Free Light Chain Research Articles

Safety and Efficacy of Teclistamab in Patients With Relapsed or Refractory AL Amyloidosis

ABSTRACTIntroductionTeclistamab has demonstrated deep responses in patients with multiple myeloma in the MajesTEC‐1 study. However, the safety and efficacy of teclistamab in patients with AL amyloidosis are unknown.MethodsWe retrospectively analyzed patients with biopsy‐proven relapsed/refractory AL amyloidosis who were treated with teclistamab from December 2022 to February 2024 at the University of Pennsylvania. The data cutoff was 2/29/24. Adverse events (AE) were extracted from the electronic medical record. Patients were assessed for hematologic and organ response per consensus guidelines.ResultsEight patients were included in this case series: median age 63 (range 59–67), 75% female, 88% White. All eight patients achieved at least very good partial response (VGPR) and had normalization of free light chains (FLC), and six (75%) patients achieved undetectable FLC levels. Of the six patients with immunofixation completed, all six (100%) achieved hematologic complete response (hCR). The median time to hematologic VGPR and hCR was 13 days (range 12–18 days) and 88 days (range 32–150 days), respectively. The median duration of follow‐up was 8.5 months (range 1–14 months). Of the five patients with cardiac involvement, four (80%) achieved a cardiac response. Of the seven patients with renal involvement, two patients already achieved renal response prior to teclistamab, and of the remaining five, three (60%) achieved renal response. Six patients (75%) developed low‐grade cytokine release syndrome (CRS). No patients developed ICANS. Neutropenia and AKI both occurred in 25% of patients, respectively.ConclusionsIn this series of patients, teclistamab showed outstanding depth of response and was well‐tolerated. Teclistamab shows promise in treating patients with relapsed AL amyloidosis.

Prevalence of monoclonal proteins in patients with isolated hypogammaglobulinemia on serum protein electrophoresis

Isolated hypogammaglobulinemia (IH) is an electrophoretic pattern that can be encountered on serum protein electrophoresis (SPEP) and is defined as a decreased but morphologically normal γ-globulin fraction with normal α- and β-globulin fractions. SPEP is mainly used to detect monoclonal proteins which are usually observed as additional peaks in the electropherogram. However, they may also be more discretely present in a significant proportion of patients presenting with IH. Therefore, we aimed to evaluate i) via both retrospective and prospective analysis to what extent paraproteins as identified by immunofixation are present in patients demonstrating IH on SPEP and ii) whether other parameters may predict their presence in IH-patients. For this purpose, we first reviewed historic SPEP- and immunofixation results in our tertiary hospital and determined paraprotein prevalence in this retrospective cohort. This analysis showed immunofixation was requested in only 519/3938 (13.2%) historic IH-results with 52/519 (10%) patients demonstrating paraproteins. Next, various laboratory parameters were compared between paraprotein-positive and -negative patients and subjected to logistic regression models but regrettably, no parameter could be retained as promising predictor of paraproteins. Lastly, to confirm paraprotein prevalence seen in the historical query, we conducted a six-month prospective analysis during which immunofixation was requested more frequently in IH-cases during routine diagnostics and which showed paraproteins to be present in 20/83 (24.1%) of IH-patients. Hence, as up to 24% of patients with IH may harbour paraproteins, one should consider performing follow-up analyses (e.g. immunofixation, urine electrophoresis and/or free light chain analysis) for all IH-cases identified via SPEP.

Early dFLC response by C1D7 predicts complete hematologic response in systemic AL amyloidosis.

Daratumumab and bortezomib, the first-line drugs for AL amyloidosis, typically yield a complete hematologic response (CHR) rate of nearly 60% when used in combinations. An early achievement of CHR is crucial in amyloidosis. We retrospectively evaluated the relationship between dFLC (the difference between free light chain) reduction by Day 7 in Cycle 1 (C1D7) and CHR, organ response, and survival in 48 newly diagnosed AL amyloidosis patients receiving daratumumab, bortezomib, and dexamethasone. The CHR rate within six months was 66.7%. Using Receiver Operating Characteristic Curve curve analysis, we predicted CHR based on a dFLC reduction in C1D7 (67.0% change, optimal sensitivity 87.5%, specificity 81.3%). We introduce the novel concept of "rapid hematologic dFLC response", defined as a reduction in dFLC levels ≥ 67% in C1D7. The CHR rate in rapid responders' groups was higher than that in slow responders' group (90.3% vs. 23.5%, P<0.01). After a median follow-up of 19 months (range: 0.3-57), the renal response rate in rapid responders was higher than that in slow responders (72.0% vs. 27.5%, P = 0.025). The median major organ deterioration event-free survival in the rapid responders' group (not reached) was significantly superior to that in the slow responders' group (19m, 95% CI: 1.79-23.14m, P = 0.048). In conclusion, early dFLC reduction in C1D7 indicates a high possibility of CHR and organ response and may allow for early modification of therapy in selected patients.

