Key Information
Amyloid A (AA) amyloidosis is a rare but serious complication of chronic inflammatory diseases like rheumatoid arthritis (RA), causing progressive organ dysfunction in the kidneys, neurons, or gastrointestinal tract. Tofacitinib is an oral, small-molecule Janus kinase (JAK) inhibitor, used for the treatment of moderate and severe RA (2, 3). Here, we report a case of a 76-year-old woman with RA who developed renal disorder due to AA amyloidosis and immunoglobulin A nephropathy (IgAN). Tofacitinib therapy improved her kidney involvement. This patient developed RA at the age of 60. Anti-tumour necrosis factor a (anti-TNF-a) agents, infliximab and golimumab, tocilizumab (TCZ), and abatacept (ABA) were administered, in that order, to treat her active RA.
In December 2014, the patient, who was receiving ABA, was admitted to our department due to worsening kidney function. Signs of declining kidney function included a serum creatinine (s-Cr) level of 1.18 mg/dL (normal, 0.41-0.75), a proteinuria of 2.60 g/day (normal, 0.15), and over 100 red blood cells (RBCs) per high power field (/HPF) (normal, 5) with granular and erythrocytic casts.