[AA Amyloidosis: recent knowledges on pathophysiology].

Abstract

PURPOSE: Amyloidosis is a rare disease associated with an underestimated frequency because of the need of a pathological diagnosis identifying extracellular deposits with affinity for Congo red. There are moreover 20 proteins that can form extracellular fibril deposits. Some amyloidosis forms are more common than others, especially AA amyloidosis and AL amyloidosis. Among genetic amyloidosis, the transthyretin related amyloidosis is the most prevalent. The amyloid frequency could also be increased if amyloidosis related to Alzheimer's disease or prion's disease is included. In the absence of specific treatment for amyloidosis, researches are focused on amyloidosis pathophysiology especially, on AA amyloid pathophysiology. CURRENT KNOWLEDGE AND KEY POINTS: Amyloid is not only composed of fibrils but also of proteoglycanes, P component and amyloid-enhancing factor. A new research aim is focused on the cells involved in amyloid formation and on the relationship between amyloid, proteoglycanes and P component. FUTURE PROSPECTS AND PROJECTS: It was demonstrated that, in the absence of macrophages, an extracellular amyloid formation was possible with amyloid-enhancing factor as starting point. Some inhibitors of intra or extracellular amyloid formation are still to be discovered. Anti-P component has been recently developed; it was successful in the treatment of murin AA amyloidosis and gave some hope concerning the treatment of human amyloidosis.