A Modern Primer on Light Chain Amyloidosis in 592 Patients With Mass Spectrometry-Verified Typing

Severe gastroparesis complicated by gastric perforation caused by lightchain amyloidosis

AL-Amyloidosis is a rare systemic disease that can occur in patients with monoclonal gammopathy or multiple myeloma. As multiple organs may be affected by deposition of amyloid fibrils, the clinical presentation varies considerably, and the diagnostic process may be challenging.We report on a 59-year-old female who suffered from gastroesophageal reflux symptoms, nausea, epigastric pain, and meteorism over several years. Repeated upper GI endoscopies including biopsies and CT scans were unremarkable except for unspecific enlargement of mesenterial lymph nodes.A few weeks after a surgical hiatal hernia repair with fundoplication, the patient developed massive distension of the stomach and the proximal duodenum resulting in gastric perforation. Histopathological staining of gastric biopsies and mesenterial lymph nodes using hematoxylin and eosin was unremarkable. Because of endoscopic findings (submucosal hematomas, and ulcerations) and the unexplained severe motility disorder, histopathological staining was performed using Congo red. Extensive amyloid deposits were seen. Further workup confirmed AL amyloidosis caused by monoclonal gammopathy. Specific oncological treatment was started.The rare differential diagnosis of amyloidosis should be taken into account in patients with unexplained motility disorders, unspecific gastrointestinal symptoms, and abdominal lymphadenopathy. In the presented case, delayed diagnosis of AL amyloidosis in the gastrointestinal tract led to severe gastroparesis resulting in gastric perforation. Specific histopathologic staining can confirm the diagnosis.

Cardiac Response Dynamics in Newly Diagnosed Light-Chain Amyloidosis Patients With Early and High-Quality Hematologic Response

Background

The goal of hematological response has been well established in the treatment of systemic light chain amyloidosis. However, the pattern of cardiac response remains unknown.

Objectives

This study was designed to investigate the cardiac response dynamics in patients with an early and high-quality hematological response.

Methods

This retrospective study included newly diagnosed patients who achieved a hematological response of very good partial response or better within 3 months after treatment beginning. Four cardiac response criteria were tested at fixed time points (3, 6, 12, and 24 months after therapy initiation): cardiac complete response, cardiac very good partial response, cardiac partial response (carPR), and cardiac no response.

Results

A total of 201 patients were included, with the median follow-up 37.0 months (Q1-Q3: 18.0-56.5 months). The cardiac response reached a plateau at 24 months, while cardiac complete response, cardiac very good partial response, and carPR were achieved in 21.4% (28 of 131), 38.9% (51 of 131), and 20.6% (27 of 131) of the patients, respectively. At every fixed time point within 12 months after treatment initiation, patients who achieved a carPR or better consistently had better survival than did those who did not. At 3 months, an NT-proBNP concentration ≥3,716 pg/mL was the only factor associated with a decreased likelihood of achieving a carPR within 12 months (OR: 0.269; 95% CI: 0.137-0.512; P < 0.001).

Conclusions

This study emphasizes the importance of monitoring cardiac response dynamics for disease surveillance. In patients who achieve early and high-quality hematological response, it is important to achieve carPR within 12 months.

Graded Organ Response and Progression Criteria for Kidney Immunoglobulin Light Chain Amyloidosis

Importance

Kidney light chain (AL) amyloidosis is associated with a risk of progression to kidney replacement therapy (KRT) and death. Several studies have shown that a greater reduction in proteinuria following successful anticlonal therapy is associated with improved outcomes.

Objective

To validate graded kidney response criteria and their association with kidney and overall survival (OS).

Design, Setting, and Participants

This retrospective, multicenter cohort was conducted at 10 referral centers for amyloidosis from 2010 to 2015 and included patients with kidney AL amyloidosis that was evaluable for kidney response and who achieved at least hematologic partial response within 12 months of diagnosis. The median follow-up was 69 (54-88) months. Data analysis was conducted in 2023.

Exposure

Four kidney response categories based on the reduction in pretreatment 24-hour urine protein (24-hour UP) levels: complete response (kidCR, 24-hour UP ≤200 mg), very good partial response (kidVGPR, >60% reduction in 24-hour UP), partial response (kidPR, 31%-60% reduction), and no response (kidNR, ≤30% reduction). Kidney response was assessed at landmark points (6, 12, and 24 months) and best kidney response.

Main Outcomes and Measures

Cumulative incidence of progression to KRT and OS.

Results

Seven-hundred and thirty-two patients (335 women [45.8%]) were included, with a median (IQR) age of 63 (55-69) years. The median (IQR) baseline 24-hour proteinuria and estimated glomerular filtration rate was 5.3 (2.8-8.5) g per 24 hours and 72 (48-92) mL/min/1.73m2, respectively. In a competing-risk analysis, the 5-year cumulative incidence rates of progression to KRT decreased with deeper kidney responses as early as 6 months from therapy initiation (11%, 12%, 2.1%, and 0% for kidNR, kidPR, kidVGPR, and kidCR, respectively; P = .002) and were maintained at 12 months and 24 months and best kidney response. Patients able to achieve kidCR/kidVGPR by 24 months and at best response had significantly better OS compared with kidPR/kidNR. Kidney progression, defined as a 25% or greater decrease in estimated glomerular filtration rate, was associated with cumulative incidence of progression to KRT and OS.

Conclusions and Relevance

The results of this cohort study suggest that graded kidney response criteria offers clinically and prognostically meaningful information for treating patients with kidney AL amyloidosis. The response criteria potentially inform kidney survival based on the depth of reduction in 24-hour proteinuria levels and demonstrate an OS advantage for those able to achieve kidCR/kidVGPR compared with kidPR/kidNR. Taken together, achievement of at least kidVGPR by 12 months is needed to ultimately improve kidney and patient survival.