Abstract 4112944: A diagnostic challenge overcome with persistent clinical suspicion in a case of cardiac AL amyloidosis

Case: A 62-year old male with a history of chronic kidney disease and paroxysmal atrial fibrillation presented with several months of fatigue, a progressive decline in functional status (NYHA IIIb-IV), weight loss, and intermittent lower extremity swelling. Blood pressure was 92/72 mmHg on presentation, and heart rate was 90 bpm. Physical examination revealed a jugular venous pressure of 12-14 cm H2O and 2+ bilateral lower extremity edema with mild wheezing. Methods/workup: Laboratories are shown in Table 1 and were notable for a serum free light chain ratio of 0.14. Transthoracic echocardiogram (figure 1) revealed a left ventricular (LV) ejection fraction of 33% with increased LV wall thickness and severe bi-atrial enlargement. Bone marrow biopsy revealed 2% lambda restricted plasma cells without evidence of amyloid deposits; metastatic bone survey was negative. A fat pad biopsy and endomyocardial biopsy stained negative for amyloid with Congo red. Cardiac MRI showed diffuse, circumferential subendocardial late gadolinium enhancement, most compatible with cardiac amyloidosis (figure 2). The patient also had a chest CT scan that demonstrated a few patchy nodular pulmonary infiltrates. Given his extensive negative workup, he was referred to pulmonary and endobronchial biopsy was positive for amyloid on Congo red staining (figure 3). Biopsy tissue typing revealed Lambda subtype AL amyloidosis. Management: The patient was started on Daratumumab, Cyclophosphamide, Bortezomib, and Dexamethasone by Hematology. Unfortunately, about a month after his diagnosis, he developed worsening heart failure despite treatment. He was admitted to an outside hospital with refractory cardiogenic shock and passed away during that admission. Discussion: The diagnosis of AL amyloidosis requires a high index of suspicion for prompt diagnosis and treatment. We present a case in which cardiac amyloidosis was suspected based on the patient’s clinical picture and cardiac imaging; however, multiple initial biopsies were negative. An expedited, multimodal and interdisciplinary diagnostic assessment is imperative as prognosis with chemotherapy is highly dependent on extent of AL disease, patient functional status, and presence of cardiac compromise. Elevated natriuretic peptides, troponins, autonomic dysfunction, and hypotension are negative prognostic features.

Serum levels of free light chains and syndecan-1 in patients with rheumatoid arthritis and systemic lupus erythematosus.

Systemic autoimmune rheumatic diseases (SARDs) are characterized by chronic inflammation. Reliable biomarkers are crucial for diagnosis, monitoring disease progression and therapeutic responses. This study explores serum Syndecan-1 (SDC-1) as a biomarker for these conditions and its relationship with free light chain (FLC) levels. A retrospective analysis was performed on sera from 60 patients with rheumatoid arthritis (RA) and from 60 with systemic lupus erythematosus (SLE), alongside 50 healthy donors (HD). Κ- and λ- FLCs were determined by turbidimetric assay, while SDC-1 levels by ELISA. Kruskal-Wallis test, Wilcoxon-Mann-Whitney U test, multivariable linear regression and Spearman's correlation were employed to compare biomarker levels across groups and to explore correlations. SDC-1, κ-FLC, and λ-FLC were significantly increased in RA and SLE patients compared with HD (p< 0.001), while no significant differences in the κ/λ ratio were observed among the groups (p= 0.4). A significant difference in subject age was also identified. However, multivariate regression analysis indicated that RA and SLE are significantly associated with the levels of these markers, with minimal confounding by age. A significant correlation was observed separately in all groups between the FLC markers. Conversely, no correlation was detected between SDC-1 and FLCs, nor between these markers and age or disease activity indices. Elevated serum levels of FLCs and SDC-1 in RA and SLE patients compared with HD underscore their potential as biomarkers for SARDs. The findings also suggest sustained plasma cell activation, supporting the multifaceted role of SDC-1 in the pathogenesis of SARDs.

Assessing the Manufacturability and Critical Quality Attribute Profiles of Anti-IL-8 Immunoglobulin G Mutant Variants.

