Immunoglobulin light chain amyloidosis: 2016 update on diagnosis, prognosis, and treatment

Periorbital purpura can be the only initial symptom of primary light chain amyloidosis: A case report

BACKGROUND

Primary light chain amyloidosis is a rare and complex disease with complex clinical features and is highly susceptible to misdiagnosis and underdiagnosis in the early stages.

CASE SUMMARY

We report a case of a 47-year-old female patient whose only initial symptom was periorbital purpura, which was not taken seriously enough. As the disease progressed, pleural effusion gradually appeared, and after systematic diagnosis and treatment, she was diagnosed with "primary light chain amyloidosis". She achieved rapid hematological remission after treatment with a daratumumab + bortezomib + cyclophosphamide + dexamethasone regimen.

CONCLUSION

Periorbital purpura can be the only initial symptom of primary light chain amyloidosis; we should pay attention to the cases where the initial clinical symptoms are only periorbital purpura.

Computational evidences of a misfolding event in an aggregation-prone light chain preceding the formation of the non-native pathogenic dimer

Antibody light chain amyloidosis is a disorder in which protein aggregates, mainly composed of immunoglobulin light chains, deposit in diverse tissues impairing the correct functioning of organs. Interestingly, due to the high susceptibility of antibodies to mutations, AL amyloidosis appears to be strongly patient-specific. Indeed, every patient will display their own mutations that will make the proteins involved prone to aggregation thus hindering the study of this disease on a wide scale. In this framework, determining the molecular mechanisms that drive the aggregation could pave the way to the development of patient-specific therapeutics. Here, we focus on a particular patient-derived light chain, which has been experimentally characterized. We investigated the early phases of the aggregation pathway through extensive full-atom molecular dynamics simulations, highlighting a structural rearrangement and the exposure of two hydrophobic regions in the aggregation-prone species. Next, we moved to consider the pathological dimerization process through docking and molecular dynamics simulations, proposing a dimeric structure as a candidate pathological first assembly. Overall, our results shed light on the first phases of the aggregation pathway for a light chain at an atomic level detail, offering new structural insights into the corresponding aggregation process.

Amyloidosis initially only manifesting as oral mucosal hemorrhagic lesions: a case series report

Amyloidosis is a heterogeneous series of diseases associated with extracellular amyloid protein depositions, which can involve multiple organs and tissues, leading to tissue structure alterations and organ dysfunction. The tongue is the most frequently involved site of oral amyloidosis, and one of its characteristic clinical presentations is macroglossia. Here, we report 3 extremely rare cases of amyloidosis exclusively appearing as multiple blood blisters, petechiae, and ecchymoses of the oral mucosa, in the absence of common clinical manifestations of oral and systemic amyloidosis. In a word, we highlight the possibility of oral mucosal hemorrhagic lesions as the initial clinical signs of systemic amyloidosis and the significance of the early and timely diagnosis of amyloidosis.

Emerging from the shadows: A rare case of gastrointestinal AL amyloidosis presenting as hematemesis

We document a unique presentation of light chain (AL) amyloidosis in a 62-year-old man exhibiting as acute hematemesis and chronic abdominal discomfort. Esophagogastroduodenoscopy disclosed marked thickening of gastric and duodenal folds, gastroduodenal nodularity, and friable ulcerations. Biopsy confirmed amyloidosis. Subsequent investigations ratified a diagnosis of systemic AL amyloidosis with cardiac involvement. Initiation of the cyclophosphamide, bortezomib, and dexamethasone (CyBorD) regimen, along with tafamidis and doxycycline for cardiac pathology, led to substantial improvement of abdominal symptoms. This case highlights the variability in amyloidosis presentations and the importance of early diagnosis.

Prevalence of Race/Ethnicity Reporting in Light Chain (AL) Amyloidosis Clinical Research in the USA

Little is known about racial differences in the incidence of light chain (AL) amyloidosis despite the well-documented racial disparities in the epidemiology of other plasma cell disorders. The goal of this study was to examine the extent to which published clinical research in AL amyloidosis report information on patients' race. Clinical research publications in AL amyloidosis between January 1, 2010, and December 31, 2020, from the USA were identified. In addition to the reporting of race, study design, funding, cohort size, year of publication, impact factor of publication journal, and first author degree were abstracted. Among papers reporting race, we also assessed whether ethnicity was reported separately. A PubMed search yielded 2,770 papers of which 220 met the pre-specified criteria for analysis. Of those, 37 (16.5%) reported race. Single institution publications, those with physicians as first authors, and those published in journals with impact factor 6 or higher were less likely to report race. On multivariate analysis, only single institution studies were negatively associated with race reporting. Of the 37 papers reporting race, none defined it in methods, 16% stated how race was identified, and 19% discussed its significance. Ethnicity was reported in 6 studies. Our results indicate that race/ethnicity is underreported in USA. AL amyloidosis clinical literature leads to a challenge for identifying potential racial/ethnic disparities. Standards for collecting and reporting racial/ethnic demographics are needed. Clear and consistent reporting of race and ethnicity of clinical populations is a necessary first step in identifying disparities and promoting equitable care.

Machine Learning Approaches in Diagnosis, Prognosis and Treatment Selection of Cardiac Amyloidosis

Cardiac amyloidosis is an uncommon restrictive cardiomyopathy featuring an unregulated amyloid protein deposition that impairs organic function. Early cardiac amyloidosis diagnosis is generally delayed by indistinguishable clinical findings of more frequent hypertrophic diseases. Furthermore, amyloidosis is divided into various groups, according to a generally accepted taxonomy, based on the proteins that make up the amyloid deposits; a careful differentiation between the various forms of amyloidosis is necessary to undertake an adequate therapeutic treatment. Thus, cardiac amyloidosis is thought to be underdiagnosed, which delays necessary therapeutic procedures, diminishing quality of life and impairing clinical prognosis. The diagnostic work-up for cardiac amyloidosis begins with the identification of clinical features, electrocardiographic and imaging findings suggestive or compatible with cardiac amyloidosis, and often requires the histological demonstration of amyloid deposition. One approach to overcome the difficulty of an early diagnosis is the use of automated diagnostic algorithms. Machine learning enables the automatic extraction of salient information from “raw data” without the need for pre-processing methods based on the a priori knowledge of the human operator. This review attempts to assess the various diagnostic approaches and artificial intelligence computational techniques in the detection of cardiac amyloidosis.

Identification of AL proteins from 10 λ-AL amyloidosis patients by mass spectrometry extracted from abdominal fat and heart tissue

BACKGROUND

Systemic AL amyloidosis arises from the misfolding of patient-specific immunoglobulin light chains (LCs). Potential drivers of LC amyloid formation are mutational changes and post-translational modifications (PTMs). However, little information is available on the exact primary structure of the AL proteins and their precursor LCs.

OBJECTIVE

We analyse the exact primary structure of AL proteins extracted from 10 λ AL amyloidosis patients and their corresponding precursor LCs.