A review regarding the article 'Prevalence of Valvular Heart Disease in Cardiac Amyloidosis and Impact on Survival'

Cardiac amyloidosis (CA) is a condition characterized by the accumulation of amyloid fibrils in the heart muscle, resulting in an infiltrative cardiomyopathy. The presence of amyloid protein can impact different parts of the heart, including the valves. Limited data is available on the prevalence and prognostic significance of valvular heart disease (VHD) in CA. However, advancements in imaging technology have allowed for accurate noninvasive diagnosis of CA, eliminating the need for confirmatory endomyocardial biopsy and improving our understanding of this dual pathology. The development of targeted drug therapies for CA and transcatheter valve replacement or repair for VHD has significantly improved the prognosis for patients with both conditions. This review will discuss the findings of this original research and provide an overview of current researches on VHD in CA, as well as the progress in diagnosing and treating CA with VHD.

Renal Response Criteria for Clinical Trials in Amyloid Light Chain Amyloidosis

Immunoglobin light chain (AL) amyloidosis is a rare disease characterized by organ deposition of amyloid fibrils, most commonly in the heart and kidney. Disease heterogeneity necessitates organ-specific assessment to determine prognosis and response or progression. To facilitate development of new therapies, the Amyloidosis Forum (a public-private partnership between the US Food and Drug Administration and the nonprofit Amyloidosis Research Consortium) held a series of meetings and formed multiple working groups to identify clinical trial end points and analytic strategies. This report summarizes the recommendations of Renal Working Group. Estimated glomerular filtration rate (eGFR) and proteinuria were selected to evaluate eligibility, response, and/or progression in the context of investigational clinical trials for patients with AL amyloidosis. Accurate response assessments at the earliest possible time point were emphasized. The context of use, specific patient population, and the investigational therapeutic mechanism should ultimately drive selection of appropriate end points to evaluate renal response/progression in AL amyloidosis clinical trials.

Amino acid sequence homology of monoclonal serum free light chain dimers and tissue deposited light chains in AL amyloidosis: a pilot study

OBJECTIVES

Diagnosis of light chain amyloidosis (AL) requires demonstration of amyloid deposits in a tissue biopsy followed by appropriate typing. Previous studies demonstrated increased dimerization of monoclonal serum free light chains (FLCs) as a pathological feature of AL. To further examine the pathogenicity of FLC, we aimed at testing amino acid sequence homology between circulating and deposited light chains (LCs).

METHODS

Matched tissue biopsy and serum of 10 AL patients were subjected to tissue proteomic amyloid typing and nephelometric FLC assay, respectively. Serum FLC monomers (M) and dimers (D) were analyzed by Western blotting (WB) and mass spectrometry (MS).

RESULTS

WB of serum FLCs showed predominance of either κ or λ type, in agreement with the nephelometric assay data. Abnormal FLC M-D patterns typical of AL amyloidosis were demonstrated in 8 AL-λ patients and in one of two AL-κ patients: increased levels of monoclonal FLC dimers, high D/M ratio values of involved FLCs, and high ratios of involved to uninvolved dimeric FLCs. MS of serum FLC dimers showed predominant constant domain sequences, in concordance with the tissue proteomic amyloid typing. Most importantly, variable domain sequence homology between circulating and deposited LC species was demonstrated, mainly in AL-λ cases.

CONCLUSIONS

This is the first study to demonstrate homology between circulating FLCs and tissue-deposited LCs in AL-λ amyloidosis. The applied methodology can facilitate studying the pathogenicity of circulating FLC dimers in AL amyloidosis. The study also highlights the potential of FLC monomer and dimer analysis as a non-invasive screening tool for this disease.

Immunoglobulin light chain amyloidosis: 2024 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light or heavy chain are deposited in tissues. Clinical features depend on organs involved but can include heart failure with preserved ejection fraction, nephrotic syndrome, hepatic dysfunction, peripheral/autonomic neuropathy, and "atypical smoldering multiple myeloma or MGUS."

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for the diagnosis of AL amyloidosis. Organ biopsy is not required in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory. The gold standard is laser capture mass spectroscopy.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP or BNP), serum troponin T(or I), and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four stages; 5-year survivals are 82%, 62%, 34%, and 20%, respectively.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure. Current first-line therapy with the best outcome is daratumumab, bortezomib, cyclophosphamide, and dexamethasone. The goal of therapy is a ≥VGPR. In patients failing to achieve this depth of response options for consolidation include pomalidomide, stem cell transplantation, venetoclax, and bendamustine.

FUTURE CHALLENGES

Delayed diagnosis remains a major obstacle to initiating effective therapy prior to the development of end-stage organ failure. Trials of antibodies to deplete deposited fibrils are underway.

Cardiac Amyloidosis: Clinical Features, Pathogenesis, Diagnosis, and Treatment

Cardiac amyloidosis is a type of amyloidosis that deserves special attention as organ involvement significantly worsens the prognosis. Cardiac amyloidosis can be grouped under three main headings: immunoglobulin light chain (AL) amyloidosis that is dependent on amyloidogenic monoclonal light chain production; hereditary Transthyretin (TTR) amyloidosis that results from accumulation of mutated TTR; and wild-type (non-hereditary) TTR amyloidosis formerly known as senile amyloidosis. Although all three types cause morbidity and mortality due to severe heart failure when untreated, they contain differences in their pathogenesis, clinical findings, and treatment. In this article, the clinical features, pathogenesis, diagnosis, and treatment methods of cardiac amyloidosis will be explained with an overview, and an awareness will be raised in the diagnosis of this disease.

