Amyloid A nephropathy is a possible complication of chronic inflammatory disease. Proteinuria and kidney failure are the main features of the disease. Tocilizumab (TCZ), an IL6-R antibody approved for rheumatoid arthritis, is a promising choice for histologically demonstrated nephropathy. We describe a case of kidney amyloid associated with Sweet syndrome treated with TCZ. The patient was affected by Sweet syndrome associated with proteinuria. Kidney biopsy showed amyloid deposits. During the follow-up, cutaneous and renal findings were refractory to many immunosuppressive regimen (cyclophosphamide, leflunomide, interferon and steroid). After few years, the patient developed rapidly progressive nephropathy associated with nephrotic syndrome (proteinuria up to 6 g/die). A second kidney biopsy was performed and it showed worsening of amyloid nephropathy. Thus, TCZ was administrated (8 mg/kg once a month) and it stabilized kidney function and induced partial remission of the nephrotic syndrome in the following 2 years.
Keywords: Amyloidosis A; Interleukin 6; Kidney biopsy; Nephrotic syndrome; Sweet syndrome; Tocilizumab.