MATERIALS AND METHODS

By cDNA sequencing of the precursor LC genes in combination with mass spectrometry of the AL proteins, the exact primary structure and PTMs were determined. This information was used to analyse their biochemical properties.

RESULTS

All AL proteins comprise the V_L and a small part of the C_L with a common C-terminal truncation region. While all AL proteins retain the conserved native disulphide bond of the V_L, we found no evidence for presence of other common PTMs. The analysis of the biochemical properties revealed that the isoelectric point of the V_L is significantly increased due to introduced mutations.

CONCLUSION

Our data imply that mutational changes influence the surface charge properties of the V_L and that common proteolytic processes are involved in the generation of the cleavage sites of AL proteins.

In-hospital mortality in amyloid light chain amyloidosis: analysis of the Premier Healthcare Database

Aim: Describe the clinical and economic burden of hospitalizations for amyloid light chain (AL) amyloidosis. Materials & methods: This retrospective analysis used nationally representative hospital discharge data (2017-2020) to report discharge status, resource use and costs for hospitalizations among patients with AL amyloidosis. Results: Of 1341 patients identified, 92% were discharged alive and 8% experienced in-hospital death. Compared with the average US hospital stay during 2017-2019 (4.7 days, mean costs of $13,046 and mean charges of $54,496), hospital stays for AL amyloidosis were longer and costlier (9.7 days, $27,098.61, $111,233.91), especially in patients with in-hospital death (12.2 days, $44,966, $182,338.18). Conclusion: AL amyloidosis is associated with significant clinical and economic burden.

AL Amyloidosis for Cardiologists: Awareness, Diagnosis, and Future Prospects: JACC: CardioOncology State-of-the-Art Review

Amyloid light chain (AL) amyloidosis is a rare, debilitating, often fatal disease. Symptoms of cardiomyopathy are common presenting features, and patients often are referred to cardiologists. Cardiac amyloid infiltration is the leading predictor of death. However, the variable presentation and perceived rarity of the disease frequently lead to delay in suspecting amyloidosis as a cause of heart failure, leading to misdiagnoses and a marked delay in diagnosis, with devastating consequences for the patient. A median time from symptom onset to correct diagnosis of about 2 years is often too long when median survival from diagnosis for patients with AL amyloidosis and cardiomyopathy is 4 months to 2 years. The authors highlight the challenges to diagnosis, identify gaps in the current knowledge, and summarize novel treatments on the horizon to raise awareness about the critical need for early recognition of symptoms and diagnosis of AL amyloidosis aimed at accelerating treatment and improving outcomes for patients.

Idiopathic membranous nephropathy with renal amyloidosis: A case report

Background

Immunoglobulin light chain amyloidosis is a clonal, non-proliferative plasma cell disorder, in which fragments of immunoglobulin light chain are deposited in tissues. Clinical features depend on organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic failure, peripheral/autonomic neuropathy, and atypical multiple myeloma. Membranous nephropathy (MN) is a group of diseases characterized by deposition of immune complexes under the epithelial cells of glomerular basement and diffuse thickening of the basement membrane. Most patients with idiopathic MN (IMN) have been exposed to phospholipase A2 receptor (PLA2R) antigen, and anti-PLA2R antibodies that attack podocytes can be detected in their blood. IMN combined with amyloidosis nephropathy without secondary factors is rare. The present study describes a patient with IMN combined with immunoglobulin light chain amyloidosis nephropathy.

Case report

A 39-year-old man was admitted to our hospital because of weight loss and edema. His clinical manifestation was nephrotic syndrome. Renal pathology revealed MN. A positive Congo red staining and the pathognomonic apple-green birefringence under cross-polarized light were considered to be associated with amyloid nephropathy. Immunofluorescence showed that λ light chain was positive. Heavy chain deposition disease and amyloid-associated protein amyloidosis were excluded by immunofluorescence and immunohistochemistry, respectively. Subsequent examinations showed that his serum was negative for antibodies against the PLA2R, but PLA2R was present in renal tissue. The final diagnosis was IMN with light chain amyloid nephropathy.

Conclusion

Renal amyloidosis accompanied by IMN is uncommon. Attention should be paid to the subtype of the disease and the exclusion of secondary factors. Perfect clinical and pathological examination are helpful for the classification and staging of the disease. Congo red staining, light microscopy, immunofluorescence, immunohistochemistry, electron microscopic examination, pathological tissue staining for PLA2R antigen and testing for anti-PLA2R antibody in serum are helpful.

Epidemiology and clinical manifestations of cardiac amyloidosis

Cardiac amyloidosis, once considered a rare disease, has garnered significant attention over the last few years due to three key reasons: first, increased recognition of this disease in conjunction with various common cardiac conditions such as heart failure with preserved ejection fraction and aortic stenosis; second, due to the advent of promising new therapies for light chain disease (AL), transthyretin (ATTR) cardiomyopathy, and amyloid neuropathy; finally, the advancements in cardiac imaging including echocardiography, magnetic resonance imaging, and nuclear cardiac scintigraphy aid in non-biopsy diagnosis of ATTR cardiac amyloidosis. The hereditary forms of ATTR have further come into importance with the availability of genetic testing and increased prevalence of certain mutations in African Americans. Recognition of non-cardiac clues to this disease has gained importance and reiterates that high clinical suspicion, detailed patient history, and examination with appropriate use of imaging are vital to confirm the diagnosis.

Doxycycline Combined With Bortezomib-Cyclophosphamide-Dexamethasone Chemotherapy for Newly Diagnosed Cardiac Light-Chain Amyloidosis: A Multicenter Randomized Controlled Trial

Background: Doxycycline was demonstrated in a retrospective study to be associated with greater survival in patients with light chain (AL) amyloidosis. Therefore, we prospectively compared the efficacy of bortezomib-cyclophosphamide-dexamethasone (CyBorD) and CyBorD combined with doxycycline for cardiac AL amyloidosis. Methods: This was a multicenter, open-label randomized controlled trial. Patients with Mayo 2004 stage II-III AL amyloidosis were included. Patients were randomized to doxycycline 100 mg twice daily along with 9 cycles of CyBorD (doxycycline group) or to 9 cycles of CyBorD alone (control group). The primary outcome was 2-year progression-free survival (PFS). PFS was defined as the time from randomization to death, hematologic progression or organ progression (heart, kidney or liver). Hematologic progression was defined based on substantial increase in free light chain. Increase in either N-terminal pro B-type natriuretic peptide or cardiac troponin was the main criterion for defining cardiac progression. Cardiac PFS, defined as the time from randomization to cardiac progression or death, was compared between groups in an exploratory analysis. The corresponding treatment hazard ratio was estimated using a Cox regression model. Results: 140 patients underwent randomization, with 70 in each group. The median age was 61 (range, 33-78) years with a male: female ratio of 1.75:1. Stage II disease was present in 34 (48.6%) and 33 (47.1%) patients in the doxycycline and control groups, respectively. After a median follow-up duration of 24.4 months, 32/70 (45.7%) of patients in the doxycycline group and 30/70 (42.9%) of patients in the control group experienced progression. PFS was not significantly different between groups (hazard ratio 0.97, 95% CI, 0.59-1.60, p=0.91). Cardiac progression occurred in 29/70 (41.4%) of patients in the doxycycline group and 26/70 (37.1%) of patients in the control group. The death rates for both groups by the end of follow-up was the same, 25/70 (35.7%). There were no significant differences observed for either cardiac PFS (hazard ratio 0.91, 95% CI, 0.54-1.55, p=0.74) or overall survival (hazard ratio 1.04, 95% CI, 0.60-1.81, p=0.89). Conclusions: Our trial demonstrated that doxycycline combined with CyBorD failed to prolong PFS or cardiac PFS compared with CyBorD alone in cardiac AL amyloidosis. Clinical Trial Registration: URL: https://clinicaltrials.gov Unique Identifier: NCT03401372.