AL amyloidosis: Singapore Myeloma Study Group consensus guidelines on diagnosis, treatment and management

AL amyloidosis is the most common form of systemic amyloidosis. However, the non-specific nature of presenting symptoms requires the need for a heightened clinical suspicion to detect unexplained manifestations in the appropriate clinical setting. Early detection and treatment are crucial as the degree of cardiac involvement emerges as a primary prognostic predictor of survival in a patient with AL amyloidosis. Following the diagnosis of AL amyloidosis with appropriate tissue biopsies, prompt treatment with a bortezomib, cyclophosphamide and dexamethasone-based first-line induction with or without daratumumab should be initiated. The goal of treatment is to achieve the best haematologic response possible, ideally with involved free light chain <20 mg/L, as it offers the best chance of organ function improvement. Treatment should be changed if patients do not achieve a partial response within 2 cycles of treatment or very good partial response after 4 cycles or after autologous stem cell transplant, as achievement of profound and prolonged clonal responses translates to better organ response and long-term outcomes. Early involvement of multidisciplinary subspecialists such as renal physicians, cardiologists, neurologists, and gastroenterologists for optimal maintenance and support of involved organs is recommended for optimal management of patients with AL amyloidosis.

[Hemostasis disorders in patients with systemic AL-amyloidosis]

AIM

To analyze the frequency and nature of hemorrhagic and thrombotic complications in patients with systemic AL-amyloidosis and compare with laboratory changes in the hemostasis system.

MATERIALS AND METHODS

The prospective study included 40 patients with newly diagnosed AL-amyloidosis. To detect amyloid, all patients underwent bone marrow trephine biopsy and duodenal biopsy, and 28 (70%) patients underwent biopsy of the affected organ. Before the start of therapy, all patients were determined the platelet count, activated partial thromboplastin time, thrombin time, fibrinogen concentration, time of XIIa-dependent fibrinolysis, antithrombin III, D-dimer, activity of blood coagulation factors VIII, X and vWF. The statistical part of the study was carried out using the IBM SPSS Statistics 2017 system software (SPSS, Chicago, IL, USA).

RESULTS

In 20 (50%) patients, hemorrhages on the skin and mucous membranes were diagnosed as vascular purpura. Before the start of therapy, 7 (17.5%) patients had thrombosis, including leg vein thrombosis (5 patients), ischemic stroke (2 patients). There was a direct correlation between thrombotic complications and cutaneous hemorrhagic syndrome (p=0.007). In 15 (75%) cases, cutaneous hemorrhagic syndrome was accompanied by hypercoagulable shifts in the hemostasis system. Of the 20 patients with cutaneous hemorrhagic syndrome, 19 (95%) patients had kidney damage, including 15 patients with nephrotic syndrome. Hematoma type of bleeding, as well as heavy bleeding was not observed, including after a biopsy of the internal organs. According to the totality of hemostasis indicators, hypercoagulation syndrome was more often observed (in 23; 56% of patients). Hypocoagulation was diagnosed only in 2 (5%) patients with liver damage, 16 (39%) patients had normocoagulation.

CONCLUSION

Cutaneous hemorrhagic syndrome is the most common clinical manifestation of disorders in the hemostasis system in patients with AL-amyloidosis. The relationship of hemorrhages on the skin with nephrotic syndrome has been established, which may indicate a single pathogenetic mechanism. Cutaneous hemorrhagic syndrome is associated with hypercoagulable shifts in hemostasis and a high risk of thrombotic complications.

Clinical characterization and outcomes of a cohort of colombian patients with AL Amyloidosis

Background

Amyloid light chain (AL) amyloidosis is characterized by amyloid fibril deposition derived from monoclonal immunoglobulin light chains, resulting in multiorgan dysfunction. Limited data exist on the clinical features of AL amyloidosis.

Objective

This study aims to describe the clinical characteristics, treatments, and outcomes in Colombian patients with AL amyloidosis.

Methods

A retrospective descriptive study was conducted at three high-complexity centers in Medellín, Colombia. Adults with AL amyloidosis diagnosed between 2012 and 2022 were included. Clinical, laboratory, histological, treatment, and survival data were analyzed.

Results

The study included 63 patients. Renal involvement was most prevalent (66%), followed by cardiac involvement (61%). Multiorgan involvement occurred in 61% of patients. Amyloid deposition was most commonly detected in renal biopsy (40%). Bortezomib-based therapy was used in 68%, and 23.8% received high-dose chemotherapy with autologous hematopoietic stem cell transplantation (HDCT-ASCT). Hematological response was observed in 95% of patients with available data. Cardiac and renal organ responses were 15% and 14%, respectively. Median overall survival was 45.1 months (95% CI: 22.2-63.8). In multivariate analysis, cardiac involvement was significantly associated with inferior overall survival (HR 3.27; 95% CI: 1.23-8.73; p=0.018), HDCT-ASCT had a non-significant trend towards improved overall survival (HR 0.25; 95% CI: 0.06-1.09; p=0.065).

Conclusions

In this study of Colombian patients with AL amyloidosis, renal involvement was more frequent than cardiac involvement. Overall survival and multiorgan involvement were consistent with data from other regions of the world. Multivariate analysis identified cardiac involvement and HDCT-AHCT as possible prognostic factors.

Hematologic Disorders and the Nervous System

OBJECTIVE

This article discusses the epidemiology, diagnosis, treatment, and prevention of neurologic complications of red blood cell, platelet, and plasma cell disorders.

LATEST DEVELOPMENTS

Cerebrovascular complications can occur in patients with blood cell and platelet disorders. Treatment strategies to prevent stroke are available for patients with sickle cell disease, polycythemia vera, and essential thrombocythemia. A diagnosis of thrombotic thrombocytopenic purpura should be considered in patients with neurologic symptoms, hemolytic anemia, thrombocytopenia, mild renal insufficiency, and fever. Plasma cell disorders can be associated with peripheral neuropathy, and classification of the monoclonal protein type and neuropathy aid in diagnosis. Patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) syndrome can present with arterial and venous neurologic events.

ESSENTIAL POINTS

This article discusses the neurologic complications of blood cell disorders and the most recent advances in prevention and treatment.

