[A case of gastrointestinal amyloidosis and hypoproteinemia improved by tocilizumab]

A woman in her 70s presented with dehydration and malnutrition due to watery diarrhea. She was examined and diagnosed with gastrointestinal amyloidosis accompanied by a protein-losing gastroenteropathy secondary to rheumatoid arthritis. She first underwent treatment with an anti-tumor necrosis factor alpha (TNF-α) antibody for secondary amyloidosis, but due to lack of adequate response, she was switched to an anti-interleukin (IL)-6 receptor antibody. Her clinical symptoms subsequently improved, and endoscopy revealed a marked decrease of amyloid protein deposits in the digestive tract. She was followed up for 3 years while continuing to receive the anti-IL-6 receptor antibody, with no recurrence. Although secondary amyloidosis is a fatal disease associated with chronic inflammatory diseases, clinical symptoms and prognosis have recently been improved by intervention with biological therapies. In particular, anti-IL-6 receptor antibodies have been reported to be superior to anti-TNF-α antibodies in the treatment of secondary amyloidosis and are expected to play a central role in treating secondary amyloidosis in the future.