Current diagnosis and treatment of AL amyloidosis in Japan: a nationwide epidemiological survey

Abstract

Immunoglobulin light chain (AL) amyloidosis is a plasma cell disorder characterized by the deposition of insoluble fibrillary protein derived from misfolded immunoglobulin light chains in several organs, resulting in organ failure and death. However, little information is available about the prevalence and demographic characteristics of AL amyloidosis and the treatment strategy for the condition in Japan. The Amyloidosis Research Committee, Intractable Disease Division, of the Japanese Ministry of Health and Welfare, retrospectively conducted a nationwide survey of Japanese patients with AL amyloidosis who visited affiliated hospitals from January 2012 to December 2014. The number of patients with AL amyloidosis who visited the hospitals during the study period was 3170, and its incidence was estimated to be 4.2 per million person-years in Japan. For the second questionnaire, we collected 741 patients with AL amyloidosis (median age, 65 years; 59% males). The most commonly affected organ was the kidneys, followed by the heart, gastrointestinal tract, and autonomic nervous system. Only 53% of patients were accurately diagnosed by immunohistochemistry using an anti-light chain antibody. Cardiac amyloidosis was diagnosed at later stages. The leading non-transplant regimen was the bortezomib-combined regimen.