Early-phase manufacturability assessment of high-concentration therapeutic monoclonal antibodies (mAbs) involves screening of process-related risks impacting their translation into the clinic. Manufacturing a mAb at scale relies on cost-effective and robust approaches to derisk manufacturability parameters, such as viscosity, conformational stability, aggregation, and process-related impurities. Using a panel of model anti-IL-8 IgG1 mutants, we investigate upstream and downstream processability, phase behavior, and process-related impurities. We correlate trends in the biophysical properties of mAbs with their cell growth, expression, filtration flux, solubility, and post-translational modifications. We find significant trends in increased relative free light chain expression with heavy chain mutants and detect a requirement for adjusted operation pH for cation exchange polishing steps with charge-altering variants. Moreover, trends between phase stability and high-concentration viscosity were observed. We also investigated unique correlations between increased glycosylation and biophysical behavior. Further in-depth analysis and modeling are required to elucidate the impact of the mAb sequence on the metabolism of the expression system, solubility limits, and alternative gelation models as future directions.

A sex-dependent algorithm including kappa free light chain for multiple sclerosis diagnosis.

Multiple sclerosis (MS) diagnosis includes the presence of restricted oligoclonal bands (OCB) in cerebrospinal fluid (CSF), but it has several limitations, as it is an observer-dependent time-consuming technique and offers a dichotomous result. Thus kappa free light chains (KFLC) have emerged as a quantitative alternative. However, the cut-off values for KFLC have not been well established yet and it is not clear if differences between sexes exist. We aim to evaluate these and to compare the diagnostic accuracy of KFLC concentrations and their related indexes versus OCB. For that purpose, paired CSF and serum samples were collected and immediately processed for albumin, total protein, immunoglobulins and OCB, then frozen at -20°C. KFLC was measured in a BN II (Siemens Healthineers, Germany). KFLC-derived indexes were calculated. Diagnostic accuracy was evaluated by the area under the curve (AUC), Youden's index and odds ratio. From the 193 patients included, 56 were classified as MS according to the 2017 McDonald criteria. K-index, Q KFLC and Reiber's diagram showed good accuracy in MS diagnosis when studied distinguishing between sexes, similar to OCB. Cut-offs for K-index and Q KFLC change substantially between sex having the highest AUC similar than OCB. A sex-dependent algorithm combining the use of K-index, Q KFLC and OCB yields the highest diagnostic accuracy. In conclusion, CSF KFLC measurement is a rapid, quantitative and easy-to-standardize tool that used through the proposed sex-dependent algorithm may reduce the number of manual OCB tests performed.

Intracapillary monoclonal IgM deposits disease with massive pseudothrombi: A clinicopathologic study of 4 cases and literature review.

Intracapillary monoclonal IgM deposits disease (ICMDD) has long been considered a hallmark of Waldenström macroglobulinemia (WM) nephropathy. Intracapillary immunoglobulin thrombi are the characteristic features of cryoglobulinemic glomerulonephritis. Here, we reported 4 cases of ICMDD with massive pseudothrombi but without WM or cryoglobulinemia. We retrospectively analyzed the clinical and pathologic features of patients diagnosed with ICMDD with massive pseudothrombi. A total of 4 patients (2 men and 2 women) aged 62 to 73 years were enrolled in this study. Microscopic hematuria, edema, and renal insufficiency were present in all patients, along with low serum C3 and C4 in 2 patients. Hematologic examination showed abnormal serum free light chain ratios in all patients and high levels of serum IgM in 3 patients. IgM-κ monoclonal band was identified by serum immunofixation electrophoresis in 3 patients. One patient was diagnosed with small B-cell lymphoma by bone marrow aspiration. Renal biopsy specimen showed massive periodic acid-Schiff-positive hyaline thrombi in the glomerular capillary lumens and also less mesangial, subendothelial, and subepithelial deposits on light microscopy. Immunofluorescence indicated positive staining for IgM (++) and κ light chain staining in the glomerular capillary lumens, capillary walls, and mesangium in all patients. By electron microscopy, the glomerular capillary lumens were filled with homogeneous high-electron-dense deposits without substructure. Two patients were treated with prednisone combined with cyclophosphamide, and 2 received plasma cell-targeted chemotherapy. One patient achieved partial renal remission. Intracapillary monoclonal IgM deposits disease is a rare disease and not always related to WM. Most patients have IgM monoclonal immunoglobulinemia; renal biopsy specimens mainly show a large number of pseudothrombi in the glomerular capillary lumens. Cyclophosphamide is effective in some patients.

Monoclonal Gammopathy in Patients with Neuropathy.

