Novel monoclonal antibodies: A really specific therapy for light chain amyloidosis.

Light chain amyloidosis is a rare disease caused by clonal plasma cells in the bone marrow generating an excessive amount of immunoglobulin light chains. These chains misfold and produce insoluble fibrils that deposit in various organs, including the heart, kidneys, liver, nervous system, and digestive tract. Life expectancy and symptoms during the course of the disease vary depending on which and how many organs are affected. Targeted plasma cell therapy has significantly advanced the clinical management of amyloidosis, with ongoing progress. However, current clinical studies are investigating innovative targets, drug combinations and treatment strategies to improve therapeutic outcomes by minimizing adverse effects and refining patient prognosis in these challenging hematological conditions. In this paper, we review the state of the art regarding the use of anti-amyloid antibodies, as a revolutionary and innovative approach in the current scenario of amyloid treatment.

Supporting Role of Adequate Affected Tissue Biopsy in the Diagnostic Algorithm for Cardiac Amyloidosis.

Amyloidosis is a pathology that occurs as a result of the accumulation of various misfolded proteins in the extracellular space. It is a significant cause of morbidity and mortality due to multi-organ involvement. One of the most important determinants of mortality and morbidity is cardiac involvement. Cardiac amyloidosis (CA) may present with a variety of clinical findings. In this article, we aim to demonstrate the supportive role of cardiac and extra-cardiac tissue in the routine diagnostic pathway for CA.

Lymphocytic Myocarditis with Increased Left Ventricular Thickness: A Rare Presentation Mimicking Cardiac Amyloidosis.

BACKGROUND Lymphocytic myocarditis is an inflammatory condition of the heart that may present with a wide spectrum of symptoms and signs, ranging from asymptomatic to life-threatening cardiogenic shock and ventricular arrhythmia. Lymphocytic myocarditis usually presents as chamber dilation. However, increased left ventricular thickness is relatively rare. We present a case of lymphocytic myocarditis with increased left ventricular thickness which mimics the presentation of cardiac amyloidosis. CASE REPORT An 80-year-old Chinese man presented to the emergency room due to recurrent chest tightness. Wheezing and crackling were heard in both lungs, along with bilateral lower-extremity edema. He had elevated cardiac troponin T and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. Bedside echocardiogram showed left ventricular diastolic dysfunction and increased left ventricular thickness. Holter monitoring showed paroxysmal atrial fibrillation (AF) and atrial flutter. 99ᵐTechnetium-pyrophosphate scintigraphy showed grade 1 myocardial uptake. Endomyocardial biopsy revealed lymphocytic myocarditis. The patient was put on steroids, managed with diuretics to alleviate the symptoms of congestion, and amiodarone for conversion of AF to sinus rhythm. He had no deterioration of cardiac function in the follow-ups, but there was still asymmetric interventricular septal hypertrophy. CONCLUSIONS Lymphocytic myocarditis may lead to increased left ventricular thickness in some rare cases. In the setting of unexplained increased left ventricular thickness, one should consider lymphocytic myocarditis as a differential diagnosis. In addition, endomyocardial biopsy should be performed as early as possible to confirm the diagnosis and identify the type of inflammation, which helps with treatment and prognosis.

Amyloid Typing in Cardiac Amyloidosis Using Western Blotting.

BACKGROUND: Cardiac amyloidosis (CA) is characterized by the extracellular deposition of misfolded protein in the heart. Precise identification of the amyloid type is often challenging, but critical, since the treatment and prognosis depend on the disease form and the type of deposited amyloid. Coexistence of clinical conditions such as old age, monoclonal gammopathy, chronic inflammation, or peripheral neuropathy in a patient with cardiomyopathy creates a differential diagnosis between the major types of CA: amyloidosis light chains (AL), amyloidosis transthyretin (ATTR) and amyloidosis A (AA). OBJECTIVES: To demonstrate the utility of the Western blotting (WB)-based amyloid typing method in patients diagnosed with cardiac amyloidosis where the type of amyloid was not obvious based on the clinical context. METHODS: Congo red positive endomyocardial biopsy specimens were studied in patients where the type of amyloid was uncertain. Amyloid proteins were extracted and identified by WB. Mass spectrometry (MS) of the electrophoretically resolved protein-in-gel bands was used for confirmation of WB data. RESULTS: WB analysis allowed differentiation between AL, AA, and ATTR in cardiac biopsies based on specific immunoreactivity of the electrophoretically separated proteins and their characteristic molecular weight. The obtained results were confirmed by MS. CONCLUSIONS: WB-based amyloid typing method is cheaper and more readily available than the complex and expensive gold standard techniques such as MS analysis or immunoelectron microscopy. Notably, it is more sensitive and specific than the commonly used immunohistochemical techniques and may provide an accessible diagnostic service to patients with amyloidosis in Israel.