Health-Related Quality of Life Instruments for Clinical Trials in AL Amyloidosis: Report from the Amyloidosis Forum HRQOL Working Group

Systemic AL (light chain) amyloidosis is a rare protein misfolding disorder associated with plasma cell dyscrasia affecting various organs leading to organ dysfunction and failure. The Amyloidosis Forum is a public-private partnership between the Amyloidosis Research Consortium and the US Food and Drug Administration Center for Drug Evaluation and Research with the goal of accelerating the development of effective treatments for AL amyloidosis. In recognition of this goal, 6 individual working groups were formed to identify and/or provide recommendations related to various aspects of patient-relevant clinical trial endpoints. This review summarizes the methods, findings, and recommendations of the Health-Related Quality of Life (HRQOL) Working Group. The HRQOL Working Group sought to identify existing patient-reported outcome (PRO) assessments of HRQOL for use in clinical trials and practice deemed relevant across a broad spectrum of patients with AL amyloidosis. A systematic review of the AL amyloidosis literature identified 1) additional signs/symptoms not currently part of an existing conceptual model, and 2) relevant PRO instruments used to measure HRQOL. The Working Group mapped content from each identified instrument to areas of impact in the conceptual model to determine which instrument(s) provide coverage of relevant concepts. The SF-36v2^® Health Survey (SF-36v2; QualityMetric Incorporated, LLC) and Patient-Reported Outcomes Measurement Information System-29 Profile (PROMIS-29; HealthMeasures) were identified as instruments relevant to patients with AL amyloidosis. Existing evidence of reliability and validity was evaluated with a recommendation for future work focused on estimating clinically meaningful within-patient change thresholds for these instruments. For sponsors, the context of use-including specific research objectives, trial population, and investigational product under study-should inherently drive selection of the appropriate PRO instrument and endpoint definitions to detect meaningful change and enable patient-focused drug development.

Axillary Lymphadenopathy as an Initial Presentation of Systemic Amyloidosis: A Case Report and Literature Review

Amyloidosis rarely presents as localized lymphadenopathy. Various studies have elucidated the varied presentation and manifestations of this interesting disease. We reviewed the literature and found 36 cases of primary amyloidosis with lymph node enlargement as a presentation, and 17 of the 36 cases (47%) had systemic involvement on further work up. We describe a patient who presented with an isolated right axillary mass. Clinical examination and radiology were indicative of a lymph node enlargement with no evidence of malignancy in the breasts or lungs. Histopathological examination was indicative of amyloidosis. A further work up including serum, urine biochemistry, cardiac work up, bone marrow examination, and a kidney biopsy revealed systemic amyloidosis. Patient was treated with daratumumab and CyBorD (cyclophosphamide, bortezomib, and dexamethasone) followed by a stem cell transplantation. Patient is in remission for 1 year, at the time of submission of this report. Therefore, we conclude (1) systemic amyloidosis presenting as an isolated lymph node enlargement is rare, (2) a structured systemic work up is imperative for early diagnosis and proper management of amyloidosis, when there is an index of suspicion, and (3) use of novel therapeutic options such as CD38 + antibody (daratumumab) and stem cell transplant have positive impact on disease outcomes.

Persistent diarrhea with petechial rash - unusual pattern of light chain amyloidosis deposition on skin and gastrointestinal biopsies: A case report

BACKGROUND

Amyloidosis is a rare disease characterized by extracellular deposition of misfolded protein aggregated into insoluble fibrils. Gastrointestinal involvement in systemic amyloidosis is common, but is often subclinical or presents as vague and nonspecific symptoms. It is rare for gastrointestinal symptoms to be the main presenting symptom in patients with systemic amyloidosis, causing it to be undiagnosed until late-stage disease.

CASE SUMMARY

A 53 year-old man with diarrhea, hematochezia, and weight loss presented to a community hospital. Colonoscopy with biopsy at that time was suspicious for Crohn disease. Due to worsening symptoms including nausea, vomiting, and a new petechial rash, an abdominal fat pad biopsy was done. The biopsy showed papillary and adnexal dermal amyloid deposition, in a pattern usually seen with cutaneous amyloidosis. However, Cytokeratin 5/6 was negative, excluding cutaneous amyloidosis. The patterns of nodular amyloidosis, subcutaneous amyloid deposits and perivascular amyloid were not seen. Periodic Acid-Schiff stain was negative for lipoid proteinosis, Congo red was positive for apple green birefringence on polarization and amyloid typing confirmed amyloid light chain amyloidosis. Repeat endoscopic biopsies of the gastrointestinal tract showed amyloid deposition from the esophagus to the rectum, in a pattern usually seen in serum amyloid A in the setting of chronic inflammatory diseases, including severe inflammatory bowel disease. Bone marrow biopsy showed kappa-restricted plasma cell neoplasm.

CONCLUSION

Described is an unusual presentation of primary systemic amyloidosis, highlighting the risk of misdiagnosis with subsequent significant organ dysfunction and high mortality.

Case Report: Monoclonal Gammopathies of Clinical Significance-Associated Myopathy: A Case-Based Review

Monoclonal gammopathies of clinical significance (MGCS)-associated myopathy is a group of muscular MGCS-based rare manifestations. It mainly includes amyloid light chain (AL) amyloidosis and sporadic late-onset nemaline myopathy with monoclonal gammopathy of undetermined significance. When myopathy manifests as the initial or sole clinical symptom, it can often be delayed or misdiagnosed as other myopathies. We report the case of a 60-year-old man who initially presented with fatigue and muscle weakness of the symmetric proximal lower limbs. Muscle biopsy did not reveal mononuclear cell infiltration, atrophy, necrosis, or positive Congo red staining results. The results of serum protein electrophoresis and immunofixation electrophoresis were negative. No specific diagnosis was established. After 1 year, the patient was diagnosed with AL amyloidosis after myocardial and fat pad biopsies were performed and myopathy was diagnosed as AL amyloidosis-associated myopathy after reassessment. The patient received CyBorD regime chemotherapy and achieved hematological and organ remission. Therefore, we reviewed the clinical and pathological manifestations of MGCS-associated myopathies. Based on published articles and the present case, we conclude that comprehensive screening for MGCS in unexplained myopathy is essential to avoid misdiagnosis or delayed diagnosis.

