Recent Advances in the Diagnosis, Risk Stratification, and Management of Systemic Light-Chain Amyloidosis

Current status and prospect of anti-amyloid fibril therapy in AL amyloidosis

Amyloid light-chain (AL) amyloidosis is a rare hematological disease that produces abnormal monoclonal immunoglobulin light chains to form amyloid fibrils that are deposited in tissues, resulting in organ damage and dysfunction. Advanced AL amyloidosis has a very poor prognosis with a high risk of early mortality. The combination of anti-plasma cell therapy and amyloid fibrils clearance is the optimal treatment strategy, which takes into account both symptoms and root causes. However, research on anti-amyloid fibrils lags far behind research on anti-plasma cells, and there is currently no approved treatment that could clear amyloid fibrils. Nevertheless, anti-amyloid fibril therapies are being actively investigated recently and have shown potential in clinical trials. In this review, we aim to outline the preclinical work and clinical efficacy of fibril-directed therapies for AL amyloidosis.

Neurosurgical Intervention for Nerve and Muscle Biopsies

(1) Background: Neurologic and musculoskeletal diseases represent a considerable portion of the underlying etiologies responsible for the widely prevalent symptoms of pain, weakness, numbness, and paresthesia. Because of the subjective and often nonspecific nature of these symptoms, different diagnostic modalities have been explored and utilized. (2) Methods: Literature review. (3) Results: Nerve and muscle biopsy remains the gold standard for diagnosing many of the responsible neurological and musculoskeletal conditions. However, the need for invasive tissue sampling is diminishing as more investigations explore alternative diagnostic modalities. Because of this, it is important to explore the current role of neurosurgical intervention for nerve and muscle biopsies and its current relevance in the diagnostic landscape of neurological and musculoskeletal disorders. With consideration of the role of nerve and muscle biopsy, it is also important to explore innovations and emerging techniques for conducting these procedures. This review explores the indications and emerging techniques for neurological intervention for nerve and muscle biopsies. (4) Conclusions: The role of neurosurgical intervention for nerve and muscle biopsy remains relevant in diagnosing many neurological and musculoskeletal disorders. Biopsy is especially relevant as a supportive point of evidence for diagnosis in atypical cases. Additionally, emerging techniques have been explored to guide diagnostics and biopsy, conduct less invasive biopsies, and reduce risks of worsening neurologic function and other symptoms secondary to biopsy.

Healthcare Resource Utilization and Cost-of-Illness in Systemic Light Chain (AL) Amyloidosis in Europe: Results From the Real-World, Retrospective EMN23 Study

OBJECTIVES

To report healthcare resource utilization (HCRU) and safety outcomes in systemic light chain (AL) amyloidosis from the EMN23 study.

MATERIALS AND METHODS

The retrospective, observational, multinational EMN23 study included 4,480 patients initiating first-line treatment for AL amyloidosis in 2004-2018 and assessed, among other objectives, HCRU and safety outcomes. HCRU included hospitalizations, examinations, and dialysis; safety included serious adverse events (SAEs) and adverse events of special interest (AESIs). Data were descriptively analyzed by select prognostic factors (e.g., cardiac staging by Mayo2004/European) for 2004-2010 and 2011-2018. A cost-of-illness analysis was conducted for the UK and Spain.

RESULTS

HCRU/safety and dialysis data were extracted for 674 and 774 patients, respectively. Of patients with assessed cardiac stage (2004-2010: 159; 2011-2018: 387), 67.9% and 61.0% had ≥ 1 hospitalization, 56.0% and 51.4% had ≥ 1 SAE, and 31.4% and 28.9% had ≥ 1 AESI across all cardiac stages in 2004-2010 and 2011-2018, respectively. The per-patient-per-year length of hospitalization increased with disease severity (cardiac stage). Of patients with dialysis data (2004-2010: 176; 2011-2018: 453), 23.9% and 14.8% had ≥ 1 dialysis session across all cardiac stages in 2004-2010 and 2011-2018, respectively. The annual cost-of-illness was estimated at €40,961,066 and €31,904,386 for the UK and Spain, respectively; dialysis accounted for ∼28% (UK) and ∼35% (Spain) of the total AL amyloidosis costs.

CONCLUSIONS

EMN23 showed that the burden of AL amyloidosis is substantial, highlighting the need for early disease diagnosis and effective treatments targeting the underlying pathology.

Outcomes of Modified Mayo Stage IIIa and IIIb Cardiac Light-Chain Amyloidosis: Real-World Experience in Clinical Characteristics and Treatment-67 Patients Multicenter Analysis

Light-chain amyloidosis (AL) is a rare multisystem disorder characterized by the deposition of misfolded amyloid fibrils derived from monoclonal immunoglobulin light chains in various organs. One of the most common organs involved in AL is the heart, with 50-70% of patients clinically symptomatic at diagnosis. We conducted a multi-center, retrospective analysis of 67 patients diagnosed between July 2012 and August 2022 with the European 2012 modification of Mayo 2004 stage III cardiac AL. The most important factors identified in the univariate Cox analysis contributing to a longer OS included Eastern Cooperative Oncology Group performance status (ECOG PS) ≤ 1, New York Heart Association functional classification (NYHA FC) ≤ 2, the use of autologous stem cell transplantation (ASCT) after induction treatment, achieving a hematological response (≥very good partial response) and cardiac (≥partial response) response after first-line treatment. The most important prognostic factors with the most significant impact on OS improvement in patients with modified Mayo stage III cardiac AL identified by multivariate Cox analysis are ECOG PS ≤ 1, NYHA FC ≤ 2, and achieving hematological response ≥ VGPR and cardiac response ≥ PR after first-line treatment.

