Effect of infliximab induction therapy on secondary systemic amyloidosis associated with Crohn's disease: case report and review of the literature.

Secondary systemic (AA) amyloidosis is reported as a serious complication that occurs in long-standing Crohn's disease (CD), with an incidence of 0.3-10.9%. Various therapeutic approaches using medicines and elemental diet have been recommended, but still there are no established standards of treatment for secondary systemic amyloidosis in CD. Only a few studies have shown the role of TNFα ihibitors in the treatment of AA amyloidosis over a long term period. We report the case of a 24-year-old male with CD complicated by AA amyloidosis with renal and gastrointestinal tract involvement treated with infliximab as induction therapy. Intestinal AA amyloidosis progression occurred at the same time with the development of CD as an early complication, whereas duration of CD prior to the diagnosis of renal AA amyloidosis was 6 years. Infliximab therapy (3 infusions) caused a significant decrease of serum amyloid A protein (by 97.9%), C-reactive protein (by 70%), improvement of disease activity index, and CD caused clinical symptoms. At the same time gradual progression of the renal damage (reduction of renal function) was not affected by the treatment. Direct efficacy of infliximab infusions on serum amyloid protein level may support the hypothesis of TNFα induced reduction on the progression of AA amyloidosis described in previous study reports. Targeted histological analysis of tissue biopsy is crucial to clarify the presence of AA amyloidosis in CD induced multiorgan damage cases.