Control of AA amyloidosis complicating Crohn's disease: a clinico-pathological study.

BACKGROUND: Immunosuppressive drugs may prevent or partially reverse progression of renal AA-amyloidosis, a rare complication of Crohn's disease, often fatal due to renal failure.

MATERIALS AND METHODS: The clinical, biological and pathological data of 16 patients treated since 1976 were reviewed. Serum amyloid A was determined in surviving patients.

RESULTS: The median age of the 16 patients (13 men) was 23·5 years (range 16-69). At Crohn's disease onset, Montreal phenotypes were similar to reported data. Out of 15 patients with renal insufficiency, 8 developed a nephrotic syndrome and 7 a low grade proteinuria. The single patient without renal insufficiency had nephrotic syndrome. A significant correlation (P < 0·05) between the extension of renal amyloid A and sclerosis was found in 12 patients. One patient had a 10 year remission of nephrotic syndrome with immunosuppressive drugs. In 6 patients treated with anti-TNF-α (Tumor-Necrosis-Factor-α) agents, anaphylactic reaction (1/6), death from septic shock (1/6), 5-year remission (1/6) or reduction of nephrotic syndrome (1/6) and stabilization of renal insufficiency (2/6) were observed. Surgery was performed in 10 patients. Kidney transplantation was performed in 5 of the 8 patients dialysed for end-stage renal failure. Among 6/16 patients (37%) still alive, 3 belong to the 5 transplanted patients (survival: 3-20 years) and 3 to the anti-TNF-α drugs treated patients; all but one exhibited a low serum amyloid A level.

CONCLUSIONS: Suppression of Crohn's disease inflammation potentially leads to the control of amyloid A production, assessed by a decrease of serum amyloid A. Kidney transplantation provides a long survival.