The incidence of monoclonal gammopathy of undetermined significance (MGUS) in the population of over 50-year-olds is approximately 3% and increases with age. The association between MG and neuropathy has been of interest for several years, but the causal relationship has not yet been clarified. For 682 patients who visited the Department of Neurology and requested tests for MG work-up, we retrospectively collected demographic and clinical information, such as age, gender, diagnosis, and neurologic and laboratory test results, from their medical records. Out of a total of 682 patients who were suspected of neuropathy and tested for monoclonal gammopathy (MG), twelve (1.76%) showed MG on their serum protein electrophoresis. The most common form was IgM-κ with five patients, followed by IgG-κ, IgG-λ, and biclonal IgG-λ and IgA-κ. The results of the immunoglobulin quantitation test and free light chain assay showed that involved M-protein values in these patients were increased. Some patients were positive for anti-myelin-associated glycoprotein (MAG) antibody, anti-GD1b IgM antibody, anti-GM1 IgG & IgM antibody, and anti-cardiolipin IgM antibody. Also, some had antinuclear antibody (ANA) or antineutrophil cytoplasmic antibody (ANCA). In the future, it is necessary to investigate the pathogenic relationship between M-protein and autoantibodies in patients with neuropathies.

Free Immunoglobulin Light Chains in Patients With Myocarditis: a New Biomarker of Inflammation and Heart Failure

To study the concentration of immunoglobulin free light chains (FLCs) in patients with myocarditis in comparison with non-inflammatory heart diseases, their relationship with inflammatory markers and the severity of chronic heart failure (CHF). This study included 77 patients (31 women, mean age 54.1±13.3 years): 41 patients with myocarditis verified by myocardial biopsy (n=18) or using a noninvasive diagnostic algorithm, 31 patients with noninflammatory CHF (comparison group), and 5 patients with monoclonal gammopathy identified during the study (4 of them were diagnosed with AL amyloidosis with heart damage). In the myocarditis group, CHF was diagnosed in 29 patients, mean stage IIA, functional class (FC) 2-3, with a mean left ventricular ejection fraction 43%. In the comparison group, patients had predominantly IIA stage, FC 2-3 CHF without systolic dysfunction. The blood concentration of kappa and lambda FLC types was measured with Cloneus S-FLC-K TIA Kit and Cloneus S-FLC-L TIA Kit. Concentrations were considered normal at FLC-kappa 4.84-14.20 mg/l, FLC-lambda 7.03-22.50 mg/l, and the FLC-kappa/lambda ratio 0.426-1.050. Increased FLC concentrations were found in 58% of patients with myocarditis and in 77% of patients in the comparison group. The FLC-lambda concentration was significantly higher in the comparison group; there were no significant differences between the groups in FLC-kappa and their ratio. The closest significant correlations in both groups and the entire cohort were noted between FLCs of either type and CHF, as well as the requirement for loop diuretics (correlation coefficients, 0.60-0.90), independent on the severity of systolic dysfunction. Myocarditis patients also showed correlations of FLCs with the titer of antibodies to cardiomyocyte nuclear antigens, levels of C-reactive protein, leukocytes, neutrophils, erythrocyte sedimentation rate, and the concentration of N-terminal fragment of brain natriuretic peptide. In a subgroup of 10 myocarditis patients who were treated with immunosuppressants, FLCs of both types were significantly lower than in the comparison group; only with the persistence of severe CHF was an increase in FLCs noted. An increased FLC concentration can be considered as an important pathogenesis component that reflects both the specific mechanisms of myocarditis and the severity of CHF. In the absence of a statistically significant increase in general inflammatory markers in the blood of myocarditis patients, the measurement of FLCs can be used as an additional diagnostic marker and predictor of the decompensated variant of the course of myocarditis. However, the diagnostic and prognostic significance of FLC concentration in patients without CHF requires a further study.

Free Kappa light chain in a sample of Egyptian multiple sclerosis patients (a pilot study)

BackgroundMultiple sclerosis is a chronic autoimmune-mediated demyelinating disease of the central nervous system that is usually associated with varying degrees of progressive disability. Free Kappa light chain (FKLC) has attracted growing attention as a significant diagnostic marker of MS. Our aim was to study the diagnostic utility of cerebrospinal fluid free Kappa light chain and related indices in a sample of Egyptian MS patients vs. CSF IgG oligoclonal bands. It was a prospective case–control study of MS patients carried in our hospital during the period from January 2021 till January 2022. Our study carried on 30 patients with multiple sclerosis and other inflammatory neurologic diseases and 20 age and sex matched controls. The study measured FKLC in the CSF and serum sample pairs of patients and control group. Indices calculated using FKLC measured in CSF and serum included; FKLC index, FKLC intrathecal fraction and quotient of FKLC. Indices were used to assess intrathecal synthesis of FKLC considering blood–CSF barrier function. Receiver operating characteristic curve analysis was used to determine diagnostic performance of FKLC and related indices in comparison to CSF–OCB testing.ResultsMeasured FKLC levels as well as its calculated indices have shown statistically significant higher values among MS patients against OIND patients and healthy control group. Both FKLC index and FKLC IF were similarly showing 100% diagnostic sensitivity and 100% diagnostic specificity for MS diagnosis.ConclusionsFKLC biomarkers are proposed to be highly sensitive and easy to detect first-line markers of intrathecal immunoglobulin synthesis with accurate performance and low cost that might prove to be promising diagnostic markers of MS.

