Secondary MGUS after autologous hematopoietic progenitor cell transplantation in plasma cell myeloma: a matter of undetermined significance

Abstract

Plasma cell myeloma, characterized by clonally aberrant plasma cells that produce abnormal monoclonal Igs, is the most common indication for autologous hematopoietic progenitor cell transplantation (AHPCT) in North America. We observed appearance of new monoclonal gammopathies different from the original protein in the post-AHPCT setting and termed this condition 'secondary MGUS' (monoclonal gammopathy of undetermined significance). Hence, we performed a retrospective, single institution review of serum protein electrophoresis/immunofixation electrophoresis data in 92 AHPCT recipients from the period 2000 --2009. In all, 22 of 92 patients (24%) undergoing AHPCT met criteria for secondary MGUS. Contrary to previous studies, often referred to as 'abnormal protein banding,' we did not observe this condition as a favorable prognostic indicator in affected patients when compared with the control group (P ¼ 0.686). However, we did note that a subgroup of the study cohort who developed secondary MGUS after a prolonged latency (410 months) had an improved median OS compared with the remainder of the study cohort (75 months vs 41 months, P ¼ 0.005). As there have been significant advancements in understanding the pathobiology and clinical significance of MGUS, we believe that secondary MGUS merits dedication of resources for investigation to determine its true clinical relevance, prognostic value and pathophysiology.

Natural history and prognostic impact of oligoclonal humoral response in patients with multiple myeloma after autologous stem cell transplantation: long-term results from a single institution

“…What creates some confusion is that the same phenomenon has been described under different names: oligoclonal or abnormal protein bands (APB), 5,6 apparent isotype class switching, 6 atypical serum immunofixation patterns (ASIPs), 9 or even more recently as secondary monoclonal gammopathies of undetermined significance (MGUS). 12,13 There is also a wide range of incidence of the oligoclonal humoral response among different series, ranging from 7% to 73%. [5][6][7][8][9]12,13 In the present study it was 34%.…”

“…12,13 There is also a wide range of incidence of the oligoclonal humoral response among different series, ranging from 7% to 73%. [5][6][7][8][9]12,13 In the present study it was 34%. One reason for this discrepancy is the denominator of this percentage.…”

“…6,8,9,12 However, reports on this are controversial. 7,13,14 The aim of the present study was to investigate the incidence, biological characteristics and prognostic value of the oligoclonal bands in patients with MM who underwent ASCT at our institution in the last 18 years.…”

Challenges of measuring monoclonal proteins in serum

“…Such additional M-proteins commonly occur after autologous stem cell transplants with rates as high as 73% being reported [7][8][9][10]. The development of oligoclonal bands and/or a second M-protein following autologous stem cell transplantation in MM has been reported to be a favorable prognostic sign for most patients [11]. A recent report of allogeneic stem cell transplants found an overall median overall survival of 115.3 months in patients who developed a second M-protein vs. 31.0 months in individuals not developing such proteins [12].…”

Secondary monoclonal gammopathy of undetermined significance after allogeneic stem cell transplantation in multiple myeloma

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Several terms have been used to describe this phenomenon, including abnormal protein band, oligoclonal protein bands, transient mono-or oligoclonal gammopathy, apparent isotype switch, oligoclonal humoral response, atypical serum immunofixation pattern, and in myeloma patients, as we will use in this study, secondary monoclonal gammopathy of undetermined significance MGUS (sMGUS). 18 We consider post-transplant MGUS as a subtype of sMGUS.…”