Serum Immunoglobulin Free Light Chain Research Articles

Applying Machine Learning to Support Early Diagnosis of Light-Chain Amyloidosis: A Combination of Knowledge-Based Approach with Data-Driven Approach

Introduction Immunoglobulin light chain (AL) amyloidosis is a rare disease involving the clonal proliferation of bone-marrow-residing plasma cell and resulting in overproduction of serum immunoglobulin free light chains that affects multiple organs. There are several available effective treatments including autologous stem cell transplant, bortezomib, anti-CD38 antibodies, and immunomodulatory drugs. However, because of the atypical symptoms and signs of this disease, diagnostic delays are still the major challenge resulting in poor prognosis. In recent years, machine learning (ML) models have been used to assist in early diagnosis. Therefore, to address this clinical unmet need, we aim to build ML algorithms from clinical data and assess their performance in differentiating AL amyloidosis from similar conditions. Methods Monocenter medical records data were collected from 49 patients with AL amyloidosis and 198 non-AL amyloidosis patients on a ratio of 1:4 in Peking University People's Hospital between January 1, 2013, and December 31, 2021. The non-AL amyloidosis group were patients with diseases of similar symptoms including autoimmune liver disease, myocarditis, and hypertrophic cardiomyopathy. Variables for model development were selected from 30 demographic characteristics and clinical features from routine clinical examination based on the results of recursive feature elimination and hematologists' knowledge. We proposed a four-step approach to develop and evaluate the diagnostic models. In the first step, all patients were randomly allocated into a training set and a testing set with a ratio of 4:1. Second, we derived five separate ML models including logistic regression, support vector machine (SVM), extreme gradient boosting (XGBoost), light gradient boosting (LightGBM), and CatBoost algorithms to differentiate AL amyloidosis from other diseases with similar symptoms and validated the models using five-fold cross validation methods. Third, parameters of model with the highest areas under the receiver operating characteristic curves (AUROC) were updated in the full training set. Finally, the performances of the selected model were evaluated by AUROC, sensitivity, specificity and F1-score in the testing set. Results Twelve features including alanine aminotransferase, troponin, albumin, aspartate aminotransferase, activated partial thromboplastin time, albumin and globulin (A/G) ratio, direct bilirubin, platelet, fibrinogen, blood urea nitrogen, body weight and age were selected to construct ML models. The AUROC values for AL amyloidosis differential diagnosis were 0.55 with logistic regression, 0.63 with SVM, 0.84 with XGBoost, 0.89 with LightGBM, and 0.88 with CatBoost. The LightGBM model, which achieved the highest AUROC, also achieved the best performance with a sensitivity of 0.92, a specificity of 0.60, a F1-score of 0.73, a negative predictive value of 0.97, a positive predictive value of 0.60, and an accuracy of 0.82. Conclusion Our results show that the LightGBM model has the best performance to identify patients with AL amyloidosis from patients with similar symptoms. This novel ML-based diagnostic model has potential to assist in the earlier diagnosis of AL amyloidosis in clinical settings. Further studies are needed to confirm these findings in different study populations.

Method Comparison and Workflow Differences Using the Same Free Light Chain Assay on 2 Analyzer Platforms.

The Freelite assay (The Binding Site) is utilized to quantify serum immunoglobulin free light chains (sFLC), which is crucial for diagnosing and monitoring plasma cell dyscrasias (PCDs). Using the Freelite test, we compared methods and evaluated workflow differences across two analyzer platforms. sFLC concentrations were measured in 306 fresh serum specimens (cohort A) and 48 frozen specimens with documented sFLC >20 mg/dL (cohort B). Specimens were analyzed on the Roche cobas 8000 and Optilite analyzers using the Freelite κ and λ assays. Performance was compared using Deming regression. Workflow was compared by assessing turnaround time (TAT) and reagent usage. For cohort A specimens, Deming regression revealed a slope of 1.04 (95% CI, 0.88-1.02) and an intercept of -0.77 (95% CI, -0.57 to 1.85) for sFLCκ and a slope of 0.90 (95% CI, -0.04 to 1.83) and intercept of 1.59 (95% CI, -3.12 to 6.25) for sFLCλ. Regression of the κ/λ ratio revealed a slope of 2.44 (95% CI, 1.47-3.41) and intercept of -8.13 (95% CI, -16.82 to 0.58) with a concordance kappa of 0.80 (95% CI, 0.69-0.92). The proportion of specimens with TAT >60 min was 0.33% and 8% for the Optilite and cobas, respectively (P < 0.001). The Optilite required 49 (P < 0.001) and 12 (P = 0.016) fewer tests for sFLCκ and sFLCλ relative to the cobas. Cohort B specimens showed similar but more dramatic results. Analytical performance of the Freelite assays was comparable on the Optilite and cobas 8000 analyzers. In our study, the Optilite required less reagent, had a slightly reduced TAT, and eliminated manual dilutions for samples with sFLC concentrations >20 mg/dL.