Time trajectory of cardiac function and its relation with survival in patients with light-chain cardiac amyloidosis

AIMS

We aimed to analyse the time-serial change of cardiac function in light-chain (AL) cardiac amyloidosis patients undergoing active chemotherapy and its relationship with patient outcome.

METHODS AND RESULTS

Seventy-two patients with AL cardiac amyloidosis undergoing active chemotherapy who had two or more echocardiographic examinations were identified from a prospective observational cohort (n = 34) and a retrospective cohort (n = 38). Echocardiographic parameters were obtained immediately prior to 1-3, 3-6, 6-12, and 12-24 months after the first chemotherapy. Study endpoint was a composite of death or heart transplantation (HT). During a median of 32 months (interquartile range 8-51) follow-up, 33 patients (45.8%) died and 4 patients (5.6%) underwent HT. Echocardiograms immediately prior to the first chemotherapy did not show differences between the patients with adverse events vs. those without. Significant increase in mitral E/e' ratio and decline in left ventricular global longitudinal strain (LV-GLS) was observed, starting at 3-6 months after the first chemotherapy only in those who experienced adverse events on follow-up, which was also evident in those who responded to chemotherapy. Multivariate analysis demonstrated that B-natriuretic peptide >500 pg/mL and troponin I >0.15 ng/dL at initial diagnosis, hospitalization for heart failure, E/e' >15, and LV-GLS <10% during follow-up were independent predictors of outcome.

CONCLUSIONS

In AL cardiac amyloidosis patients undergoing active chemotherapy, the deterioration of LV function may occur, starting even at 3-6 months after the first chemotherapy. Serial echocardiography may help identify those who experience a clinical event in the near future despite active chemotherapy.

Nerve biopsy: Current indications and decision tools

After initial investigation of patients presenting with symptoms suggestive of neuropathy, a clinical decision is made for a minority of patients to undergo further assessment with nerve biopsy. Many nerve biopsies do not demonstrate a definitive pathological diagnosis and there is considerable cost and morbidity associated with the procedure. This highlights the need for appropriate selection of patients, nerves and neuropathology techniques. Additionally, concomitant muscle and skin biopsies may improve the diagnostic yield in some cases. Several advances have been made in diagnostics in recent years, particularly in genomics. The indications for nerve biopsy have consequently changed over time. This review explores the current indications for nerve biopsies and some of the issues surrounding its use. Also included are comments on alternative diagnostic modalities that may help to supplant or reduce the use of nerve biopsy as a diagnostic test. These primarily include extraneural biopsy and neuroimaging techniques such as magnetic resonance neurography and nerve ultrasound. Finally, we propose an algorithm to assist in deciding when to perform nerve biopsies.

Extremely Rare Intraoral Presentation of Localized Amyloidosis

Purpose

To present an extremely rare case of localized amyloidosis of the mucosa of the maxillary alveolar ridge. Case Report. A 71-year-old man was referred to the Department of Oral Surgery, School of Dental Medicine, University of Zagreb, for a persistent nodular formation in the edentulous ridge of the anterior maxillary region. The nodular formation had a reddish color, solid consistency, and an approximate size of 40 × 15 mm. Orthopantomographic imaging excluded bone resorption and defects. Histopathological assessments of the biopsy specimen showed that the stroma was occupied by a multiplied, partially hyalinized connective tissue. The samples were subsequently stained with Congo red, and collagen accumulation under polarized light showed an apple-green birefringence indicating amyloid. Subsequently, the nodular formation was completely excised and a maxillary total denture was made. The patient showed normal tissue healing with no sign of recurrence at a follow-up assessment 1.5 years after the procedure.

Conclusion

This is only the third reported case of localized amyloidosis of the alveolar ridge mucosa. Histopathological analysis is the first step for diagnosis, but systemic tests, blood counts, urinalysis, bone marrow biopsy, electrocardiography, and digestive endoscopy are recommended to rule out a systemic disease.

Search for AL amyloidosis risk factors using Mendelian randomization

In amyloid light chain (AL) amyloidosis, amyloid fibrils derived from immunoglobulin light chain are deposited in many organs, interfering with their function. The etiology of AL amyloidosis is poorly understood. Summary data from genome-wide association studies (GWASs) of multiple phenotypes can be exploited by Mendelian randomization (MR) methodology to search for factors influencing AL amyloidosis risk. We performed a 2-sample MR analyzing 72 phenotypes, proxied by 3461 genetic variants, and summary genetic data from a GWAS of 1129 AL amyloidosis cases and 7589 controls. Associations with a Bonferroni-defined significance level were observed for genetically predicted increased monocyte counts (P = 3.8 × 10-4) and the tumor necrosis factor receptor superfamily member 17 (TNFRSF17) gene (P = 3.4 × 10-5). Two other associations with the TNFRSF (members 6 and 19L) reached a nominal significance level. The association between genetically predicted decreased fibrinogen levels may be related to roles of fibrinogen other than blood clotting. be related to its nonhemostatic role. It is plausible that a causal relationship with monocyte concentration could be explained by selection of a light chain-producing clone during progression of monoclonal gammopathy of unknown significance toward AL amyloidosis. Because TNFRSF proteins have key functions in lymphocyte biology, it is entirely plausible that they offer a potential link to AL amyloidosis pathophysiology. Our study provides insight into AL amyloidosis etiology, suggesting high circulating levels of monocytes and TNFRSF proteins as risk factors.

Understanding and recognizing cardiac amyloidosis

Cardiac amyloidosis is an infiltrative abnormality that causes myocardial thickening and dysfunction. Historically, it has been underrecognized as a cause of heart failure and was often misdiagnosed. In the past decade, the cardiology community has improved the understanding of the subtypes of these protein-based infiltrates and how they play a role in heart failure. This article reviews the pathophysiology, presentation, diagnosis, and management of cardiac amyloidosis.

