Background/Purpose: The most frequent underlying diseases responsible for AA amyloidosis worldwide are rheumatoid arthritis, juvenile idiopathic arthritis and ankylosing spondylitis, while familial Mediterranean fever (FMF) is responsible for almost 60% of the cases in Turkey and in countries where the FMF is prevalent. Tocilizumab (TCZ), an IL-6 antagonist, seems to be a promising agent in AA amyloidosis associated with rheumatic disorders, while there is no data regarding its use in amyloidosis due to FMF. We herein describe the short-term results of TCZ treatment in 7 patients with amyloidosis secondary to FMF. 

Methods: We described a series of adult FMF patients complicated with amyloidosis and treated with TCZ (8 mg/kg once monthly) in one reference center. Diagnosis of AA amyloidosis was confirmed in the renal biopsy specimens in all patients with Congo red and immunohistochemical staining.

Results: The longest duration on the treatment with TCZ was 16 months in one patient, while 3 months in 3 patients with the shortest follow-up. At the beginning of TCZ treatment all patients had proteinuria, which was severe (>10 g/day) in 2. Following treatment with TCZ, proteinuria was normalized in one (Case with the longest duration of treatment), and considerably decreased in 5. The ameliorative effect of TCZ on proteinuria seemed to begin as early as 3 months. The renal function was normal in all but 3 patients at the beginning, and remained stable throughout the follow-up (Table 1).

Conclusion:

To our knowledge this is the first report showing the efficacy of TCZ on renal amyloidosis secondary to FMF. While previous reports confirm the efficacy of TCZ in amyloidosis secondary to other rheumatic diseases, our findings suggest that this effect can be extended to other diseases.

 Table 1. Demographic, clinical and laboratory features of study patients