The mechanism of action, pharmacological characteristics, and clinical utility of the amyloid depleter birtamimab for the potential treatment of AL amyloidosis

Amyloid light chain (AL) amyloidosis is a progressive plasma cell disorder caused by amyloid deposition resulting in organ damage and failure. Current standard-of-care treatments target clonal plasma cells, the source of misfolded light chains (amyloid precursors), yet only half of patients with advanced disease survive ≥6 months. The amyloid depleter birtamimab is an investigational humanized monoclonal antibody that binds misfolded κ and λ light chains with high specificity and was designed to neutralize soluble toxic light chain aggregates and promote phagocytic clearance of deposited amyloid. Post hoc analyses from the Phase 3 VITAL trial suggested birtamimab plus standard of care confers a survival benefit in patients with advanced (Mayo Stage IV) AL amyloidosis. AFFIRM-AL (NCT04973137), a Phase 3 confirmatory trial of birtamimab plus standard of care in patients with Mayo Stage IV AL amyloidosis, is ongoing. This review summarizes birtamimab's mechanism of action, attributes, and potential clinical utility.

[Diagnostics of cardiac amyloidosis]

The early diagnosis of cardiac amyloidosis is decisive for the success of treatment of affected persons. The thorough clinical investigation of the patient should be followed by appropriate diagnostics using modern procedures. The main symptoms are dyspnea, loss of performance and edema and in later stages cardiac arrhythmias in the form of atrioventricular conduction disturbances and atrial fibrillation but ventricular arrhythmias occur more rarely. During heart failure due to cardiac amyloidosis an increase of cardiac enzymes frequently occurs (e.g., creatine kinase, troponin, N‑terminal pro-brain natriuretic peptide), which can be included in the risk stratification and treatment monitoring, taking certain limitations into consideration. The investigation of light chains in serum and/or urine should be carried out immediately, as soon as there is a clinical and echocardiographic suspicion of cardiac amyloidosis. Subsequently, either cardiac magnetic resonance imaging (MRI) or bone scintigraphy should be carried out, depending on the locally available options. Depending on the results of these two imaging procedures, a decision must be made as to whether further diagnostic steps (e.g., endomyocardial biopsy) are necessary. In the last decade bone scintigraphy has proven to be a blessing for the diagnostics of cardiac amyloidosis but many partial aspects and limitations necessitate special and careful consideration. A Perugini score of 2 or 3 is initially "indicative" of cardiac amyloidosis but not yet "confirmative" for a specific subtype. Only after an additional negative result of the light chain determination, can the diagnosis of ATTR amyloidosis be noninvasively made. Cardiac amyloidosis shows a particularly characteristic contrast enhancement in cardiac MRI, which mostly begins in the inner (subendocardial) layers of the basal left ventricular (LV) wall and frequently appears to be circular in the cross-sectional view of the left ventricle. Supplementary T1 and extracellular volume fraction mapping results, which are shown as color-coded maps, enable the rapid and elegant assessment of the myocardial structure and the extent of amyloid deposition. An additional investigation of the TTR gene is recommended in the case of ATTR amyloidosis for a differentiation between hereditary and acquired ATTR, as from this, further therapeutic consequences can be derived.

[Systemic forms of amyloidosis with cardiac manifestation]

The term amyloidosis summarizes heterogeneous diseases in which a misfolding of protein structures occurs. These misfolded proteins can fundamentally be deposited anywhere in the body and lead to malfunction of the affected organ. There are preferential sites of deposition depending on which protein is misfolded. Cardiac transthyretin (ATTR) amyloidosis is a rare cause of cardiomyopathy and part of an underdiagnosed systemic disease. For cardiac ATTR amyloidosis, which involves deposition of misfolded tranthyretin either as a wild type (wtATTR) or as a mutated form (mATTR or hATTR), evidence-based treatment options have recently become available with slowing of the progression of the cardiomyopathy and a significant reduction of hospitalization rates. Therefore, it is important to diagnose this severe disease at an early stage and to differentiate it from other forms of amyloidosis. A clinical screening is easily possible by determination of free light chains using imaging examinations (cardiac magnetic resonance imaging or scintigraphic procedures) and immunofixation before the definitive diagnosis is made based on a biopsy and/or genetic tests. An interdisciplinary work-up involving hemato-oncology, nephrology, neurology and other disciplines, is indispensable when cardiac amyloidosis is suspected.

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.

Amyloidoma and Plasmacytoma Presented as a Solitary Lung Nodule in a Patient of Multiple Myeloma With AL-Amyloidosis: A Case Report and Review of Literature

Nodular amyloidoma in the lungs is a rare entity, also the occurrence of extramedullary plasmacytoma (EMP) in the lungs is rare. To have concomitant EMP and amyloidoma presented as a single lung mass is even rarer. There was only one similar case reported in the abstract form previously. Our case did not respond to many novel chemotherapy agents, suggesting that this combination of amyloidoma and plasmacytoma belonged to a poor prognosis entity, requiring different treatment modalities, such as early bone marrow transplantation or CART (chimeric antigen receptors T) therapy.

