Soluble suppression of tumorigenicity 2 (sST2), but not galactin‐3, adds to prognostication in patients with systemic AL amyloidosis independent of NT‐proBNP and troponin T
AbstractBACKGROUNDThe use of electrophoresis to monitor monoclonal immunoglobulins migrating in the β fraction may be difficult because of their comigration with transferrin and complement proteins.METHODSImmunoassays specific for IgGκ, IgGλ, IgAκ, IgAλ, IgMκ, and IgMλ heavy/light chain (HLC) were validated for use in the clinical laboratory. We assessed sample stability, inter- and intraassay variability, linearity, accuracy, and reference intervals for all 6 assays. We tested accuracy by verifying that the sum of the concentrations for the HLC-pairs accounted for the total immunoglobulins in each of 129 healthy sera, and that the HLC-pair ratios (rHLCs) were outside the reference interval in 97% of 518 diagnostic multiple myeloma (MM) samples.RESULTSWe assessed diagnostic samples and posttreatment sera in 32 IgG and 30 IgA patients for HLC concentrations, rHLC, and total immunoglobulins and compared these nephelometry results with serum protein electrophoresis (SPEP) and immunofixation electrophoresis (IFE). In sample sets from patients with IgG MM, the sensitivity of SPEP was almost the same as for rHLC, and no additional advantage was conferred by running HLC assays. In pre- and posttreatment samples from patients with IgA MM, the SPEP, rHLC, and IFE identified clonality in 28%, 56%, and 61%, respectively. In addition, when M-spikes were quantifiable, the concentration of the involved HLC was linearly related to that of the SPEP M-spike, with a slope near 1.CONCLUSIONSThe use of IgA HLC assays for monitoring β-migrating IgA monoclonal proteins can substitute for the combination of SPEP, IFE, and total IgA quantification.
Kinetics of organ response and survival following normalization of the serum free light chain ratio in AL amyloidosis
Abstract Objective To determine the prognosis of patients with non‐secretory myeloma. Methods We studied 124 patients diagnosed with multiple myeloma who had no monoclonal protein detected on serum and urine immunofixation at diagnosis and on all subsequent follow‐up testing (non‐secretory myeloma). The overall survival ( OS ) of patients with non‐secretory myeloma was compared with 6953 patients with typical myeloma seen during the same time period in whom a monoclonal protein was detected at the time of diagnosis. Results One hundred and twenty‐four patients met criteria for non‐secretory multiple myeloma. The median follow‐up was 102 months (range, 1–204 months). The median progression‐free survival with initial therapy was 28.6 months, and the median OS was 49.3 months. There was a significant improvement in OS since 2001; median survival 43.8 months (prior to 2001) vs. 99.2 months (2001–2012), P < 0.001. OS was superior in patients with a normal baseline FLC ratio ( n = 10) compared to patients with an abnormal ratio ( n = 19), medians not reached in both groups. Prior to 2001, OS was similar in non‐secretory myeloma ( n = 86) and secretory myeloma ( n = 4011), median 3.6 vs. 3.5 yr, respectively, P = 0.63. However, among patients diagnosed between 2001 and 2012, OS was superior in non‐secretory myeloma ( n = 36) compared to secretory myeloma ( n = 2942), median 8.3 vs. 5.4 yr, respectively, P = 0.03. Conclusions Non‐secretory myeloma is an uncommon subtype of multiple myeloma. In the last decade, there has been an improvement in the survival of non‐secretory myeloma and appears superior to secretory myeloma.
AbstractBackgroundData regarding multiple myeloma (MM) that develops after kidney transplantation (KTx) are scarce. The outcomes of these patients were evaluated in a retrospective study.MethodsPatients with newly diagnosed MM after KTx were selected. Patients with a diagnosis of MM or those who received treatment for monoclonal gammopathy of renal significance (MGRS) prior to KTx were excluded.ResultsBetween 2001 and 2012, seven patients developed MM after KTx. Reasons for ESRD included ADPKD (1), C1q nephropathy (1), MPGN (2), hypertensive nephrosclerosis (2), and chronic interstitial nephritis (1). Before KTx, only four patients had monoclonal protein studies, four had monoclonal gammopathy of undermined significance (MGUS), and two of them had clonal plasma cells in bone marrow. Median follow‐up after MM was 70 months (range 19–100). Median survival was 80 months. Median time from KTx to MM was 72 months (range 3–204 months). The Kidney allograft failed in four patients due to monoclonal protein‐related renal disease. Five patients received chemotherapy: bortezomib (n = 3), lenalidomide (n = 2), melphalan (n = 1), thalidomide (n = 1), pomalidomide (n = 1), and high‐dose dexamethasone (n = 1). Three patients received ASCT.ConclusionMultiple myeloma after KTx is rare. Most patients who develop MM had MGUS prior to KTx. There is significant renal involvement in these patients. Survival is not worse when compared to MM without KTx. Further work is needed to identify the best treatment options for these patients.
Inherited forms of amyloidosis are rare; of these, transthyretin‐related (ATTR) is the most common, but non‐ATTR has been described as well. We studied a large case series of ATTR and a small series of non‐ATTR to better determine the mutation frequencies and geographic distributions of these inherited forms of amyloidosis in the United States. We performed a retrospective cross‐sectional study of 284 ATTR and non‐ATTR patients seen at Mayo Clinic in Rochester, Minnesota, from 1 January 1970 through 29 January 2013. Mutations were identified by DNA sequencing, restriction fragment length polymorphism, or mass spectroscopy. The genetic testing method was unknown for several patients, but a small proportion were identified by family history or by classical clinical presentation associated with a specific mutation. The most common ATTR mutations were Thr60Ala (24%), Val30Met (15%), Val122Ile (10%), and Ser77Tyr (5%). Non‐ATTR mutations included gelsolin (n = 3), apolipoprotein A‐I (n = 6), apolipoprotein A‐II (n = 1), fibrinogen A‐α (n = 9), and lysozyme (n = 1). Although rare, ATTR and, to a lesser extent, non‐ATTR are prevalent in the United States and should be considered for patients presenting in the appropriate clinical context.
Clinical characteristics and healthcare utilization of patients with multicentric Castleman disease
SummaryMulticentric Castleman disease (MCD) is a rare lymphoproliferative disease. Little is known about how patient clinical features and healthcare utilization varies by human immunodeficiency virus (HIV) status and disease subtype. Data of MCD patients identified between 2000 and 2009 were collected from medical records at two United States treatment centres. Clinical, demographic, and biochemical characteristics, drug therapies and medical utilization were descriptively reported by HIV status and cell histology, and statistically compared with the Fisher's Exact and Kruskal–Wallis tests. Patients (n = 59) had a pathologically and clinically confirmed MCD diagnosis: plasmacytic (42%), hyaline vascular (29%) and mixed (15%); 10% had HIV infection. In the first year after diagnosis, MCD patients on average saw a healthcare provider more than six times, were hospitalized at least once and underwent frequent radiological and laboratory testing. Rituximab was the most commonly used drug therapy, followed by corticosteroids and conventional chemotherapy. One‐ and 2‐year survival was excellent in HIV‐negative patients (100% and 97%, respectively) but inferior for HIV‐positive cases (67% and 67%, respectively). Heterogeneous treatment decisions were observed in this MCD study; HIV status was the only distinguishing clinical criteria associated with pharmacotherapies. Additional research is necessary to guide treatment of this rare lymphoproliferative disorder.