Advanced Case of Cardiac Amyloidosis Presents With Chronic Diarrhea

Late diagnosis of light chain (AL) amyloidosis can lead to catastrophic consequences on the quality of life of affected patients and overall disease prognosis. Therefore, clinicians should have high suspicion and recognize clinical red flags for amyloidosis. This case report presents a 65-year-old female who presented to the emergency department with chronic diarrhea and significant weight loss with significant hypotension. The patient was treated four weeks prior to admission with a five-day course of nitrofurantoin for urinary tract infection. The initial workup was positive for Clostridium difficile(C.diff), which was treated medically; however, the patient started to complain of mild shortness of breath accompanied by mildly elevated brain natriuretic peptide (BNP). Later on, the patient had a cardiac arrest and was appropriately resuscitated. Subsequent ECHO showed significant left ventricular hypertrophy, raising high suspicion of myocardial infiltration. Because of persistent diarrhea despite aggressive medical management and an inconclusive workup, the patient underwent colonoscopy with duodenum biopsy, which revealed amyloid deposition confirmed by Congo red staining. The patient afterward suffered from a stroke and recurrent syncopal episodes requiring critical care admission. Due to a compromised quality of life, the patient eventually opted for hospice care. In view of insufficient prospective data spotlighting AL amyloidosis, all patients should be treated within clinical trials whenever possible and ideally evaluated for autologous hematopoietic cell transplantation (HCT) eligibility.

Supportive Care and Symptom Management for Patients With Immunoglobulin Light Chain (AL) Amyloidosis

Immunoglobulin light chain (AL) amyloidosis is a disorder of clonal plasma cells characterized by deposition of amyloid fibrils in a variety of tissues, leading to end-organ injury. Renal or cardiac involvement is most common, though any organ outside the central nervous system can develop amyloid deposition, and symptomatic presentations may consequently vary. The variability and subtlety of initial clinical presentations may contribute to delayed diagnoses, and organ involvement is often quite advanced and symptomatic by the time a diagnosis is established. Additionally, while organ function can improve with plasma-cell-directed therapy, such improvement lags behind hematologic response. Consequently, highly effective supportive care, including symptom management, is essential to improve quality of life and to maximize both tolerance of therapy and likelihood of survival. Considering the systemic nature of the disease, close collaboration between clinicians is essential for effective management.

Laboratory Detection and Initial Diagnosis of Monoclonal Gammopathies

CONTEXT.—

The process for identifying patients with monoclonal gammopathies is complex. Initial detection of a monoclonal immunoglobulin protein (M protein) in the serum or urine often requires compilation of analytical data from several areas of the laboratory. The detection of M proteins depends on adequacy of the sample provided, available clinical information, and the laboratory tests used.

OBJECTIVE.—

To develop an evidence-based guideline for the initial laboratory detection of M proteins.

DESIGN.—

To develop evidence-based recommendations, the College of American Pathologists convened a panel of experts in the diagnosis and treatment of monoclonal gammopathies and the laboratory procedures used for the initial detection of M proteins. The panel conducted a systematic literature review to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation approach, recommendations were created based on the available evidence, strength of that evidence, and key judgements as defined in the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework.

RESULTS.—

Nine guideline statements were established to optimize sample selection and testing for the initial detection and quantitative measurement of M proteins used to diagnose monoclonal gammopathies.

CONCLUSIONS.—

This guideline was constructed to harmonize and strengthen the initial detection of an M protein in patients displaying symptoms or laboratory features of a monoclonal gammopathy. It endorses more comprehensive initial testing when there is suspicion of amyloid light chain amyloidosis or neuropathies, such as POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome, associated with an M protein.

Modified Body Mass Index as a Novel Nutritional and Prognostic Marker in Patients with Cardiac Amyloidosis

The nutritional assessment is gaining clinical relevance since cardiac cachexia and malnutrition are emerging as novel markers of functional status and prognosis in many cardiovascular disorders, including cardiac amyloidosis (CA). This study aimed to evaluate the prognostic role of different nutritional indices for cardiovascular mortality in patients with CA and subgroups. Fifty CA patients (26 AL and 24 ATTR wild-type) were retrospectively analyzed. All patients underwent a comprehensive clinical and laboratory evaluation. Conventional body mass index (cBMI), modified BMI (mBMI), new BMI (nBMI) and prognostic nutritional index (PNI) were analyzed. Multivariate regression analysis was performed to identify the association between nutritional and other clinical-laboratory parameters with cardiovascular death. Compared to ATTRwt patients, those with AL showed lower mBMI values. No significant difference was observed for the other nutritional indices. During a median follow-up of 11.2 months, a lower mBMI quartile was associated with worse survival, in both groups. In multivariate analysis, mBMI emerged as an independent predictor for cardiovascular death. This study showed that mBMI is a novel index of malnutrition and an independent risk factor for cardiovascular mortality in patients with CA in both AL and ATTRwt form.

COVID-19 and Light Chain Amyloidosis, Adding Insult to Injury

Light chain (AL) amyloidosis is a potentially fatal disease of monoclonal plasma cells that leads to accumulation of light chain amyloid fibrils, organ damage, and the manifestations of clinical disease. Meanwhile, coronavirus disease 2019 (COVID-19) is a disease caused by infection with the severe acute respiratory syndrome coronavirus 2 virus, with the potential to cause severe systemic illness and death. There is significant overlap in the demographics and comorbidities observed in AL amyloidosis and those associated with highest risk for severe morbidity and mortality due to COVID-19. This overlap creates unique challenges in caring for patients with AL amyloidosis, which are further compounded by the immunosuppressive nature of anti-plasma cell therapies, the need for frequent clinical assessments, and the exclusion of AL amyloidosis patients from initial COVID-19 vaccine trials. Herein, we highlight many of the relevant concerns related to COVID-19 and the treatment of AL amyloidosis, summarize a general approach for AL amyloidosis management amidst the ongoing COVID-19 pandemic, and discuss current guidance about COVID-19 vaccination of patients with AL amyloidosis.