Amyloidosis: What does pathology offer? The evolving field of tissue biopsy

Since the mid-nineteenth century pathology has followed the convoluted story of amyloidosis, recognized its morphology in tissues and made identification possible using specific staining. Since then, pathology studies have made a significant contribution and advanced knowledge of the disease, so providing valuable information on the pathophysiology of amyloid aggregation and opening the way to clinical studies and non-invasive diagnostic techniques. As amyloidosis is a heterogeneous disease with various organ and tissue deposition patterns, histology evaluation, far from offering a simple yes/no indication of amyloid presence, can provide a wide spectrum of qualitative and quantitative information related to and changing with the etiology of the disease, the comorbidities and the clinical characteristics of patients. With the exception of cardiac transthyretin related amyloidosis cases, which today can be diagnosed using non-biopsy algorithms when stringent clinical criteria are met, tissue biopsy is still an essential tool for a definitive diagnosis in doubtful cases and also to define etiology by typing amyloid fibrils. This review describes the histologic approach to amyloidosis today and the current role of tissue screening biopsy or targeted organ biopsy protocols in the light of present diagnostic algorithms and various clinical situations, with particular focus on endomyocardial and renal biopsies. Special attention is given to techniques for typing amyloid fibril proteins, necessary for the new therapies available today for cardiac transthyretin related amyloidosis and to avoid patients receiving inappropriate chemotherapy in presence of plasma cell dyscrasia unrelated to amyloidosis. As the disease is still burdened with high mortality, the role of tissue biopsy in early diagnosis to assure prompt treatment is also mentioned.

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.

Treatment patterns and outcomes in light chain amyloidosis: An institutional registry of amyloidosis report in Argentina

Light chain (AL) amyloidosis is a form of systemic amyloidosis, causing organ dysfunction, mainly affecting the heart and kidney. Patient-tailored and risk-adapted decision making is critical in AL amyloidosis management. There is limited real-world evidence data from Argentina and Latin America regarding the treatment approaches for AL amyloidosis. This retrospective cohort study aimed to describe the treatment patterns and outcomes in adult patients (>18 years) diagnosed with AL amyloidosis at the Hospital Italiano in Buenos Aires, Argentina, using a 10-yearfollow-up data (June 1, 2010 to May 31, 2019) from the institutional registry of amyloidosis (IRA). The study population had a mean age of 63 years and 54.4% weremale. Heart and kidney were the most frequently affected organs. Of the 90 eligible patients included in the study, 70underwent treatment. Bortezomib-based regimen was the preferred first-line treatment (75.7% patients). Overall,54.4% of the patients presented a deep response (complete or very good partial response). Median overall survival (OS) was 5years, the 1-year OS and progression free survival rates were 80% (95% confidence interval [CI]: 68–87) and 80% (95%CI 68–87)), respectively. This study provides vital real-world evidence for the long-term treatment patterns and survival in a large cohort of AL amyloidosis patients in Argentina.

Real world data on light chain cardiac amyloidosis: Still a delayed diagnosis

Cardiac amyloidosis (CA) represents a myocardial disorder developed by fibril deposition of a heterogeneous group of misfolding proteins. Despite being rare, a high clinical index of suspicion and novel advanced diagnostic methods seem to facilitate its early recognition. Currently nine types of cardiac amyloidosis have been described with AL and ATTR being the most common. Light chain amyloidosis (AL) is a life-threatening disease, resulting from clonal plasma cells that produce amyloidogenic light chain fragments causing organ damage including the heart. Morbidity and mortality of these patients is strongly associated with the severity of cardiac involvement. Thus, early and precise diagnosis is crucial for prompt treatment initiation. In this study, we retrospectively analyzed data of 36 consecutive patients who were diagnosed with AL amyloidosis and treated in our center over the past 15 years. Heart involvement was present in 33 (92%) of them while 76% had severe cardiac disease as of stage IIIa and IIIb, according to the Mayo2004/European staging system. Almost one third of these patients experienced an early death occurring the first five months of diagnosis. To capture everyday clinical practice, we provide details on clinical presentation, diagnostic challenges, and outcome of these patients.

PARACENTRAL ACUTE MIDDLE MACULOPATHY IN CENTRAL RETINAL VEIN OCCLUSION COMPLICATING AMYLOID LIGHT-CHAIN AMYLOIDOSIS

PURPOSE

To describe a case of paracentral acute middle maculopathy associated with central retinal vein occlusion in a patient affected by amyloid light-chain amyloidosis.

METHODS

One patient with confirmed diagnosis of amyloid light-chain amyloidosis, displaying paracentral acute middle maculopathy and central retinal vein occlusion, was recruited. The patient underwent complete ophthalmologic examination and multimodal imaging, including: fundus autofluorescence, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and optical coherence tomography angiography.

RESULTS

Fundus autofluorescence showed a ferning pattern, corresponding to linear hypofluorescence in late-phase indocyanine green angiography and delayed venous filling, detected by fluorescein angiography. Structural optical coherence tomography revealed a hyper-reflective line located in the outer plexiform layer, corresponding to the prominent middle limiting membrane, along with several placoid lesions. Optical coherence tomography angiography found that the superficial capillary plexus was preserved, whereas vessel density was reduced in both the deep capillary plexus and the choriocapillaris. After 1 year of follow-up, the patient achieved an almost complete morphological recovery.

CONCLUSION

Multimodal imaging described in depth the morphological features of a case of combined paracentral acute middle maculopathy and central retinal vein occlusion in a patient affected by amyloid light-chain amyloidosis.

