Monoclonal Immunoglobulin Light Chains Research Articles

Diagnostic Modalities in the Detection of Cardiac Amyloidosis.

Cardiac amyloidosis (CA) results mainly from the infiltration of the myocardium by either immunoglobulin light-chain fibrils (AL) or transthyretin fibrils (ATTR), causing restrictive cardiomyopathy and eventually death if untreated. AL derives from monoclonal immunoglobulin light chains produced by plasma cell clones in the bone marrow, while ATTR is the misfolded form of hepatically derived transthyretin (TTR) protein and can be hereditary (ATTRv) or wild-type (ATTRwt). Over the last decade, improvements in diagnostic imaging and better clinical awareness have unleashed a notable presence of CA in the community, especially ATTR in the elderly population. These multimodality imaging modalities include echocardiography, cardiac magnetic resonance, and radionuclide scintigraphy with bone-avid tracers. There has been remarkable progress in the therapeutic landscape as well, and there are disease-modifying therapies available now that can alter the course of the disease and improve survival if initiated at an early stage of the disease. There remains an unmet need for detecting this disease accurately and early so that these patients can benefit the most from newly emerging therapies.

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

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

Cardiac Amyloidosis: A Contemporary Review of Medical and Surgical Therapy.

Amyloidosis is a systemic disease initiated by deposition of misfolded proteins in the extracellular space, due to which multiple organs may be affected concomitantly. Cardiac amyloidosis, however, remains a major cause of morbidity and mortality in this population due to infiltrative /restrictive cardiomyopathy. This review attempts to focus on contemporary medical and surgical therapies for the different types of cardiac amyloidosis. Amyloidosis affecting the heart are predominantly of the transthyretin type (acquired in the older or genetic in the younger patients), and the monoclonal immunoglobulin light chain (AL) type which is solely acquired. A rare form of secondary amyloidosis AA type can also affect the heart due to excessive production and accumulation of the acute-phase protein called Serum Amyloid A" (SAA) in the setting of chronic inflammation, cancers or autoinflammatory disease. More commonly AA amyloidosis is seen in the liver and kidney. Other rare types are Apo A1 and Isolated Atrial Amyloidosis (AANF). Medical therapies have made important strides in the clinical management of the two common types of cardiac amyloidosis. Surgical therapies such as mechanical circulatory support and cardiac transplantation should be considered in appropriate patients. Future research using AI driven algorithms for early diagnosis and treatment as well as development of newer genetic engineering technologies will drive improvements in diagnosis, treatment and patient outcomes.

Urine Immunofixation Electrophoresis for Diagnosis of Monoclonal Gammopathy: Evaluation of Methods for Urine Concentration.

Examination of urine by immunofixation electrophoresis (UIFE) is one of the tests recommended for screening and monitoring of monoclonal gammopathies, especially multiple myeloma. Unlike the serum free light chain measurement, a positive result on urine immunofixation is diagnostic for monoclonal immunoglobulin light chains. Urine is usually concentrated, generally by membrane filtration, prior to electrophoresis. Alternative methods to membrane filtration for urine concentration were examined. Residual urine specimens submitted for urine protein electrophoresis were concentrated by precipitation of the proteins by ammonium sulfate salt precipitation, precipitation with ethanol and acetonitrile, and by desiccation. The concentrated specimens were subjected to immunofixation electrophoresis using antisera to free light chains (FLC). The results were compared with those from conventional immunofixation electrophoresis using specimens concentrated by membrane filtration. Ammonium sulfate, ethanol, and acetonitrile precipitation results were less than satisfactory. Concentration by desiccation provided results comparable, if not better than, those by membrane filtration and conventional UIFE. The cost of desiccation is minimal compared to more than $5.00/specimen cost of concentration by membrane filtration. The differences in the results with conventional UIFE and the method described here are likely due to (a) variability in the reactivity of different antisera to free monoclonal light chains, and (b) obscuration of monoclonal free light chains by co-migration with intact immunoglobulin monoclonal proteins. Concentrating urine by desiccation for immunofixation electrophoresis is technically simple, inexpensive, and provides results comparable to concentrating by membrane filtration. Using FLC provides a more sensitive assay than using conventional antisera.

