The complementary role of histology and proteomics for diagnosis and typing of systemic amyloidosis

Response rates to second-line treatment with daratumumab bortezomib dexamethasone (DVD) in relapsed/refractory light chain amyloidosis (AL) after initial Bortezomib-based regime

Bortezomib is regularly used as frontline therapy for systemic AL amyloidosis. We assess the efficacy of second-line daratumumab-bortezomib-dexamethasone (DVD) in AL amyloidosis in bortezomib-exposed patients. A total of 116 patients treated with second-line DVD were identified from a prospective observational study of newly diagnosed AL amyloidosis (ALchemy). DVD was initiated in both the relapsed setting or where there was an inadequate response defined as very good partial response (VGPR) or VGPR with organ progression/lack of organ improvement. A complete response (CR)/VGPR to second-line DVD was achieved in 81 (69.8%) patients. A CR/VGPR was achieved in 67 (79.7%) in those who achieved a VGPR/CR to first line versus 14/32 (43.8%) in those who did not. Where DVD was initiated due to an inadequate response to first line (vs. at relapse), the median event-free survival (EFS) was 18 vs. 34 months (p = 0.002). If a CR/VGPR was achieved to DVD, the 2-year EFS was still lower in those with prior inadequate response 54% vs. 66% (p = 0.062). DVD is an efficacious second-line treatment in systemic AL amyloidosis in a bortezomib-exposed population. However, the response to DVD is poorer in those with an inadequate response to first-line bortezomib.

Fine-needle aspiration of amyloidoma: A critical analysis

BACKGROUND

Amyloid, presenting as a mass, is termed amyloidoma. Among the reported cases, fine-needle aspiration (FNA) of amyloid is often misinterpreted as acellular nondiagnostic material.

METHODS

A computer search of all FNAs was performed and cases diagnosed as amyloidoma were identified.

RESULTS

Among 11,956 cases and 20,634 FNAs, there were six cases and 12 FNAs of amyloidoma. One case with mucin/myxoid matrix was misinterpreted as amyloid, which on our review was Congo red negative. All five other cases of amyloidoma were adequate for evaluation. The smears showed most of the aspirated contents in the middle of the slide and it did not spread when smeared. The amyloid was present as large chunks of waxy, smooth, orangophilic/cyanophilic fragments on Papanicolaou stain and as basophilic fragments on Diff-Quik stain in a clean background. In cases with lymphoma/myeloma, there were admixed lymphocytes and/or plasma cells. Unlike fibrous tissue, amyloid aspirates well and provides adequate material for interpretation. The clean background distinguishes it from mucin/myxoid matrix. Congo red stain was positive with apple green birefringence in all five cases. Further subtyping by mass spectrometry showed AL (κ) type in three patients and AIns (insulin) type in one patient. In one patient with lymphoma, the subtyping was not done.

CONCLUSION

FNA of amyloidoma is rare (0.04%), but an optimal method for diagnosis and subtyping, avoiding unwanted surgical interventions. Although mistaken for fibrous tissue, which aspirates poorly, abundant acellular orangophilic/cyanophilic material on FNA should raise a suspicion for amyloid. Unlike mucin/myxoid matrix, amyloid does not smear the background.

Strong positive light chain immunostaining in a patient with transthyretin amyloidosis

The two most common systemic amyloidosis types are immunoglobulin light chain (AL) and amyloid transthyretin (ATTR) amyloidosis, in which the precursor proteins responsible for amyloidosis are light chain and transthyretin, respectively. Identification of precursor proteins is paramount to determine the type of amyloidosis, given that both amyloidosis types lack specificity in clinical presentation. Congo red staining followed by immunohistochemistry or immunofluorescence using fibril protein-specific antibodies is crucial for the diagnosis of amyloidosis. Here we describe a patient who was initially diagnosed with AL amyloidosis due to strong positive kappa light chain staining results. However, the diagnosis was corrected to hereditary ATTR amyloidosis using mass spectrometry and gene sequencing, confirming the important role of mass spectrometry in identifying the amyloid precursor protein and ruling out false-positive result from immunohistochemistry.

Role of EBUS-TBNA/EUS-FNA and mass spectrometry for diagnosis and typing of lymph node amyloidosis: 10-year experience in two tertiary care academic centers

BACKGROUND

The objectives of this study were to investigate the utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA)/endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for the diagnosis of amyloidosis coupled with the feasibility of mass spectrometry (MS) for amyloid subtyping.

METHODS

All patients who had amyloid diagnosed by EBUS-TBNA/EUS-FNA at two tertiary care centers from 2011 to 2020 were retrieved along with the MS subtype, clinical findings, and outcomes.

RESULTS

Eight patients were included: seven underwent EBUS-TBNA of mediastinal lymph nodes, and one underwent EUS-FNA of a periportal lymph node. Ages ranged from 37 to 79 years (median, 69 years), with equal numbers of men and women. Presenting clinical history included one case each of follicular lymphoma, lymphoplasmacytic lymphoma, rheumatoid arthritis, possible sarcoid, cirrhosis, and chronic renal insufficiency, and one case each of suspected pulmonary and cardiac amyloidosis. All cases showed waxy, amorphous material on direct smears (n = 5) or ThinPrep slides (n = 3), which were confirmed as amyloid on Congo Red staining. Immunohistochemistry showed dominant lambda staining in two of three cases. MS was performed in all cases and identified five of the light-chain (AL) type, one of the heavy-chain/AL type, and two suggestive of AL amyloidosis. Bone marrow biopsy performed in seven patients demonstrated that three had monoclonal plasma cells and one had lymphoplasmacytic lymphoma. Two of four patients with systemic amyloidosis received chemotherapy and remained alive, whereas three with localized disease remained stable under observation.

CONCLUSIONS

EBUS-TBNA/EUS-FNA is effective for amyloidosis diagnosis and provides adequate material for ancillary tests, including MS, which can identify the precursor amyloidogenic protein, leading to appropriate patient management.

Precise diagnosis and typing of early-stage renal immunoglobulin-derived amyloidosis by label-free quantification of parallel reaction monitoring-based targeted proteomics

BACKGROUND

Early diagnosis and typing are crucial for improving the prognosis of patients with renal amyloidosis. Currently, Untargeted proteomics based precise diagnosis and typing of amyloid deposits are crucial for guiding patient management. Although untargeted proteomics achieve ultra-high-throughput by selecting the most abundant eluting cationic peptide precursors in series for tandem MS events, it lacks in sensitivity and reproducibility, which may not be suitable for early-stage renal amyloidosis with minor damages. Here, we aimed to develop parallel reaction monitoring (PRM)-based targeted proteomics to achieve high sensitivity and specificity by determining absolute abundances and codetecting all transitions of highly repeatable peptides of preselected amyloid signature and typing proteins in identifying early-stage renal immunoglobulin-derived amyloidosis.