Amyloid Formation by Globular Proteins: The Need to Narrow the Gap Between in Vitro and in Vivo Mechanisms

The globular to fibrillar transition of proteins represents a key pathogenic event in the development of amyloid diseases. Although systemic amyloidoses share the common characteristic of amyloid deposition in the extracellular matrix, they are clinically heterogeneous as the affected organs may vary. The observation that precursors of amyloid fibrils derived from circulating globular plasma proteins led to huge efforts in trying to elucidate the structural events determining the protein metamorphosis from their globular to fibrillar state. Whereas the process of metamorphosis has inspired poets and writers from Ovid to Kafka, protein metamorphism is a more recent concept. It is an ideal metaphor in biochemistry for studying the protein folding paradigm and investigating determinants of folding dynamics. Although we have learned how to transform both normal and pathogenic globular proteins into fibrillar polymers in vitro, the events occurring in vivo, are far more complex and yet to be explained. A major gap still exists between in vivo and in vitro models of fibrillogenesis as the biological complexity of the disease in living organisms cannot be reproduced at the same extent in the test tube. Reviewing the major scientific attempts to monitor the amyloidogenic metamorphosis of globular proteins in systems of increasing complexity, from cell culture to human tissues, may help to bridge the gap between the experimental models and the actual pathological events in patients.

Hypovitaminosis D Is Prevalent in Patients With Renal AL Amyloidosis and Associated With Renal Outcome

INTRODUCTION

Vitamin D deficiency is common, but no data have been reported on vitamin D levels in light chain (AL) amyloidosis.

PATIENTS AND METHODS

In this exploratory study, stored serum samples from 173 patients with newly diagnosed AL amyloidosis were analyzed for vitamin studies which included 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂D] and vitamin D binding protein (DBP). Measurements were made by liquid chromatography-tandem mass spectrometry. Kidney survival and overall survival (OS) were assessed in association to vitamin D status.

RESULTS

Cardiac and kidney involvement occurred in 69% and 63% of patients, respectively. 25(OH)D deficiency (<20 ng/mL) was seen in 56.6% of the patients and was notably found among patients with heavy proteinuria (96%), hypoalbuminemia (84.3%) and morbidly obese patients (68.3%). Heavy proteinuria (>5 gr/24-h) and vitamin D supplementation were independent predictors of 25(OH)D level on nominal multivariate regression analysis. 1,25(0H)₂D deficiency was noted in 37.6% of patients and was independently associated with low eGFR and hypoalbuminemia. Progression to ESRD occurred in 23.7% of evaluable patients. Patients who progressed to ESRD had lower serum 25(OH)D and 1,25(OH)₂D levels compared to those who did not progress to ESRD. On a multivariate analysis, severe 25(OH)D deficiency was an independent predictor of progression to ESRD as was renal stage, while 1,25(OH)₂D deficiency was not.

CONCLUSIONS

Hypovitaminosis D is common in AL amyloidosis, particularly among patients with heavy proteinuria. Severe 25(OH)D deficiency at time of diagnosis predicts progression to ESRD.

Multimodality imaging approach to cardiac amyloidosis: part 2

With recent advances in cardiac imaging, genetics, and treatment options, cardiac amyloidosis (CA) is now recognized as an important and under diagnosed condition contributing to cardiovascular morbidity and mortality. Although still considered a rare disease, CA is now recognized as an important contributor to heart failure with preserved ejection fraction (HFPEF) and low gradient aortic stenosis, two important conditions commonly faced in clinical practice. This review uses clinical scenarios to highlight the complementary role of traditional imaging tools such as electrocardiogram (ECG) and echocardiography (echo) in conjunction with advanced cardiac imaging with cardiac magnetic resonance (CMR) and nuclear cardiac scintigraphy using bone avid tracers in the comprehensive workup of CA. We also highlight the importance of workup of light chain disease as part of integration of imaging findings and discuss the key aspects of various imaging modalities. Finally, an algorithm integrating clinical suspicion, laboratory testing, and imaging in the workup of CA is presented.

Unusual Case of Nephrotic Syndrome From Light Chain Amyloidosis in a 37-Year-Old Patient

Amyloidosis with renal involvement is a well-known cause of nephrotic syndrome. Immunoglobulin light-chain amyloidosis (AL), which is a result of monoclonal light-chain deposition in the kidney from plasma cell dyscrasia, is rare before the age of 40 and typically occurs in old patients. Most cases of renal amyloidosis in young patients are secondary to chronic inflammatory disease. We are reporting a case of a 37-year-old male who was transferred to our hospital for evaluation of possibly acquired bleeding disorder. He was initially presented to an outside hospital with bleeding per rectum for three days duration and one-week history of abdominal pain and bloating. He was found to have nephrotic range proteinuria with hypoalbuminemia and hyperlipidemia. A kidney biopsy was performed to identify the cause of his nephrotic syndrome, and a biopsy showed AL amyloidosis. Bone marrow biopsy performed showed plasma cell myeloma, and the patient was started on induction chemotherapy. Even though the incidence of AL amyloidosis is low before age of 40, we should always perform monoclonal gammopathy workup in patients with nephrotic syndrome regardless of the age. Prompt bone marrow biopsy should be performed to confirm the diagnosis, and starting the treatment as one of the factors that affect the prognosis of AL amyloidosis is early diagnosis.