Amyloid Protein in AL-Amyloidosis. Natural History and Potential for Regression

Amyloid light chain amyloidosis is the most commonly seen form of systemic amyloidosis and is characterized by the accumulation of circulating monoclonal immunoglobulin light chain precursors arising from an abnormal clone of plasma cells. These light chain precursors demonstrate a propensity for misfolding, aggregation and deposition as highly stable fibrillar cross-linked beta sheets in various tissues and organs in a manner characteristic of other forms of systemic amyloidosis. There have been great advances in the treatment of the underlying plasma cell dyscrasia with improved long-term survival but the persistence of extracellular amyloid deposits in the tissues of vital organs, particularly the heart and kidney remains a significant cause of morbidity and mortality even in those patients in whom a hematological complete response has been achieved. This review focuses on the importance of early diagnosis and treatment on limiting the extent of amyloid protein accumulation and organ dysfunction and the current state of knowledge on the potential for resorption and clearance of these amyloid deposits in patients with amyloid light chain amyloidosis. The status of current novel anti-fibrillar agents is reviewed and future strategies for effectively intervening to improve organ function and survival these individuals is discussed.

Comparison of Renal Function before and after Autologous Stem Cell Transplantation in Egyptian Patients with Multiple Myeloma and Renal Insufficiency: A Retrospective Study.

Renal failure is a common feature of multiple myeloma (MM) that occurs in 20%-40% of newly diagnosed patients with MM and is the result of monoclonal immunoglobulin light chains. Many studies have examined the effect of autologous stem cell transplantation (ASCT) in MM patients with renal impairment and the safety of performing the transplantation in patients with renal failure. This study aimed to compare renal function before and after ASCT in Egyptian MM patients with renal insufficiency to evaluate the effect of ASCT on renal recovery. Our study included 31 MM patients with renal impairment out of 400 patients who met the criteria of the International Myeloma Working Group for symptomatic MM. The estimated glomerular filtration rate (eGFR) calculated by the Modification of Diet in Renal Disease formula was compared before and after the transplant. Only four patients (12.9%) were dependent on dialysis. Six of those with a history of hemodialysis (HD) who were either dependent on dialysis or dialyzed according to need achieved independence from HD. There was no significant correlation between the degree of renal impairment and the disease's status at the time of transplantation (P = 0.86). The study showed significant improvements in serum creatinine levels compared with its value before the transplant (P = 0.016) and in eGFR (P = 0.004). In total, 45% of patients achieved renal improvement, shown by a 25% increase in GFR above the baseline. There was a significant improvement of renal function after ASCT in MM patients with renal impairment.

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

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

Outcomes Associated with Clone-Directed Therapies for Monoclonal Gammopathy of Renal Significance

