Cytostatic therapy for AA amyloidosis complicating psoriatic spondyloarthropathy

Abstract

Psoriatic spondyloarthropathy (PSA) can occasionally be complicated by AA amyloid, and renal amyloidosis should be suspected in patients with PSA who have unexplained proteinuria. The diagnosis of amyloidosis can be made either histologically or by radiolabelled serum amyloid P component (SAP) scintigraphy. Prognosis is determined by the extent of organ involvement and associated impairment of function, and by the degree of response of the underlying disease to anti-inflammatory therapy. A review of the literature identified less than a dozen cases of AA amyloidosis complicating PSA, and the outcome in most cases was poor. We report here the favourable clinical course of a middle-aged Caucasian male patient with severe PSA who developed renal AA amyloidosis, in whom treatment with oral chlorambucil led to stabilization of the amyloid deposits and resolution of the associated nephrotic syndrome. We review the diagnosis and treatment of AA amyloidosis, including the management of patients with underlying inflammatory spondyloarthropathies, and propose the possible role of a therapeutic trial of anti-tumour necrosis factor alpha in patients with amyloid complicating inflammatory rheumatic diseases.