Complete Remission of Nephrotic Syndrome Without Resolution of Amyloid Deposit After Anti-Tumor Necrosis Factor α Therapy in a Patient With Ankylosing Spondylitis.

In secondary amyloid A amyloidosis resulting from rheumatologic diseases, tumor necrosis factor α blockers have been reported to be effective in the treatment of both arthritis and amyloidosis. However, there have been few reports concerning the alterations of renal tissue histology before and after long-term tumor necrosis factor α blockers therapy in secondary renal amyloidosis. We report the histological change after tumor necrosis factor α blocker therapy in patient with amyloid A amyloidosis and nephrotic syndrome secondary to underlying ankylosing spondylitis. The patient achieved complete remission of nephrotic syndrome after 17 months of etanercept treatment. We performed the second kidney biopsy after 40 months, and there was little change in the degree of amyloid deposition in the mesangial area and capillary loops compared with the first biopsy. The interstitial inflammation and foot process effacement, however, were fully recovered.