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Plasma Cell Disorders
Plasma cell proliferative index predicts outcome in immunoglobulin light chain amyloidosis treated with stem cell transplantation
M. Hasib Sidiqi,1 Mohammed A. Aljama,1 Dragan Jevremovic,2
William G. Morice,2 Michael Timm,2 Francis K. Buadi,1 Rahma Warsame,1 Martha Q. Lacy,1 Angela Dispenzieri,1 David Dingli,1 Wilson I. Gonsalves,1 Shaji Kumar,1 Prashant Kapoor,1 Taxiarchis Kourelis,1 Nelson Leung,3 William J. Hogan1 and Morie Gertz1
1Division of Hematology, Department of Internal Medicine; 2Department of Laboratory Medicine and Pathology and 3Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
ABSTRACT
The plasma cell proliferative index provides an insight into plasma cell biology in plasma cell disorders and is an important prognostic marker in myeloma and smoldering myeloma. We analyzed the prognostic impact of the plasma cell proliferative index in 513 patients with systemic immunoglobulin light chain (AL) amyloidosis undergoing stem cell transplantation at the Mayo Clinic between 1st January 2003 and 31st August 2016. Two cohorts were identified according to Low or Elevated plasma cell proliferative index. Patients with an Elevated plas- ma cell proliferative index had more cardiac involvement (56% vs. 44%; P=0.01), less renal involvement (55% vs. 70%; P=0.001), and were more likely to have 10% or over bone marrow plasma cells (58% vs. 32%; P<0.0001) compared to those with a Low plasma cell proliferative index. Both progression-free survival and overall survival were lower in patients with an Elevated compared to Low plasma cell proliferative index: median progression-free survival 44 vs. 95 months (P<0.0001) and median overall survival 102 vs. 143 months (P=0.0003). All-cause mortal- ity at 100 days was higher in patients with an Elevated plasma cell pro- liferative index (elevated 10.3% vs. low 4.3%; P=0.008). On multivariate analysis Elevated plasma cell proliferative index was an independent prognostic factor for overall survival (Hazard Ratio 1.5, 95%CI: 1.1-2.1; P=0.021). The plasma cell proliferative index is an important prognostic tool in patients with AL amyloidosis undergoing stem cell transplant.
Introduction
Immunoglobulin light chain (AL) amyloidosis is a multi-system disorder charac- terized by a plasma cell or B-cell clone producing misfolded light chain proteins that deposit in tissues causing tissue damage and organ dysfunction.1 Patients with AL amyloidosis typically have a low tumor burden with the majority of patients having bone marrow plasma cells (BMPC) of less than 10% at diagnosis.2 The plas- ma cell proliferative index (PCPI) provides an insight into plasma cell biology in plasma cell disorders. It recognizes cells that are actively synthesizing DNA and gives an indication of the proliferative rate of the malignant plasma cells. The bone marrow PCPI has been identified as a strong prognostic marker in both active mul- tiple myeloma and smoldering myeloma.3-5 Data regarding its utility in AL amyloi- dosis are scant, with an early report suggesting patients with an elevated PCPI had a worse overall survival.6 However, this pre-dated the use of autologous stem cell transplant (ASCT) therapy for AL amyloidosis and the advent of novel therapies as therapeutic options for patients with AL amyloidosis.
Ferrata Storti Foundation
Haematologica 2018 Volume 103(7):1229-1234
Correspondence:
gertz.morie@mayo.edu
Received: January 30, 2018. Accepted: April 16, 2018. Pre-published: April 19, 2018.
doi:10.3324/haematol.2018.189985
Check the online version for the most updated information on this article, online supplements, and information on authorship & disclosures: www.haematologica.org/content/103/71229
©2018 Ferrata Storti Foundation
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