Monoclonal gammapathies: Epidemiological, immunochemical and etiological analysis of a series of 50 cases

During the period from September 2022 to January 2023, 50 cases of monoclonal gammopathy (GM) were collected at the Avicenne military hospital in Marrakech. The average age of the patients was 62 years. Thirty patients were male and 20 were female. The etiological diagnosis could be established for the 50 observations: 5 were classified as GM of undetermined significance (GMSI), 42 were classified as myeloma, two case of Waldenström's disease and one case of AL amyloidosis. The clinical symptomatology was dominated by bone pain in 78% of patients with a deterioration in general condition in 43%. The most frequently found biological abnormalities were anemia in 62% of patients, renal failure in 48% of patients and 19% had hypercalcemia. A monoclonal peak was found in the electrophoreses of 45 patients (90%), of whom 6 migrated to the beta zone and 39 migrated to the gamma zone. The IgG Kappa isotype was the most frequent with a rate of 56%, followed by IgG Lambda (27%), IgA Kappa (8%), IgA Lambda (3%), IgM Lambda (3%) and lambda free light chains (3%).

Immunoglobulin free light chain-kappa, a novel biomarker of inflammation and cardiovascular risk, decreases after smoking cessation in association with NT-proBNP

Abstract Introduction Inflammation plays an important role in the development and progression of cardiovascular diseases. Unhealthy diet, infection, and smoking coupled with genetic factors induce inflammation in the heart and blood vessels by activating nuclear factor kappa B, which regulates the transcription of immunoglobulin free light chain (FLC)-κ in B-cells and the production of multiple inflammatory molecules. FLCs are novel biomarkers of inflammation, and their levels are associated with overall mortality in a general population and with cardiovascular outcomes. Purpose This study aimed to investigate the effect of smoking cessation (SC) on levels of FLCs as well as of the inflammation and heart failure markers. Methods Inclusion criterion was first-visit smokers with desire to quit smoking at our outpatient clinic. Smoking patients with nicotine dependence were treated with transdermal nicotine patches or orally administrated varenicline. Various clinical parameters, including inflammatory markers such as FLC levels, were measured on their first visit to our outpatient clinic for SC and after 3 months of successful and unsuccessful SC. Paired t-test or Wilcoxon signed-rank test was performed to evaluate changes in these parameters before and after SC. Results Out of 96 patients who participated in this study, 76 patients (55 males and 21 females) succeeded in SC over a period of 3 months. Body mass index (BMI) significantly increased from baseline to 3 months after initiating SC (from 23.8 to 24.2, p=0.004) in patients with successful SC. On the other hand, levels of various inflammatory markers; FLC-κ, FLC-κ/FLC-λ, and the neutrophil-to-lymphocyte ratio) significantly decreased from baseline to 3 months (from 27.5 to 24.7 mg/L, p = 0.042; from 1.2 to 1.2 mg/L, p = 0.010; and from 2.0 to 1.9, p = 0.024, respectively). In contrast, no significant changes occurred in these parameters among patients with unsuccessful SC. Percent changes of FLC-κ levels from baseline to 3 months were significantly correlated with those of CRP (r=0.217, p=0.034) and NT-proBNP (r=0.335, p&amp;lt;0.001) levels. Conclusion The FLC-κ level, a novel inflammatory and cardiovascular risk biomarker, decreased in smoking patients after their SC despite the increase in body weight, suggesting that the beneficial effect of SC overcomes potential risks by body weight increase. The results also suggest that a decrease in the FLC-κ level after SC is associated with a reduction of load on the heart as well as decrease in inflammation.

Validation of two simple scores to identify increased risk of transthyretin amyloid cardiomyopathy in heart failure with preserved ejection fraction