Autosomal dominant chronic tubulointerstitial nephropathy: do not forget amyloidosis.

Amyloidosis is a rare cause of inherited kidney disease, with most variants responsible for prominent glomerular involvement. In this issue, Kmochová et al. reported the first description of autosomal dominant medullary amyloidosis due to apolipoprotein A4 variants, resulting in slowly progressive chronic kidney disease with minimal proteinuria. Combining next-generation sequencing with histopathological studies incorporating Congo red staining and mass spectrometry should be considered in the diagnostic workup of hereditary tubulointerstitial disorders not identified after routine genetic testing.

Clinical spectrum of Transthyretin amyloidogenic mutations among diverse population origins.

PURPOSE: Coding mutations in the Transthyretin (TTR) gene cause a hereditary form of amyloidosis characterized by a complex genotype-phenotype correlation with limited information regarding differences among worldwide populations. METHODS: We compared 676 diverse individuals carrying TTR amyloidogenic mutations (rs138065384, Phe44Leu; rs730881165, Ala81Thr; rs121918074, His90Asn; rs76992529, Val122Ile) to 12,430 non-carriers matched by age, sex, and genetically-inferred ancestry to assess their clinical presentations across 1,693 outcomes derived from electronic health records in UK biobank. RESULTS: In individuals of African descent (AFR), Val122Ile mutation was linked to multiple outcomes related to the circulatory system (fold-enrichment = 2.96, p = 0.002) with the strongest associations being cardiac congenital anomalies (phecode 747.1, p = 0.003), endocarditis (phecode 420.3, p = 0.006), and cardiomyopathy (phecode 425, p = 0.007). In individuals of Central-South Asian descent (CSA), His90Asn mutation was associated with dermatologic outcomes (fold-enrichment = 28, p = 0.001). The same TTR mutation was linked to neoplasms in European-descent individuals (EUR, fold-enrichment = 3.09, p = 0.003). In EUR, Ala81Thr showed multiple associations with respiratory outcomes related (fold-enrichment = 3.61, p = 0.002), but the strongest association was with atrioventricular block (phecode 426.2, p = 2.81 × 10- 4). Additionally, the same mutation in East Asians (EAS) showed associations with endocrine-metabolic traits (fold-enrichment = 4.47, p = 0.003). In the cross-ancestry meta-analysis, Val122Ile mutation was associated with peripheral nerve disorders (phecode 351, p = 0.004) in addition to cardiac congenital anomalies (fold-enrichment = 6.94, p = 0.003). CONCLUSIONS: Overall, these findings highlight that TTR amyloidogenic mutations present ancestry-specific and ancestry-convergent associations related to a range of health domains. This supports the need to increase awareness regarding the range of outcomes associated with TTR mutations across worldwide populations to reduce misdiagnosis and delayed diagnosis of TTR-related amyloidosis.

Bilateral Hilar and Mediastinal Lymphadenopathy as an Initial Manifestation of Amyloidosis.

A 75-year-old male visited our hospital with bilateral hilar lymph node swelling detected on chest radiography during an annual medical checkup. Chest computed tomography revealed swelling of multiple hilar mediastinal lymph nodes. Histopathological and immunohistochemical examinations of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) specimens from the hilar lymph nodes revealed amyloid deposition. Bilateral hilar and mediastinal lymphadenopathies can be the first manifestations of amyloidosis diagnosed using EBUS-TBNA.

Gastroduodenal Involvement in AL Amyloidosis: Case Report and Literature Review.

Gastrointestinal amyloidosis is a rare condition commonly found in the setting of systemic AL amyloidosis. Amyloid can deposit throughout the gastrointestinal tract and the resulting symptoms vary depending on the site of deposition. Gastrointestinal (GI) manifestations can range from weight loss or abdominal pain, to more serious complications like gastrointestinal bleeding, malabsorption, dysmotility, and obstruction. This case describes a patient with known history of IgG lambda AL amyloidosis, presenting with epigastric pain and unintentional weight loss found to have gastroduodenal amyloidosis. The definitive diagnosis of GI amyloidosis requires endoscopic biopsy with Congo red staining and visualization under polarized light microscopy. There are currently no specific guidelines for the management of GI amyloidosis. Generally, the goal is to treat the underlying cause of the amyloidosis along with symptom management. Our patient is being treated with cyclophosphamide, bortezomib, and dexamethasone (CyBorD) and started on hemodialysis due to progression of renal disease.

