Abstract BACKGROUND Analytically sensitive techniques for measuring minimal residual disease (MRD) in multiple myeloma (MM) currently require invasive and costly bone marrow aspiration. These methods include immunohistochemistry (IHC), flow cytometry, quantitative PCR, and next-generation sequencing. An ideal MM MRD test would be a serum-based test sensitive enough to detect low concentrations of Ig secreted from multifocal lesions. METHODS Patient serum with abundant M-protein before treatment was separated on a 1-dimensional SDS-PAGE gel, and the Ig light-chain (LC) band was excised, trypsin digested, and analyzed on a Q Exactive mass spectrometer by LC-MS/MS. We used the peptide's abundance and sequence to identify tryptic peptides that mapped to complementary determining regions of Ig LCs. The clonotypic target tryptic peptides were used to monitor MRD in subsequent serum samples with prior affinity enrichment. RESULTS Sixty-two patients were tested, 20 with no detectable disease by IHC and 42 with no detectable disease by 6-color flow cytometry. A target peptide that could be monitored was identified in 57 patients (91%). Of these 57, detectable disease by LC-MS/MS was found in 52 (91%). CONCLUSIONS The ability to use LC-MS/MS to measure disease in patients who are negative by bone marrow–based methodologies indicates that a serum-based approach has more analytical sensitivity and may be useful for measuring deeper responses to MM treatment. The method requires no bone marrow aspiration.
Improved Outcomes After Autologous Hematopoietic Cell Transplantation for Light Chain Amyloidosis: A Center for International Blood and Marrow Transplant Research Study
Purpose Autologous hematopoietic cell transplantation, or autotransplantation, is effective in light-chain amyloidosis (AL), but it is associated with a high risk of early mortality (EM). In a multicenter randomized comparison against oral chemotherapy, autotransplantation was associated with 24% EM. We analyzed trends in outcomes after autologous hematopoietic cell transplantation for AL in North America. Patients and Methods Between 1995 and 2012, 1,536 patients with AL who underwent autotransplantation at 134 centers were identified in the Center for International Blood and Marrow Transplant Research database. EM and overall survival (OS) were analyzed in three time cohorts: 1995 to 2000 (n = 140), 2001 to 2006 (n = 596), and 2007 to 2012 (n = 800). Hematologic and renal responses and factors associated with EM, relapse and/or progression, progression-free survival and OS were analyzed in more recent subgroups from 2001 to 2006 (n = 197) and from 2007 to 2012 (n = 157). Results Mortality at 30 and 100 days progressively declined over successive time periods from 11% and 20%, respectively, in 1995 to 2000 to 5% and 11%, respectively, in 2001 to 2006, and to 3% and 5%, respectively, in 2007 to 2012. Correspondingly, 5-year OS improved from 55% in 1995 to 2000 to 61% in 2001 to 2006 and to 77% in 2007 to 2012. Hematologic response to transplantation improved in the latest cohort. Renal response rate was 32%. Centers performing more than four AL transplantations per year had superior survival outcomes. In the multivariable analysis, cardiac AL was associated with high EM and inferior progression-free survival and OS. Autotransplantation in 2007 to 2012 and use of higher dosages of melphalan were associated with a lowered relapse risk. A Karnofsky score less than 80 and creatinine levels 2 mg/m2 or greater were associated with worsened OS. Conclusion Post-transplantation survival in AL has improved, with a dramatic reduction in early post-transplantation mortality and excellent 5-year survival. The risk-benefit ratio for autotransplantation has changed, and randomized comparison with nontransplantation approaches is again warranted.
Blaming the Right Fluorescent in Situ Hybridization
Aims Prognostication and treatment selection for cardiac amyloidosis requires accurate amyloid typing. The aim of this study was to investigate the utility of histomorphology for predicting type. Methods and results Autopsy cases with cardiac amyloidosis (1998–2010) were typed by the use of mass spectrometry‐based proteomics. Deposition patterns were correlated with amyloid type. Among 108 decedents (mean age 75 years; 69% men), 107 had a single type, including transthyretin (ATTR) (60 cases), amyloid light chain (AL) (32 λ; 12 κ), amyloid A (AA) (two), and apolipoprotein AIV (AApoAIV) (one). Interstitial deposition was more extensive in AL amyloidosis cases than in ATTR cases [odds ratio (OR) 6.8, P = 0.0004]. Histomorphological patterns of interstitial deposition were mixed in 61% of AL amyloidosis cases and in 61% of ATTR cases, but diffuse pericellular deposits favoured AL amyloidosis (OR 10.7, P = 0.0001), nodular deposits favoured ATTR (OR 3.1, P = 0.0229), and discrete pericellular deposits tended to partially favour ATTR (OR 1.7, P = 0.1970). Arterial and venous deposits each favoured AL amyloidosis (OR ranging from 9.3 to 192.0, P‐value ranging from 0.0022 to <0.0001), and were severe in AL amyloidosis. Endocardial deposits favoured AL amyloidosis (OR 46.3, P < 0.0001) and were also more severe in AL amyloidosis. Conclusions The extent and distribution of cardiac amyloidosis strongly correlate with amyloid type, suggesting fundamental differences in the pathobiology of deposition. The tendency for mixed patterns to occur limits the practicality and accuracy of using histopathology for amyloid typing.
Thrombocytosis distinguishes POEMS syndrome from chronic inflammatory demyelinating polyneuropathy
ABSTRACTIntroductionPOEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) syndrome may be mistaken for chronic inflammatory demyelinating polyneuropathy (CIDP). Differentiating the 2 entities is crucial, as there are major treatment implications.MethodsWe compared platelet counts in 136 POEMS patients and 67 CIDP controls.ResultsOf the patients with POEMS, 53.7% had thrombocytosis, compared with 1.5% of those with CIDP (P < 0.0001). The median platelet count in patients with POEMS was 467,000/μl compared with 275,000/μl in those with CIDP (P < 0.0001).ConclusionsThrombocytosis is a helpful indicator to prompt clinicians to consider the diagnosis of POEMS syndrome in patients who are thought to have CIDP, and is an important reminder of the increased risk of thrombotic events in POEMS syndrome. Muscle Nerve 52: 658–659, 2015
Predictors of early response to initial therapy in patients with newly diagnosed symptomatic multiple myeloma