Local Insulin-Derived Amyloidosis Model Confronted with Silymarin: Histological Insights and Gene Expression of MMP, TNF-α, and IL-6

Amyloidosis is a heterogeneous group of protein deposition diseases associated with the presence of amyloid fibrils in tissues. Analogs of insulin that are used for treating diabetic patients (including regular insulin) can form amyloid fibrils, both in vitro and in vivo as reported in patients. The main purpose of this study was the induction of localized insulin-generated amyloidosis and the observation of silymarin effects on this process. In order to obtain amyloid structures, regular insulin was incubated at 37 °C for 24 h. Congo red absorbance and transmission electron microscopy images validated the formation of amyloid fibrils. Those fibrils were then injected subcutaneously into rats once per day for 6, 12 or 18 consecutive days in the presence or absence of silymarin, and caused development of firm waxy masses. These masses were excised and stained with Hematoxylin and Eosin, Congo red and Thioflavin S. Histological examination showed adipose cells and connective tissue in which amyloid deposition was visible. Amyloids decreased in the presence of silymarin, and the same effect was observed when silymarin was added to normal insulin and injected subsequently. Furthermore, plasma concentrations of MMP2, TNF-α, and IL-6 inflammatory factors were measured, and their gene expression was locally assessed in the masses by immunohistochemistry. All three factors increased in the amyloidosis state, while silymarin had an attenuating effect on their plasma levels and gene expression. In conclusion, we believe that silymarin could be effective in counteracting insulin-generated local amyloidosis.

When to Suspect and How to Approach a Diagnosis of Amyloidosis

Diagnoses of amyloidosis, particularly transthyretin amyloid cardiomyopathy (ATTR-CM), are steadily increasing throughout the world, but the condition remains underdiagnosed. Patients with amyloidosis may present to a range of medical and surgical specialties, often with multisystemic disease, and a high index of clinical suspicion is required for diagnosis. Bone scintigraphy and cardiovascular magnetic resonance (CMR) imaging offer highly sensitive and specific imaging modalities for cardiac amyloidosis. Histological confirmation of amyloid deposition and amyloid type remains the cornerstone of diagnosis for most amyloid types, with transthyretin amyloid cardiomyopathy the exception, which may be diagnosed by validated nonbiopsy diagnostic criteria in the majority. Histological diagnosis of amyloid has been enhanced by laser capture microdissection and tandem mass spectrometry. Early diagnosis and treatment prior to the development of end-organ damage remains essential to improving morbidity and mortality for patients with amyloidosis.

Coexistent transthyretin amyloid cardiomyopathy and monoclonal gammopathy: Diagnostic challenges and prognostic implications

Establishing an accurate diagnosis of amyloid subtype in patients with coexistent cardiac amyloidosis and monoclonal gammopathy is crucial due to treatment and prognostic implications. Here, we discuss a case of coexistent diagnoses of transthyretin amyloid cardiomyopathy and smoldering multiple myeloma, highlighting the challenges associated with the possibility of several disease combinations and the limitations of diagnostic testing. In addition, the importance of clinical clues such as disease course and progression, patient preference, and multidisciplinary collaboration should not be discounted in the diagnostic and management approach of these patients.

Systematic literature review of evidence in amyloid light-chain amyloidosis

Introduction: Treatment of amyloid light-chain (AL) amyloidosis, a rare disease with a <5-year lifespan, remains challenging. This systematic literature review (SLR) aimed to evaluate the current evidence base in AL amyloidosis. Methods: Literature searches on clinical, health-related quality of life, economic and resource use evidence were conducted using the Embase, MEDLINE and Cochrane databases as well as gray literature. Results: This SLR yielded 84 unique studies from: five randomized controlled trials; 54 observational studies; 12 health-related quality of life studies, none with utility values; no economic evaluation studies; and 16 resource use studies, none with indirect costs. Conclusion: This SLR highlights a paucity of published literature relating to randomized controlled trials, utility values, economic evaluations and indirect costs in AL amyloidosis.

Physiology, Diagnosis and Treatment of Cardiac Light Chain Amyloidosis

AL (light-chain) amyloidosis is a systemic disease in which amyloid fibers are formed from kappa or lambda immunoglobulin light chains, or fragments thereof, produced by a neoplastic clone of plasmocytes. The produced protein is deposited in tissues and organs in the form of extracellular deposits, which leads to impairment of their functions and, consequently, to death. Despite the development of research on pathogenesis and therapy, the mortality rate of patients with late diagnosed amyloidosis is 30%. The diagnosis is delayed due to the complex clinical picture and the slow progression of the disease. This is the type of amyloidosis that most often contributes to cardiac lesions and causes cardiac amyloidosis (CA). Early diagnosis and correct identification of the type of amyloid plays a crucial role in the planning and effectiveness of therapy. In addition to standard histological studies based on Congo red staining, diagnostics are enriched by tests to determine the degree of cardiac involvement. In this paper, we discuss current diagnostic methods used in cardiac light chain amyloidosis and the latest therapies that contribute to an improved patient prognosis.