Abstract Background Transthyretin Amyloid Cardiomyopathy (ATTR-CM) is an emerging underdiagnosed cause of heart failure (HF). 99mTc-3, 3-diphosphono-1,2-propanodicarboxylic acid (DPD) allows ATTR-CM diagnosis in the absence of histology. Recently two simple clinical scores to identify increased risk of ATTR-CM in patients with heart failure and preserved left ventricular ejection fraction have been developed and validated. Purpose To assess the prevalence of ATTR-CM in a Mediterranean cohort of patients at risk, and to externally validate the Mayo ATTR-CM and T-Amylo scores. We also explore its diagnostic accuracy improvement by adding N-terminal pro-B-type natriuretic peptide (NT-proBNP). Methods Retrospective cohort study of consecutive patients with suspected cardiac amyloidosis referred to DPD between March 2017 and November 2020. Scans were reported using a visual grading system (0 to 3 increasingly; 2-3 positive) on planar images. Patients with clonal dyscrasia or those without rule-out tests (serum free light chain assay, and serum and urine protein electrophoresis with immunofixation) were excluded. Discrimination was obtained using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve based on the ATTR-CM score [High risk: score ≥ 6. Components: age (60-69 = 2 points; 70-79 = 3 points; ≥80 = 4 points), male sex = 2 points, hypertension = -1 point, ejection fraction &amp;lt;60% = 1 point, posterior wall thickness ≥12 mm = 1 point, relative wall thickness (septal + posterior wall thickness/left ventricular end diastolic diameter) &amp;gt;0.57 = 2 points], and T-amylo score [High risk: score &amp;gt; 6. Components: age ≥ 80 years = 1 point, interventricular septum thickness ≥16 mm = 2 points, low QRS interval voltage = 2 points, male gender = 3 points, and carpal tunnel syndrome = 3 points. Calibration was assessed with the Hosmer-Lemeshow goodness-of-fit test. Results A total of 200 patients were included with a mean age of 78.5 ± 11 years, 45.5% male, left ventricular ejection fraction 58% ± 12 and a median NT-proBNP of 2310 pg/mL (Table 1). 81 (40.5%) and 10 (5.0%) patients were categorized as a high-risk group due to ATTR-CM score value ≥6 and simplified T-Amylo score &amp;gt;6, respectively. Prevalence of ATTR-CM was 17.5%. The AUC for the Mayo ATTR-CM and T-Amylo scores in our cohort were 0.83 (95% CI 0.75-0.90) and 0.79 (95% CI 0.69-0.88) respectively, with an appropriated calibration (Figure 1). The addition of NT-proBNP to the scores did not increase the AUC (p=0.19 and p=0.08), with a Net Reclassification Improvement (NRI) of 0.055 (95% CI - 0.110 to 0.206) and 0.033 (95% CI - 0.113 to 0.224) respectively. Conclusion These two simple clinical scores are valid and reliable tools for ATTR-CM diagnosis in our Mediterranean cohort. Added to clinical suspicion, can improve the diagnostic workup for ATTR-CM, irrespective of NT-proBNP values.

Dissecting Secondary Immunodeficiency: Identification of Primary Immunodeficiency within B-Cell Lymphoproliferative Disorders

Distinguishing between primary (PID) and secondary (SID) immunodeficiencies, particularly in relation to hematological B-cell lymphoproliferative disorders (B-CLPD), poses a major clinical challenge. We aimed to analyze and define the clinical and laboratory variables in SID patients associated with B-CLPD, identifying overlaps with late-onset PIDs, which could potentially improve diagnostic precision and prognostic assessment. We studied 37 clinical/laboratory variables in 151 SID patients with B-CLPD. Patients were classified as “Suspected PID Group” when having recurrent-severe infections prior to the B-CLPD and/or hypogammaglobulinemia according to key ESID criteria for PID. Bivariate association analyses showed significant statistical differences between “Suspected PID”- and “SID”-groups in 10 out of 37 variables analyzed, with “Suspected PID” showing higher frequencies of childhood recurrent-severe infections, family history of B-CLPD, significantly lower serum Free Light Chain (sFLC), immunoglobulin concentrations, lower total leukocyte, and switch-memory B-cell counts at baseline. Rpart machine learning algorithm was performed to potentially create a model to differentiate both groups. The model developed a decision tree with two major variables in order of relevance: sum κ + λ and history of severe-recurrent infections in childhood, with high sensitivity 89.5%, specificity 100%, and accuracy 91.8% for PID prediction. Identifying significant clinical and immunological variables can aid in the difficult task of recognizing late-onset PIDs among SID patients, emphasizing the value of a comprehensive immunological evaluation. The differences between “Suspected PID” and SID groups, highlight the need of early, tailored diagnostic and treatment strategies for personalized patient management and follow up.