Magnetismm-4: An Open Label, Phase 1B/2 Umbrella Study of Elranatamab in Combination with Other Anti-Cancer Treatments for Patients with Multiple Myeloma

Background Elranatamab (PF-06863135) is a humanized bispecific molecule that targets multiple myeloma (MM) cells via B-cell maturation antigen (BCMA) and T cells via CD3 to induce T cell-mediated cytotoxicity. In MagnetisMM-1 (NCT03269136), an ongoing, phase 1 study in patients with relapsed or refractory MM (RRMM), subcutaneous (SC) elranatamab yielded an overall response rate (ORR) of 64% and had a manageable safety profile (Jakubowiak et al, J Clin Oncol, 2022). In the phase 2 MagnetisMM-3 (NCT04649359) study in patients with heavily pretreated RRMM, SC elranatamab was well tolerated and yielded an ORR of 61% at the recommended phase 2 dose (Lesokhin et al, J Clin Oncol, 2022). Study Design and Methods MagnetisMM-4 (NCT05090566) is a phase 1B/2, open label, non-randomized, multicenter, umbrella study of elranatamab in combination with other anti-cancer treatments for patients with MM. The estimated enrollment is 105 patients. The study is split into 2 sub-studies (Figure 1). In each sub study, a 2 step-up priming dose of elranatamab will be employed to mitigate the risk of cytokine release syndrome and a Bayesian logistic regression model will be utilized for dose escalation. Sub-study A (SSA) is comprised of 2 phases in which patients will receive elranatamab + the gamma-secretase inhibitor (GSI) nirogacestat. Studies have shown that GSIs block BCMA cleavage and can potentially enhance BCMA-directed therapy (Eastman et al, Blood, 2019; Pont et al, Blood, 2019; Cowan et al, Blood, 2019). Phase 1 of SSA is designed to evaluate the safety, tolerability and select a recommended dose and regimen for the combination of elranatamab and nirogacestat. The primary endpoint for SSA Phase 1 is dose limiting toxicity (DLT) up to 35 days. Phase 2 of SSA will further evaluate the efficacy and safety of the combination of elranatamab and nirogacestat. The primary endpoint for SSA phase 2 is objective response rate (ORR) assessed every 4 weeks for ~2 years. A key secondary endpoint in both phases of SSA is the incidence of treatment-emergent adverse events (TEAEs). In sub-study B (SSB), patients will receive elranatamab + lenalidomide + dexamethasone. The dose escalation part of SSB is designed to assess the safety and tolerability of elranatamab in combination with lenalidomide and dexamethasone. The primary outcome of the dose escalation part is DLT up to 42 days. The dose expansion part of SSB is designed to evaluate the overall safety profile of elranatamab in combination with lenalidomide and dexamethasone. The primary endpoints of the dose expansion part of SSB are incidence of TEAEs and laboratory abnormalities across the duration of the study. A key secondary endpoint in SSB is ORR. Additional secondary endpoints in both SSA and SSB are time to response, duration of response, complete response (CR) rate, duration of CR, progression-free survival, overall survival, minimal residual disease negativity rate, immunogenicity to elranatamab, and elranatamab pharmacokinetics. Inclusion criteria in SSA and SSB include age ≥18 years, RRMM with ≥3 prior lines of therapy, refractory to at least one immunomodulatory drug, one proteasome inhibitor, and one anti-CD38 antibody, measurable disease by serum M-protein ≥0.5g/dL, urinary M-protein excretion ≥200mg/24h, or serum immunoglobulin free light chain (FLC) ≥10mg/dL and abnormal serum immunoglobulin kappa to lambda FLC ratio, and Eastern Cooperative Oncology Group performance status ≤1 (Table 1). Exclusion criteria include active plasma cell leukemia, amyloidosis, stem cell transplant within 12 weeks prior to enrolment or active graft-versus-host disease, POEMS syndrome, any active uncontrolled infection, impaired cardiovascular function or clinically significant cardiovascular disease within 6 months prior to enrolment, and previous administration with an investigational drug within 30 days or 5 half-lives preceding the first dose of study treatment. In SSA, patients who received prior treatment with a BCMA-bispecific antibody are excluded, and in SSB, patients who received prior treatment with BCMA-directed therapy are excluded. The study is enrolling the Phase 1 portions and is being opened at multiple sites in the United States and Canada. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Retinal oxygen saturation in monoclonal gammopathies patients: Apilot study.

The aim of this pilot study was to assess oxygen saturation in retinal blood vessels in patients with monoclonal gammopathies (MGs). Thirty-one patients with MGs (11 women and 20 men, mean age 65.9± 8.9 years) were enrolled during 2016-2020. The patients were diagnosed at the Haemato-Oncology Department and subsequently examined at the Ophthalmology Department before initiating systemic therapy. All patients were subjected to automatic retinal oximetry (Oxymap ehf.) and had their fundus photographed (Topcon TRC-50DX retinal camera). We assessed the association between retinal oxygen saturation (SatO2 ) - arterial SatO2 , venous SatO2 and arterio-venous (AV) difference-and MGs parameters: serum monoclonal immunoglobulin (M-protein) level and serum immunoglobulin-free light chains (FLC kappa and lambda), total protein, serum viscosity, haemoglobin, albumin, lactate dehydrogenase, C-reactive protein, creatinine and serum calcium level. Hyperviscosity-related retinopathy was also evaluated. Statistical analysis showed a significant positive correlation (r=0.462; p=0.009) between the AV difference and the haemoglobin level. A significant, medium strong negative correlation was found between the AV difference and the serum levels of the monoclonal light lambda chains (r=-0.450; p=0.011). Contrary to expectations, no statistically significant correlation was found between retinal oxygen saturation and the total protein or viscosity. This study found correlation between retinal oxygen saturation and certain parameters in the blood of patients with MGs. Increasing levels of monoclonal immunoglobulin seem to reduce oxygen absorption in retinal arterioles, resulting in a lower AV difference, particularly in patients with a high free light chain level.