Cu(II) Binding Increases the Soluble Toxicity of Amyloidogenic Light Chains

Light chain amyloidosis (AL) is caused by the aberrant overproduction of immunoglobulin light chains (LCs). The resulting abnormally high LC concentrations in blood lead to deposit formation in the heart and other target organs. Organ damage is caused not only by the accumulation of bulky amyloid deposits, but extensive clinical data indicate that circulating soluble LCs also exert cardiotoxic effects. The nematode C. elegans has been validated to recapitulate LC soluble toxicity in vivo, and in such a model a role for copper ions in increasing LC soluble toxicity has been reported. Here, we applied microscale thermophoresis, isothermal calorimetry and thermal melting to demonstrate the specific binding of Cu²⁺ to the variable domain of amyloidogenic H7 with a sub-micromolar affinity. Histidine residues present in the LC sequence are not involved in the binding, and yet their mutation to Ala reduces the soluble toxicity of H7. Copper ions bind to and destabilize the variable domains and induce a limited stabilization in this domain. In summary, the data reported here, elucidate the biochemical bases of the Cu²⁺-induced toxicity; moreover, they also show that copper binding is just one of the several biochemical traits contributing to LC soluble in vivo toxicity.

Adequate Antibody Response to COVID-19 Vaccine in Patients with Monoclonal Gammopathies and Light Chain Amyloidosis

OBJECTIVE

Determine the COVID-19 seroconversion rate for patients with multiple myeloma receiving a COVID-19 vaccine.

MATERIALS AND METHODS

After 45 patients received their second COVID-19 vaccine dose, their serum IgG antibodies were measured: 22 with monoclonal gammopathy (MG) of unknown significance, 3 with smoldering myeloma, 2 with light chain amyloidosis, and 18 with MG (9 in remission, 6 out of remission, and 3 with free light-chain gammopathy alone). A second serum specimen was retained for 16 patients with MG. Their antibody levels were compared to those of 78 uninfected healthy vaccinated control patients.

RESULTS

Three patients with MG had low antibody levels on blood collected 98, 100, and 113 days after the initial vaccine dose (2 with MG of unknown significance and 1 with hypogammaglobulemia). The other 40 patients with MG (seroconversion rate 93%) and both patients with amyloidosis produced antibodies. Relative to days after vaccination, patients with MG had lower antibody levels than control patients.

CONCLUSION

After receiving a COVID-19 vaccine, most patients with MG produce anti-SARS-CoV-2 antibodies comparable to levels in uninfected vaccinated healthy control patients.

Outcomes of bortezomib combination chemotherapies in autologous stem cell transplantation-ineligible patients with AL amyloidosis

Background

Treatment protocols for light chain (AL) amyloidosis have been derived from myeloma treatment. Bortezomib is a key drug used for the treatment of myeloma and AL amyloidosis. We retrospectively investigated the efficacy and toxicity of bortezomib- based chemotherapy in patients with newly diagnosed AL amyloidosis.

Methods

We reviewed the outcomes of newly diagnosed autologous stem cell transplantation (auto-SCT)-ineligible AL amyloidosis patients who received bortezomib-based chemotherapy at a referral center between 2011 and 2017.

Results

Of 63 patients who received bortezomib-based chemotherapy, 32 were male, and the median age was 66 years (range, 42‒82 yr). The hematologic overall response rate (ORR) was 65.1%, and the chemotherapy regimen with the best hematologic response was VMP (75.7%, 28/37). Sixty patients had significant organ (heart or kidney) involvement; 28.3% of patients (N=17) had major organ responses after chemotherapy. With a median follow- up of 34 months, there was no significant difference in progression-free survival (P=0.49) or overall survival (P =0.67) according to regimen. Most hematologic and non-hematologic problems were manageable.

Conclusion

Various chemotherapy combinations based on bortezomib are currently employed in the clinical setting, but no difference was found in terms of efficacy or toxicity.

Three Primary Cancers in a Veteran With Agent Orange and Agent Blue Exposures

A Vietnam War veteran's exposures likely contributed to his cancer diagnoses, but these associations are confounded by his substance use, particularly cigarette smoking.

Silver Nanoparticles as a Tool for the Study of Spontaneous Aggregation of Immunoglobulin Monoclonal Free Light Chains

Some misfolded proteins, e.g., immunoglobulin monoclonal free light chains (FLC), tend to form fibrils. Protein deposits in tissue may lead to amyloidosis and dysfunction of different organs. There is currently no technique allowing for the identification of FLC that are prone to aggregate. The development of such a method would enable the early selection of patients at high risk of developing amyloidosis. The aim of this study was to investigate whether silver nanoparticles (AgNPs) could be a useful tool to study the process of aggregation of FLC and their susceptibility to form the protein deposits. Mixtures of AgNPs and urine samples from patients with multiple myeloma were prepared. To evaluate the aggregation process of nanoparticles coated with proteins, UV-visible spectroscopy, transmission electron microscopy, and the original laser light scattering method were used. It has been shown that some clones of FLC spontaneously triggered aggregation of the nanoparticles, while in the presence of others, the nanoparticle solution became hyperstable. This is probably due to the structure of the chains themselves, unique protein-AgNPs interactions and perhaps correlates with the tendency of some FLC clones to form deposits. Nanoparticle technology has proven to be helpful in identifying clones of immunoglobulin FLC that tend to aggregate.

Advances in Diagnosis and Treatment of Cardiac and Renal Amyloidosis

Diagnoses of amyloidosis are increasing annually, and advances in bone scintigraphy and cardiac MRI accompanied by development of nonbiopsy diagnostic criteria have specifically led to a huge increase in transthyretin amyloidosis cardiomyopathy (ATTR-CM) diagnoses worldwide. Tafamidis use is increasing, and there are several ongoing phase III clinical trials of novel agents that promise to transform the treatment landscape for patients with ATTR-CM. In systemic light chain (AL) amyloidosis, more effective chemotherapeutic agents continue to improve patient outcomes. Accelerating the removal of amyloid deposits to accompany these therapies remains the holy grail. However, in the meantime, early diagnosis is undoubtedly key in improving patient outcomes.