Background: Monoclonal Gammopathy of Renal Significance (MGRS) is a category of diseases not meeting criteria for cancer, in which a clonal population of B-lymphoid or plasma cells produces a nephrotoxic protein leading to kidney injury. Informal consensus has arisen that therapy targeting the causal clone is most likely to be efficacious, and the primary goal of therapy is to prolong renal survival. Light chain (AL) amyloidosis has been extensively studied, yet there is a paucity of data describing outcomes associated with clone-directed therapy for the various subtypes of non-AL MGRS. Methods: This was a retrospective analysis of patients treated at two National Cancer Institute (NCI)-designated cancer centers in the United States. Medical records of adult patients seen between January 2010 and March 2023 were screened for MGRS. Patients were eligible if they had renal biopsy-confirmed histopathologic findings compatible with MGRS. AL amyloidosis was excluded. The primary outcome was renal survival, defined as time from diagnosis of MGRS to requiring renal replacement therapy (RRT) or renal transplant, with patients censored at last follow up or death. Baseline characteristics were described, including 24-hour proteinuria, estimated glomerular filtration rate (eGFR), whether a clonal population of B cells or plasma cells could be identified on histopathologic examination of marrow or lymph node biopsy, concentration of monoclonal protein, and involved serum free light chain concentration. Initial therapy was reported, although differences in outcomes across therapeutic strategies were not compared. Baseline clinical characteristics between patients who required RRT and those who did not were compared. Baseline clinical variables and time to RRT were compared across the two most common MGRS subtypes in the cohort: proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) and light chain deposition disease (LCDD). Continuous variables were compared across subgroups using Wilcoxon rank-sum test. Time-to-event outcomes were analyzed according to the Kaplan-Meier method. All analyses were conducted using R version 3.6.1. Results: In total, 65 patients were included, 23 (35%) of whom ultimately required RRT or transplant. Four patients died, all after RRT. Median baseline proteinuria was 2802 mg/24h (IQR 972.5 - 4492.0) and median eGFR was 33.0 mL/min (IQR 23 - 53) for the entire cohort. In all cases proteinuria was mostly albumin. Median baseline involved light chain concentration was 8.3 mg/dL (IQR 3.1 - 26.4). A majority of patients (n=33, 51%) had no identifiable serum monoclonal protein. The two most common MGRS subtypes were PGNMID (n = 26) followed by LCDD (n = 21). Clonal populations thought to be causing MGRS were identified in 41/64 patients (64%), including 37 (58%) with plasma cell clones, 1 (2%) with a lymphoplasmacytic lymphoma clone, and 3 (4.7%) with other B-cell clones. Clones were not identified in 23 (36%). The most common chemotherapy agents included bortezomib (n=42, 64%) and rituximab (n=14, 22%). Compared to patients not requiring RRT, patients requiring RRT had higher baseline proteinuria (median 3531 vs. 1980 mg/24h, p<0.001) and lower eGFR (median 16 v. 44 mL/min, p<0.001); differences in serum free light chain concentrations were not significant ( Figure 1). A clonal population thought to be causing MGRS was identified on bone marrow biopsy in a majority of LCDD patients (n = 20, 95%), while clones were infrequently found in PGNMID (n = 6, 23%). The vast majority (n=20, 95%) of patients with LCDD received bortezomib-based therapy. Initial therapy in patients with PGNMID was more evenly divided: 9 (35%) received bortezomib-based therapy, 10 (38%) received rituximab-based therapy, and 6 (23%) received other regimens. Despite differences in therapeutic approach, patients with LCDD and in patients with PGNMID had similar risk of RRT (cumulative risk 35% v. 43%, p=0.54; HR 0.83 (95% CI 0.52-1.33); p =0.44) ( Figure 2). Conclusion: Patients with MGRS remain at high risk of requiring RRT even with clone-directed therapy. Despite differences in pathogenic clones and therapeutic strategies, outcomes of patients with PGNMID and LCDD are similar. Because the severity of baseline renal function across MGRS histologies predicts renal survival, early diagnosis and treatment is likely critical to improving renal outcomes.

Value of nuclide scintigraphy in the diagnosis and prognosis of cardiac amyloidosis.

Amyloidosis is a local or systemic disease caused by the deposition of misfolded proteins outside the cell, with rapid progression, and dire prognosis. Common types of cardiac amyloidosis are monoclonal immunoglobulin light chain amyloidosis (AL-CA) and transthyretin cardiac amyloidosis (ATTR-CA). Nuclear medicine examinations can be accurate, rapid, and non-invasive to help diagnose diseases and can effectively predict the prognosis of patients with CA. Technetium (99Tcm)-labeled bisphosphonate imaging has been included in the consensus of experts and has become the first-line imaging method for the diagnosis of ATTR-CA. 123I-metaiodoenzylguanidine (MIBG) as a norepinephrine analogue can effectively assess cardiac sympathetic innervation in patients with CA. Aβ- amyloid imaging agents such as 11C-pittsburgh compound B and 18F-flubetaben are expected to be new techniques for diagnosing AL-CA and incorporating them into cardiac staging systems for AL-CA patients in the future. New imaging agents such as 18F-NaF has been widely used in the diagnosis, treatment response monitoring, and prognosis assessment of CA. Summarizing the research value of nuclide imaging in CA may provide new ideas for clinical realization of early detection of CA and accurate assessment of disease prognosis.

