Intraglomerular deposition of fibrin/fibrinogen-related antigen in children with various renal diseases.

The localization of intraglomerular deposits of fibrin (Fb)/fibrinogen (Fg)-related antigen (FRA) in children with various glomerular diseases was determined by an immunohistopathologic method using an anti-Fg antibody capable of detecting FRA, an anti-D-dimer antibody capable of detecting crosslinked Fb (XLFb) and its derivatives (XLFbDP), and by a method using the effect of monochloroacetic acid (MCA) treatment on kidney sections. In proliferative glomerulonephritis (PGN), XLFbs were detected within the capillaries and extension beyond the mesangium was seen in severe PGN. The FRA within the mesangium of minimal or mild PGN was composed of the non-XLFb substance. The FRA within Bowman's space of most PGN had disappeared after MCA treatment, suggesting a non-XLFb substance. The presence of FRA within electron-dense deposits (EDD) suggested that FRA deposits are associated with immune-complex deposits in the glomeruli.