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.

Diagnosing Systemic Amyloidosis Presenting as Carpal Tunnel Syndrome: A Risk Nomogram to Guide Biopsy at Time of Carpal Tunnel Release

BACKGROUND

As carpal tunnel syndrome often precedes other signs of systemic amyloidosis, tenosynovial biopsy at the time of carpal tunnel release may facilitate early diagnosis and treatment. However, evidence-based guidelines for amyloidosis screening during carpal tunnel release have not been established. We sought to develop a predictive model for amyloidosis after carpal tunnel release to inform screening efforts.

METHODS

We performed a retrospective cohort study of adults without known amyloidosis undergoing at least 1 carpal tunnel release from 2000 to 2019 with use of the national Veterans Health Administration database. After estimating the cumulative incidence of amyloidosis after carpal tunnel release, we identified risk factors, constructed a predictive nomogram based on a multivariable subdistribution-hazard competing-risks model, and performed cross-validation.

RESULTS

Among 89,981 patients undergoing at least 1 carpal tunnel release, 310 were subsequently diagnosed with amyloidosis at a median interval of 4.5 years, corresponding to a cumulative incidence of 0.55% (95% confidence interval [CI]: 0.47% to 0.63%) at 10 years. Amyloidosis diagnosis following carpal tunnel release was associated with an increased hazard of heart failure (hazard ratio [HR], 4.68; 95% CI: 4.26 to 5.55) and death (HR, 1.27; 95% CI: 1.07 to 1.51) after adjustment for potential confounders. Age, male sex, Black race, monoclonal gammopathy of undetermined significance or multiple myeloma, rheumatoid arthritis, atrial fibrillation, spinal stenosis, and bilateral carpal tunnel syndrome were independently associated with increased risk of amyloidosis diagnosis and were included in the risk nomogram.

CONCLUSIONS

Amyloidosis diagnosis after carpal tunnel release is rare but is associated with poor outcomes. We present an amyloidosis-risk nomogram to help guide tenosynovial biopsy at time of carpal tunnel release.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Diagnosis and treatment of cardiac amyloidosis: position statement of the German Cardiac Society (DGK)

Systemic forms of amyloidosis affecting the heart are mostly light-chain (AL) and transthyretin (ATTR) amyloidoses. The latter is caused by deposition of misfolded transthyretin, either in wild-type (ATTRwt) or mutant (ATTRv) conformation. For diagnostics, specific serum biomarkers and modern non-invasive imaging techniques, such as cardiovascular magnetic resonance imaging (CMR) and scintigraphic methods, are available today. These imaging techniques do not only complement conventional echocardiography, but also allow for accurate assessment of the extent of cardiac involvement, in addition to diagnosing cardiac amyloidosis. Endomyocardial biopsy still plays a major role in the histopathological diagnosis and subtyping of cardiac amyloidosis. The main objective of the diagnostic algorithm outlined in this position statement is to detect cardiac amyloidosis as reliably and early as possible, to accurately determine its extent, and to reliably identify the underlying subtype of amyloidosis, thereby enabling subsequent targeted treatment.

One Hundred Cases of Localized Laryngeal Amyloidosis - Evidence for Future Management

OBJECTIVE/HYPOTHESIS

To update the current understanding of localized laryngeal amyloidosis by analyzing the NHS National Amyloidosis Database and to further clarify the important ongoing management issues.

STUDY DESIGN

Retrospective review, case series.

METHODS

Patients with laryngeal amyloid were identified from the database of the NHS National Amyloidosis Center, UCL, Royal Free Hospital, London between 2000 and 2017. Patient demographics and disease profile were collated, including the exact location of amyloid deposit, treatments if any, and progression of disease.

RESULTS

One hundred and three patients with localized laryngeal amyloid where identified from the database, with a mean age of 54 at diagnosis and female to male ratio of 54:49. Three patients were excluded from further analysis due to limited database information. The majority of amyloid was found in either the supraglottis (44) or glottis (53) but all the laryngeal subsites were involved. One-third of the patients (34) had amyloid in more than one laryngeal subsite. No patients were found to progress to systemic amyloid, but many progressed locally to other subsites or further down the LTB tree (29%). Three patients were successfully treated with radiotherapy after other modalities had failed.

CONCLUSIONS

This is the largest case series reported to date of localized laryngeal amyloidosis. It highlights the high incidence of multifocal disease and the significant proportion of patients who progressed, not to systemic amyloidosis but to more extensive localized amyloid. We recommend that in all cases of laryngeal amyloid, patients should undergo a thorough assessment of the upper and lower airways and have ongoing surveillance for at least 15 years.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1912-E1917, 2021.

Non-invasive detection and differentiation of cardiac amyloidosis using 99mTc-pyrophosphate scintigraphy and 11C-Pittsburgh compound B PET imaging

PURPOSE

To investigate the utility of the combined use of ¹¹C-Pittsburgh compound B (¹¹C-PiB) positron emission tomography (PET) imaging and ^99mTc-pyrophosphate (^99mTc-PYP) scintigraphy for detection and differentiation of three major types of cardiac amyloidosis, i.e. immunoglobulin light chain (AL), hereditary transthyretin (ATTRv), and wild-type transthyretin (ATTRwt) amyloidosis.

