[Immunoglobulin light chain amyloidosis: recent molecular, clinical and therapeutic approach]

AL amyloidosis is a rare disorder characterised by tissue deposition of a fibrillary proteinaceous material, formed from monoclonal immunoglobulin light (or exceptionally heavy) chains. Although it may complicate multiple myeloma or B-cell lymphomas, AL amyloidosis is often associated with a low burden of clonal plasma cells ("primitive" AL amyloidosis). The mechanisms involved in the formation of AL amyloid deposits remain unclear, but are probably related to structural peculiarities of monoclonal immunoglobulin light chains. AL amyloidosis is usually a systemic disease, often revealed by renal involvement, the most common complication of the disease. The longterm prognosis of AL amyloidosis is poor, mainly related to amyloid restrictive cardiomyopathy leading to congestive heart failure. Oral melphalan and prednisone is considered the standard treatment for AL amyloidosis, but with limited increase in the median survival. High-dose intra-venous melphalan with autologous stem cell transplantation is an effective treatment, aimed at eliminating the clonaly expanded plasma cells, which has been shown to induce complete hematologic remissions and to prolong survival. However, the tolerability of such treatment is low, limiting its use to selected patients. The development of new drugs, able to interfere with amyloid fibril deposition, may provide a new therapeutic approach.