Clinical and Cardiovascular Magnetic Resonance Imaging Features of Cardiac Amyloidosis.

Amyloidosis is a systemic disease characterized by the accumulation of insoluble aggregates in various organs, leading to parenchymal damage. When these amyloid fibrils are deposited in the extracellular matrix of the cardiac structures, the condition is referred to as cardiac amyloidosis (CA). The extent of organ involvement determines the degree of cardiac impairment, which can significantly impact prognosis. The two most implicated proteins in CA are transthyretin and misfolded monoclonal immunoglobulin light chains. These proteins give rise to two distinct clinical forms of CA: transthyretin amyloidosis (ATTR-CA) and light-chain amyloidosis (AL-CA). ATTR-CA is further classified into two subtypes: ATTRm-CA, which occurs at a younger age and is caused by hereditary misfolded mutated proteins, and ATTRwt-CA, which is an acquired wild-type form more commonly observed in older adults, referred to as senile amyloidosis. While AL-CA was considered the most prevalent form for many years, recent autopsy studies have revealed an increase in cases of ATTRwt-CA. This narrative review aims to describe the clinical and imaging features of CA, with a particular focus on cardiac complications and mortality associated with the AL form. Early identification and differentiation of CA from other disorders are crucial, given the higher risk and severity of cardiac involvement in AL-CA. Furthermore, emphasis is placed on the potential utility of cardiovascular magnetic resonance imaging in detecting early cases of CA.

New Onset Nephrotic - Range Proteinuria in a Patient with Chronic Kidney Disease - Not Always What it Seems

Light chain deposition disease (LCDD) is a rare condition that is characterized by the deposition of monoclonal immunoglobulin light chains in glomerular and tubular basement membranes. We report the case of a 72-year-old male with long-standing and stable chronic kidney disease (CKD) presumably due to hypertension.

Pathological characteristics of light chain crystalline podocytopathy

Monoclonal immunoglobulin light chain (LC) crystalline inclusions within podocytes are rare, poorly characterized entities. To provide more insight, we now present the first clinicopathologic series of LC crystalline podocytopathy (LCCP) encompassing 25 patients (68% male, median age 56 years). Most (80%) patients presented with proteinuria and chronic kidney disease, with nephrotic syndrome in 28%. Crystalline keratopathy and Fanconi syndrome were present in 22% and 10%, respectively. The hematologic condition was monoclonal gammopathy of renal significance (MGRS) in 55% and multiple myeloma in 45%. The serum monoclonal immunoglobulin was IgG κappa in 86%. Histologically, 60% exhibited focal segmental glomerulosclerosis (FSGS), often collapsing. Ultrastructurally, podocyte LC crystals were numerous with variable effacement of foot processes. Crystals were also present in proximal tubular cells as light chain proximal tubulopathy (LCPT) in 80% and in interstitial histiocytes in 36%. Significantly, frozen-section immunofluorescence failed to reveal the LC composition of crystals in 88%, requiring paraffin-immunofluorescence or immunohistochemistry, with identification of kappa LC in 87%. The LC variable region gene segment, determined by mass spectrometry of glomeruli or bone marrow plasma cell sequencing, was IGKV1-33 in four and IGKV3-20 in one. Among 21 patients who received anti-plasma cell-directed chemotherapy, 50% achieved a kidney response, which depended on a deep hematologic response. After a median follow-up of 36 months, 26% progressed to kidney failure and 17% died. The mean kidney failure-free survival was 57.6 months and was worse in those with FSGS. In sum, LCCP is rare, mostly associates with IgG κappa MGRS, and frequently has concurrent LCPT, although Fanconi syndrome is uncommon. Paraffin-immunofluorescence and electron microscopy are essential to prevent misdiagnosis as primary FSGS since kidney survival depends on early diagnosis and subsequent clone-directed therapy.

