Identification of amyloid protein AA in formalin-fixed, paraffin-embedded tissue section by immunoperoxidase method

Abstract

New major proteins of amyloid fibril are recently determined successively and then new classification of amyloidosis of these major proteins have been undertaken. In this paper, we performed to identify amyloid proteins in formalin fixed, paraffin embedded tissue section by immunohistochemical methods. The usefulness of potassium permanganate reaction (Wright method), distinguishing indirectly amyloid protein AA from the other forms of amyloid proteins, was also done in this study. Indirect immunoperoxidase method anti-AA serum applied to 16 cases of secondary amyloidosis and 27 cases of amyloidosis with plasma cell dyscrasia (PCD) consisting of both primary amyloid 16 cases and myeloma-associated one 11 cases.
The most frequent underlying disease in secondary amyloidosis was found to be rheumatoid arthritis (69%). Regarding immunoperoxidase method, protein AA was positive in the secondary amyloidosis and negative in the amyloid with PCD. All cases of secondary amyloidosis were sensitive to potassium permanganate treatment. Therefore, we would like to emphasize that immunoperoxidase method using anti-AA serum is quite useful directly to identify protein AA without performing amino acid analysis of amyloid fibril protein.