Detailed Structure and Pathophysiological Roles of the IgA-Albumin Complex in Multiple Myeloma

Immunoglobulin A (IgA)-albumin complexes may be associated with pathophysiology of multiple myeloma, although the etiology is not clear. Detailed structural analyses of these protein-protein complexes may contribute to our understanding of the pathophysiology of this disease. We analyzed the structure of the IgA-albumin complex using various electrophoresis, mass spectrometry, and in silico techniques. The data based on the electrophoresis and mass spectrometry showed that IgA in the sera of patients was dimeric, linked via the J chain. Only dimeric IgA can bind to albumin molecules leading to IgA-albumin complexes, although both monomeric and dimeric forms of IgA were present in the sera. Molecular interaction analyses in silico implied that dimeric IgA and albumin interacted not only via disulfide bond formation, but also via noncovalent bonds. Disulfide bonds were predicted between Cys34 of albumin and Cys311 of IgA, resulting in an oxidized form of albumin. Furthermore, complex formation prolongs the half-life of IgA molecules in the IgA-albumin complex, leading to excessive glycation of IgA molecules and affects the accumulation of IgA in serum. These findings may demonstrate why complications such as hyperviscosity syndrome occur more often in patients with IgA dimer producing multiple myeloma.

Evaluating the incidence of engraftment syndrome with different melphalan formulations in adult multiple myeloma and immunoglobulin light chain amyloidosis patients undergoing autologous hematopoietic cell transplantation

BACKGROUND

Engraftment syndrome (ES) is a common complication of autologous hematopoietic cell transplantation (HCT). The difference in incidence of ES between melphalan formulations has not been widely reported throughout the literature and would allow for a more comprehensive understanding of the advantages and disadvantages of both melphalan formulations.

PATIENTS AND METHODS

This retrospective, single-center, observational study evaluated 83 adult multiple myeloma and immunoglobulin light chain amyloidosis patients who received either propylene glycol-containing (PG) or propylene glycol-free (PG-free) melphalan 140 mg/m² as single-agent conditioning chemotherapy for autologous HCT from May 31, 2015 to May 31, 2019. The primary outcome was to assess the incidence of ES, as defined using the Maiolino criteria, with both melphalan formulations. Secondary outcomes included an analysis of potential risk factors for the development of ES, as well as an evaluation of overall length of stay (LOS).

RESULTS

The incidence of ES for PG and PG-free melphalan did not differ significantly, 14/39 (35.9%) and 12/44 (27.3%) (P = 0.4), respectively. No potential risk factors for ES were identified on multivariate logistic regression analysis. A statistically significant difference in number of days to engraftment was identified for PG and PG-free melphalan, 15.56 vs. 13.82 days (P = 0.01), respectively; although, this did not translate to a decrease in LOS, 19.9 vs. 18.59 days (P = 0.14).

CONCLUSIONS

The incidence of ES did not differ significantly between melphalan formulations. Future research is needed to determine whether the faster time to engraftment seen with PG-free melphalan may translate to a decrease in LOS.

The Clinical and Economic Burden of Newly Diagnosed Hereditary Transthyretin (ATTRv) Amyloidosis: A Retrospective Analysis of Claims Data

INTRODUCTION

Little is known about the burden of hereditary transthyretin (ATTRv) amyloidosis, a genetic, progressive, and fatal disease caused by extracellular deposition of transthyretin amyloid fibrils. The study's aim was to estimate costs and disease burden associated with ATTRv amyloidosis in a real-world setting.

METHODS

Using IBM® MarketScan® Commercial and Medicare Supplemental data, we identified patients at least 18 years of age with newly diagnosed ATTRv amyloidosis. Diagnosis required at least one medical claim with relevant diagnosis code (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] 277.30-.31, 277.39; ICD-10-CM E85.0-.4, E85.89, E85.9) between January 1, 2014 and December 31, 2016, and at least one additional criterion occurring during study period (2013-2017): at least 15 days diflunisal use without more than a 30-day gap; liver transplant; or claim with codes E85.1 or E85.2. First diagnosis date was study index. Continuous enrollment 1-year pre-index (baseline) and post-index (follow-up) was required. Patients with baseline amyloidosis diagnosis were excluded. Outcomes of interest were comorbidities and 1-year follow-up healthcare utilization and costs (also reported quarterly).

RESULTS

Among 185 qualifying patients, mean age was 59.2 years (standard deviation 15.2), 54.1% were female, and baseline Charlson comorbidity index was 2.2 (2.5). Neuropathy (30.3%), diabetes (27.0%), and cardiovascular-related comorbidities, including dyspnea (25.9%) and congestive heart failure (21.6%), were common during follow-up. Nearly a quarter of patients (24.9%) were hospitalized during follow-up. Most hospitalizations and emergency department visits occurred in the first quarter post-diagnosis (18.9%, 17.8%, respectively) and dropped in subsequent quarters. The annual mean total cost was $64,066, with inpatient services contributing the majority of the expenses ($34,461), followed by outpatient ($23,853), and then pharmacy ($5752). As with utilization, costs were highest in the first quarter post-diagnosis and dropped in subsequent quarters.

CONCLUSION

Patients newly diagnosed with ATTRv amyloidosis have substantial healthcare utilization and costs in the first year, primarily the initial months, post-diagnosis. Further research should examine later costs associated with disease progression and end-of-life care.

The Role of Cardiovascular MRI in Cardio-Oncology

"Cardiac imaging is an essential tool in the field of cardio-oncology. Cardiovascular magnetic resonance (CMR) stands out for its accuracy, reproducibility, and ability to provide tissue characterization. These attributes are particularly helpful in screening and diagnosing cardiotoxicity, infiltrative disease, and inflammatory cardiac disease. The ability of CMR to detect subtle changes in cardiac function and tissue composition has made it a useful tool for understanding the pathophysiology of cardiotoxicity. Because of these unique features, CMR is gaining prominence in both the clinical and research aspects of cardio-oncology."

[Monoclonal gammopathy of renal significance: consensus of hematologists and nephrologists of Russia on the establishment of nosology, diagnostic approach and rationale for clone specific treatment]

Monoclonal gammopathy of renal significance (MGRS) is a new nosology in modern nephrology and oncohematology. MGRS is defined as kidney injury due to nephrotoxic monoclonal immunoglobulin produced by the B-cell line clone which does not reach the hematological criteria for specific treatment initiation. Monoclonal proteins pathological effects on kidney parenchyma result in irreversible decline of kidney function till the end stage renal disease that in line with the position of International Consensus of hematologists and nephrologists determinates critical necessity for clone specific treatment in patients with MGRS despite the absence of hematological indications for treatment initiation. Main challenge of MGRS in Russian Federation is an inaccessibility of an in-time diagnostic and appropriate treatment for the great majority of patients due to the following reasons: 1) limited knowledge about the MGRS among hematologists and nephrologists; 2) lack of necessary diagnostic resources in most health-care facilities; 3) lack of approved clinical recommendations and medical economic standards for treatment of this pathological entity. Consensus document comprises the opinion of experts leading nephrologists and hematologists of Russian Federation on the problem of MGRS including the incoherence in nosology classification, diagnostics approach and rationale for clone specific treatment. Consensus document is based on conclusions and agreements reached during the conference of leading nephrologists and hematologists of Russia which was held in the framework of symposia Plasma cell dyscrasias and lymphoproliferative diseases: modern approaches to therapy, 1516 of March 2019, Pavlov First Saint Petersburg State Medical University. The present Consensus is intended to define the principal practical steps to resolve the problem of MGRS in Russian Federation that are summarized as final clauses.