Understanding AL amyloidosis with a little help from in vivo models.

Monoclonal immunoglobulin (Ig) light chain amyloidosis (AL) is a rare but severe disease that may occur when a B or plasma cell clone secretes an excess of free Ig light chains (LCs). Some of these LCs tend to aggregate into organized fibrils with a β-sheet structure, the so-called amyloid fibrils, and deposit into the extracellular compartment of organs, such as the heart or kidneys, causing their dysfunction. Recent findings have confirmed that the core of the amyloid fibrils is constituted by the variable (V) domain of the LCs, but the mechanisms underlying the unfolding and aggregation of this fragment and its deposition are still unclear. Moreover, in addition to the mechanical constraints exerted by the massive accumulation of amyloid fibrils in organs, the direct toxicity of these variable domain LCs, full-length light chains, or primary amyloid precursors (oligomers) seems to play a role in the pathogenesis of the disease. Many in vitro studies have focused on these topics, but the variability of this disease, in which each LC presents unique properties, and the extent and complexity of affected organs make its study in vivo very difficult. Accordingly, several groups have focused on the development of animal models for years, with some encouraging but mostly disappointing results. In this review, we discuss the experimental models that have been used to better understand the unknowns of this pathology with an emphasis on in vivo approaches. We also focus on why reliable AL amyloidosis animal models remain so difficult to obtain and what this tells us about the pathophysiology of the disease.

Machine learning algorithms to automate differentiating cardiac amyloidosis from hypertrophic cardiomyopathy.

Cardiac amyloidosis has a poor prognosis, and high mortality and is often misdiagnosed as hypertrophic cardiomyopathy, leading to delayed diagnosis. Machine learning combined with speckle tracking echocardiography was proposed to automate differentiating two conditions. A total of 74 patients with pathologically confirmed monoclonal immunoglobulin light chain cardiac amyloidosis and 64 patients with hypertrophic cardiomyopathy were enrolled from June 2015 to November 2018. Machine learning models utilizing traditional and advanced algorithms were established and determined the most significant predictors. The performance was evaluated by the receiver operating characteristic curve (ROC) and the area under the curve (AUC). With clinical and echocardiography data, all models showed great discriminative performance (AUC > 0.9). Compared with logistic regression (AUC 0.91), machine learning such as support vector machine (AUC 0.95, p = 0.477), random forest (AUC 0.97, p = 0.301) and gradient boosting machine (AUC 0.98, p = 0.230) demonstrated similar capability to distinguish cardiac amyloidosis and hypertrophic cardiomyopathy. With speckle tracking echocardiography, the predictive performance of the voting model was similar to that of LightGBM (AUC was 0.86 for both), while the AUC of XGBoost was slightly lower (AUC 0.84). In fivefold cross-validation, the voting model was more robust globally and superior to the single model in some test sets. Data-driven machine learning had shown admirable performance in differentiating two conditions and could automatically integrate abundant variables to identify the most discriminating predictors without making preassumptions. In the era of big data, automated machine learning will help to identify patients with cardiac amyloidosis and timely and effectively intervene, thus improving the outcome.

The dark side of current analytic methods for Bence Jones Proteinuria.

Bence Jones proteinuria (BJP) refers to monoclonal free immunoglobulin light chains detected in urine, deriving from the clonal expansion of plasma cells in the bone marrow in patients with plasma cell dyscrasias, associated with monoclonal gammopathies of uncertain origin. This review summarizes routinely diagnostic procedures to assess BJP highlighting critical steps of pre-analytical, analytical, and post-analytical phases. The best option for BJP detection is the first morning void urine sample and immunofixation electrophoresis detection technique (IFE) the recommended method, with the employment of specific polyvalent antisera. Other qualitative tests for a quick evaluation of BJP are currently available. Densitometric analysis performed on the 24-hour urine is the recommended method to quantify BJP. To overcome the 24-hour collection, it is possible to use morning urine sample and correlate the assessed value of BJP to creatininuria. In addition to the traditional ones, we here reviewed screening methods currently used to avoid false negatives and reduce the time around test (TAT), together with immunochemical quantification methods for increased sensitivity, after checking BJP by IFE. Mass spectrometry emerges as a new challenge in the determination of BJP. The employment of different based-assays methods may be useful for diagnostic purposes to improve the accuracy of BJP monitoring in monoclonal gammopathies.

