Study of light-, electron- and immunofluorescence microscopy of urinary sediment in amyloidosis.

Urinary sediment of 11 patients with amyloidosis and 12 without (with proteinuria or in good health) have been sutdied by different morphological techniques. By light microscopy, an amyloid-related substance was occasionally demonstrated both in patients with amyloidosis and in control subjects. Immunofluorescence (IF) showed substance A (amyloid component) to be present in some cases of amyloidosis and in controls. On electron-microscopy, fibrils with characteristic appearance of amyloid substance were found in some cases of amyloidosis (4 out of 11), but were also found in controls. It therefore seems difficult to establish the diagnosis of amyloidosis by microscopic studies of the urinary sediment.