An investigation of the protein components of amyloid using immunoperoxidase and permanganate methods on tissue sections.

Amyloid deposits in tissue from 8 patients with generalized primary amyloidosis, 11 patients with generalized secondary amyloidosis, 11 nasopharyngeal carcinomas, 11 basal cell carcinomas, 4 islet cell tumours, 4 medullary carcinomas of the thyroid and 9 cases of lichen amyloidosis were studied using the indirect immunoperoxidase and peroxidase-antiperoxidase methods with specific antisera against Amyloid A (AA) protein and human immunoglobulin lambda and kappa light chains. The permanganate method of Wright was also applied to tissue sections. Positive staining for AA protein was observed only in secondary amyloidosis. There was excellent correlation between AA positivity and permanganate sensitivity. Positivity for immunoglobulin light chains was not observed in secondary amyloidosis but was noted in 5 (63%) cases of primary amyloidosis and 18-27% of intratumour amyloidosis. Lichen amyloidosis did not stain for AA protein or light chains. It is shown that assessment of the permanganate reaction and AA positivity of amyloid deposits can reliably differentiate secondary from primary amyloidosis and may contribute significantly to selection of patients for appropriate therapy.