Magnetismm-3: An Open-Label, Multicenter, Non-Randomized Phase 2 Study of Elranatamab (PF-06863135) in Patients with Relapsed or Refractory Multiple Myeloma

Background: Multiple myeloma (MM) is a hematological B-cell malignancy that remains incurable for most patients. Almost all patients, including those who initially respond to treatment, are expected to relapse and subsequently cycle through multiple lines of treatment. The addition of proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies has improved patient outcomes; however, survival of patients after these agents is very poor and highlights an unmet medical need in the relapsed/refractory MM population. Elranatamab (PF-06863135) is a humanized bi-specific antibody that targets both BCMA-expressing MM cells and CD3-expressing T cells, with binding resulting in T-cell mediated cytotoxicity. Elranatamab preclinical studies have demonstrated anti-tumor activity and delayed tumor progression. A Phase 1 study, MagnetisMM-1 (ClinicalTrials.gov ID: NCT03269136), with the aim of characterizing the efficacy, safety, pharmacokinetics, and pharmacodynamics of elranatamab as single agent and in combination with immunomodulatory agents for patients with relapsed/refractory MM is ongoing.Study Design and Methods: MagnetisMM-3 is an open-label, multicenter, non-randomized, Phase 2 study to evaluate the efficacy and safety of elranatamab monotherapy in patients with relapsed/refractory MM who are refractory to at least one proteasome inhibitor, one immunomodulatory drug, and one anti-CD38 antibody (ClinicalTrials.gov ID: NCT04649359). Approximately 150 patients will be enrolled to one of two independent parallel cohorts: those naïve to BCMA-directed therapies (Cohort A) and those with previous exposure to BCMA-directed therapy (Cohort B). The primary endpoint is objective response rate, according to International Myeloma Working Group [IMWG] response criteria. Secondary endpoints include duration of response, cumulative complete response (CR) rate, duration of cumulative CR, progression-free survival, time to response, minimal residual disease negativity rate, overall survival, safety, plasma concentrations, and immunogenicity of elranatamab.Key inclusion criteria are age ≥18 years, MM diagnosis according to IMWG criteria and with measurable disease based on IMWG criteria as defined by at least 1 of the following: Serum M-protein ≥0.5 g/dL by SPEP, Urinary M-protein excretion ≥200 mg/24 hours by UPEP; Serum immunoglobulin free light chain ≥10 mg/dL (≥100 mg/L) and abnormal serum immunoglobulin kappa to lambda free light chain ratio (<0.26 or >1.65). Eligible patients should also have ECOG performance status ≤2, be refractory to at least one proteasome inhibitor, one immunomodulatory drug, and one anti-CD38 antibody and be relapsed/refractory to their last treatment regimen. Key exclusion criteria are smoldering MM, active plasma cell leukemia, amyloidosis, POEMS syndrome, active, uncontrolled bacterial, fungal or viral infections, stem cell transplant within 12 weeks of enrollment, any other active malignancy within 3 years prior to enrollment (except for adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ), or having received previous administration of an investigational drug within 30 days or 5 half-lives (whichever is longer) of the first dose of elranatamab. This study is, or is planned to be, open at centers in the USA, Australia, Canada, Belgium, France, Germany, Japan, Poland, Spain, and the UK. DisclosuresLesokhin: Genetech: Research Funding; Serametrix, Inc: Patents & Royalties; pfizer: Consultancy, Research Funding; Behringer Ingelheim: Honoraria; Trillium Therapeutics: Consultancy; bristol myers squibb: Research Funding; Iteos: Consultancy; Janssen: Honoraria, Research Funding. Iida: Ono: Honoraria, Research Funding; Glaxo SmithKlein: Research Funding; Janssen: Honoraria, Research Funding; Abbvie: Research Funding; Chugai: Research Funding; Celgene: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Bristol-Myers Squibb: Research Funding; Daiichi Sankyo: Research Funding; Amgen: Research Funding. Ma: Pfizer Inc: Current Employment, Current equity holder in publicly-traded company. Sullivan: Pfizer Inc: Current Employment, Current equity holder in publicly-traded company. Raab: Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees.

Alteration of the Gut Microbiome in Chronic Kidney Disease Patients and Its Association With Serum Free Immunoglobulin Light Chains.

