Hindawi Publishing Corporation Bone Marrow Research Volume 2012, Article ID 238961, 5 pages doi:10.1155/2012/238961 Review Article Autologous Stem Cell Transplant for AL Amyloidosis Vivek Roy Division of Hematology/Oncology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA Correspondence should be addressed to Vivek Roy, roy.vivek@mayo.edu Received 16 December 2011; Accepted 12 March 2012 Academic Editor: Gordon Cook Copyright © 2012 Vivek Roy. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. AL amyloidosis is caused by clonal plasma cells that produce immunoglobulin light chains which misfold and get deposited as amyloid ﬁbrils. Therapy directed against the plasma cell clone leads to clinical beneﬁt. Melphalan and corticosteroids have been the mainstay of treatment for a number of years and the recent availability of other eﬀective agents (IMiDs and proteasome inhibitors) has increased treatment options. Autologous stem cell transplant (ASCT) has been used in the treatment of AL amyloidosis for many years. It is associated with high rates of hematologic response and improvement in organ function. However, transplant carries considerable risks. Careful patient selection is important to minimize transplant related morbidity and mortality and ensure optimal patient outcomes. As newer more aﬀective therapies become available the role and timing of ASCT in the overall treatment strategy of AL amyloidosis will need to be continually reassessed. 1. Introduction Amyloidosis is a disease of protein misfolding in which the involved protein acquires an abnormal beta-pleated sheet conﬁguration rather than the native alpha helical state [1]. The amyloid protein is insoluble, and its deposition in various tissues causes tissue damage and organ dysfunction. Amyloidosis can be of various types based on the precursor protein involved in amyloid formation. More than 20 diﬀer- ent human ﬁbrillar amyloid proteins have been described [2], and accurate identiﬁcation of the type is crucial to treatment planning. It is also important to distinguish localized from systemic amyloidosis since patients presenting with localized amyloidosis generally do not need systemic treatment. The most common type of systemic amyloidosis (primary amyloidosis or AL amyloidosis) is caused by production of immunoglobulin light chain or light chain fragment secondary to an underlying plasma cell dyscrasia. Other systemic amyloidoses (secondary amyloidoses) include AA amyloid (caused as a result of chronic inﬂammatory disease), ATTR caused by alteration in transthyretin (TTR) protein because of one of several mutations (familial amyloid) or misfolding of wild-type transthyretin protein (senile amyloidosis), and dialysis-related amyloidosis (deposition of beta 2 microglobulin). Primary amyloidosis is the only type of systemic amy- loidosis that responds to cytotoxic chemotherapy directed against the abnormal plasma cell clone, the source of amyloidogenic light chains. Other treatment strategies to prevent amyloid formation by altering the equilibrium between soluble precursor and insoluble ﬁbrils, destabilizing the amyloid ﬁbril protein, or antibodies directed against amyloid ﬁbrils are being investigated and show promise but are not available for clinical use [3–5]. This paper will focus on the role of autologous hemato- poietic stem cell transplantation for primary systemic amy- loidosis. 2. Treatment of Amyloidosis The ultimate goal of treatment of amyloidosis is to improve organ function, prolong survival, and enhance quality of life. The mainstay of treatment is cytotoxic chemotherapy directed against the plasma cells to decrease the level of circulating amyloid causing light chains. This, in turn, can be expected to slow down further amyloid deposition and improve the prospects for mobilization or dissolution of already deposited amyloid and reversal of organ damage. Treatment of AL amyloid has evolved over the years and has closely paralleled the developments in multiple myeloma