METHODS AND RESULTS

In 10 discovery cohort cases, Congo red-stained FFPE slices were micro-dissected and analyzed by data-dependent acquisition-based untargeted proteomics for preselection of typing specific proteins and peptides. Further, a list of proteolytic peptides from amyloidogenic proteins and internal standard proteins were quantified by PRM-based targeted proteomics to validate performance for diagnosis and typing in 26 validation cohort cases. The diagnosis and typing effectiveness of PRM-based targeted proteomics in 10 early-stage renal amyloid cases was assessed via a comparison with untargeted proteomics. A peptide panel of amyloid signature proteins, immunoglobulin light chain and heave chain in PRM-based targeted proteomics showed significantly distinguishing ability and amyloid typing performance in patients. The diagnostic algorithm of targeted proteomics with a low amount of amyloid deposits in early-stage renal immunoglobulin-derived amyloidosis showed better performance than untargeted proteomics in amyloidosis typing.

CONCLUSIONS

This study demonstrates that the utility of these prioritized peptides in PRM-based targeted proteomics ensure high sensitivity and reliability for identifying early-stage renal amyloidosis. Owing to the development and clinical application of this method, rapid acceleration of the early diagnosis, and typing of renal amyloidosis is expected.

Binding of serum-derived amyloid-associated proteins to amyloid fibrils

BACKGROUND

Amyloid signature proteins such as serum amyloid P component, apolipoprotein E (ApoE), and ApoA-IV generally co-localise with amyloid, regardless of the types of amyloid precursor protein or the organs. Most of these proteins derive from serum and have reportedly been involved in amyloid fibril formation and stabilisation, as well as in excretion and degradation of amyloid precursor proteins. However, the processes and mechanisms by which these specific proteins deposit together with amyloid fibrils have not been clarified.

METHODS

We analysed the binding of serum proteins to amyloid fibrils derived from amyloid β and insulin in vitro by using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

Specific serum proteins including ApoA-I, ApoE, ApoA-IV, ApoC-III and vitronectin adhered to amyloid fibrils at high concentrations in vitro. In addition, the profile of these proteins commonly occurred in both amyloid β and insulin amyloid fibrils and was mostly consistent with the composition of amyloid signature proteins. We also showed that high concentrations of serum proteins can adhere to amyloid fibrils in a short time.

CONCLUSIONS

Our in vitro results suggest that amyloid signature proteins coexist with amyloid primarily dependent on the binding of each serum protein, in the extracellular fluid, to amyloid fibrils.

Cardiac transplantation in transthyretin amyloid cardiomyopathy: Outcomes from three decades of tertiary center experience

Aims

Transthyretin cardiac amyloidosis (ATTR-CM) is a progressive and fatal cardiomyopathy. Treatment options in patients with advanced ATTR-CM are limited to cardiac transplantation (CT). Despite case series demonstrating comparable outcomes with CT between patients with ATTR-CM and non-amyloid cardiomyopathies, ATTR-CM is considered to be a contraindication to CT in some centers, partly due to a perceived risk of amyloid recurrence in the allograft. We report long-term outcomes of CT in ATTR-CM at two tertiary centers.

Materials and methods and Results

We retrospectively evaluated ATTR-CM patients across two tertiary centers who underwent transplantation between 1990 and 2020. Pre-transplantation characteristics were determined and outcomes were compared with a cohort of non-transplanted ATTR-CM patients. Fourteen (12 male, 2 female) patients with ATTR-CM underwent CT including 11 with wild-type ATTR-CM and 3 with variant ATTR-CM (ATTRv). Median age at CT was 62 years and median follow up post-CT was 66 months. One, three, and five-year survival was 100, 92, and 90%, respectively and the longest surviving patient was Censored > 19 years post CT. No patients had recurrence of amyloid in the cardiac allograft. Four patients died, including one with ATTRv-CM from complications of leptomeningeal amyloidosis. Survival among the cohort of patients who underwent CT was significantly prolonged compared to UK patients with ATTR-CM generally (p < 0.001) including those diagnosed under age 65 years (p = 0.008) or with early stage cardiomyopathy (p < 0.001).

Conclusion

CT is well-tolerated, restores functional capacity and improves prognosis in ATTR-CM. The risk of amyloid recurrence in the cardiac allograft appears to be low.

Immunoglobulin Light Chain Amyloidosis: Diagnosis and Risk Assessment

Immunoglobulin light chain (AL) amyloidosis is a clonal plasma cell disorder with multiple clinical presentations. The diagnosis of AL amyloidosis requires a high index of suspicion, making a delay in diagnosis common, which contributes to the high early mortality seen in this disease. Establishing the diagnosis of AL amyloidosis requires the demonstration of tissue deposition of amyloid fibrils. A bone marrow biopsy and fat pad aspirate performed concurrently have a high sensitivity for the diagnosis of AL amyloidosis and negate the need for organ biopsies in most patients. An accurate diagnosis requires amyloid typing via additional testing, including tissue mass spectrometry. Prognostication for AL amyloidosis is largely driven by the organs impacted. Cardiac involvement represents the single most important prognostic marker, and the existing staging systems are driven by cardiac biomarkers. Apart from organ involvement, plasma cell percentage on the bone marrow biopsy, specific fluorescence in situ hybridization findings, age at diagnosis, and performance status are important prognostic markers. This review elaborates on the diagnostic testing and prognostication for patients with newly diagnosed AL amyloidosis.

Current approaches to the diagnosis and management of amyloidosis

Amyloidosis is a collection of diseases caused by the misfolding of proteins that aggregate into insoluble amyloid fibrils and deposit in tissues. While these fibrils may aggregate to form insignificant localised deposits, they can also accumulate in multiple organs to the extent that amyloidosis can be an immediately life-threatening disease, requiring urgent treatment. Recent advances in diagnostic techniques and therapies are dramatically changing the disease landscape and patient prognosis. Delays in diagnosis and treatment remain the greatest challenge, necessitating physician awareness of the common clinical presentations that suggest amyloidosis. The most common types are transthyretin (ATTR) amyloidosis followed by immunoglobulin light-chain (AL) amyloidosis. While systemic AL amyloidosis was previously considered a death sentence with no effective therapies, significant improvement in patient survival has occurred over the past 2 decades, driven by greater understanding of the disease process, risk-adapted adoption of myeloma therapies such as proteosome inhibitors (bortezomib) and monoclonal antibodies (daratumumab) and improved supportive care. ATTR amyloidosis is an underdiagnosed cause of heart failure. Technetium scintigraphy has made noninvasive diagnosis much easier, and ATTR is now recognised as the most common type of amyloidosis because of the increased identification of age-related ATTR. There are emerging ATTR treatments that slow disease progression, decrease patient hospitalisations and improve patient quality of life and survival. This review aims to update physicians on recent developments in amyloidosis diagnosis and management and to provide a diagnostic and treatment framework to improve the management of patients with all forms of amyloidosis.

