To characterize renal amyloidosis in patients with rheumatoid arthritis and stages of amyloid nephropathy.
The trial covered 30 patients (6 males and 24 females) with documented rheumatoid arthritis (RA) complicated with secondary AA-amyloidosis. Amyloidosis diagnosis was confirmed in all the patients morphologically, the samples were studied with the peroxidase immunohistochemical method using specific monoclonal antibodies to SAA. Clinical manifestations of RA were assessed by the disease activity, functional impairment of the joints, x-ray alterations, extraarticular signs of RA, etc. All the patients were examined clinically, total blood count and biochemical tests were made.
In 23 (77%) of 30 examinees with RA, proteinuria as the first clinical symptom of AA-amyloidosis emerged with the first 15 years of RA. RA of the second-third degree of activity were diagnosed in 25 (83%) patients, 21 (70%) patients had apparent destructive changes in the joints (x-ray stage III-IV). Severe functional insufficiency of the joints was observed in 25 (83%) patients, deformation of the joints - in 27 (90%) patients. Clinically, renal amyloidosis was characterized by change of stages - from moderate proteinuria to nephrotic syndrome and renal failure. Prognosis of amyloid nephropathy in RA depends on duration of the proteinuric stage: if this stage is short (3 years maximum), the prognosis is worse than in its long duration.
RA ranks first among causes of secondary AA-amyloidosis. Development of AA-amyloidosis in RA patients is most probable in the first 15 years of the course of the articular process. Amyloidosis is more frequent in patients with severe clinical manifestations of RA.