Microdeposits of amyloid in sclerocalcific heart valves: a histochemical and immunofluorescence study.

Amyloid associated with seven sclerotic and two normal aortic and mitral valves was studied. The sclerotic valve amyloid contained microfibrils with typical random orientation and a fibril width of 9.5-12.5 nm. The amyloid deposits demonstrated permanganate-resistant Congophilia and contained the amino acid tryptophan. Immunofluorescence studies showed P-component in amyloid deposits of 6 of 7 valves, but none of the sclerotic valves contained amyloid fibril proteins of the AL (primary), AA (secondary), AEt (medullary thyroid carcinoma) or ASc1 (senile cardiac) types. Two non-sclerotic valves, removed from a patient with systemic amyloidosis, showed permanganate-sensitive Congophilic amyloid deposits which contained amyloid fibril protein AA.