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.

Amyloidosis of the Heart and Kidney

Amyloidosis encompasses a collection of disorders of pathological protein folding. The extracellular location where these “amyloid fibril” proteins are deposited determines the clinical presentation of the disease. The abnormal architecture of these fibrils makes them insoluble and not easily removed, leading to disruption of normal tissue structure and interference with normal physiology. Amyloidosis of the heart and kidney can be inherited, secondary to unrelated diseases, or due to a plasma cell disorder. This review will focus on immunoglobulin light chain amyloidosis, which is life-threatening and must be diagnosed as early as possible by employing precise and accurate typing to ensure timely and frequently curative therapy.

Characteristics and natural history of early-stage cardiac transthyretin amyloidosis

AIMS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is increasingly diagnosed at an early stage of the disease natural history, defined as National Amyloidosis Centre (NAC) ATTR Stage I. The natural history of early-stage ATTR-CM remains poorly characterized.

METHODS AND RESULTS

A retrospective multi-centre observational study of 879 patients with ATTR-CM, either wild-type TTR genotype or carrying the p.V142I TTR variant, and NAC ATTR Stage I biomarkers at the time of diagnosis who did not receive disease-modifying therapy for amyloidosis. Disease characteristics at diagnosis that were independently associated with mortality by Cox regression analysis were N-terminal pro-B-type natriuretic peptide (NT-proBNP), TTR genotype, and troponin T. Patients were categorized into NAC ATTR Stage Ia, defined as a furosemide equivalent diuretic requirement of <0.75 mg/kg and an NT-proBNP ≤500 ng/L or ≤1000 ng/L in the presence of atrial fibrillation, and NAC ATTR Stage Ib comprising all remaining Stage I patients. Median estimated survival among the 88% NAC ATTR Stage Ib patients was 75 (95% CI 57-93) months compared with >100 months in the 12% with Stage Ia disease [hazard ratio for death 5.06 (95% confidence interval 1.23-20.87); P = 0.025] despite significant cardiovascular morbidity at the time of diagnosis which increased during follow-up, including among patients diagnosed in NAC ATTR Stage Ia. Estimated survival among UK NAC ATTR Stage Ia patients was comparable to UK general population controls (P = 0.297).

CONCLUSION

Patients with NAC ATTR Stage I ATTR-CM can be further stratified according to NT-proBNP concentration and diuretic requirement at diagnosis. Patients with Stage Ia ATTR-CM have significant cardiovascular morbidity despite good short- and mid-term survival.

Cardiac Amyloidosis

Amyloid deposits are defined by their tinctorial properties. Under the light microscope amyloid deposits are eosinophilic and amorphous when stained with hematoxylin and eosin. With Congo red staining the deposits are positive and under polarized light will exhibit green birefringence. Sixty years later electron microscopy demonstrated that all deposits were fibrillar. All amyloid deposits are protein derived. The clinical characteristics will be driven by the nature of the protein subunit. In cardiology, the 2 most common subunits accounting for well more than 90% of cardiac amyloidosis are either immunoglobulin light chain, amyloid light-chain (AL) amyloidosis, or transthyretin; transthyretin (TTR) amyloidosis. Although 70% of patients with systemic amyloidosis have cardiac involvement the diagnosis is made by cardiologists only 20% of the time, suggesting significant gaps in knowledge in how to establish a workflow to arrive at a diagnosis in everyday practice.

Suspicion, screening, and diagnosis of wild-type transthyretin amyloid cardiomyopathy: a systematic literature review

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt CM) is a more common disease than previously thought. Awareness of ATTRwt CM and its diagnosis has been challenged by its unspecific and widely distributed clinical manifestations and traditionally invasive diagnostic tools. Recent advances in echocardiography and cardiac magnetic resonance (CMR), non-invasive diagnosis by bone scintigraphy, and the development of disease-modifying treatments have resulted in an increased interest, reflected in multiple publications especially during the last decade. To get an overview of the scientific knowledge and gaps related to patient entry, suspicion, diagnosis, and systematic screening of ATTRwt CM, we developed a framework to systematically map the available evidence of (i) when to suspect ATTRwt CM in a patient, (ii) how to diagnose the disease, and (iii) which at-risk populations to screen for ATTRwt CM. Articles published between 2010 and August 2021 containing part of or a full diagnostic pathway for ATTRwt CM were included. From these articles, data for patient entry, suspicion, diagnosis, and screening were extracted, as were key study design and results from the original studies referred to. A total of 50 articles met the inclusion criteria. Of these, five were position statements from academic societies, while one was a clinical guideline. Three articles discussed the importance of primary care providers in terms of patient entry, while the remaining articles had the cardiovascular setting as point of departure. The most frequently mentioned suspicion criteria were ventricular wall thickening (44/50), carpal tunnel syndrome (42/50), and late gadolinium enhancement on CMR (43/50). Diagnostic pathways varied slightly, but most included bone scintigraphy, exclusion of light-chain amyloidosis, and the possibility of doing a biopsy. Systematic screening was mentioned in 16 articles, 10 of which suggested specific at-risk populations for screening. The European Society of Cardiology recommends to screen patients with a wall thickness ≥12 mm and heart failure, aortic stenosis, or red flag symptoms, especially if they are >65 years. The underlying evidence was generally good for diagnosis, while significant gaps were identified for the relevance and mutual ranking of the different suspicion criteria and for systematic screening. Conclusively, patient entry was neglected in the reviewed literature. While multiple red flags were described, high-quality prospective studies designed to evaluate their suitability as suspicion criteria were lacking. An upcoming task lies in defining and evaluating at-risk populations for screening. All are steps needed to promote early detection and diagnosis of ATTRwt CM, a prerequisite for timely treatment.