ObjectivesGut dysbiosis is associated with chronic kidney disease (CKD), and serum free immunoglobulin light chains (FLCs) are biomarkers for CKD. This study aims to assess the CKD gut microbiome and to determine its impact on serum FLC levels.MethodsTo control for confounders, 100 patients and sex- and age-matched healthy controls (HCs) were recruited. The gut microbiome was assessed by sequencing 16S rRNA gene V3-V4 hypervariable regions. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was applied to infer functional metabolic pathways. When observing group differences in the microbiome and predicted metabolic pathways, demographic confounders were adjusted using binary logistic regression; when examining impacts of the gut microbiome and metabolic pathways on serum FLCs, factors influencing FLC levels were adjusted using multiple regression.ResultsPrincipal coordinate analysis revealed a significantly different bacterial community between the CKD and HC groups (P < 0.05). After adjusting for confounders, lower Chao 1, observed species and Shannon indices based on binary logistic regression predicted CKD prevalence. Actinobacteria, Alistipes, Bifidobacterium and Bifidobacterium longum enrichment, upregulation of metabolic pathways of bacterial toxin, chloroalkane and chloroalkene degradation, and Staphylococcus aureus infection also predicted CKD prevalence (P < 0.05). Furthermore, depletion of Actinobacteria and Bifidobacterium and reduced chloroalkane and chloroalkene degradation predicted high levels of FLC λ (P < 0.05).ConclusionsGut dysbiosis in CKD patients was confirmed by controlling for confounders in the present study. Additionally, the association between gut dysbiosis and FLC λ levels demonstrates the existence of crosstalk between the microbiome and immune response in CKD.

Serum immunoglobulin free light chains and their association with clinical phenotypes, serology and activity in patients with IgG4-related disease

The clinical utility of serum immunoglobulin free light chains (sFLC) in IgG4-related disease (IgG4-RD) is unknown. Herein we evaluated their association with clinical phenotypes, serology and activity in patients with IgG4-RD. Cross-sectional study that included 45 patients with IgG4-RD, and as controls 25 with Sjögren’s syndrome (SS) and 15 with sarcoidosis. IgG4-RD patients were classified in clinical phenotypes: pancreato-hepato-biliary, retroperitoneum/aorta, head/neck-limited and Mikulicz/systemic; as well as proliferative vs. fibrotic phenotypes. We assessed the IgG4-RD Responder Index (IgG4-RD RI) at recruitment and measured IgG1, IgG4, κ and λ sFLC serum levels by turbidometry. sFLC levels were similar among IgG4-RD, SS and sarcoidosis groups. Regarding the IgG4-RD patients, the mean age was 49 years, 24 (53.3%) were men and 55.5% had activity. Eight (17.7%) belonged to pancreato-hepato-biliary, 6 (13.3%) to retroperitoneum/aorta, 14 (31.1%) to head/neck-limited, 16 (35.5%) to Mikulicz/systemic phenotypes, whereas 36 (80%) to proliferative and 9 (20%) to fibrotic phenotypes. High κ sFLC, λ sFLC and κ/λ ratio were present in 29 (64.4%), 13 (28.9%) and 13 (28.9%) of IgG4-RD patients, respectively. There were no differences in sFLC among IgG4-RD phenotypes. κ sFLC and κ/λ ratio correlated positively with the number of involved organs and IgG4-RD RI. Patients with renal involvement had higher κ sFLC and λ sFLC. The AUC for κ sFLC and λ sFLC, for renal involvement was 0.78 and 0.72, respectively. Active IgG4-RD had higher levels of κ sFLC and more frequently a high κ/λ ratio. The AUC for κ sFLC and κ/λ ratio for predicting active IgG4-RD was 0.67 and 0.70, respectively. sFLC correlated positively with IgG1 and IgG4 levels. sFLC may be useful as a biomarker of disease activity as well as multiorgan and renal involvement. In particular, a high κ/λ ratio may identify patients with active disease.

Phase 2 Trial of Ixazomib, Cyclophosphamide and Dexamethasone for Treatment of Previously Untreated Light Chain Amyloidosis

Phase 2 Trial of Ixazomib, Cyclophosphamide and Dexamethasone for Treatment of Previously Untreated Light Chain Amyloidosis

Cardiac amyloidosis mimicking acute coronary syndrome: a case report and literature review.

BackgroundCardiac amyloidosis, a progressive cardiac disease, results from the accumulation of undegraded proteinaceous substrates in the extracellular matrix of the heart. It may present as acute coronary syndrome (ACS); therefore, a clear distinction remains challenging in clinical practice. We describe a case of cardiac amyloidosis mimicking ACS.Case summaryA 72-year-old man experienced chest discomfort for 2 days. He gradually developed dyspnoea during the preceding month. Electrocardiogram (ECG) showed sinus rhythm with right bundle branch block and low voltage. Echocardiography revealed concentric left ventricular thickening, biatrial dilation, and preserved ejection fraction with predominantly left ventricular basal hypokinesis. Serial testing of the cardiac biomarkers showed persistently increased high-sensitive cardiac troponin T levels and normal serum creatine kinase myocardial band levels. He was diagnosed with ACS with haemodynamic stability. However, coronary angiography demonstrated non-obstructive coronary arteries. Furthermore, significant macroglossia and periorbital purpura were noticed. Laboratory investigations revealed elevated serum immunoglobulin free light chain (FLC) kappa and lambda levels with an increased FLC ratio. Histological analysis of the biopsied abdominal skin confirmed amyloidosis.DiscussionCardiac amyloidosis often presents as restrictive cardiomyopathy. The usual symptoms include dyspnoea and peripheral oedema. Chest pain may manifest rarely, leading to misdiagnosis as coronary artery disease. Some findings suggestive of cardiac amyloidosis include clinical signs such as amyloid deposits, dyspnoea, low ECG voltage, and basal-predominant hypokinesis with relative apical sparing in echocardiography. Serum FLC test and abdominal skin biopsy can confirm the diagnosis of amyloidosis when a myocardial biopsy is not feasible.