Soluble B-cell maturation antigen levels for disease monitoring in oligo- and non-secretory relapsed multiple myeloma

Soluble B-cell maturation antigen (sBCMA) is overexpressed on multiple myeloma (MM) cells. We investigated whether sBCMA levels correlated with other myeloma tumor volume indicators and its utility in monitoring oligo-secretory/non-secretory (O-S/Non-S) MM. In 115 patients with newly diagnosed MM, sBCMA was compared with M-protein levels, bone marrow plasma cells (BMPCs), circulating tumor cells (CTCs), and total diffusion volume (tDV; estimated by whole-body diffusion-weighted magnetic resonance imaging) at diagnosis. sBCMA levels increased significantly with International Staging System stage, chromosome 1q21 gain/amplification and CTC levels. sBCMA also correlated strongly with %BMPC (r = 0.65), moderately with tDV (r = 0.55) and paraprotein levels (involved immunoglobulin in IgG and IgA subtypes, r = 0.44 and 0.4; involved free light-chain levels in light-chain-only MM, r = 0.61, all P < 0.05). Longitudinal changes in sBCMA were consistent with disease status in both 17 O-S/Non-S and other secretory MM cases. Furthermore, sBCMA levels increased as early as 6 months pre-relapse in almost all O-S/Non-S relapsed patients. Thus, sBCMA correlates strongly with total tumor volume in MM, as assessed using different modalities. We suggest that sBCMA is useful, not only for monitoring responses in patients with O-S/Non-S MM but also for early relapse detection and prediction.

Tumefactive Pulmonary amyloidosis in an elderly male: A Diagnostic Dilemma

Abstract Introduction/Objective Tumefactive pulmonary amyloidosis is a rare variant of pulmonary amyloidosis characterized by the extracellular deposition of abnormal protein fibrils in the lung parenchyma, forming tumor-like masses called amyloidomas. Although most cases are clinically silent, it may present with findings that mimic a wide range of respiratory conditions (eg. primary or metastatic malignant nodules, granulomatous disease, multiple pulmonary hamartomas etc), thereby necessitating a comprehensive and broad-based approach to differential diagnosis. Methods/Case Report We present a case of an 88-year-old male with a history of smoking and multiple comorbidities. He presented with numerous bilateral pulmonary nodules identified on a CT scan, concerning for malignancy. A biopsy from a left upper lobe lesion revealed necrotic tissue and was non-diagnostic. A PET scan to assess for metastatic disease was unremarkable, and demonstrated mild hypermetabolic activity, confined to the lungs, with standardized uptake values (SUV) ranging from 4.3 to a maximum SUV of 8.9. A subsequent right lung biopsy was positive for amyloid, confirmed by Congo red staining. A Mass spectrometry analysis further identified the amyloid as AL type. Serum, and urine protein electrophoresis with immunofixation were negative for M protein and the serum free light chain assay was normal as well. Significantly, the bone marrow biopsy also yielded normal results, and the patient was diagnosed with a localized form of AL amyloidosis. Results (if a Case Study enter NA) NA Conclusion This case highlights how tumefactive pulmonary amyloidosis poses a diagnostic challenge due to its rarity and resemblance to malignancy on imaging. Careful histopathological examination, including immunohistochemical stains and amyloid typing, was pivotal in establishing the correct diagnosis and underscores the essential role of pathology and laboratory medicine in differentiating rare pulmonary conditions, along with the need for a multidisciplinary approach in complex diagnostic scenarios.

Hepatocyte-derived Igκ promotes HCC progression by stabilizing electron transfer flavoprotein subunit α to facilitate fatty acid β-oxidation

BackgroundLipid metabolism dysregulation is a key characteristic of hepatocellular carcinoma (HCC) onset and progression. Elevated expression of immunoglobulin (Ig), especially the Igκ free light chain with a unique Vκ4-1/Jκ3 rearrangement in cancer cells, is linked to increased malignancy and has been implicated in colon cancer tumorigenesis. However, the role of Igκ in HCC carcinogenesis remains unclear. The aim of this study was to elucidate the pivotal roles of hepatocyte-derived Igκ in HCC development.MethodsThe rearrangement sequence and expression level of hepatocyte-derived Igκ in HCC cells were determined via RT-PCR, Sanger sequencing, immunohistochemistry, and western blot analysis. The function of Igκ in HCC tumorigenesis was assessed by silencing Igκ using siRNA or gRNA in various HCC cell lines. To assess the role of Igκ in HCC pathogenesis in vivo, a mouse model with hepatocyte-specific Igκ knockout and diethylnitrosamine (DEN) and carbon tetrachloride (CCL4)-induced HCC was utilized. The molecular mechanism by which Igκ affects HCC tumorigenesis was investigated through multiomics analyses, quantitative real-time PCR, immunoprecipitation, mass spectrometry, immunofluorescence, and metabolite detection.ResultsWe confirmed that Igκ, especially Vκ4-1/Jκ3-Igκ, is highly expressed in human HCC cells. Igκ depletion inhibited HCC cell proliferation and migration in vitro, and hepatocyte-specific Igκ deficiency ameliorated HCC progression in mice with DEN and CCL4-induced HCC in vivo. Mechanistically, Vκ4-1/Jκ3-Igκ interacts with electron transfer flavoprotein subunit α (ETFA), delaying its protein degradation. Loss of Igκ led to a decrease in the expression of mitochondrial respiratory chain complexes III and IV, resulting in aberrant fatty acid β-oxidation (FAO) and lipid accumulation, which in turn inhibited HCC cell proliferation and migration.ConclusionOur findings indicate that the Igκ/ETFA axis deregulates fatty acid β-oxidation, contributing to HCC progression, which suggests that targeting fatty acid metabolism may be an effective HCC treatment strategy. The results of this study suggest that hepatocyte-derived Vκ4-1/Jκ3-Igκ may serve as a promising therapeutic target for HCC.