Novel approaches to diagnosis and management of hereditary transthyretin amyloidosis

Hereditary transthyretin amyloidosis (ATTRv) is a severe, adult-onset autosomal dominant inherited systemic disease predominantly affecting the peripheral and autonomic nervous system, heart, kidney and the eyes. ATTRv is caused by mutations of the transthyretin (TTR) gene, leading to extracellular deposition of amyloid fibrils in multiple organs including the peripheral nervous system. Typically, the neuropathy associated with ATTRv is characterised by a rapidly progressive and disabling sensorimotor axonal neuropathy with early small-fibre involvement. Carpal tunnel syndrome and cardiac dysfunction frequently coexist as part of the ATTRv phenotype. Although awareness of ATTRv polyneuropathy among neurologists has increased, the rate of misdiagnosis remains high, resulting in significant diagnostic delays and accrued disability. A timely and definitive diagnosis is important, given the emergence of effective therapies which have revolutionised the management of transthyretin amyloidosis. TTR protein stabilisers diflunisal and tafamidis can delay the progression of the disease, if treated early in the course. Additionally, TTR gene silencing medications, patisiran and inotersen, have resulted in up to 80% reduction in TTR production, leading to stabilisation or slight improvement of peripheral neuropathy and cardiac dysfunction, as well as improvement in quality of life and functional outcomes. The considerable therapeutic advances have raised additional challenges, including optimisation of diagnostic techniques and management approaches in ATTRv neuropathy. This review highlights the key advances in the diagnostic techniques, current and emerging management strategies, and biomarker development for disease progression in ATTRv.

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.

Change in N-terminal pro-B-type natriuretic peptide at 1 year predicts mortality in wild-type transthyretin amyloid cardiomyopathy

OBJECTIVES

Wild-type transthyretin amyloid cardiomyopathy (wtATTR-CM) is a progressive and fatal condition. Although prognosis can be determined at the time of diagnosis according to National Amyloidosis Centre (NAC) transthyretin amyloidosis (ATTR) stage, the clinical course varies substantially between individuals. There are currently no established measures of rate of disease progression. Through systematic analysis of functional, biochemical and echocardiographic disease-related variables we aimed to identify prognostic markers of disease progression in wtATTR-CM.

METHODS

This is a retrospective observational study of 432 patients with wtATTR-CM diagnosed at the UK NAC, none of whom received disease-modifying therapy. The association between mortality from the 12-month timepoint and change from diagnosis to 12 months in a variety of disease-related variables was explored using Cox regression.

RESULTS

Change in N-terminal pro-B-type natriuretic peptide concentration (∆ NT-proBNP) at 12 months from diagnosis was the strongest predictor of ongoing mortality and was independent of both change in other disease-related variables (HR 1.04 per 500 ng/L increase (95% CI 1.01 to 1.07); p=0.003) and a range of known prognostic variables at the time of diagnosis (HR 1.07 per 500 ng/L increase (95% CI 1.02 to 1.13); p=0.007). An increase in NT-proBNP of >500 ng/L, >1000 ng/L and >2000 ng/L during the first year of follow-up occurred in 45%, 35% and 16% of patients, respectively.

CONCLUSION

Change in NT-proBNP concentration during the first year of follow-up is a powerful independent predictor of mortality in wtATTR-CM.

Updates on the Diagnosis and Treatment of Peripheral Autonomic Neuropathies

PURPOSE OF REVIEW

Autonomic neuropathies are a complex group of disorders and result in diverse clinical manifestations that affect the cardiovascular, gastrointestinal, urogenital, and sudomotor systems. We focus this review on the diagnosis and treatment of peripheral autonomic neuropathies. We summarize the diagnostic tools and current treatment options that will help the clinician care for individuals with peripheral autonomic neuropathies.

RECENT FINDINGS

Autonomic neuropathies occur often in conjunction with somatic neuropathies but they can also occur in isolation. The autonomic reflex screen is a validated tool to assess sympathetic postganglionic sudomotor, cardiovascular sympathetic noradrenergic, and cardiac parasympathetic (i.e., cardiovagal) function. Initial laboratory evaluation for autonomic neuropathies includes fasting glucose or oral glucose tolerance test, thyroid function tests, kidney function tests, vitamin-B12, serum, and urine protein electrophoresis with immunofixation. Other laboratory tests should be guided by the clinical context. Reduced intraepidermal nerve density on skin biopsy is a finding, not a diagnosis. Skin biopsy can be helpful in selected individuals for the diagnosis of disorders affecting small nerve fibers; however, we strongly discourage the use of skin biopsy without clinical-physiological correlation. Ambulatory blood pressure monitoring may lead to early identification of patients with cardiovascular autonomic neuropathy in the primary care setting. Disease-modifying therapies should be used when available in combination with nonpharmacological management and symptomatic pharmacologic therapies. Autonomic function testing can guide the therapeutic decisions and document improvement with treatment. A systematic approach guided by the autonomic history and standardized autonomic function testing may help clinicians when identifying and/or counseling patients with autonomic neuropathies. Treatment should be individualized and disease-modifying therapies should be used when available.

A Pilot Study of Rare Renal Amyloidosis Based on FFPE Proteomics

Renal amyloidosis typically manifests albuminuria, nephrotic-range proteinuria, and ultimately progresses to end-stage renal failure if diagnosed late. Different types of renal amyloidosis have completely different treatments and outcomes. Therefore, amyloidosis typing is essential for disease prognosis, genetic counseling and treatment. Thirty-six distinct proteins currently known to cause amyloidosis that have been described as amyloidogenic precursors, immunohistochemistry (IHC) or immunofluorescence (IF), can be challenging for amyloidosis typing especially in rare or hereditary amyloidosis in clinical practice. We made a pilot study that optimized the proteomics pre-processing procedures for trace renal amyloidosis formalin-fixed paraffin-embedded (FFPE) tissue samples, combined with statistical and bioinformatics analysis to screen out the amyloidosis-related proteins to accurately type or subtype renal amyloidosis in order to achieve individual treatment. A sensitive, specific and reliable FFPE-based proteomics analysis for trace sample manipulation was developed for amyloidosis typing. Our results not only underlined the great promise of traditional proteomics and bioinformatics analysis using FFPE tissues for amyloidosis typing, but also proved that retrospective diagnosis and analysis of previous cases laid a solid foundation for personalized treatment.

Nerve biopsy in acquired neuropathies

A diagnosis of neuropathy can typically be determined through clinical assessment and focused investigation. With technological advances, including significant progress in genomics, the role of nerve biopsy has receded over recent years. However, making a specific and, in some cases, tissue-based diagnosis is essential across a wide array of potentially treatable acquired peripheral neuropathies. When laboratory investigations do not suggest a definitive diagnosis, nerve biopsy remains the final step to ascertain the etiology of the disease. The present review highlights the utility of nerve biopsy in confirming a diagnosis, while further illustrating the importance of a tissue-based diagnosis in relation to treatment strategies, particularly when linked to long-term immunosuppressive therapies.