Comprehensive Review of AL amyloidosis: some practical recommendations

Amyloid light chain (AL) amyloidosis is among the more common and more severe of the amyloidoses usually involving the slow proliferation of a bone-marrow-residing plasma cell (PC) clone and the secretion of unstable immunoglobulin-free light chains (FLC) that infiltrate peripheral tissues and result in detrimental end-organ damage. Disease presentation is rather vague, and the hallmark of treatment is early diagnosis before irreversible end-organ damage. Once diagnosed, treatment decision is transplant-driven whereby ~20% of patients are eligible for autologous stem cell transplantation (ASCT) with or without bortezomib-based induction. In the setting of ASCT-ineligibility, bortezomib plays a central role in upfront treatment with the recent addition of daratumumab to the current emerging standard of care. In general, management of AL amyloidosis is aimed at achieving deep, durable responses with very close monitoring for early detection of relapse/refractory disease. This article provides a comprehensive review of the management of patients with AL amyloidosis including goals of therapy, current treatment guidelines in the setting of both ASCT-eligibility and ineligibility, treatment response monitoring recommendations, toxicity management, and treatment of relapse/refractory disease.

Recent Advances and Current Dilemmas in the Diagnosis and Management of Transthyretin Cardiac Amyloidosis

Cardiac amyloidosis (CA) is an increasingly recognized cause of heart failure, arrhythmias, and sudden cardiac death. While CA was previously rapidly fatal, recent advances in diagnosis and treatment have significantly improved outcomes. Advances in cardiac imaging and biomarkers have critically improved the accuracy and efficiency with which CA is diagnosed, even allowing for the noninvasive diagnosis of transthyretin CA. Cardiac magnetic resonance imaging, technetium nuclear imaging, echocardiography, and blood-based biomarkers have established important and complementary roles in the management and advancement of care. At the same time, the development of novel targeted amyloid therapies has allowed patients with CA to live longer and potentially achieve better quality of life. Still, despite this significant progress, there remain critical ongoing questions in the field. Accordingly, within this review we will highlight recent advances in cardiac imaging and therapeutics for CA, while focusing on key opportunities for further optimization of care and outcomes among this growing population. Specifically, we will discuss ongoing debates in the diagnosis of CA, including the interpretation of indeterminate cardiac imaging findings, the best technique to screen asymptomatic transthyretin amyloidosis gene mutation carriers for cardiac involvement, and the ideal method for monitoring response to CA treatment. We will additionally focus on recent advances in treatment for transthyretin amyloidosis-CA, including a discussion of available agents as well as highlighting ongoing clinical trials. Together, these data will allow clinicians to emerge with a greater understanding of the present and future of diagnosis, management, and potentially enhanced outcomes in this rapidly advancing field.

Updates in Cardiac Amyloidosis Diagnosis and Treatment

PURPOSE OF REVIEW

Cardiac amyloidosis is an underrecognized cause of heart failure. We review clinical clues to the diagnoses, a rational approach to testing, and current and emerging therapies.

RECENT FINDINGS

Advances in the diagnosis of amyloid cardiomyopathy include (1) use of ^99mtechnetium (^99mTc) bone-avid compounds which allow accurate noninvasive diagnosis of transthyretin cardiac amyloidosis (ATTR-CM) in the context of a negative monoclonal light chain screen; and (2) the use of serum and urine immunofixation electrophoresis with serum free light chains as an accurate first diagnostic step for light chain cardiac amyloidosis (AL-CM). Advances in treatment include tafamidis for ATTR-CM and immunologic therapies for AL-CM. With the advent of accurate noninvasive diagnostic modalities and effective therapies, early recognition of cardiac amyloidosis is paramount to implement a diagnostic algorithm and expeditiously institute effective therapies to minimize morbidity and mortality.

Correlation between urine ACR and 24-h proteinuria in a real-world cohort of systemic AL amyloidosis patients

A 24-h urine protein collection (24hUP), the gold standard for measuring albuminuria in systemic AL amyloidosis, is cumbersome and inaccurate. We retrospectively reviewed 575 patients with systemic AL amyloidosis to assess the correlation between a urine albumin to creatinine ratio (uACR) and the 24hUP. The uACR correlated strongly with 24hUP at diagnosis (Pearson’s r = 0.87, 95% CI 0.83–0.90) and during the disease course (Pearson’s r = 0.88, 95% CI 0.86–0.90). A uACR ≥300 mg/g estimated a 24hUP ≥ 500 mg with a sensitivity of 92% and specificity of 97% (area under the receiver operating curve = 0.938, 95% CI 0.919–0.957). A uACR cutoff of 3600 mg/g best predicted a 24hUP > 5000 g (sensitivity 93%, specificity 94%), and renal stage at diagnosis was strongly concordant using either 24hUP or uACR as the proteinuria measure (k = 0.823, 95% CI 0.728–0.919). In patients with serial urine collections, a > 30% decrease in uACR predicted a > 30% decrease in 24hUP with a sensitivity of 94%. In conclusion, the uACR is a reliable and convenient method for ruling out proteinuria >500 mg per day, prognosticating renal outcomes, and assessing renal response to therapy. Further studies are needed to validate the uACR cutoffs proposed in this study.

Lousada I. The Amyloidosis Forum: a public private partnership to advance drug development in AL amyloidosis

BACKGROUND

Immunoglobulin light chain (AL) amyloidosis is a rare, multi-systemic disorder characterized by two disease processes: an underlying plasma cell dyscrasia that provides the source of pathologic light chains, and the resulting organ dysfunction caused by deposition of amyloid light chain fibrils. There are no FDA approved treatments for AL amyloidosis; regimens developed for multiple myeloma are used off-label to treat the plasma cell disorder and no therapies are directed at organ deposition. Thus, an unmet medical need persists despite advances in disease management. A public-private partnership was recently formed between the Amyloidosis Research Consortium (ARC) and the US Food and Drug Administration (FDA) to bridge scientific gaps in drug development for the treatment of AL amyloidosis.

