy (day 3 of presentation) using primary antibody to human parvovirus B19 capsid proteins VP1 and VP2 and anti-mouse-HRP secondary antibody. Strong positive staining indicated by arrows is noted in the cytoplasm of hypertrophic podocytes (a original magnification x100), parietal epithelial cells (b original magnification x 100), and tubular epithelium (c original magnification x 40). Negative staining in hyperplastic podocytes from a different case of collapsing glomerulopathy associated with anabolic steroid use, stained as a negative control (d original magnification x 100). HIVAN and lupus associated collapsing podocytopathy cases also stained negatively for parvovirus B19 (data not shown). Non-specific mouse IgG with same anti-mouse-HRP was used on additional section from patient’s same biopsy as a negative control and was negative throughout the biopsy specimen (e original magnification x100, f original magnification 40x)