Hereditary neuropathies: A pathological perspective

Hereditary neuropathies may result from mutations in genes expressed by Schwann cells or neurons that affect selectively the peripheral nervous system (PNS) or may represent a minor or major component of complex inherited diseases that involve also the central nervous system and/or other organs and tissues. The chapter is constantly expanding and reworking, thanks to advances of molecular genetics; next-generation sequencing is identifying a plethora of new genes and is revolutionizing the diagnostic approach. In the past, diagnostic sural nerve biopsies paved the way to the discovery and elucidation of major genes and molecular pathways associated to most frequent hereditary motor-sensory neuropathies. Nowadays, a sural nerve biopsy may prove useful in selected cases for the differential diagnosis of an acquired neuropathy when clinical examination, nerve conduction studies, and molecular tests are not sufficiently informative. Skin biopsy has emerged as a minimally invasive window on the PNS, which may provide biomarkers of progression and clues to the physiopathology and molecular pathology of inherited neuropathies. The aim of our review is to illustrate the pathological features of more frequent and paradigmatic hereditary neuropathies and to highlight their correlations with the roles of the involved genes and functional consequences of related molecular defects.

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.

Paraproteinaemic neuropathy: MGUS and beyond

Paraproteinaemic neuropathies comprise a heterogeneous group of neuro-haematological conditions with some distinct neurological, haematological and systemic phenotypes. The spectrum of disease varies from mild to severe, indolent to rapidly progressive and from small fibre sensory involvement to dramatic sensorimotor deficits. The haematological association may be overlooked, resulting in delayed treatment, disability, impaired quality of life and increased mortality. However, the presence of an irrelevant benign paraprotein can sometimes lead to inappropriate treatment. In this review, we outline our practical approach to paraproteinaemic disorders, discuss the utility and limitations of diagnostic tests and the distinctive clinical phenotypes and touch on the complex multidisciplinary management approaches.

Acquired and inherited amyloidosis: Knowledge driving patients' care

Until recently, systemic amyloidoses were regarded as ineluctably disabling and life-threatening diseases. However, this field has witnessed major advances in the last decade, with significant improvements in therapeutic options and in the availability of accurate and non-invasive diagnostic tools. Outstanding progress includes unprecedented hematological response rates provided by risk-adapted regimens in light chain (AL) amyloidosis and the approval of innovative pharmacological agents for both hereditary and wild-type transthyretin amyloidosis (ATTR). Moreover, the incidence of secondary (AA) amyloidosis has continuously reduced, reflecting advances in therapeutics and overall management of several chronic inflammatory diseases. The identification and validation of novel therapeutic targets has grounded on a better knowledge of key molecular events underlying protein misfolding and aggregation and on the increasing availability of diagnostic, prognostic and predictive markers of organ damage and response to treatment. In this review, we focus on these recent advancements and discuss how they are translating into improved outcomes. Neurological involvement dominates the clinical picture in transthyretin and gelsolin inherited amyloidosis and has a significant impact on disease course and management in all patients. Neurologists, therefore, play a major role in improving patients' journey to diagnosis and in providing early access to treatment in order to prevent significant disability and extend survival.

Treatment of AL Amyloidosis: Mayo Stratification of Myeloma and Risk-Adapted Therapy (mSMART) Consensus Statement 2020 Update

Immunoglobulin light chain (AL) amyloidosis is a clonal plasma cell disorder leading to progressive and life-threatening organ failure. The heart and the kidneys are the most commonly involved organs, but almost any organ can be involved. Because of the nonspecific presentation, diagnosis delay is common, and many patients are diagnosed with advanced organ failure. In the era of effective therapies and improved outcomes for patients with AL amyloidosis, the importance of early recognition is further enhanced as the ability to reverse organ dysfunction is limited in those with a profound organ failure. As AL amyloidosis is an uncommon disorder and given patients' frailty and high early death rate, management of this complex condition is challenging. The treatment of AL amyloidosis is based on various anti-plasma cell therapies. These therapies are borrowed and customized from the treatment of multiple myeloma, a more common disorder. However, a growing number of phase 2/3 studies dedicated to the AL amyloidosis population are being performed, making treatment decisions more evidence-based. Supportive care is an integral part of management of AL amyloidosis because of the inherent organ dysfunction, limiting the delivery of effective therapy. This extensive review brings an updated summary on the management of AL amyloidosis, sectioned into the 3 pillars for survival improvement: early disease recognition, anti-plasma cell therapy, and supportive care.

Heart Failure Association of the ESC, Heart Failure Society of America and Japanese Heart Failure Society Position statement on endomyocardial biopsy

Endomyocardial biopsy (EMB) is an invasive procedure, globally most often used for the monitoring of heart transplant (HTx) rejection. In addition, EMB can have an important complementary role to the clinical assessment in establishing the diagnosis of diverse cardiac disorders, including myocarditis, cardiomyopathies, drug-related cardiotoxicity, amyloidosis, other infiltrative and storage disorders, and cardiac tumours. Improvements in EMB equipment and the development of new techniques for the analysis of EMB samples have significantly improved diagnostic precision of EMB. The present document is the result of the Trilateral Cooperation Project between the Heart Failure Association of the European Society of Cardiology, the Heart Failure Society of America, and the Japanese Heart Failure Society. It represents an expert consensus aiming to provide a comprehensive, up-to-date perspective on EMB, with a focus on the following main issues: (i) an overview of the practical approach to EMB, (ii) an update on indications for EMB, (iii) a revised plan for HTx rejection surveillance, (iv) the impact of multimodality imaging on EMB, and (v) the current clinical practice in the worldwide use of EMB.

Heart Failure Association, Heart Failure Society of America, and Japanese Heart Failure Society Position Statement on Endomyocardial Biopsy

Endomyocardial biopsy (EMB) is an invasive procedure, globally most often used for the monitoring of heart transplant rejection. In addition, EMB can have an important complementary role to the clinical assessment in establishing the diagnosis of diverse cardiac disorders, including myocarditis, cardiomyopathies, drug-related cardiotoxicity, amyloidosis, other infiltrative and storage disorders, and cardiac tumors. Improvements in EMB equipment and the development of new techniques for the analysis of EMB samples has significantly improved the diagnostic precision of EMB. The present document is the result of the Trilateral Cooperation Project between the Heart Failure Association of the European Society of Cardiology, Heart Failure Society of America, and the Japanese Heart Failure Society. It represents an expert consensus aiming to provide a comprehensive, up-to-date perspective on EMB, with a focus on the following main issues: (1) an overview of the practical approach to EMB, (2) an update on indications for EMB, (3) a revised plan for heart transplant rejection surveillance, (4) the impact of multimodality imaging on EMB, and (5) the current clinical practice in the worldwide use of EMB.