Diverse patterns of antibody variable gene repertoire disruption in patients with amyloid light chain (AL) amyloidosis

Immunoglobulin light chain amyloidosis is the most common form of systemic amyloidosis. AL amyloidosis is caused by a misfolded light chain produced by a clonal population of plasma cells. Disease status currently is defined by measuring the absolute quantity of serum free light chain protein, but this measurement often fails to identify the subclinical presence of clonal cells that may merit additional therapy. Next generation sequencing has the sensitivity to measure the relative amount of dominating light chains within the repertoire of a patient, and this technique is in clinical use to identify clonal populations of plasma cells for multiple myeloma, a related disorder. In this proof-of-concept study, we used bone marrow aspirates of AL amyloidosis positive patients and used reverse transcription of the antibody transcriptome followed by next generation sequencing to identify antibody variable-diversity-joining gene sequences for patients with immunoglobulin light chain amyloidosis, and demonstrate that this technology can be used to identify the dominant clone. The data also reveal differing patterns of overall antibody repertoire disruption in different patients. This method merits further study in larger prospective studies to establish its utility in detecting residual disease for patients with immunoglobulin light chain amyloidosis.

Amyloid Proteins and Peripheral Neuropathy

Painful peripheral neuropathy affects millions of people worldwide. Peripheral neuropathy develops in patients with various diseases, including rare familial or acquired amyloid polyneuropathies, as well as some common diseases, including type 2 diabetes mellitus and several chronic inflammatory diseases. Intriguingly, these diseases share a histopathological feature-deposits of amyloid-forming proteins in tissues. Amyloid-forming proteins may cause tissue dysregulation and damage, including damage to nerves, and may be a common cause of neuropathy in these, and potentially other, diseases. Here, we will discuss how amyloid proteins contribute to peripheral neuropathy by reviewing the current understanding of pathogenic mechanisms in known inherited and acquired (usually rare) amyloid neuropathies. In addition, we will discuss the potential role of amyloid proteins in peripheral neuropathy in some common diseases, which are not (yet) considered as amyloid neuropathies. We conclude that there are many similarities in the molecular and cell biological defects caused by aggregation of the various amyloid proteins in these different diseases and propose a common pathogenic pathway for "peripheral amyloid neuropathies".

Outcomes with early vs. deferred stem cell transplantation in light chain amyloidosis

In the presence of effective treatment options for systemic light chain (AL) amyloidosis, autologous stem cell transplantation (ASCT) is sometimes deferred after stem cell collection. We designed this retrospective study to compare overall survival (OS) between patients who proceed directly to ASCT after stem cell collection and those who defer ASCT. We included patients with AL amyloidosis who had stem cell collection at Mayo Clinic, Minnesota, from 2004 to 2018. ASCT was considered "early" if performed within 90 days of collection, and "deferred" if performed after 90 days, or not done by last follow up. We included 651 patients; 527 underwent early ASCT and 124 deferred ASCT. There was no difference in OS with early vs. deferred ASCT (median OS: 13.0 vs. 11.4 years, respectively, P = 0.28). There was no difference in OS between the 2 groups among patients with early or advanced Mayo Stage. Among patients who achieved ≥very good partial response at the time of collection, OS in the early and deferred groups was 14.2 and 13.4 years, respectively (P = 0.06). Survival outcomes are similar with early and deferred ASCT. Further studies are needed to identify patients who would benefit from each approach.

A real-life cohort study of immunoglobulin light-chain (AL) amyloidosis patients ineligible for autologous stem cell transplantation due to severe cardiac involvement or advanced disease

Objective: To study the outcome of patients with AL amyloidosis who were ineligible for high dose melphalan (HDM) and autologous stem cell transplantation (ASCT).Methods: A real-life retrospective observational cohort study of Dutch patients with AL amyloidosis ineligible for HDM and ASCT was performed at the University Medical Center Groningen from January 2001 until April 2017. Primary outcome measure was overall survival (OS). Secondary outcome measures were hematological response (HR), organ responses, and treatment toxicity.Results: Eighty-four patients were included. Ineligibility was due to NYHA class III/IV (n = 58), otherwise advanced disease (n = 11), advanced age (n = 14), or treatment refusal (n = 1). Early death (<3 months) rate was high (44%). Median OS improved from 4 months in period 2001-2009 (n = 36) to 8 months in period 2009-2017 (n = 48, p = .02). HR was seen in 29%, and 42% of the patients, respectively. Median OS was 36 months after induction treatment with bortezomib (n = 32) and 18 months with immunomodulatory imide drug (IMID) (n = 16), both higher than median OS (7 months) with other regimens (n = 27). Incidence of toxicity was high (51%).Conclusion: OS improved in this high-risk group over the years, especially after introduction of new treatment modalities. However, early death rate remains high, illustrating the need for more effective treatment.

Approach to the Diagnosis of Amyloidosis

Amyloidosis is heterogeneous group of disorder characterized by extracellular deposition of misfolded insoluble proteinaceous material with cross beta pleated sheet structure leading to organ dysfunction. This disease is rare and indeed heterogeneous, as it may be hereditary (familial amyloidosis), secondary to spectrum of inflammatory conditions (AA amyloidosis) or member of plasma cell neoplasm family (AL amyloidosis). AL amyloidosis is the most common type of amyloid, however, is rarely accompanied by multiple myeloma or other lymphoproliferative disorder. This disparity in its origin and presentation needs to be addressed by exhaustive battery of investigation tools, to arrive at right diagnosis with correct typing. This is of utmost importance in guiding the treating physicians to choose appropriate therapeutic options. This review deals with diagnostic approach to amyloidosis and its various subtypes.

Light chain amyloidosis induced inflammatory changes in cardiomyocytes and adipose-derived mesenchymal stromal cells

Light chain (AL) amyloidosis is a progressive, degenerative disease characterized by the misfolding and amyloid deposition of immunoglobulin light chain (LC). The amyloid deposits lead to organ failure and death. Our laboratory is specifically interested in cardiac involvement of AL amyloidosis. We have previously shown that the fibrillar aggregates of LC proteins can be cytotoxic and arrest the growth of human RFP-AC16 cardiomyocytes in vitro. We showed that adipose-derived mesenchymal stromal cells (AMSC) can rescue the cardiomyocytes from the fibril-induced growth arrest through contact-dependent mechanisms. In this study, we examined the transcriptome changes of human cardiomyocytes and AMSC in the presence of AL amyloid fibrils. The presence of fibrils causes a 'priming' immune response in AMSC associated with interferon associated genes. Exposure to AL fibrils induced changes in the pathways associated with immune response and extracellular matrix components in cardiomyocytes. We also observed upregulation of innate immune-associated transcripts (chemokines, cytokines, and complement), suggesting that amyloid fibrils initiate an innate immune response on these cells, possibly due to phenotypic transformation. This study corroborates and expands our previous studies and identifies potential new immunologic mechanisms of action for fibril toxicity on human cardiomyocytes and AMSC rescue effect on cardiomyocytes.