The importance of serum immunoglobulin free light chain assessment for predicting outcome in patients with newly diagnosed multiple myeloma in real clinical practice

Background. The prognosis of patients with multiple myeloma (MM) is significantly different depending on the biological characteristics of the tumor substrate, the microenvironment of the bone marrow, as well as factors associated with the patient’s body. Therefore, the search for new reliable and easily identifiable prognostic markers is relevant for the effective management of patients with this disease.The objective of the study was to assess the prognostic value of the study of serum free light chains (FLC) of immunoglobulins κ and λ and their ratio κ / λ FLC in the blood serum of patients with newly diagnosed MM in real clinical practice.Materials and methods. 369 patients with first diagnosed MM (134 men and 235 women) were examined who were hospitalized in the hematology department of the City Clinical Hospital No. 2 Novosibirsk in the period since January 2012 to December 2017. The median age of the patients was 67 (32–82) years. All patients received induction courses of chemotherapy based on bortezomib. The control group consisted of 56 conditionally healthy individuals: 34 women (60.7 %) and 22 (39.3 %) men with a median age of 62 (40–68) years. The concentration of FLC-κ and FLC-λ (mg / L) in blood serum was determined by immunoturbidimetric method on a Hitachi 911 automated biochemical analyzer using the Freelite Human Lambda and Freelite Human Kappa reagent kits (Binding Site, Great Britain).Results. It was found that in patients with MM, the concentration of serum FLC-κ or FLC-λ was statistically significantly higher compared to the control group and varied depending on the type of MM (p &lt;0.001). The diagnostic sensitivity of the quantitative determination of FLC and their ratio for MM was 98.64 %, compared with 94.04 % in a standard immunochemical study. The values of the ratio κ / λ FLC &lt;0.04 or&gt; 65, as well as the concentration of FLC-κ and FLC-λ are higher than the median obtained in the whole group (FLC-κ ≥702 mg / L and FLC-λ ≥493.2 mg / L), correlate with known factors of poor prognosis for MM (with a high concentration of β2‑microglobulin (&gt;3.5 mg / L) (r = 0.461; p &lt;0.001), plasma cell bone marrow infiltration &gt;60 % (r = 0.420; p &lt;0.001), renal failure (creatinine &gt;177 μmol / L) (r = 0.380; p = 0.002), and also with high lactate dehydrogenase activity (&gt;450 U / L) (r = 0.520; p &lt;0.001) and is associated with poor outcomes. The median overall survival in the group of patients with κ / λ FLC &lt;0.04 or &gt;65 was 49 months compared to 76 months in the group with κ / λ FLC 0.04–65 (log-rank p = 0.012).Conclusion. The determination of free FLC in the blood serum of patients with MM can be used to assess the prognosis of their survival. The value of the κ / λ FLC ratio &lt;0.04 or &gt;65 allows us to divide patients with MM into risk groups with significantly different outcomes and can be used to identify patients at high risk who need more aggressive therapy and more detailed monitoring of the response.

Blood mass spectrometry detects residual disease better than standard techniques in light-chain amyloidosis

In patients with immunoglobulin light-chain (AL) amyloidosis, depth of hematologic response correlates with both organ response and overall survival. Our group has demonstrated that screening with a matrix-assisted laser desorption/ionization-time-of-flight (TOF) mass spectrometry (MS) is a quick, sensitive, and accurate means to diagnose and monitor the serum of patients with plasma cell disorders. Microflow liquid chromatography coupled with electrospray ionization and quadrupole TOF MS adds further sensitivity. We identified 33 patients with AL amyloidosis who achieved amyloid complete hematologic response, who also had negative bone marrow by six-color flow cytometry, and who had paired serum samples to test by MS. These samples were subjected to blood MS. Four patients (12%) were found to have residual disease by these techniques. The presence of residual disease by MS was associated with a poorer time to progression (at 50 months 75% versus 13%, p = 0.003). MS of the blood out-performed serum and urine immunofixation, the serum immunoglobulin free light chain, and six-color flow cytometry of the bone marrow in detecting residual disease. Additional studies that include urine MS and next-generation techniques to detect clonal plasma cells in the bone marrow will further elucidate the full potential of this technique.