Autopsy findings in a patient with primary systemic AL (kappa light chain) amyloidosis

First described by Rokitansky in 1842, and further characterized by Virchow in 1854, amyloidosis is a disorder caused by amyloid deposition, a fibrillary insoluble protein. The clinical spectrum of amyloidosis is broad, as the amyloid deposition may virtually occur in all tissues. Herein, we report the case of a 66-year-old man with a long-lasting emaciating disease, diagnosed, at autopsy, with primary systemic amyloidosis. Amyloid protein deposition was found in many tissues and organs. The involvement of the vessels’ wall rendered ischemic injury most prominent in the intestinal loops causing mesenteric ischemia. Despite the thorough organic involvement, the immediate cause of death was aspiration bronchopneumonia. Massive amyloid deposition was found in virtually all major organs, such as the heart, liver, kidneys, spleen, pancreas, adrenals, prostate, skin, and thyroid: the latter, a complication of the amyloidosis known as amyloid goiter. Post-mortem review of the deceased’s laboratory workup showed a slightly abnormal kappa:lambda ratio in the blood; however, no clonal lymphoplasmacytic disorder was confirmed in the bone marrow and other lymphoreticular system organs either by the microscopic examination and immunohistochemical staining. Laser-capture microdissection and tandem mass spectrometry of the splenic tissue detected a peptide profile consistent with an immunoglobulin Kappa light chain. The presence of amyloid purpura favors the diagnosis of primary systemic amyloidosis.

Paraffin Immunofluorescence Increases Light-Chain Detection in Extra-Renal Light Chain Amyloidosis and Other Light-Chain-Associated Diseases

CONTEXT.—

Distinguishing the different types of amyloid is clinically important because treatments and outcomes are different. Mass spectrometry is the new gold standard for amyloid typing, but it is costly and not widely available. Therefore, immunolabeling remains the first step in identifying the most common types of amyloidosis. In amyloid subtyping, direct immunofluorescence works well when applied to frozen sections, but immunohistochemistry on formalin-fixed, paraffin-embedded material often yields poor results, particularly for light chain amyloidosis. Recently, paraffin immunofluorescence has been described as a valuable salvage technique in renal pathology when frozen sections are not available but it has not been evaluated for extra-renal diseases.

OBJECTIVES.—

To evaluate the use of paraffin immunofluorescence for light-chain detection in extra-renal amyloidosis and other light-chain-associated diseases.

DESIGN.—

First, we compared the staining intensity of both light chains between paraffin immunofluorescence and immunohistochemistry on a retrospective cohort of 28 cases of amyloidosis that have been previously typed. Then, we studied the role of paraffin immunofluorescence as an addition to our classical immunohistochemistry panel for amyloidosis typing.

RESULTS.—

In the retrospective cohort, we found that paraffin immunofluorescence outperformed immunohistochemistry for light-chain detection. Then, in the prospective part of the study, we showed that the proportion of correctly classified cases increased from 50% to 71.9% with the adjunction of second-intention paraffin immunofluorescence to the immunohistochemistry procedure.

CONCLUSIONS.—

We therefore view paraffin immunofluorescence as a significant addition to the routine workflow for detection of light-chain-related diseases.

Autologous stem cell transplantation vs bortezomib based chemotheraphy for the first-line treatment of systemic light chain amyloidosis in the UK

OBJECTIVES

The benefit of autologous stem cell transplantation (ASCT) in the treatment of light chain (AL) amyloidosis requires re-evaluation in the modern era. This retrospective case-matched study compares ASCT to bortezomib for the treatment of patients with AL amyloidosis.

METHODS

Newly diagnosed patients with AL amyloidosis treated with ASCT or bortezomib between 2001 and 2018 were identified. Patients were excluded if the time from diagnosis to treatment exceeded 12 months. Patients were matched on a 1:1 basis, using a propensity-matched scoring approach.

RESULTS

A total of 136 propensity score-matched patients were included (ASCT n = 68, bortezomib n = 68). There was no significant difference in overall survival at two years (P = .908, HR: 0.95, CI: 0.41-2.20). For ASCT vs bortezomib: overall haematological response rate at 6 months was 90.6% vs 92.5%; organ response at 12 months: cardiac (70.0% vs 54%, P > .999), renal (74% vs 24%, P = .463) liver (21% vs 22%, P = .048); median progression-free survival (50 vs 42 months P = .058, HR: 0.61, CI: 0.37-1.02) and time to next treatment (68 vs 45 months, P = .145, HR: 0.61, CI: 0.31-1.19). More patients required treatment in the bortezomib group compared to ASCT group at 24 months (41 vs 23, Chi-squared P = .004) and 48 months (57 vs 41, Chi-squared P = .004).

CONCLUSIONS

This small retrospective study suggests that there is no clear survival advantage of ASCT over bortezomib therapy. A prospective randomised controlled trial evaluating ASCT in AL amyloidosis is critically needed.

Diagnosis of amyloid beyond Congo red

PURPOSE OF REVIEW

Amyloidoses are a group of rare and heterogeneous diseases in which abnormally folded proteins deposit in tissues and lead to organ damage. A brief review of advances in the diagnosis of extracerebral systemic amyloidoses in the context of recent advances in their clinical management is provided.

RECENT FINDINGS

Although steady progress in the treatment of AL and AA has evolved over many years, significant advances in the treatment of ATTR, transthyretin-derived amyloidosis, have been achieved only recently. This coincides with the emergence of nontissue diagnosis of cardiac ATTR in both the hereditary and wild-type settings. The latter is emerging as possibly the most prevalent type of systemic amyloidosis.Available treatments are amyloid protein type dependent and, hence, following amyloid detection, amyloid protein typing is necessary. Although mass spectrometry has emerged as the preferred method of amyloid typing, careful application of immune methods is still clinically useful but caution and experience, as well as awareness of the limitations of each method, are necessary in their interpretation.

SUMMARY

Despite significant advances in the treatment of the systemic amyloidoses, outcomes remain poor, primarily due to delays in diagnosis. Precise diagnosis of the amyloid protein type is critical for treatment selection.

