AL amyloidosis: advances in diagnosis and management

Macroglossia in endocrine and metabolic disorders: current evidence, perspectives and challenges

Macroglossia is an uncommon condition characterized by chronic, painless and abnormal enlargement of the tongue. A multitude of medical conditions can cause macroglossia. Major endocrine and metabolic disorders associated with macroglossia include genetic, congenital and acquired conditions, such as mucopolysaccharidoses; acquired and congenital hypothyroidism and myxedema; transient neonatal diabetes mellitus; acromegaly and amyloidosis. Macroglossia is often associated (~57-60%) with all types of mucopolysaccharidoses, particularly type I (Hurler syndrome) and type II (Hunter syndrome), being a prominent feature of the disorder. It may also occur in patients with acquired and congenital hypothyroidism and myxedema, being a common sign of congenital hypothyroidism with an approximate prevalence of 12-25% at the time of diagnosis. Macroglossia is a predominant oral finding in subjects with transient neonatal diabetes mellitus (~44%), acromegaly (54-69%) and amyloidosis (10-25%), particularly AL amyloidosis (20-40%) whereas is considered a hallmark of the disease. Secondary to macroglossia various disturbances may occur, such as difficulty in speech or eating, orthodontic anomalies or even more serious conditions including upper airway obstruction or obstructive sleep apnea. Until now, no comprehensive review has been conducted focusing on macroglossia in endocrine and metabolic disorders. The objective of this review is to summarize literature on the etiology and epidemiology of macroglossia in major endocrine and metabolic disorders. It highlights key aspects such as pathophysiology, clinical presentation, diagnostic evaluation, management and prognosis of macroglossia in the context of endocrine and metabolic disorders.

Quantitative risk factor analysis of prior disease condition and socioeconomic status with the multiple myeloma development: nationwide cohort study

Early diagnosis and following management are important determinants of the prognosis of multiple myeloma (MM). However, screening for MM is not routinely performed because it is rare disease. In this study, we evaluated the association of prior disease condition and socioeconomic status (SES) with MM diagnosis and developed a simple predictive model that can identify patients at high risk of developing MM who may need screening using nationwide database from South Korea. According to multivariate logistic regression analysis, eight prior disease conditions and SES before diagnosis were shown to be predictors of MM development and selected for score development. Total prediction scores were categorized into four groups: patients without any risk (≤ 0) intermediate-1 (0.5-9), intermediate-2 (9-14), and high risk (> 14). The odds ratios for developing MM in the intermediate-1, intermediate-2, and high-risk groups were 1.29, 3.07, and 4.62, respectively. The association of prior disease conditions and SES with MM diagnosis were demonstrated and the simple scoring system to predict the MM risk was developed. This scoring system is also provided by web-based application and could be a useful tool to support clinicians in identifying potential candidates for MM screening.

Safety of Subcutaneous Daratumumab in Anti-CD38 Monoclonal Antibody-Naïve Patients with Plasma Cell Disorders: A Multicenter Real-Life Experience

BACKGROUND

Daratumumab, an anti-CD38 monoclonal antibody, is used for treatment of multiple myeloma (MM) and light chain amyloidosis at an intravenous dosage of 16 mg/kg or at a subcutaneous fixed dose of 1800 mg. However, the subcutaneous formulation has only recently been approved in Europe, and real-life data on its safety are still few.

OBJECTIVE

In this multicenter retrospective real-life experience, we provided evidence for the safety of subcutaneous daratumumab in plasma cell disorders.

PATIENTS AND METHODS

A total of 189 patients diagnosed with MM or light chain amyloidosis were included in this retrospective study, and all subjects were daratumumab-naïve. Primary endpoint was safety of subcutaneous daratumumab, especially for infusion-related reaction (IRR) incidence and severity. All patients received premedication with dexamethasone, paracetamol, and antihistamine, with montelukast usage in 85% of cases.

RESULTS

Eight patients (4%) experienced IRRs, mainly of grade I-II, and other frequent toxicities were: hematological (thrombocytopenia, 4%; neutropenia, 5%; lymphopenia, 6%) and non-hematological (pneumonia, 4%; diarrhea, 2%; and cytomegalovirus reactivation, 0.5%). In our multicenter retrospective real-life experience, subcutaneous daratumumab was well-tolerated with an excellent safety profile with a very low (4%) IRR incidence, even in frailer MM patients with severe renal impairment or increased body weight.

CONCLUSIONS

Subcutaneous daratumumab was safe in a real-life setting including patients with severe renal failure and advanced disease. However, further studies on larger and prospective cohorts are required to confirm our real-life observations.