METHODS

Whole-body ¹¹C-PiB PET and ^99mTc-PYP scintigraphy were performed in 17 patients with AL amyloidosis, 22 patients with ATTRv, and eight patients with ATTRwt amyloidosis. The correlations between organ involvement and the uptake of ¹¹C-PiB and ^99mTc-PYP were analyzed in each patient.

RESULTS

Cardiac amyloidosis was detectable by ^99mTc-PYP scintigraphy or ¹¹C-PiB PET in all systemic amyloidosis patients with cardiac involvement. ^99mTc-PYP scintigraphy and ¹¹C-PiB PET showed an interesting complementary relation. Strict combination of positive ¹¹C-PiB and negative ^99mTc-PYP uptake (PiB pattern) was observed in all AL amyloidosis patients with cardiac involvement. In contrast, strict combination of positive ^99mTc-PYP and negative ¹¹C-PiB uptake (PYP pattern) was observed in all ATTRwt amyloidosis patients with cardiac involvement. ATTRv amyloidosis patients with cardiac involvement were divided into two groups: PiB pattern or PYP pattern. All of the early-onset V30M (p.V50M) ATTRv patients showed the PiB pattern, whereas all of the late-onset V30M and non-V30M ATTRv patients showed the PYP pattern.

CONCLUSIONS

All three major types of cardiac amyloidosis can be detected and differentiated non-invasively by combined use of the two amyloid imaging methods and TTR gene testing.

Systemic Amyloidosis Due to Clonal Plasma Cell Diseases

Immunoglobulin light chain amyloidosis is the most common systemic amyloidosis. The pathogenetic mechanism is deposition of fibrils of misfolded immunoglobulin free light chains, more often lambda, typically produced by clonal plasma cells. Distinct Ig light chain variable region genotypes underlie most light chain amyloidosis and dictate tissue tropism. Light chain amyloidosis fibrils cause distortion of the histologic architecture and direct cytotoxicity, leading to rapidly progressive organ dysfunction and eventually patient demise. A high index of clinical suspicion with rapid tissue diagnosis and commencement of combinatorial, highly effective cytoreductive therapy is crucial to avoid irreversible organ damage and early mortality.

[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.

[Suspected cardiac amyloidosis - diagnostic steps for evaluation]

Cardiac amyloidosis is a rare cause of cardiomyopathy, however, it is part of an underdiagnosed underlying systemic disease. For transthyretin (ATTR) amyloidosis, which is caused by the deposition of incorrectly folded transthyretin, either as the wild-type (wtATTR) or mutated (mATTR) form, novel evidence-based treatment options were recently shown to reduce disease progression as well as hospitalisation rates for heart failure. Thus, it is important to establish early and reliable diagnosis of cardiac involvement with ATTR amyloidosis.Modern non-invasive imaging (cardio magnetic resonance (CMR) and scintigraphic methods) together with immune fixation with determination of free light chains allow fast and reliable clinical screening for cardiac amyloidosis, whereas endomyocardial biopsy and genetics are used for confirmation of the underlying diagnosis. Interdisciplinary teams including hemato-oncology, neurology, nephrology in addition to cardiology are essential to enable personalized targeted treatment strategies.

[Monoclonal gammapathy of renal significance (MGRS) at the current state: terminology, diagnosis and treatment]

In this article we discussed the current state of monoclonal gammapathy of renal significance (Monoclonal Gammopathy of Renal Significance MGRS) and revealed problems of B-cell clone secreting nephrotoxic monoclonal immunoglobulin identification. We followed 276 patients with monoclonal gammapathy including patients with non-amyloid nephropathy. The majority of patients had systemic AL-amyloidosis. We established better survival of the treated patients with systemic AL-amyloidosis in comparison with retrospective untreated cohort. We considered current treatment of patients with non-amyloid nephropathy and focused on the crucial role of multidisciplinary approach in management of these patients.

Antibody-based immunotherapy for treatment of immunoglobulin light-chain amyloidosis

Immunoglobulin light-chain (AL) amyloidosis is a clonal plasma cell disorder characterised by production and deposition of misfolded monoclonal light chains in vital organs with potential to cause irreversible organ damage. The treatment of AL amyloidosis has evolved along the lines of multiple myeloma (MM) owing to clonal plasma cells being at the root of both disease processes. Treatment with melphalan and autologous haematopoietic cell transplantation, as well as proteasome inhibitors and immunomodulatory agents, are the standard of care for AL amyloidosis. While these treatment modalities are highly effective against the neoplastic plasma cells, patients often relapse and those with advanced disease may be unable to tolerate these treatments due to side-effects. Immunotherapy with monoclonal antibodies, bispecific antibodies, antibody-drug conjugates and chimeric antigen receptor T cells have revolutionised the treatment armamentarium for MM. These novel immunotherapy agents are in the early phases of evaluation and clinical development for patients with AL amyloidosis. The present review aims to discuss the role of novel immunotherapies currently in development and their potential for use in the treatment of AL amyloidosis.

