[Ankylosing spondylitis with type AA amyloidosis. 6 cases].

The authors have studied 6 cases of systemic AA amyloidosis associated with ankylosing spondylitis. Renal failure occurred in all patients a mean of 19 years after the clinical onset of the rheumatic disease. Three patients progressed rapidly (between 3 months and 3 years) to end-stage renal failure. Such an outcome did not depend upon early onset of the renal impairment, degree of inflammation or treatment with colchicine. All patients were alive 2 to 10 years later, and this confirms a better prognosis than with AL amyloidosis. The utility of combining Wright's permaganate reaction with immunological methods to characterize the amyloid deposits was also confirmed. It is concluded that amyloidosis is a rare complication of ankylosing spondylitis and probably depends on a genetic predisposition. The possibility of amyloidosis should be kept in mind when proteinuria or renal failure appear in the course of ankylosing spondylitis.