Diagnosis and referral of patients with AL amyloidosis in Portugal: results from a Delphi panel

Light chain amyloidosis (AL) is a complex disorder defined by the extracellular deposition of insoluble amyloid fibrils formed by intact or fragmented immunoglobulin light chains, leading to cell dysfunction, rapid organ deterioration, and, ultimately, death. Although the clinical presentation of AL is directly connected to organ involvement, signs and symptoms of AL are frequently nonspecific, misinterpreted, and late recognized. Thus, an early diagnosis combined with effective therapies to cease disease progression and rescue organ function is essential. The aim of this study was to assess the knowledge and characterize the current clinical practice regarding AL diagnosis and referral among Portuguese physicians. A Delphi-like panel (one round only) with a group of national experts from different medical specialties (cardiology, hematology, internal medicine, nephrology, and neurology) was carried out online, in which 30 statements were classified using a 4-point Likert scale. For each statement, the consensus level was set at 70% for "fully agree/disagree" and the majority level was defined as >70% in agreement or disagreement. Although the results suggest the existence of adequate general knowledge of AL amyloidosis, they also disclosed the necessity to raise awareness for this disease. Overall, this Delphi panel revealed a high lack of consensus regarding the diagnosis and early management of patients with AL among different specialties despite the qualified majority obtained in 26 statements. An optimized strategy for AL early diagnosis, transversal to several medical fields, is urgently needed. Moreover, referral centers with access to diagnostic technology and a network of diverse specialties should be established to foster an early diagnosis and better disease approach to boost the possibility of a better outcome for patients with AL.

Updates in Plasma Cell Dyscrasias and Related Monoclonal Immunoglobulin-Mediated Renal Disease

Pathogenic roles of monoclonal immunoglobulins in kidney disease have been attributed previously to malignant plasma cell and lymphoproliferative disorders such as multiple myeloma, lymphoplasmacytic lymphoma, chronic lymphocytic leukemia, or amyloid light chain amyloidosis. Improved technology, advancements in molecular diagnostics, and highly sensitive imaging techniques have established the need to redefine monoclonal gammopathies and the kidney disorders that are associated with monoclonal immunoglobulins regardless of tumor burden. This has led to the establishment of monoclonal gammopathy with renal significance (MGRS). MGRS was defined by the International Kidney and Monoclonal Gammopathy Research Group in 2012 as a clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin and does not meet previously defined hematological criteria for treatment of a specific malignancy. MGRS encompasses a wide array of pathologies with knowledge surrounding its incidence, prognosis, and management continuously increasing. This review examines the current evidence on the diagnosis, prognosis, pathogenesis, and therapy of plasma cell dyscrasias and related MGRS.

Difficulties in the Diagnosis of Fibrinogen Aα-Chain Amyloidosis-Literature Review and Case Report of a Patient After Kidney Transplantation

BACKGROUND

Amyloidosis is a very heterogeneous disease. Correct diagnosis is extremely important because of the various treatment options for different types of amyloidosis. This study presents a case report and literature review of the misdiagnosis of fibrinogen Aα-chain amyloidosis (AFib amyloidosis).

CASE PRESENTATION

We report a 65-year-old man diagnosed with proteinuria in 2009. The kidney biopsy revealed the presence of Congo red-stained amyloid deposits. During differential diagnosis, amyloid deposits were discovered in adipose tissue and gingiva. Bone marrow trephine biopsy showed a predominance of lambda chains presenting plasmocytes. Based on performed medical examination, light chain amyloidosis was identified. Therefore, the patient received high-dose melphalan and underwent successful autologous peripheral blood stem cell transplantation. However, proteinuria, worsening of the kidneys' function, and incorrect levels of free light chains were still observed. In 2019, due to continuous treatment failure, a previously acquired kidney biopsy was examined by mass spectrometry, and numerous fibrinogen deposits were identified. Recommended DNA analysis revealed that the patient had AFib amyloidosis. Therefore, chemotherapy treatment was abandoned, and successful kidney transplantation was performed.

CONCLUSION

Today, it is essential for medical practitioners to remember the possibility of rare and hereditary types of amyloidosis. There are multiple cases where a diagnosis was wrong or delayed because of the atypical course of the disease, the coexistence of another disease, and the rarity of AFib amyloidosis, and all of these reasons may result in the wrong treatment that will delay the right therapy. However, with the new, more precise diagnostics methods, such situations will become rare.

