Novel histochemical approaches to the prealbumin-related senile and familial forms of systemic amyloidosis

The immunoperoxidase method, the autoclave method, and a newly developed alkaline-guanidine method were used to distinguished senile (SAA) and familial types (FAP) of prealbulin-related amyloidosis in formalin-fixed, paraffin-embedded tissue sections. Because all the amyloid deposits of SSA and FAP reacted positively with the anti-prealbumin antiserum, a classification of the amyloid fibril proteins of FAP and SSA immunohistochemistry, using polyclonal anti-prealbumin antisera, was not feasible. Both the senile and familial forms of amyloidosis showed unchanged Congophilia after prolonged autoclaving. In the alkaline-guanidine method, FAP amyloids were resistant to incubation for 2 hours. On the other hand, amyloid deposits of SSA lost the Congophilia and green birefringence with 2 hours' alkaline-guanidine treatment. Therefore, the autoclave method combined with the alkaline-guanidine method will considerably facilitate differentiation of SSA and FAP, without specific antisera.