Diagnostic and Prognostic Values of Cardiopulmonary Exercise Testing in Cardiac Amyloidosis.

Cardiac amyloidosis (CA) is a myocardial disease characterized by extracellular amyloid infiltration throughout the heart, resulting in increased myocardial stiffness, and restrictive heart wall chamber behavior. Its diagnosis among patients hospitalized for cardiovascular diseases is becoming increasingly frequent, suggesting improved disease awareness, and higher diagnostic capacities. One predominant functional manifestation of patients with CA is exercise intolerance, objectified by reduced peak oxygen uptake (VO2 peak), and assessed by metabolic cart during cardiopulmonary exercise testing (CPET). Hemodynamic adaptation to exercise in patients with CA is characterized by low myocardial contractile reserve and impaired myocardial efficiency. Rapid shallow breathing and hyperventilation, in the absence of ventilatory limitation, are also typically observed in response to exercise. Ventilatory inefficiency is further suggested by an increased VE-VCO2 slope, which has been attributed to excessive sympathoexcitation and a high physiological dead space (VD/VT) ratio during exercise. Growing evidence now suggests that, in addition to well-established biomarker risk models, a reduced VO2 peak is potentially a strong and independent predictive factor of adverse patient outcomes, both for monoclonal immunoglobulin light chain (AL) or transthyretin (ATTR) CA. Besides generating prognostic information, CPET can be used for the evaluation of the impact of therapeutic interventions in patients with CA.

MO232: Amyloidosis AL in Nephrology

Abstract BACKGROUND AND AIMS Systemic AL amyloidosis is a rare pathology associated with the precipitation of monoclonal immunoglobulin light chains in the form of fibrils in various organs. Clinical presentations are extremely variable and diagnosis is often delayed. The two most affected organs are the kidney and the heart. The treatment is based on chemotherapy to eliminate the medullary clone that produces the monoclonal light chain. However, the outcome is still poor. The aim of our study was to describe the demographic, clinicobiological, histological, therapeutic and evolutionary characteristics of AL amyloidosis in our population. METHOD We carried out a single-center retrospective descriptive trial of patients who were diagnosed with histologically confirmed AL amyloidosis in our Nephrology Department during the period from 2014 to 2021. RESULTS We enrolled 12 patients with a mean age of 61.25 ± 8.17years. The sex ratio (M/F) was 3. The histological confirmation of AL amyloidosis was based on biopsies: kidney (n = 7) and salivary glands (n = 5). The immunoglobulin type was Ig G Lambda in 75% of cases (n = 9), IgG kappa in 16.6% of cases (n = 2) and IgM in 8.3% of cases (n = 1). The cause of amyloidosis was multiple myeloma in 66.6% of cases (n = 8) and Waldenström disease in 8.3% of cases (n = 1). The mean creatinine at diagnosis was 441.33 ± 334.47 umol/L, i.e. a median creatinine clearance (MDRD) of 36.67 ± 46.77 mL/min. At the time of diagnosis, 50% of the patients (n = 6) had end-stage renal disease and 25% (n = 3) had reached it after a few more months. The mean proteinuria was 6.33 g/24 h within 83.3% of cases (n = 10) with the presence of a nephrotic syndrome. The cardiac involvement was found in 58% of the patients (n = 7) at the time of diagnosis with a Mayo Clinic prognostic score of III. The neurological involvement was observed in 8.3% of cases (n = 1) and was confirmed by spinal MRI as polyradiculoneuritis. As for the therapeutical management, 75% of the patients (n = 9) received first-line treatment with Bortezomib Cyclophosphamide Dexamethasone, and 16.6 of the patients (n = 2) were treated with corticosteroids and Melphalan (the 12th patient died early). The outcome was fatal in 41.5% (n = 5) and the cause of death was a state of septic shock, and the rest of the patients are alive with a mean follow-up of 1 year. CONCLUSION AL Amyloidosis is one of the most severe complications of monoclonal lymphocyte proliferation. This overgrowth is most frequently related to myeloma, and rarely to another malignant B-cell disease. The prognosis is related to cardiac and renal impairment. It requires urgent management to improve its outcome and to reduce mortality.