A validated composite organ and hematologic response model for early assessment of treatment outcomes in light chain amyloidosis

Newly diagnosed AL amyloidosis patients were evaluated to develop a model for early assessment of treatment benefit at 6 months, integrating both hematologic (HR) and organ response (OR) assessment (testing cohort, Mayo: n = 473; validation cohort, Pavia: n = 575). Multiple OR were assessed as follows: All OR (AOR): response in all organs, mixed OR (MOR): response in some organs, no OR (NOR)]. AOR rates at 6 months improved with deepening HR; complete response (CR; 38%, 35%), very good partial response (VGPR; 30%, 26%), and partial response (PR; 16%, 21%), respectively. A composite HR/OR (CHOR) model was developed using incremental scoring based on hazard ratios with scores of 0–3 for HR (0—CR, 1—VGPR, 2—PR, 3—no response) and 0–2 for OR (0—AOR, 1—MOR, 2—NOR). Patients could be divided into two distinct CHOR groups (scores 0–3 and 4–5), with median OS in group 1 and group 2: Not reached vs. 34 months, p < 0.001 [Mayo] and 87 vs. 23 months, p < 0.001 [Pavia]. In conclusion, we developed a model that can assess multiple organs concurrently, and integrate both HR and OR assessments to determine early clinical benefit with treatment, which may be used as a surrogate end-point in trials and to compare outcomes with different therapies.

Fatal amyloid formation in a patient's antibody light chain is caused by a single point mutation

In systemic light chain amyloidosis, an overexpressed antibody light chain (LC) forms fibrils which deposit in organs and cause their failure. While it is well-established that mutations in the LC’s V_L domain are important prerequisites, the mechanisms which render a patient LC amyloidogenic are ill-defined. In this study, we performed an in-depth analysis of the factors and mutations responsible for the pathogenic transformation of a patient-derived λ LC, by recombinantly expressing variants in E. coli. We show that proteolytic cleavage of the patient LC resulting in an isolated V_L domain is essential for fibril formation. Out of 11 mutations in the patient V_L, only one, a leucine to valine mutation, is responsible for fibril formation. It disrupts a hydrophobic network rendering the C-terminal segment of V_L more dynamic and decreasing domain stability. Thus, the combination of proteolytic cleavage and the destabilizing mutation trigger conformational changes that turn the LC pathogenic.

Amyloid light chain amyloidosis, shortened to AL amyloidosis, is a rare and often fatal disease. It is caused by a disorder of the bone marrow. Usually, cells in the bone marrow produce Y-shaped proteins called antibodies to fight infections. In AL amyloidosis, these cells release too much of the short arm of the antibody, known as its light chain, and the light chains also carry mutations. The antibodies are no longer able to assemble properly, and instead misfold and form structures, known as amyloid fibrils. The fibrils build up outside the cells, gradually causing damage to tissues and organs that can lead to life-threatening organ failure.

Due to the rareness of the disease, diagnosis is often overlooked and delayed. People experience widely varying symptoms, depending on the organs affected. Also, given the diversity of antibodies people make, every person with AL amyloidosis has a variety of mutations implicated in their disease. It is thought that mutations in the antibody light chain make it unstable and prone to misfolding, but it remains unclear which specific mutations trigger a cascade of amyloid fibril formation.

Now, Kazman et al. have pinpointed the exact mechanism in one case of the disease. First, tissue biopsies from a woman with advanced AL amyloidosis were analyzed, and the defunct antibody light chain was isolated. Eleven mutations were identified in the antibody light chain, only one of which was found to be responsible for the formation of the harmful fibrils. The next step was to determine how this one small change was so damaging. The experiments showed that after the antibody light chain was cut in two, a process that happens naturally in the body, this single mutation transforms it into a protein capable of causing disease.

In this ‘bedside to lab bench’ study, Kazman et al. have succeeded in determining the molecular origin of one case of AL amyloidosis. The results have also shown that the instability of antibodies due to mutation does not alone explain the formation of amyloid fibrils in this disease and that the cutting of this protein in two is also important. It is hoped that, in the long run, this work will lead to new diagnostics and treatment options for people with AL amyloidosis.

Genomic profiling in amyloid light-chain amyloidosis reveals mutation profiles associated with overall survival

Background: Amyloid light chain (AL) amyloidosis is characterized by tissue deposition of amyloid fibres derived from immunoglobulin that can lead to irreversible organ damage. Information about genomic profiles of AL amyloidosis is lacking.Methods: In this study, we adopted a two-step strategy to investigate the mutational profile of AL amyloidosis bone marrow plasma cells (PCs) and their clinical implications. In step one, whole-exome sequencing was performed in bone marrow PCs and paired with normal tissue from 10 AL amyloidosis patients, by which we identified 10 significantly mutated genes (SMGs). In step two, we constituted a targeted gene sequencing (TGS) panel covering the frequently mutated genes identified in step one, genes reported in prior AL amyloidosis studies, and known cancer driver mutations. Then, we analysed an expanded cohort of AL amyloidosis patients (N = 48) with this panel comprising 98 genes.Results: Four recurrent mutations were identified by TGS and verified by Sanger sequencing: ASB15 (c. 844 C > T), ASCC3 (c. 1595 A > G), HIST1H1E (c. 311 C > T) and KRAS (c. 35 G > A), among which the first three mutations were associated with inferior overall survival (OS). Additionally, we found that the number of mutations identified by the TGS panel of 98 genes could be a prognostic predictor for OS.Conclusions: In summary, we revealed genomic profiling in AL amyloidosis and found mutation profiles associated with OS.

Bendamustine With Dexamethasone in Relapsed/Refractory Systemic Light-Chain Amyloidosis: Results of a Phase II Study

PURPOSE

No established treatments exist for relapsed/refractory systemic light-chain (AL) amyloidosis. Bendamustine has shown potential in the treatment of multiple myeloma. We conducted a phase II, multicenter trial to assess the efficacy and safety of bendamustine with dexamethasone (ben-dex) in patients with persistent or progressive AL amyloidosis after ≥ 1 prior therapy.

METHODS

The trial enrolled 31 patients who received bendamustine on days 1 and 2 (100 mg/m² intravenously) with 40 mg of weekly dexamethasone in 28-day cycles until disease progression or up to 6 cycles after complete hematologic response. The primary objective was the rate of partial hematologic response (PR) or better.

