Second renal biopsy specimen. A second renal biopsy was performed at the end of the treatment (six months of antiviral therapy and 24 plasma exchange therapies). The immunofluorescence pattern shows intense massive staining of the deposits totally filling the capillary lumina. Faint and irregular parietal deposits also are present along peripheral glomerular loops. The components of mixed cryoglobulinemia immunoglobulin M, usually associated with C3, are the most frequently found immunoreactants.