First Nationwide Survey of 199 Patients with Amyloid A Amyloidosis in Japan

Objective To clarify the underlying diseases, clinical manifestations, and treatment strategies for Amyloid A (AA) amyloidosis (AAA) in Japanese patients. Methods We conducted a survey on Japanese patients with AAA treated between January 1, 2012, and December 31, 2014. Results A total of 199 patients with AAA were included in the present study. The underlying diseases of AAA were rheumatoid arthritis (60.3%), uncharacterized inflammatory disorders (11.1%), neoplasms (7.0%), other rheumatic diseases (6.5%), inflammatory bowel diseases (4.5%), chronic infection (4.5%), Castleman's disease (4.0%), and autoinflammatory diseases (2.0%). The clinical manifestations at the diagnosis of AAA were moderate to severe renal dysfunction (46.2%), moderate to severe proteinuria (30.7%), intractable diarrhea (32.2%), melena (4.5%), paralytic ileus (3.5%), heart failure (11.6%), cardiac conduction disturbances (10.1%), arrhythmia (5.5%), and hypothyroidism (11.6%). Diagnostic biopsies were performed most frequently in the gastrointestinal tract (66.3%), followed by the kidneys (22.1%), heart (5.5%), abdominal fat (4.0%), and others (3.0%). Biologics were used to treat 97 patients with AAA (48.7%). Tocilizumab (TCZ) was administered to 66 patients, with 95.5% showing good responses. Anti-TNF agents were administered to 27 patients, with 74.1% showing good responses. The treatment effects of TCZ were significantly superior to those of anti-TNF agents (p