Macular amyloidosis diagnostic outcomes of skin biopsy: A systematic review.

Macular amyloidosis (MA) is a primary localized cutaneous amyloidosis, characterized by amyloid deposition in the papillary dermis. The clinical presentation includes pruritic hyperpigmented macules and patches with a reticulated or rippled pattern, primarily found on the upper back and extremities. Biopsy is an essential diagnostic tool for confirming MA. This systematic review focused on the biopsy outcomes in patients diagnosed with MA.

AIns (insulin) type amyloidoma of the extremity diagnosed by fine-needle aspiration.

Amyloid is an extracellular deposition of Congo red positive material which shows apple green birefringence under polarized light. A cytopathologist can uncommonly encounter such cases. Among the reported cases, a fine-needle aspiration (FNA) of amyloid is frequently misinterpreted as acellular nondiagnostic material. We report a case of amyloidoma of the right upper arm in a 68-year-old man with history of renal transplantation for diabetic nephropathy who presented with loss of appetite and weight loss. Physical exam showed a 7 cm hard nodular subcutaneous mass in the right upper arm. FNA yielded abundant acellular, irregular fragments of dense material, which was Congo red positive with apple green birefringence by polarized light, consistent with amyloid. Further subtyping of the amyloid by mass spectrometry, showed AIns (insulin)-type amyloid deposition. After further questioning, the patient admitted to injecting insulin at the same site for many years. Awareness of the cytological features is important for diagnosis. This is especially important when dealing with uncommon sites and without adequate clinical information.

Being a Better Starfish Thrower, Carpal Tunnel Syndrome, and Cardiac Amyloidosis: The Hand Surgeon's Opportunity to Make a Profound Difference.

In recent years, there is increasing literature in cardiac and hand surgery journals demonstrating a stronger association between seemingly idiopathic carpal tunnel and amyloidosis. Despite this, it can be difficult for hand surgeons to identify who need biopsies, and this is further complicated by the cost of a biopsy and the low likelihood that a patient has cardiac amyloidosis. In patients with cardiac amyloidosis and carpal tunnel syndrome (CTS), CTS is typically diagnosed 5-10 years prior. Early diagnosis of cardiac amyloidosis is crucial, as current medications work to slow disease progression, but do not treat existing amyloid deposits. Hand surgeons can play an essential role in early diagnosis. The patient case discussed describes a man who had a carpal tunnel biopsy because of his bilateral CTS, recurrent trigger fingers, and his age. After confirmation of amyloidosis, he was referred for cardiac amyloidosis evaluation. Testing confirmed this diagnosis, and he was started on tafamidis, which studies show provide patients an opportunity for increased survival and quality of life. The responsibility falls on cardiologists and hand surgeons to continue refining the indications for carpal tunnel biopsy and spreading awareness of carpal tunnel biopsy and amyloid testing, as much work is still needed.

Rare vertebral pathological fracture in primary amyloidosis.

Spinal involvement in primary amyloidosis is an exceedingly rare condition, presenting with typical pathological fracture symptoms that are often indistinguishable from other pathologies such as bone metastasis, metabolic disorders and infections. Histopathological studies for tissue diagnosis are the cornerstone of a definitive diagnosis, leading to successful treatment. Early diagnosis and intervention play a pivotal role in the care of patients with amyloidosis. Here, we present a unique case of a pathological fracture in the L4 vertebra following minor trauma. This fracture manifested with pain, instability and limitations in daily activities in a patient who had already been diagnosed with systemic amyloidosis and was undergoing chemotherapy. This case represents a distinct instance of vertebral involvement in amyloidosis and was managed with both chemotherapy and surgical intervention to address the spinal pathology, resulting in favourable outcomes.

Complete responses in AL amyloidosis are unequal: the impact of free light chain mass spectrometry in AL amyloidosis.