Proposed Cardiac End Points for Clinical Trials in Immunoglobulin Light Chain Amyloidosis: Report From the Amyloidosis Forum Cardiac Working Group.

Immunoglobulin light chain amyloidosis is a rare, multisystemic, phenotypically heterogenous disease affecting cardiovascular, renal, neurological, and gastrointestinal systems to varying degrees. Its underlying cause is a plasma cell dyscrasia characterized by misfolding of monoclonal immunoglobulin light chains which leads to aggregation and deposition of insoluble amyloid fibrils in target organs. Prognosis is primarily dependent on extent of cardiac involvement and depth of hematologic response to treatment. To facilitate development of new therapies, a public-private partnership was formed between the nonprofit Amyloidosis Research Consortium and the US Food and Drug Administration Center for Drug Evaluation and Research. In 2020, the Amyloidosis Forum launched an initiative to identify novel/composite end points and analytic strategies to expedite clinical trials for development of new therapies for the primary hematologic disorder and organ system manifestations. Specialized working groups identified organ-specific end points; additional working groups reviewed health-related quality of life measures and statistical approaches to data analysis. Each working group comprised amyloidosis experts, patient representatives, statisticians, and representatives from the Food and Drug Administration, the UK Medicines and Healthcare Products Regulatory Agency, and pharmaceutical companies. This review summarizes the proceedings and recommendations of the Cardiac Working Group. Using a modified Delphi method, the group identified, reviewed, and prioritized cardiac end points relevant to immunoglobulin light chain amyloidosis in the context of an antiplasma cell therapy. Prioritized cardiovascular end points included overall survival, hospitalization, N-terminal pro-B-type natriuretic peptide level, 6-minute walk test, Kansas City Cardiac Questionnaire, and cardiac deterioration progression-free survival. These recommended components will be further explored through evaluation of clinical trial datasets and formal guidance from regulatory authorities.

Monitoring Patients with Light Chain (AL) Amyloidosis during and after Therapy: Response Assessment and Identification of Relapse

Light chain amyloidosis is a complex disease where a small B-cell clone produces a monoclonal immunoglobulin light chain that causes deposits and specific organ dysfunction. The available treatment strategies aim to reduce or eliminate amyloidogenic light chain production in order to avoid amyloid deposition and allow the repair of organ damage. An international effort allowed the definition of validated hematologic and organ response criteria based on biomarkers. Recently, new methods for the assessment of minimal residual disease were also proposed but still need international validation. Lastly, a joint effort is also required to accurately define relapse/progression criteria in order to apply timely therapeutic interventions. In this review, we describe the validated response criteria and report on the future direction for the definition of progression criteria in this disease.

Cardiac amyloidosis: the pathologist’s point of view

Cardiac amyloidosis is a well-known entity recently recognized as a common etiology of heart failure. This infiltrative disease is caused by the deposition of misfolded proteins within the heart. The most common types of cardiac amyloidosis result from fibrils composed of monoclonal immunoglobulin light chains or transthyretin. Clinical presentation is usually elusive, and this can result in diagnostic delay. Diagnosis can be reached with non-invasive methods, but it often requires tissue sampling with pathological analysis. It is fundamental to determine the type of protein being deposited in order to indicate the specific treatment. In this article, we review the main features of cardiac amyloidosis with a focus on different pathological presentations of this rare disorder.