Amyloidosis in systemic lupus erythematosus.

Amyloidosis occurs in a significant proportion of patients with rheumatologic diseases. The fibrillar amyloid proteins in such patients are composed predominantly of amyloid A protein, which is characteristic of the amyloid deposits associated with chronic inflammatory diseases. Only four patients with amyloidosis associated with systemic lupus erythematosus (SLE) have been described previously; analyses of their fibrillar amyloid proteins were not reported. We present herein, a patient with SLE and amyloidosis. Histochemical staining of our patient's renal tissue with Congo red demonstrated that the amyloid deposits contained amyloid A protein, as defined by permanganate sensitivity. In addition, the patient's serum contained increased concentrations of serum amyloid A proteins. In review, each of the previously described patients with amyloidosis associated with SLE had renal amyloid deposits, with diagnosis in three during evaluation of proteinuria. Thus, although rare, amyloidosis should be considered in the differential diagnosis of proteinuria in patients with SLE.