Immunofluorescent staining for β2 laminin. Shown is the patient's biopsy specimen (left) with absence of linear immunofluorescent staining for β2 laminin and a normal adult control glomerulus (right, magnified) with linear fluorescent staining for β2 laminin of the GBM (open arrows). Cell nuclei (closed arrows) are visible more weakly in both pictures because of counterstaining.