MAIN BODY

The inaugural Amyloidosis Forum was convened at FDA on 12 November 2019 and led by a multidisciplinary panel of physicians, health outcomes professionals, and representatives from the FDA, ARC, and pharmaceutical companies. Patients provided important perspectives on the pathway to diagnosis, challenges of rigorous treatment, and the burden of disease. The panel reviewed the epidemiology, pathobiology, and clinical features of AL amyloidosis. Hematologic characteristics, staging systems, and response criteria were examined with clear consensus that a "deep response" to plasma cell-directed treatments was critical to overall survival. Emphasis was placed on the heterogeneous clinical phenotypes of AL amyloidosis, including cardiovascular, renal, neurological, and gastrointestinal system manifestations that contribute to morbidity and/or mortality, but render challenges to clinical trial endpoint selection. FDA representatives discussed regulatory perspectives regarding demonstration of clinical benefits of investigational therapies in the context of a rare disease with multi-systemic manifestations. The panel also highlighted the potential importance of well-designed health-related quality of life instruments, quantification of system organ effects, the potential of advanced imaging technologies, and survival prediction models.

CONCLUSIONS

The Amyloidosis Forum identified a clear need for novel trial designs that are scientifically rigorous, feasible, and incorporate clinically meaningful endpoints based on an understanding of the natural history of the disease in an evolving therapeutic landscape. Future forums will delve into these issues and seek to include participation from additional stakeholders.

When to Suspect a Diagnosis of Amyloidosis

Amyloidosis is a group of complex diseases caused by extracellular deposition of pathological insoluble fibrillary protein in organs and tissues and may result in severe organ dysfunction. Despite the etiological heterogeneity of systemic amyloidosis, the clinical manifestations of the different forms of amyloidosis largely overlap and depend upon the effected organ. The signs and symptoms that should raise suspicion for the potential diagnosis of amyloidosis are usually nonspecific; therefore, establishing the diagnosis is difficult, and early diagnosis requires clinical suspicion. Light chain (AL) amyloidosis may present with highly specific signs such as macroglossia and periorbital purpura, but these signs are insensitive. Amyloidosis is still underdiagnosed, even though treatments are now available and are effective in improving patient's survival and quality of life. Cardiac amyloidosis is the major determinant of survival, and the earlier it is detected the better the survival. All MGUS patients should be routinely screened for AL amyloidosis by a focused history and physical examination and routine assessment of urine albumin. The aim of this review is to provide clinicians with knowledge about the signs and symptoms that raise the suspicion of amyloidosis, bearing in mind the importance of early diagnosis of this disease.

Renal amyloidosis: validation of a proposed histological scoring system in an independent cohort

Background

In systemic amyloidosis, the kidney is frequently affected and renal involvement has a major impact on survival. Renal involvement is clinically characterized by decreased estimated glomerular filtration rate (eGFR) and proteinuria. The two most common renal amyloidosis types are light chain-related amyloidosis (AL) and serum amyloid A (AA) amyloidosis. Standardized histopathological scoring of amyloid deposits is crucial to assess disease progression. Therefore, we aimed to validate the proposed scoring system from Rubinstein et al. (Novel pathologic scoring tools predict end-stage kidney disease in light chain (AL) amyloidosis. Amyloid 2017; 24: 205–211) in an independent patient cohort.

Methods

We attempt to reproduce the scoring system, consisting of an amyloid score (AS) and a composite scarring injury score (CSIS), in a multicentre AL and AA case series. Additionally, we analysed all renal amyloidosis kidney biopsies performed in the Netherlands between 1993 and 2012.

Results

Similar to the original study, AS and CSIS correlated to eGFR (r = −0.45, P = 0.0061 and r = −0.60, P < 0.0001, respectively) but not to proteinuria at diagnosis. Furthermore, AS, but not CSIS, was associated with renal outcome. The scoring system was not reproducible in AA patients. The median incidence rate for renal amyloidosis in the Netherlands was 2.3 per million population per year, and increased during the study period.

Conclusions

In our AL case series and the original study, AS and CSIS were correlated to eGFR but not to proteinuria, and AS correlated with renal outcome. Overall, we regard this scoring system as competent for standardized histopathological assessment of amyloid deposits burden and thereby disease advancement in renal biopsies.

New developments in diagnosis, risk assessment and management in systemic amyloidosis

Amyloidosis is a group of disorders characterized by a misfolded protein that deposits in organs and compromise their function. Clinician should have a high index of suspicion because in most cases, the clinical picture is non-specific. Typing of amyloid is of utmost importance and should be an integral part of accurately diagnosing a patient. AL amyloidosis is the most common systemic amyloidosis in the western world in which the misfolded proteins are immunoglobulin light chains secreted by clonal plasma cells. New data about prognostication of AL amyloidosis patients are accumulating. The treatment goal is to eradicate the amyloidogenic plasma cell clone, by using high dose melphalan and/or novel agents (proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies against CD38). Early diagnosis is important for effectively treating the patient as late diagnosis hampers chances for organ recovery. ATTR amyloidosis is less recognized but is increasingly seen due to better recognition and improved diagnostic tools. New data about treatment options (patisiran, inotersen and tafamidis) have recently been published and are discussed.

AL Amyloidosis: Unfolding a Complex Disease

Light chain (AL) amyloidosis is a rare plasma cell dyscrasia. An estimated 12,000 people live with the disease in the United States. AL amyloidosis occurs from the misfolding of proteins that deposit in organs (heart, kidneys, digestive tract, tongue, lungs, and nervous system), leading to progressive organ damage and impairment of quality of life. The treatment of AL amyloidosis has improved greatly over the past several years, with new treatments currently in development. This article will focus on the pathophysiology, diagnosis, and treatment of AL amyloidosis.