The prognostic value of baseline serum free light chain in immunoglobulin light-chain cardiac amyloidosis

目的探讨血清游离轻链（sFLC）检测在免疫球蛋白轻链型心肌淀粉样变性（AL-CA）患者中的预后价值。方法回顾性分析2012年1月至2016年12月于北京朝阳医院确诊为AL-CA且有完整sFLC数据的30例患者，通过受试者工作特征（ROC）曲线及Mayo2012分期确定受累轻链与非受累轻链差值（dFLC）的界点并分组评估患者预后。结果30例AL-CA患者中位年龄57岁，男女比例21∶9。λ型淀粉样变22例（73.3%），累及肾脏者17例（56.7%）。30例AL-CA患者的中位dFLC为162.9（57.9~401.6）mg/L，高dFLC组的B型利钠肽（BNP）水平较低dFLC组高（3 966 ng/L对2 142 ng/L，P=0.005），中位生存时间缩短（15个月对47个月，P<0.001）。以Mayo2012分期所规定的dFLC=180 mg/L为界值将患者重新分组并进行Kaplan-Meier生存分析，高dFLC组较低dFLC组的中位生存时间仍缩短（22个月对40个月，P=0.001）。以κ型和λ型患者的κ/λ轻链比值中位数为界值，将κ型sFLC比值<3.79和λ型sFLC比值≥0.06归为低sFLC比值组，反之为高sFLC比值组，两组患者的生存分析显示，高sFLC比值组较低sFLC比值组中位生存时间缩短（25个月对37个月，P=0.021）。Cox比例风险模型进行多因素分析显示，dFLC和美国纽约心脏病学会心功能分级是影响患者生存时间的因素，其中高dFLC（dFLC>162.9 mg/L）组的死亡风险是低dFLC（dFLC≤162.9 mg/L）组的12.13（95% CI 2.98~49.30，P<0.001）倍。结论sFLC检测能够有效地提示AL-CA患者的预后。

Прогностическое значение сывороточных свободных легких цепей иммуноглобулинов при множественной миеломе в реальной клинической практике

Прогностическое значение сывороточных свободных легких цепей иммуноглобулинов при множественной миеломе в реальной клинической практике

Phase I Study of a Novel Bcl-2 Inhibitor, at-101 in Combination with Lenalidomide and Dexamethasone in Patients with Relapsed and/or Refractory Multiple Myeloma (RRMM)

Background: The development of novel treatment strategies has extended the median survival of MM to nearly a decade but the disease remains incurable and relapse is inevitable. The Bcl-2 pathway is highly relevant to MM cell survival and can be mitigated therapeutically. AT-101 is a novel, orally available pan Bcl-2 inhibitor (Bcl-2, Bcl-xl, Mcl-1, and Bcl-w). Preclinical in vitro and in vivo studies showed that AT-101 enhanced cytotoxicity of lenalidomide-dexamethasone (Rd). We conducted a phase I study in RRMM patients to establish the effective dose of AT-101 with Ld as well as record safety and preliminary efficacy of this combination (NCT02697344). Methods: Key eligibility criteria included: RRMM with measurable disease (serum monoclonal protein ≥1.0 g/dL or urine monoclonal protein &gt;200mg/24 hour or serum immunoglobulin free light chain &gt;10mg/dL AND abnormal serum free light chain ratio). Patients must have received 1-3 prior treatment regimens and have an absolute neutrophil count ≥1.0 x 109, platelets 75 x 109, creatinine clearance ≥50 mL/min, and ECOG performance status ≤2. AT-101 dosing was designed to reach a maximum daily target of 20mg (Cohort 1; 10 mg PO QD, Cohort 2; 20 mg PO QD) utilizing a standard 3 +3 dose escalation design in combination with standard doses of Rd. Treatment was given as outpatient for a maximum of 12, 28-day cycles. For pharmacodynamic studies, AT-101 alone was given in cycle 1, with R (25 mg on days 1-21) and d (40 mg weekly) added cycle 2 onwards. Results: Enrolled patients (n=10) included 60% males with median age 68.5 years (range 55-75) and median time since MM diagnosis 4.5 years (range 0.6-8.3). MM ISS stage was II/III in 7 patients and 8/10 had high-risk cytogenetics with 4 each having del17p and 1q+. Only 1 patient had t(11;14).Patients had received median 2 prior lines of therapy (range 1-3), with 7 having had prior autologous stem cell transplant (ASCT) and the initial induction regimen being bortezomib (V), R and dexamethasone (d) (VRd) in 8, Rd in 1 and cyclophosphamide (C) with Vd (VCd) in 1 patient. At the time of study entry, 3 patients were R refractory while 2 were refractory to both, V and daratumumab (Dara). Median duration of treatment was 7.5 cycles (range 2-12) and 3 patients completed all planned 12 cycles of treatment. Among the evaluable patients, dose limiting toxicities (DLTs) at 20 mg daily dose of AT-101 with 25 mg of R and 40 mg weekly included one patient with grade 4 febrile neutropenia and grade 4 neutropenia lasting 9 days and one patient with grade 4 thrombocytopenia lasting 8 days. G3/4 adverse events (AEs) included atrial flutter (n=1), white blood cell count decrease (n=3), neutropenia (n=5), febrile neutropenia (n=1) and thrombocytopenia (n=2), and back pain (n=1) . No G3/4 non-hematological AEs were noted. Any grade non-hematologic AEs seen in at least 20% (n=2) patients included fatigue (n=9), neuropathy (n=6), nausea (n=3), diarrhea (n=5), constipation (n=3), and creatinine increased (n=2). No patients experienced tumor lysis syndrome. Overall response rate (ORR) was 44% (2 each with very good partial response, VGPR and PR) and clinical benefit rate (CBR) was 89% with 2 additional patients showing minor response (MR) and 2 experiencing stable disease (SD) (Fig 1). Patients with high-risk disease had an ORR of 43% and a CBR of 100%. Median progression-free survival (PFS) for all patients was 8.1 months. Correlative analysis from patients who showed an objective response to treatment revealed a significant increase in bone marrow Th-effector cells, NK cells and cytotoxic CD8+ T-cells along with a significant decrease in immunosuppressive T-regulatory and B-regulatory cells was noted after 1 complete cycle of the combination therapy (p&lt;0.05, Fig 2). Conclusions: This is the first reported clinical trial combining a Bcl-2 inhibitor with immunomodulatory drugs (IMiDs) in MM. AT-101-Rd is a clinically active regimen with an ORR of 40% in predominantly high-risk RRMM patients with an acceptable toxicity profile. Additional patients with MM experienced clinical benefit despite refractory status to prior therapy in this early phase clinical trial. These early findings support the further investigation of AT-101 specifically, and Bcl-2 inhibitors in general, with IMiDs in patients with MM. Disclosures Ailawadhi: Celgene: Consultancy; Amgen: Consultancy, Research Funding; Pharmacyclics: Research Funding; Cellectar: Research Funding; Janssen: Consultancy, Research Funding; Takeda: Consultancy. Chanan-Khan:Xencor: Research Funding; Pharmacyclics: Research Funding; Merck: Research Funding; Jansen: Research Funding; Mayo Clinic: Employment; Ascentage: Research Funding; Millennium: Research Funding; AbbVie: Research Funding. OffLabel Disclosure: AT-101 is not currently FDA-approved for treatment of any condition.