Clonality Determination by Detecting Unmodified Monoclonal Serum Free Light Chains Using On-Probe Extraction Coupled with Liquid Chromatography-High-Resolution Mass Spectrometry.

Serum free light chains (FLCs) are an essential clinical biomarker for the diagnosis and monitoring of patients with plasma cell neoplasms. The current widely used immunoassay methods quantify total serum FLCs, which include monoclonal FLCs as well as FLCs in the polyclonal background. Patients with chronic diseases, inflammatory disorders, or renal dysfunction can have elevated total FLCs that lead to ambiguous results. These patients may benefit from a direct measurement of monoclonal FLCs. The purpose of this study was to develop a method that couples on-probe extraction (OPEX) with liquid chromatography-high-resolution mass spectrometry (LC-HR-MS), abbreviated to OPEX-MS, to directly determine the clonality of FLCs. OPEX immunocapture was performed using microprobes loaded with anti-kappa or anti-lambda light chain antibodies. Captured proteins were separated by reversed-phase LC and analyzed by HR-MS. Four cohorts of samples from unique patients were tested based on immunoassay FLC results. The LC-HR-MS analysis in the OPEX-MS method provides both a unique retention time along with deconvoluted masses of FLC monomers and dimers for each clone. The study found that 16 out of 49 (33%) kappa FLC elevated samples as well as 83 out of 100 (83%) dual kappa and lambda FLC elevated samples did not have monoclonal FLCs, which is consistent with the knowledge that there is often no clonal population in samples with mildly elevated FLC immunoassay results. The OPEX-MS method can serve as a complementary approach to directly determine clonality in patients with difficult-to-interpret FLC immunoassay results.

6411 Ozempic - Oh no! Acute Renal Failure Associated with Initiation of Semaglutide

Abstract Disclosure: K. Barney: None. D. Tahir: None. A. Pannu: None. R. Saeed: None. Background: Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist which has been proven to reduce weight in those with obesity and improve glycemic control in patients with type II diabetes mellitus. The effect of semaglutide on kidney function has not been well established. The phase 3b SUSTAIN trials revealed that when compared with other GLP-1 agonists, semaglutide exhibited more frequent acute kidney injuries [1-3]. The SUSTAIN 6 trial reported two instances of acute renal failure (ARF) in patients with chronic kidney disease, and one case of ARF in a patient with normal kidney function who was treated with semaglutide [3]. Despite these reports, the SUSTAIN 1-9 trials report no significant decline in kidney function associated with semaglutide [3-6]. Case: We present the case of a 58-year-old male with a past medical history of human immunodeficiency virus (HIV), type II diabetes mellitus, and hypertension who presented to the hospital with ARF after initiation of Ozempic (semaglutide) two months prior to presentation. On admission, vitals were stable and physical examination was benign. His pertinent labs were blood urea nitrogen (BUN) 55 mg/dL, creatinine 5.94 mg/dL (baseline 1.2 mg/dL), and urinalysis with 2+ protein. To determine the cause of his renal failure, urine sodium and creatinine were obtained to calculate his fractional excretion of sodium, which was found to be consistent with intrinsic renal disease. Further workup, including renal ultrasound, urine protein, urine eosinophils, complement and free light chain levels, and creatinine kinase, were unrevealing for cause of intrinsic renal injury. He was managed with intravenous fluids and his creatinine improved to 2.03 mg/dL. Given the acute onset of the patient’s renal failure and recent initiation of Ozempic, it was determined that this medication was the cause of his renal failure, and it was discontinued on discharge. He has since followed up with nephrology and endocrinology. He remains off Ozempic and is doing well. Conclusions: Our case highlights a rare but significant adverse effect of semaglutide on renal function. As the use of semaglutide has increased due to its rising popularity for weight loss and glycemic control in type II diabetes mellitus, the potential for renal injury should be considered and discussed with patients. Furthermore, it is imperative that semaglutide associated renal injury be considered as a cause for ARF in patients taking this medication. This case demonstrates that instances of ARF associated with semaglutide treatment are a cause for concern and further exploration. Presentation: 6/1/2024