Disease progression in cardiac transthyretin amyloidosis is indicated by serial calculation of National Amyloidosis Centre transthyretin amyloidosis stage

Aims

Cardiac transthyretin amyloidosis (ATTR‐CM) is a progressive and fatal condition. Prognosis can be determined at diagnosis according to the National Amyloidosis Centre (NAC) transthyretin amyloidosis (ATTR) stage. We sought to examine how NAC ATTR stage changes during follow‐up and whether it maintains its prognostic value throughout the disease course.

Methods and results

We performed a retrospective study of 945 patients with wild‐type ATTR‐CM (wtATTR‐CM) or hereditary ATTR‐CM associated with the V122I variant (V122I‐hATTR‐CM) who were diagnosed and serially evaluated at the UK NAC. Patients who commenced any disease‐modifying therapy for amyloidosis were censored at the time of doing so. Landmark Kaplan–Meier survival analyses were performed at diagnosis (n = 945) and at 6 ± 1 (n = 432), 12 ± 3 (n = 562), and 24 ± 3 (n = 316) months and stratified by recalculated NAC ATTR stage at the relevant time point. Cox regression analyses were performed to assess the prognostic significance during follow‐up of an increase in NAC ATTR stage from Stage I at diagnosis. Mortality in ATTR‐CM was predicted by NAC ATTR stage at each time point [Stage II vs. I, hazard ratios (HRs) 1.95–2.67; P < 0.001; Stage III vs. II, HRs 1.64–2.25; P < 0.001–0.013]. An increase from NAC ATTR Stage I, which occurred in 21%, 32%, and 44% of evaluable patients at 6, 12, and 24 months of follow‐up respectively, was highly predictive of ongoing mortality at each time point (HRs 2.58–3.22; P < 0.001) and in each genotypic subgroup (HRs 1.86–4.38; P < 0.05). Increase in NAC ATTR stage occurred earlier in V122I‐hATTR‐CM than in wtATTR‐CM (43% vs. 27% at 12 months of follow‐up; P = 0.003).

Conclusions

National Amyloidosis Centre ATTR stage predicts ongoing survival throughout the disease natural history in ATTR‐CM, and an increase from NAC ATTR Stage I at diagnosis to a higher NAC ATTR stage predicts mortality throughout follow‐up. Serial calculation of NAC ATTR stage suggests a more aggressive phenotype in V122I‐hATTR‐CM than in wtATTR‐CM.

Extracellular Matrix Injury of Kidney Allografts in Antibody-Mediated Rejection: A Proteomics Study

BACKGROUND

Antibody-mediated rejection (AMR) accounts for >50% of kidney allograft loss. Donor-specific antibodies (DSA) against HLA and non-HLA antigens in the glomeruli and the tubulointerstitium cause AMR while inflammatory cytokines such as TNFα trigger graft injury. The mechanisms governing cell-specific injury in AMR remain unclear.

METHODS

Unbiased proteomic analysis of laser-captured and microdissected glomeruli and tubulointerstitium was performed on 30 for-cause kidney biopsy specimens with early AMR, acute cellular rejection (ACR), or acute tubular necrosis (ATN).

RESULTS

A total of 107 of 2026 glomerular and 112 of 2399 tubulointerstitial proteins was significantly differentially expressed in AMR versus ACR; 112 of 2026 glomerular and 181 of 2399 tubulointerstitial proteins were significantly dysregulated in AMR versus ATN (P<0.05). Basement membrane and extracellular matrix (ECM) proteins were significantly decreased in both AMR compartments. Glomerular and tubulointerstitial laminin subunit γ-1 (LAMC1) expression decreased in AMR, as did glomerular nephrin (NPHS1) and receptor-type tyrosine-phosphatase O (PTPRO). The proteomic analysis revealed upregulated galectin-1, which is an immunomodulatory protein linked to the ECM, in AMR glomeruli. Anti-HLA class I antibodies significantly increased cathepsin-V (CTSV) expression and galectin-1 expression and secretion in human glomerular endothelial cells. CTSV had been predicted to cleave ECM proteins in the AMR glomeruli. Glutathione S-transferase ω-1, an ECM-modifying enzyme, was significantly increased in the AMR tubulointerstitium and in TNFα-treated proximal tubular epithelial cells.

CONCLUSIONS

Basement membranes are often remodeled in chronic AMR. Proteomic analysis performed on laser-captured and microdissected glomeruli and tubulointerstitium identified early ECM remodeling, which may represent a new therapeutic opportunity.

Diagnostic amyloid proteomics: experience of the UK National Amyloidosis Centre

Systemic amyloidosis is a serious disease which is caused when normal circulating proteins misfold and aggregate extracellularly as insoluble fibrillary deposits throughout the body. This commonly results in cardiac, renal and neurological damage. The tissue target, progression and outcome of the disease depends on the type of protein forming the fibril deposit, and its correct identification is central to determining therapy. Proteomics is now used routinely in our centre to type amyloid; over the past 7 years we have examined over 2000 clinical samples. Proteomics results are linked directly to our patient database using a simple algorithm to automatically highlight the most likely amyloidogenic protein. Whilst the approach has proved very successful, we have encountered a number of challenges, including poor sample recovery, limited enzymatic digestion, the presence of multiple amyloidogenic proteins and the identification of pathogenic variants. Our proteomics procedures and approaches to resolving difficult issues are outlined.

The Pathology of Amyloidosis in Classification: A Review

BACKGROUND

The amyloidoses are a rare and heterogeneous group of disorders that are characterized by the deposition of abnormally folded proteins in tissues ultimately leading to organ damage. The deposits are mainly extracellular and are recognizable by their affinity for Congo red and their yellow-green birefringence under polarized light. Current classification of amyloid in medical practice is based on the amyloid protein type. To date, 36 proteins have been identified as being amyloidogenic in humans.