ASSAY OF IMMUNOGLOBULIN FREE LIGHT CHAINS IN THE SERUM FOR EVALUATING CHEMOTHERAPY EFFICACY IN PATIENTS SUFFERING FROM MULTIPLE MYELOMA WITH INTACT MEASURABLE PARAPROTEIN

Aim. To evaluate the concentration of immunoglobulin free light chains (FLC) in comparison with that of intact measurable paraproteins (PIg) in patients with relapsed/resistant multiple myeloma (RR MM) undergoing treatment with bortezomib.Materials and methods. A retrospective study included 15 patients with RR MM with intact measurable PIg. Following 6 cycles of bortezomib treatment, an evaluation of the treatment efficacy was performed using standard criteria and by analysing serum FLC of immunoglobulins (sFLC).Results. A partial response (PR) and small response was achieved in 4 and 5 patients, respectively. The stabilization of the disease was observed in 6 patients. No cases of complete response (CR) or stringent complete response (SCR) were recorded. On the basis of the data on the concentration of sFLC after treatment, all patients were divided into 2 groups: those with an abnormal (clonal) and normal κ/λ ratio. In 11 patients with a response lower than PR, sFLC κ/λ ratio was of a clonal nature, which corresponded to changes in the concentrations of intact PIg during treatment. In 4 cases with PR, the residual tumour was determined by the presence of intact PIg within the 32–45 % range under, however, a normal sFLC κ/λ ratio.Conclusion. Treatment with bortezomib affects all processes in MM with intact PIg, such as synthesis of FLC by tumour plasma cells, a decrease in the amount of circulating sFLC in blood and in the concentration of intact PIg. Normalization of sFLC κ/λ ratio under the achievement of PR could be considered as a prognostic factor in a favourable clinical outcome.

Elevated IgM and abnormal free light chain ratio are increased in relatives from high-risk chronic lymphocytic leukemia pedigrees

Abnormal serum immunoglobulin (Ig) free light chains (FLC) are established biomarkers of early disease in multiple B-cell lymphoid malignancies, including chronic lymphocytic leukemia (CLL). Heavy chains have also been shown to be biomarkers in plasma cell disorders. An unanswered question is whether these Ig biomarkers are heritable, i.e., influenced by germline factors. CLL is heritable but highly heterogeneous. Heritable biomarkers could elucidate steps of disease pathogenesis that are affected by germline factors, and may help partition heterogeneity and identify genetic pleiotropies across malignancies. Relatives in CLL pedigrees present an opportunity to identify heritable biomarkers. We compared FLCs and heavy chains between relatives in 23 high-risk CLL pedigrees and population controls. Elevated IgM (eIgM) and abnormal FLC (aFLC) ratio was significantly increased in relatives, suggesting that these Ig biomarkers are heritable and could offer risk stratification in pedigree relatives. Within high-risk CLL pedigrees, B-cell lymphoid malignancies were five times more prevalent in close relatives of individuals with eIgM, prostate cancer was three times more prevalent in relatives of individuals with aFLC, and monoclonal B-cell lymphocytosis increased surrounding individuals with normal Ig levels. These different clustering patterns suggest Ig biomarkers have the potential to partition genetic heterogeneity in CLL and provide insight into distinct heritable pleiotropies associated with CLL.

59-Year-Old Man With Fatigue, Weight Loss, and Hepatomegaly

59-Year-Old Man With Fatigue, Weight Loss, and Hepatomegaly

Serum immunoglobulin free light chains are sensitive biomarkers for monitoring disease activity and treatment response in primary Sjögren's syndrome.