RESULTS

Patients received a median of 4 cycles (range, 2-12 cycles) with 57% of patients achieving a PR or better (11% complete response, 18% very good PR). The overall organ response was 29% among the 24 patients who had measurable organ involvement. Treatment was well tolerated with no grade 5 treatment-related adverse events (AEs). Sixty-five percent of patients had a therapy-related grade 3-4 AE. The most common AEs included myelosuppression, fatigue, and nausea/vomiting. The median overall survival was 18.2 months (95% CI, 11.3 to 43.8 months), and hematologic response was associated with prolonged survival (P = .0291). The median progression-free survival was 11.3 months (95% CI, 5.0 to 15.4 months).

CONCLUSION

Overall, ben-dex is a viable treatment option with substantial efficacy and limited toxicity for patients with pretreated AL amyloidosis who have limited therapeutic options. This trial was registered at (ClinicalTrials.gov identifier: NCT01222260).

Coagulation and fibrinolytic features in AL amyloidosis with abnormal bleeding and usefulness of tranexamic acid

Abnormal bleeding is sometimes observed in patients with immunoglobulin light chain (AL) amyloidosis. Although several theories have been proposed regarding the pathological causes of the bleeding tendency in AL amyloidosis, many lacked sufficient evidence and full consensus. We conducted a retrospective survey at a single institution to assess bleeding manifestations, methods for evaluating hematological abnormalities, and treatments for bleeding in patients with systemic AL amyloidosis over the past 13 years. The participants were 10 men and 14 women, aged 39-84 years (mean 65 years). The prevalence of bleeding was 29%. Prolonged prothrombin time (PT), elevated plasmin-α2-antiplasmin complex, and factor X deficiency were distinctive to the bleeding group. Two case studies showed that tranexamic acid was effective for treating this hematological condition. However, two patients with normal PT and activated partial thromboplastin time (APTT) also had a bleeding manifestation. The rates of administration of coagulation and fibrinolytic tests were relatively low in the non-bleeding group. Therefore, a close investigation concerning coagulation and fibrinolysis should be performed in every patient with AL amyloidosis regardless of the PT/APTT values. A more careful, comprehensive, and large-scale study is required to reinforce these findings.

Geographic Disparities in Reported US Amyloidosis Mortality From 1979 to 2015: Potential Underdetection of Cardiac Amyloidosis

Importance

Cardiac amyloidosis is an underdiagnosed disease and is highly fatal when untreated. Early diagnosis and treatment with the emerging novel therapies significantly improve survival. A comprehensive analysis of amyloidosis-related mortality is critical to appreciate the nature and distribution of underdiagnosis and improve disease detection.

Objective

To evaluate the temporal and regional trends in age-adjusted amyloidosis-related mortality among men and women of various races/ethnicities in the United States.

Design, Setting, and Participants

In this observational cohort study, death certificate information from the Centers for Disease Control and Prevention's Wide-ranging ONline Data for Epidemiologic Research database and the National Vital Statistics System from 1979 to 2015 was analyzed. A total of 30 764 individuals in the United States with amyloidosis listed as the underlying cause of death and 26 591 individuals with amyloidosis listed as a contributing cause of death were analyzed.

Exposures

Region of residence.

Main Outcomes and Measures

Age-adjusted mortality rate from amyloidosis per 1 000 000 population stratified by year, sex, race/ethnicity, and state and county of residence.

Results

Of the 30 764 individuals with amyloidosis listed as the underlying cause of death, 17 421 (56.6%) were men and 27 312 (88.8%) were 55 years or older. From 1979 to 2015, the reported overall mean age-adjusted mortality rate from amyloidosis as the underlying cause of death doubled from 1.77 to 3.96 per 1 000 000 population (2.32 to 5.43 in men and 1.35 to 2.80 in women). Black men had the highest mortality rate (12.36 per 1 000 000), followed by black women (6.48 per 1 000 000). Amyloidosis contributed to age-adjusted mortality rates as high as 31.73 per 1 000 000 in certain counties. Most southern states reported the lowest US mortality rates despite having the highest proportions of black individuals.

Conclusions and Relevance

The increased reported mortality over time and in proximity to amyloidosis centers more likely reflects an overall increase in disease diagnosis rather than increased lethality. The reported amyloidosis mortality is highly variable in different US regions. The lack of higher reported mortality rates in states with a greater proportion of black residents suggests underdiagnosis of amyloidosis, including cardiac forms of the disease, in many areas of the United States. Better understanding of the determinants of geographic and racial disparity in the reporting of amyloidosis deaths are warranted.

Crystal structure of 6aJL2-R24G light chain variable domain: Does crystal packing explain amyloid fibril formation?

Light chain amyloidosis is one of the most common systemic amyloidosis, characterized by the deposition of immunoglobulin light variable domain as insoluble amyloid fibrils in vital organs, leading to the death of patients. Germline λ6a is closely related with this disease and has been reported that 25% of proteins encoded by this germline have a change at position 24 where an Arg is replaced by a Gly (R24G). This germline variant reduces protein stability and increases the propensity to form amyloid fibrils. In this work, the crystal structure of 6aJL2-R24G has been determined to 2.0 Å resolution by molecular replacement. Crystal belongs to space group I2₁2₁2₁ (PDB ID 5JPJ) and there are two molecules in the asymmetric unit. This 6aJL2-R24G structure as several related in PDB (PDB entries: 5C9K, 2W0K, 5IR3 and 1PW3) presents by crystal packing the formation of an octameric assembly in a helicoidal arrangement, which has been proposed as an important early stage in amyloid fibril aggregation. However, other structures of other protein variants in PDB (PDB entries: 3B5G, 3BDX, 2W0L, 1CD0 and 2CD0) do not make the octameric assembly, regardless their capacity to form fibers in vitro or in vivo. The analysis presented here shows that the ability to form the octameric assembly in a helicoidal arrangement in crystallized light chain immunoglobulin proteins is not required for amyloid fibril formation in vitro. In addition, the fundamental role of partially folded states in the amyloid fibril formation in vitro, is not described in any crystallographic structure published or analyzed here, being those structures, in any case examples of proteins in their native states. Those partially folded states have been recently described by cryo-EM studies, showing the necessity of structural changes in the variants before the amyloid fiber formation process starts.

AL Amyloidosis for the Cardiologist and Oncologist: Epidemiology, Diagnosis, and Management

AL amyloidosis results from clonal production of immunoglobulin light chains, most commonly arising from a clonal plasma cell disorder. Once considered a nearly uniformly fatal disease, prognosis has improved markedly over the past 15 years, predominantly because of advances in light chain suppressive therapies. Cardiac deposition of amyloid fibrils is common, and the severity of cardiac involvement remains the primary driver of prognosis. Improvements in chemotherapy/immunotherapy have prompted a reassessment of the role of advanced cardiac therapies previously considered contraindicated in most patients, including the role of implantable cardioverter-defibrillators and cardiac transplantation. This state-of-the-art review highlights the current state of the field, including diagnosis, prognosis, and hematologic- and cardiac-specific therapies.

