Reversal of nephrotic syndrome due to reactive amyloidosis (AA-type) after excision of localized Castleman's disease.

The patient (TAL), a chronic asymptomatic HBV carrier with HBsAg-anti-HBsAg circulating immune complexes, was admitted to our hospital because of a nephrotic syndrome due to renal amyloidosis. There was no family history of hereditary amyloidosis. Recurrent arthralgias, asthenia, and weight loss were the prominent clinical features. Laboratory test results showing that severe chronic inflammatory activity had been present for 6 years. Interleukin-6 (IL-6) serum concentration was 10 times normal and C-reactive protein was 1.9 mg/ml. A complex immunological picture was also present (immune complex formation, exuberant B-cell reactivity, and decrease in the number of CD4 T cells). A localized form of Castleman's disease (CD) (plasma-cell type) was diagnosed by surgical excision of a giant axillary lymph node. AA amyloid was present in the blood vessels. Within 60 days after excision of the mass, the systemic symptoms subsided, laboratory signs of inflammatory activity disappeared and IL-6 serum concentration returned to normal, thus establishing a causal relationship between the localized Castleman's disease, elevated IL-6 concentration and the chronic inflammation responsible for AA amyloidosis. At 10 months of follow-up, the nephrotic syndrome has reversed, kidney function has slowly ameliorated, and the patient has gained 12 kg. Abdominal fat aspirates drawn to search for amyloid, positive before surgery, were subsequently negative. The latter finding, and the remission of the nephrotic syndrome, provided strong evidence for regression of the amyloid deposits. However, the HBsAg-anti-HBsAg immune complexes and depression of T-helper cell activity persist. This immunological derangement is therefore not a consequence of CD. Chronic stimulation of the immune system due to the patient's inability to eliminate HBV, in the contest of perturbed immunity, may have favored the genesis of the lymphadenopathy.