Serum immunoglobulin free light chains (FLCs) are frequently elevated in B-cell-mediated autoimmune diseases, including primary SS (pSS). The objective of this study was to assess if serum FLCs can contribute to classification, mucosa-associated lymphoid tissue (MALT) lymphoma detection, monitoring of disease activity and treatment response in pSS. Serum samples of 100 consecutive patients suspected of pSS were included. Forty-five patients fulfilled ACR-EULAR criteria for pSS. Additionally, samples of 17 pSS patients with MALT lymphoma and longitudinal samples of pSS patients treated with rituximab (n = 20), placebo (n = 10) or abatacept (n = 15) were included. Serum FLCκ/FLCλ was measured by nephelometry or turbidimetry. At diagnosis, FLCκ and FLCλ serum levels were significantly higher in pSS compared with non-SS sicca patients. The FLCκ/FLCλ ratio was abnormal in 11% of pSS patients. In established MALT-pSS patients, without recent rituximab treatment (n = 12), 50% had abnormal FLCκ/FLCλ ratios. FLC measurement had no additional value for pSS classification, compared with IgG and anti-SSA. FLC levels correlated significantly with systemic disease activity, assessed by EULAR SS Disease Activity Index (ESSDAI) and clinical ESSDAI, both cross-sectionally and longitudinally following treatment. Treatment with rituximab or abatacept significantly lowered FLC levels. FLCs show a large sensitivity to change and relative changes induced by treatment were higher compared with IgG. Serum FLCs are elevated in pSS, and abnormal FLCκ/FLCλ ratios may be indicative for the presence of MALT lymhoma. FLC levels can be used as a biomarker for systemic disease activity and monitoring treatment responses. FLCs are sensitive to change and have more favorable kinetics than IgG.

Association between abnormal serum free light chains ratio and known prognostic factors in lymphoma; a nephrology viewpoint.

Introduction: The serum immunoglobulin free light chain (FLC) assay quantities of free kappa (κ) and lambda (λ) light chains. This assay has prognostic value in plasma cell proliferative disorders. There are limited data on serum FLC in B-cell malignancies. Objectives: The aim of this study was to compare the known prognostic factors in non-Hodgkin’s lymphoma of the type B-cell and Hodgkin disease with an abnormal secretion amount of light chains in these lymphomas. Patients and Methods: The association of pretreatment FLC and FLC ratio (κ:λ) with previously known prognostic factors for lymphoma such as the international prognostic index (IPI) and B symptoms were evaluated in 50 patients with Hodgkin’s and non-Hodgkin’s lymphoma. IPI is a prognostic score given based on the clinical variables including age, disease stage, serum LDH and extra-nodal involvement. Elevated FLC and an abnormal κ:λ ratio was defined based on the previous publications. Results: The prevalence of abnormal FLC ratio was 38% in all patients and 40.9% in patients with diffuse large B-cell lymphoma. Abnormal FLC ratio was significantly associated with IPI (P=0.04) and B symptoms (P=0.02) in both groups of the patients with Hodgkin’s and non-Hodgkin’s lymphoma. The stage of the disease in Hodgkin’s lymphoma patients showed a significant relationship with the abnormal FLC ratio (P=0.04). Presence of the B symptoms in patients with Hodgkin’s lymphoma had a modest but not statistically significant association with the abnormal FLC ratio (P=0.07). Conclusion: Abnormal FLC ratio as a new potent prognostic biomarker has a significant association with IPI which is the most common clinical tool used to predict outcome in lymphoma patients. Since there is a need for developing a reliable and quantitative prognostic biomarker for lymphoma, evaluation of the independent effect of the abnormal serum FLC ratio is suggested to be considered in future prospective studies. The result of these studies will also be useful for nephrologists, while serum immunoglobulin FLC is capable to damage kidney.

The diagnostic and prognostic values of serum free light chain in patients with primary light chain amyloidosis

目的研究血清游离轻链（sFLC）检测在原发性轻链型淀粉样变（pAL）中的诊断和预后价值。方法回顾性分析2009年1月至2015年6月确诊且有完整sFLC数据的126例pAL患者的临床资料，探讨sFLC的诊断价值，并采用Cox回归法分析sFLC差值（dFLC）的预后价值。结果126例患者中男女比例为1.57∶1，中位年龄为57 (37~81）岁，λ轻链型者80例（63.5%），肾脏受累者87例（69.0%），心脏受累者79例（62.7%）。126例患者的中位dFLC为99 (1~4 263）mg/L。血清蛋白电泳、血清免疫固定电泳、尿免疫固定电泳和sFLC比值异常法检测单克隆免疫球蛋白（M蛋白）的阳性检出率分别为34.9%（44/126）、63.5%（80/126）、77.0%（97/126）和81.0%（102/126）。联合上述四种方法可将M蛋白的检出率提高至98.4%（124/126）。中位随诊16个月后，37例患者死亡，所有患者的中位生存时间尚未达到。多因素分析发现dFLC ≥130 mg/L是影响pAL患者预后的独立危险因素（HR=3.272, 95% CI 1.384~7.739，P=0.007）。结论sFLC检测可显著提高pAL患者M蛋白的检出率；高水平dFLC是影响患者预后的独立危险因素。