Fifteen year overall survival rates after autologous stem cell transplantation for AL amyloidosis

In appropriately selected patients with AL amyloidosis, autologous stem cell transplant (ASCT) is an established treatment modality with excellent outcomes and decreasing transplant related mortality (TRM) over time. We report on 15-year overall survival (OS) in 159 patients undergoing ASCT from 1996 to 2003, with median follow up of 17.1 years. Day 100 TRM was 13.2% (n = 21). The OS of ≥15 years was observed in 30% (47/159) of patients. Patients surviving ≥15 years were younger (53 vs 56 years, P = .02), less likely to have lambda as the involved light chain (62% vs 78%, P = .03) and were less likely to have heart involvement (32% vs 56%, P = .005). Median OS of patients with heart involvement vs not was 4.0 vs 11.1 years, P = .006 and actuarial 15-year OS was 23% vs 43%, respectively. A higher proportion of patients with OS ≥15 years received full-dose melphalan conditioning (81% vs 61%, P = .01), and achieved day 100 complete response (CR) (64% vs 24%, P < .001). Median OS amongst patients who achieved CR vs not was 19.3 vs 5.4 years, P < .001. Heart involvement, receiving full-dose melphalan and achieving CR remained independent predictors of OS. AL amyloidosis and related complications were the cause of death in 52% of patients overall (1-5 years post-transplant: 81%; 5-10 years: 62% and 10-15 years: 55%). These results reinforce the key role of ASCT in AL amyloidosis. With improvements in TRM and more options for relapsed disease, we expect the long-term survival post-transplant to improve significantly in the future.

Clinical Utility of 18F-Florbetaben PET for Detecting Amyloidosis Associated With Multiple Myeloma: A Prospective Case-Control Study

PURPOSE

The aims of this study were to evaluate the diagnostic performance of F-florbetaben PET/CT for detecting amyloid deposits in patients with multiple myeloma (MM) and to identify the optimal PET analysis method.

METHODS

Fourteen patients with MM were prospectively enrolled (6 with amyloidosis, 8 control subjects). Dynamic imaging of the kidneys was performed for 20 minutes, and the retention ratio was obtained. At 90 minutes after injection, PET was performed. All images were assessed qualitatively and quantitatively, and the SUVmax, SUVmean, and SUVratio were obtained. Variables were compared between the amyloidosis group and the control group. Amyloid deposition was confirmed according to international consensus guidelines.

RESULTS

Tracer uptake was abnormal in all patients with amyloidosis. The visual detection rate was excellent (100%) in the heart, stomach, and tongue but limited in the kidneys (50%) and poor (0%) in the esophagus, liver, and colon. F-florbetaben PET/CT identified 13 unexpected cases of abnormal uptake, confirming further amyloid deposition. Both spherical and manual volumes of interest showed similar diagnostic performance when evaluating amyloidosis in target organs. There was no significant difference in diagnostic performance between the SUVmax, SUVmean, and SUVratio.

CONCLUSIONS

F-florbetaben PET/CT can accurately detect systemic amyloid deposits in patients with MM. F-florbetaben PET/CT was particularly useful in the heart, stomach, and tongue but of limited value in the esophagus, liver, and colon. F-florbetaben PET/CT can provide clinical information on organ involvement and could replace pathologic examination for diagnosis of amyloidosis in the future.

Immunoglobulin Light-Chain Amyloidosis: Clinical Presentations and Diagnostic Approach

Systemic immunoglobulin light-chain (AL) amyloidosis is a rare disorder arising from a plasma cell clone that produces misfolded immunoglobulin light chains, which are deposited in various tissues and organs as amyloid fibrils. Signs and symptoms are typically vague and overlap with those arising from other common diseases; consequently, diagnosis of AL amyloidosis is challenging for clinicians. Substantial delays between onset of symptoms and diagnosis are common, and result in poorer outcomes, particularly in patients with cardiac AL amyloidosis and others who develop advanced organ dysfunction. With the need to identify AL amyloidosis as early as possible, it is important for health-care practitioners, including advanced practice clinicians and nurses, to be aware of the hallmark presenting signs and symptoms, as well as the latest practice for evaluation and diagnosis. Increased awareness of signs and symptoms associated with AL amyloidosis, particularly relating to the most frequently involved organs, the heart and kidneys, represents an opportunity for achieving earlier diagnosis. Here we review these issues in AL amyloidosis, summarize the key presenting symptoms that clinicians need to be alert to, and discuss the latest diagnostic tests, with the aim of expediting patient identification and diagnosis with the goal of improving patient outcomes.

Bortezomib-based chemotherapy reduces early mortality and improves outcomes in patients with ultra-high-risk light-chain amyloidosis: a retrospective case control study

Background: Patients with amyloid light-chain (AL) amyloidosis who have advanced cardiac damage are at risk of premature mortality. Currently, bortezomib is the mainstay in the treatment of AL amyloidosis, but the benefits of bortezomib in patients with ultra-high-risk (2004 Mayo stage IIIb or 2012 Mayo stage IV) AL amyloidosis have not been proved definitively. Methods: We performed a retrospective analysis of patients newly diagnosed with ultra-high-risk AL amyloidosis who received a bortezomib-based regimen or supportive treatment. We aimed to establish the effects of bortezomib on early mortality and long-term outcomes in this high-risk population. Results: Patients receiving bortezomib-containing chemotherapy (n = 62) and patients receiving no chemotherapy (n = 24) were included. Median overall survival (OS) was 30 months in the bortezomib group and 2 months in the control group (p < .001), and median progression-free survival (PFS) was 15.8 months (bortezomib) and 2 months (control; p < .001). The early-death rate (within 6 months of treatment) was 32.3% (bortezomib) and 66.7% (control; p < .001). In a landmark analysis assessing outcomes in patients surviving beyond 6 months, the 2-year OS and PFS in the bortezomib group were 77.3% and 65.8%, respectively. Conclusions: Bortezomib-based regimens can help to reduce early mortality and improve long-term survival in patients with ultra-high-risk AL amyloidosis.

Cryo-EM structure of a light chain-derived amyloid fibril from a patient with systemic AL amyloidosis

Amyloid fibrils derived from antibody light chains are key pathogenic agents in systemic AL amyloidosis. They can be deposited in multiple organs but cardiac amyloid is the major risk factor of mortality. Here we report the structure of a λ1 AL amyloid fibril from an explanted human heart at a resolution of 3.3 Å which we determined using cryo-electron microscopy. The fibril core consists of a 91-residue segment presenting an all-beta fold with ten mutagenic changes compared to the germ line. The conformation differs substantially from natively folded light chains: a rotational switch around the intramolecular disulphide bond being the crucial structural rearrangement underlying fibril formation. Our structure provides insight into the mechanism of protein misfolding and the role of patient-specific mutations in pathogenicity.