SUMMARY

in clinical practice, it is critical to distinguish between treatable versus non-treatable amyloidoses. Moreover, amyloidoses with a genetic component must be distinguished from the sporadic types and systemic amyloidoses must be distinguished from the localized forms. Among the systemic amyloidoses, AL continues to be the most common amyloid diagnosis in the developed world; other clinically significant types include AA, ALECT2, and ATTR. The latter is emerging as an underdiagnosed type in both the hereditary and wild-type setting. Other hereditary amyloidoses include AFib, several amyloidoses derived from apolipoproteins, AGel, ALys, etc. In a dialysis setting, systemic amyloid derived from β2 microglobulin (Aβ2M) should be considered, although a very rare hereditary variant has also been reported; several amyloidoses may be typically associated with aging and several iatrogenic types have also emerged. Determination of the amyloid protein type is imperative before specific therapy can be implemented and the current methods are briefly summarized. A brief overview of the target organ involvement by amyloid type is also included. Key Messages: (1) Early diagnosis of amyloidosis continues to pose a significant challenge and requires the participation of many clinical and laboratory specialties. (2) Determination of the protein type is imperative before specific therapy can be implemented. (3) While mass spectrometry has emerged as the preferred method of amyloid typing, careful application of immune methods is still clinically useful but caution and experience, as well as awareness of the limitations of each method, are necessary in their interpretation. (4) While the spectrum of amyloidoses continues to expand, it is critical to distinguish between those that are currently treatable versus those that are untreatable and avoid causing harm by inappropriate treatment.

Immunoelectron microscopy and mass spectrometry for classification of amyloid deposits

Amyloidosis is a shared name for several rare, complex and serious diseases caused by extra-cellular deposits of different misfolded proteins. Accurate characterization of the amyloid protein is essential for patient care. Immunoelectron microscopy (IEM) and laser microdissection followed by tandem mass spectrometry (LMD-MS) are new gold standards for molecular subtyping. Both methods perform superiorly to immunohistochemistry, but their complementarities, strengths and weaknesses across amyloid subtypes and organ biopsy origin remain undefined. Therefore, we performed a retrospective study of 106 Congo Red positive biopsies from different involved organs; heart, kidney, lung, gut mucosa, skin and bone marrow. IEM, performed with gold-labelled antibodies against kappa light chains, lambda light chains, transthyretin and amyloid A, identified specific staining of amyloid fibrils in 91.6%; in six biopsies amyloid fibrils were not identified, and in two, the fibril subtype could not be established. LMD-MS identified amyloid protein signature in 98.1%, but in nine the amyloid protein could not be clearly identified. MS identified protein subtype in 89.6%. Corresponding specificities ranged at organ level from 94-100%. Concordance was 89.6-100% for different amyloid subtypes. Importantly, combined use of both methods increased the diagnostic classification to 100%. Some variety in performances at organ level was observed.

Use of ixazomib, lenalidomide and dexamethasone in patients with relapsed amyloid light-chain amyloidosis

With improving outcomes in amyloid light-chain (AL) amyloidosis, there is a need to study novel agents in this setting. We report outcomes of 40 patients with relapsed AL amyloidosis treated with ixazomib + lenalidomide + dexamethasone (IRd). Haematological responses were assessed on an intention-to-treat basis at three months: complete response (CR) - 8 (20·5%), very good partial response (VGPR) - 8 (20·5%), partial response (PR) - 7 (17·9%) and no response (NR) - 16 (41·0%). One patient had missing data. Six patients subsequently improved response. Best responses were: CR - 10 (25·6%), VGPR - 8 (20·5%), PR - 7 (17·9%), NR - 14 (35·9%). Cardiac and renal organ responses occurred in 5·6% and 13·3% respectively. Median progession-free survival (PFS) was 17·0 months (95% CI 7·3-20·7 months), improving to 28·8 months (95% CI 20·6-37·0 months) in those achieving CR/VGPR. Median overall survival was 29·1 months (95% CI 24-33 months). Serious adverse events were seen in 14 (35·0%) patients inclusive of 15 admissions due to: infection (6/15, 40·0%), fluid overload (5/15, 33·3%), cardiac arrhythmia (2/15, 13·3%), renal dysfunction (1/15, 6·6%) and anaemia (1/15, 6·6%). In summary, IRd is an oral treatment option with a manageable toxicity profile leading to deep responses in 47% of patients with relapsed AL amyloidosis.

Cytomegalovirus reactivation after bortezomib treatment for multiple myeloma and light chain amyloidosis

OBJECTIVE

Cytomegalovirus (CMV) is an opportunistic herpesvirus, and reactivation of infection is possible in immunocompromised patients. Historically, the risk for haematology patients is restricted to those treated with an allogeneic transplant or T-cell depleting agents. Bortezomib is a highly efficacious proteasome inhibitor widely used to treat multiple myeloma and light chain (AL) amyloidosis patients. The objective of this small prospective study was to quantify the risk of CMV reactivation associated with bortezomib treatment.

METHODS

Fifty-seven consecutive multiple myeloma or AL amyloidosis patients commencing bortezomib-based therapy were included. Viral copy numbers were established at baseline and then at fortnightly intervals during treatment. Pre-emptive anti-viral treatment was initiated in patients with a viral load >7500 copies/mL.

RESULTS

Reactivation of CMV was detected in 39% (n = 12/31) of seropositive bortezomib treated patients compared with 0% of CMV seronegative patients. Detectable DNAemia developed during the first two cycles of treatment in 83% (n = 10/12) patients. Anti-viral treatment was initiated in 42% (n = 5/12), but no cases of active CMV disease were seen.

CONCLUSION

This study suggests that there is a substantial risk of CMV reactivation in CMV-seropositive plasma cell dyscrasia patients treated with bortezomib.

Proteomic Analysis for the Diagnosis of Fibrinogen Aα-chain Amyloidosis

Introduction

Hereditary fibrinogen Aα-chain (AFib) amyloidosis is a relatively uncommon renal disease associated with a small number of pathogenic fibrinogen Aα (FibA) variants; wild-type FibA normally does not result in amyloid deposition. Proteomics is now routinely used to identify the amyloid type in clinical samples, and we report here our algorithm for identification of FibA in amyloid.

Methods

Proteomics data from 1001 Congo red–positive patient samples were examined using the Mascot search engine to interrogate the Swiss-Prot database and generate protein identity scores. An algorithm was applied to identify FibA as the amyloid protein based on Mascot scores. FibA variants were identified by appending the known amyloidogenic variant sequences to the Swiss-Prot database.

Results

AFib amyloid was identified by proteomics in 64 renal samples based on the Mascot scores relative to other amyloid proteins, the presence of a pathogenic variant, and coverage of the p.449-621 sequence. Contamination by blood could be excluded from a comparison of the FibA score with that of the fibrinogen β and γ chains. The proteomics results were consistent with the clinical diagnosis. Four additional renal samples did not fulfill all the criteria using the algorithm but were adjudged as AFib amyloid based on a full assessment of the clinical and biochemical results.

Conclusion

AFib amyloid can be identified reliably in glomerular amyloid by proteomics using a score-based algorithm. Proteomics data should be used as a guide to AFib diagnosis, with the results considered together with all available clinical and laboratory information.