[Immunoglobulin amyloidosis]

AL amyloidosis is a rare disease. Its diagnosis is based on histopathology. It is always secondary to light chain, only rarely heavy chain, synthesis of monoclonal immunoglobulin, associated or not with tumoural proliferation (myeloma, Waldenström's macroglobulinaemia). Its pathophysiology has not been elucidated, but recent progress provided by biochemical and molecular biology studies has provided some data on the structural anomalies responsible for the formation of amyloid fibrils. As in AA amyloidosis, the clinical picture is heterogeneous and mainly depends on the degree and extent of the lesions. Prognosis remains poor and is influenced by the degree of cardiac, gastrointestinal, neurologic and renal involvement, but also by the presence of absence of underlying hemopathy, and particularly of myeloma. Treatment is still essentially symptomatic, but recent progress points to hope of effective treatment modalities aiming at reducing or eliminating the clone producing the immunoglobulin, or inhibiting the formation or amyloid fibrils.