A Comprehensive Multidisciplinary Diagnostic Algorithm for the Early and Efficient Detection of Amyloidosis

Amyloidosis is a rare protein misfolding disease caused by the accumulation of amyloid fibrils in various tissues and organs. There are different subtypes of amyloidosis, with light chain (AL) amyloidosis being the most common. Amyloidosis is notoriously difficult to diagnose because it is clinically heterogeneous, no single test is diagnostic for the disease, and diagnosis typically involves multiple specialists. Here, we propose an integrated, multidisciplinary algorithm for efficiently diagnosing amyloidosis. Drawing on research from several medical disciplines, we have combined clinical decisions and best practices into a comprehensive algorithm to facilitate the early detection of amyloidosis. Currently, many patients are diagnosed more than 6 months after symptom onset, yet early diagnosis is the major predictor of survival. Our algorithm aims to shorten the time to diagnosis with efficient sequencing of tests and minimizing uninformative investigations. We also recommend typing and staging of confirmed amyloidosis to guide treatment. By reducing time to diagnosis, our algorithm could lead to earlier and more targeted treatment, ultimately improving prognosis and survival.

Amyloid Arthropathy and Pseudomyopathy Associated With Multiple Myeloma Detected by 18F-Florapronol Amyloid PET/CT

ABSTRACT

We report a case of amyloid arthropathy and pseudomyopathy with multiple myeloma, detected by amyloid PET/CT using 18F-florapronol. Bone scintigraphy and 18F-FDG PET/CT in a multiple myeloma patient revealed uneven soft tissue uptakes, especially at periarticular areas. The joint capsule and intermuscular fascia showed enhancement on CT, whereas muscle enzymes were normal. These suggested amyloid arthropathy with pseudomyopathy. 18F-Florapronol amyloid PET/CT showed extensive soft tissue uptakes. Amyloid arthropathy and pseudomyopathy were confirmed after biopsy. This is the first report of amyloid PET/CT aiding in the diagnosis of unusual presentation of systemic amyloidosis.

The Peptide-Drug Conjugate Melflufen Modulates the Unfolded Protein Response of Multiple Myeloma and Amyloidogenic Plasma Cells and Induces Cell Death

Immunoglobulin light-chain (AL) amyloidosis is a rare disease caused by clonal plasma cell secretion of misfolded light chains that assemble as toxic amyloid fibrils, depositing in vital organs including the heart and kidneys, causing organ dysfunction. Plasma cell-directed therapeutics are expected to reduce production of toxic light chain by eliminating amyloidogenic cells in bone marrow, thereby diminishing amyloid fibril deposition and providing the potential for organ recovery. Melphalan flufenamide (melflufen) is a first-in-class peptide-drug conjugate that targets aminopeptidases and rapidly releases alkylating agents inside tumor cells. Melflufen is highly lipophilic, permitting rapid uptake by cells, where it is enzymatically hydrolyzed by aminopeptidases, resulting in intracellular accumulation of the alkylating agents, including melphalan. Previous data demonstrating sensitivity of myeloma cells to melflufen suggest that the drug might be useful in AL amyloidosis. We describe the effects of melflufen on amyloidogenic plasma cells in vitro and ex vivo, demonstrating enhanced cytotoxic effects in comparison to melphalan, as well as novel mechanisms of action through the unfolded protein response (UPR) pathway. These findings provide evidence that melflufen-mediated cytotoxicity extends to amyloidogenic plasma cells, and support the rationale for the evaluation of melflufen in patients with AL amyloidosis.

Search for AL amyloidosis risk factors using Mendelian randomization

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

Gastrointestinal amyloidosis: A focused review

Amyloidosis, a heterogenous group of disorders, is characterized by the extracellular deposition of autologous, insoluble, fibrillar misfolded proteins. These extracellular proteins deposit in tissues aggregated in ß-pleated sheets arranged in an antiparallel fashion and cause distortion to the tissue architecture and function. In the current literature, about 60 heterogeneous amyloidogenic proteins have been identified, out of which 27 have been associated with human disease. Classified as a rare disease, amyloidosis is known to have a wide range of possible etiologies and clinical manifestations. The exact incidence and prevalence of the disease is currently unknown. In both systemic and localized amyloidosis, there is infiltration of the abnormal proteins in the layers of the gastrointestinal (GI) tract or the liver parenchyma. The gold standard test for establishing a diagnosis is tissue biopsy followed by Congo Red staining and apple-green birefringence of the Congo Red-stained deposits under polarized light. However, not all patients may have a positive tissue confirmation of the disease. In these cases additional workup and referral to a gastroenterologist may be warranted. Along with symptomatic management, the treatment for GI amyloidosis consists of observation or localized surgical excision in patients with localized disease, and treatment of the underlying pathology in cases of systemic amyloidosis. In this review of the literature, we describe the subtypes of amyloidosis, with a primary focus on the epidemiology, pathogenesis, clinical features, diagnosis and treatment strategies available for GI amyloidosis.