[The prognostic value of baseline serum free light chain in immunoglobulin light-chain cardiac amyloidosis]

Objective: To analyze the prognostic value of baseline serum free light chain (sFLC) in immunoglobulin light-chain cardiac amyloidosis (AL-CA) . Methods: Thirty patients diagnosed with AL-CA from January 2012 to December 2016 at Beijing Chaoyang Hospital were included in this study to retrospectively evaluate the clinical data. The cut-off value of dFLC (involved sFLC minus uninvolved sFLC) was determined according to the receiver operator characteristic curve (ROC) and grouped, the prognoses of both groups were evaluated. Results: The onset age of all AL-CA patients was 57 years old. It occurred more commonly in men (21 cases, 70%) and the light chains of immunoglobulin composed mainly of type λ (22 cases, 73.3%) . Renal involvements occurred in 17 cases (56.7%) . The median value of difference between involved and uninvolved serum immunoglobulin free light chain levels (dFLC) was 162.9 (57.9-401.6) mg/L. More subjects in the high dFLC group had higher BNP (P=0.005) , and shorter median survival than those in the low dFLC group (15 months vs 47 months, P<0.001) . Similar results of median survival were observed when the patients were redivided by a new cut-off value of 180 mg/L for dFLC (high dFLC group: 22 months, low dFLC group: 40 months, P=0.001) , or a κ/λ ratio in which patients with κ type sFLC-ratio<3.79 and λ type sFLC-ratio≥0.06 were grouped into the low sFLC-ratio (37 months) , and the reverse the high sFLC-ratio ones (25 months, P=0.021) . In multivariate analysis, dFLC and New York Heart Association (NYHA) classification of cardiac function were two risk factors associated with all-cause mortality in patients, of them the hazard ratio for higher dFLC was 12.13 (95%CI 2.98-49.30, P<0.001) . Conclusion: Measurement of the sFLC level could implicate the prognosis of AL-CA.

Clinical Profile of Patients with Head and Neck Amyloidosis: A Single-Institution Retrospective Chart Review

Introduction  Isolated amyloidosis involving the head and neck is a rare entity. The pathophysiology of the localized disease appears to be distinct from that of the systemic counterpart. Systemic progression of the localized disease is unusual, and the prognosis of the localized form is excellent.

Objective  To describe the demographic and clinicopathological characteristics of patients presenting with localized head and neck subsite amyloidosis.

Methods  A retrospective chart review of the patients with head and neck amyloidosis identified by the electronic search of the electronic database of the Departments of Pathology and Otorhinolaryngology was performed. The various demographic and clinical data were tabulated.

Results  In total, seven patients (four females, three males) with localized head and neck amyloidosis (three supraglottic, three lingual and one sinonasal) were identified. Six patients had AL-amyloid deposits, and one patient had AA-amyloid deposits. Supraglottic involvement and that of the base of the tongue were treated surgically using CO2 laser, and these patients were disease-free at the last follow-up. The patient with sinonasal amyloidosis experienced symptom recurrence after six months of the functional endoscopic sinus surgery. All of the patients were screened for systemic amyloidosis with abdominal fat pad biopsy, and were found to be free of systemic spread.

Conclusion  Isolated head and neck amyloidosis, as opposed to systemic amyloidosis, has an excellent prognosis in terms of survival. Therefore, systemic amyloidosis should be excluded in all cases. The treatment of choice remains surgical excision; however, watchful waiting may be a suitable strategy for mild symptoms or for cases in which the disease was discovered incidentally.

Human amyloidosis, still intractable but becoming curable: The essential role of pathological diagnosis in the selection of type-specific therapeutics

The molecular pathogenesis of human amyloidosis has been elucidated greatly during the last 20 years. Based on the understanding of the molecular mechanisms of amyloid fibril formation and deposition, various kinds of new drugs and therapeutics have been emerging to improve the prognosis of amyloidosis and even cure this disease. In this review article, we first summarize the pathogenesis and state-of-the-art therapeutics of representative types of systemic human amyloidosis, that is, immunoglobulin light chain-related, transthyretin-related, amyloid A-associated and β₂ -microglobulin-related amyloidosis. Next, we describe the essential roles of pathological diagnosis, especially the typing diagnosis of amyloidosis to appropriately guide type-specific therapies of amyloidosis patients. Finally, we introduce the activities of the government-funded group for surveys and research of amyloidosis in Japan, especially the nation-wide pathology consultation system of amyloidosis, which started in April 2018. The nation-wide improvement of the typing diagnosis of amyloidosis is essential for the appropriate treatment and care of amyloidosis patients in Japan.

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.

Inherent Biophysical Properties Modulate the Toxicity of Soluble Amyloidogenic Light Chains

In light chain amyloidosis (AL), fibrillar deposition of monoclonal immunoglobulin light chains (LCs) in vital organs, such as heart, is associated with their severe dysfunction. In addition to the cellular damage caused by fibril deposition, direct toxicity of soluble prefibrillar amyloidogenic proteins has been reported, in particular, for cardiotoxicity. However, the molecular bases of proteotoxicity by soluble LCs have not been clarified. Here, to address this issue, we rationally engineered the amino acid sequence of the highly cardiotoxic LC H6 by introducing three residue mutations, designed to reduce the dynamics of its native state. The resulting mutant (mH6) is less toxic than its parent H6 to human cardiac fibroblasts and C. elegans. The high sequence and structural similarity, together with the different toxicity, make H6 and its non-toxic designed variant mH6 a test case to shed light on the molecular properties underlying soluble toxicity. Our comparative structural and biochemical study of H6 and mH6 shows closely matching crystal structures, whereas spectroscopic data and limited proteolysis indicate that H6 displays poorly cooperative fold, higher flexibility, and kinetic instability, and a higher dynamic state in its native fold. Taken together, the results of this study show a strong correlation between the overall conformational properties of the native fold and the proteotoxicity of cardiotropic LCs.