ABSTRACT: Amyloidogenic serum free light chains (sFLCs) drive disease progression in AL amyloidosis. Matrix-assisted laser desorption/ionization time of flight mass spectrometry-based FLC assay (FLC-MS) has greater sensitivity than conventional sFLC assays allowing for the detection of serological residual disease. We report the utility of FLC-MS in a large series of patients with AL amyloidosis assessing the impact of FLC-MS negativity after treatment on overall survival (OS) and organ response rates. Serum samples were analyzed using FLC-MS at diagnosis and at 6 and 12 months after treatment. The impact of FLC-MS negativity over standard hematologic responses on survival and organ response was assessed. A total of 487 patients were included; 290 (59%) and 349 (71.5%) had cardiac and renal involvement, respectively. There was 100% concordance between the light chain (LC) fibril type and LC isotype identified by FLC-MS. At 6 and 12 months, 81 (16.6%) and 101 (20.7%) were FLC-MS negative. Of those achieving a conventional hematologic complete response (CR) at 6 and 12 months, 45 (27.7%) and 64 (39%) were FLC-MS negative. At 12 months, median OS for CR + FLC-MS negative was not reached vs 108 months in CR + FLC-MS positive (P = .024). At 12 months, 70% of patients with FLC-MS negativity (vs 50% FLC-MS positive) achieved a cardiac response (P = .015). In a multivariate analysis, FLC-MS negativity at 12 months was an independent predictor of better outcomes. FLC-MS can detect persistent monoclonal light chains in a significant proportion of patients in a conventional hematologic CR. FLC-MS assessment promises to be a new standard for response assessment in AL amyloidosis.

Prevalence of valvular heart disease in cardiac amyloidosis and impact on survival.

BACKGROUND: Limited data exists on the prognostic impact of valvular heart disease in cardiac amyloidosis (CA). We therefore sought to define the prevalence of valvular disease in patients with CA and assess the effects of significant valve disease on survival. METHODS: This multi-center retrospective cohort study included consecutive patients with confirmed transthyretin (TTR) or light chain (AL) amyloidosis. Echocardiographic data closest to the date of amyloid diagnosis was reviewed, and severity was graded according to ASE guidelines. Kaplan-Meier survival analysis was performed to compare survival between patients with moderate or greater valve disease against those with mild or less disease. RESULTS: We included 345 patients (median age 76 years; 73 % men; 110 AL, 235TTR). The median survival for the total patient cohort with cardiac amyloidosis was 2.92 years, with 30 % of patients surviving at five years after their diagnosis. Median survival comparing AL vs ATTR was 2.58 years vs 2.82 years (p = 0.67) The most common valvular abnormalities in the total cohort were mitral (62 %) and tricuspid (66 %).regurgitation There was a statistically significant difference in median survival between patients with no or mild MR compared to those with moderate or severe MR (2.92 years vs 3.35 years, p = 0.0047) (Fig. 5). There was a statistically significant difference in median survival in patients with no or mild TR compared to those with moderate or severe TR (3.35 years vs 2.3 years, p = 0.015). CONCLUSION: Our study demonstrates a significant prevalence of mitral and tricuspid regurgitation in CA, with patients with moderate to severe MR and TR having a poorer prognosis.

Race, Genotype, and Prognosis in Black Patients With Transthyretin Cardiac Amyloidosis.

Previous studies suggest worse outcomes in patients with variant transthyretin cardiac amyloidosis (ATTR-CA) because of valine-to-isoleucine substitution at Position 122 (V122I) (ATTRv-CA) compared with patients with wild-type (WT) disease (ATTRwt-CA). Given V122I is almost exclusively found in Black patients, it is unclear if this is attributable to the biology of genotype or racial differences. Patients with ATTR-CA diagnosed between January 2001 and August 2021 were characterized into 3 categories: (1) White with ATTRwt-CA (White-WT); (2) Black with V122I ATTRv-CA (Black-V122I), and (3) Black with ATTRwt-CA (Black-WT). Event-free survival (composite of death, left ventricular assist device, or cardiac transplant) was evaluated using univariable and multivariable analyses over a median follow-up of 1.6 (0.7 to 2.90) years. Of 694 ATTR-CA patients, 502 (72%) were White-WT, 139 Black-V122I (20%), and 53 Black-WT (8%). Notably, 28% of Black patients with ATTR-CA had WT disease and not the V122I variant. Using multivariable modeling to adjust for several prognostic features, Black-V122I had higher risk of the composite adverse outcome compared with a grouped cohort of patients with WT disease (White-WT and Black-WT) (hazard ratio [HR] 1.82, confidence interval [CI] 1.30-2.56, p < 0.001). Furthermore, the Black cohort as a whole (Black-V122I and Black-WT) demonstrated greater risk of adverse outcomes compared with White-WT (HR 1.63, CI 1.19-2.24, p = 0.002). Black-V122I had greater risk of the primary end point compared with White-WT (HR 1.80, CI 1.27-2.56, p = 0.001). Black patients with ATTR-CA have worse event-free survival than White-WT despite risk adjustment. However, it remains unclear whether this is driven by differences in race or genotype given the smaller number of Black-WT patients. Approximately one-quarter of Black patients had WT, of which a greater proportion were female compared with White-WT.