Immunoglobulin Free Light Chains Research Articles

Saliva immunoglobulin free light chain analysis for monitoring disease activity and response to treatment in multiple sclerosis

BackgroundImmunoglobulin free light chains (FLC) have recently gained considerable interest as new promising intrathecal biomarkers of multiple sclerosis (MS). However, lumbar puncture is invasive and not practical for monitoring disease course. This study aimed to assess the utility of saliva FLC as a biomarker of disease activity and response to treatment in MS MethodsWestern blotting was used to study saliva FLC monomers and dimers. The intensity of immunoreactive FLC bands was quantified by electrophoresis analysis, and the obtained values were used as FLC indices to account for kappa and lambda FLC monomer and dimer levels. Firth's logistic regression analysis suitable to study small cohorts was applied to compare FLC levels between M.S. patients in relapse, MS patients in remission, and healthy controls. Association between FLC levels and clinical and radiological parameters was analyzed. Results55 MS patients and 40 healthy controls were evaluated. Saliva FLC levels were significantly higher in relapse compared to remission. Logistic regression analysis employing a combination of FLC indices confirmed the significant difference between these two groups. The FLC levels were significantly reduced by treatment with corticosteroids. During remission, patients treated with disease-modifying therapies had lower levels of FLC compared to untreated patients. The increased FLC levels were associated with the presence of gadolinium-enhancing lesions, but not with MRI T2 lesion load and EDSS scores. During individual patient follow-up, the changes of the saliva FLC levels were in concordance with the disease activity status. ConclusionsSaliva FLC levels may be a useful biomarker for discriminating between stable remission and active disease. The developed test may serve as a new, non-invasive, and inexpensive tool for monitoring disease activity and response to treatment in MS.

Correction to: Immunoglobulin free light chains: an inflammatory biomarker of diabetes.

In the original publication of this paper contains some typographical errors in Table 1.

TO012HOW DIFFERENT IS THE CLEARANCE OF LARGE MIDDLE MOLECULES AND INFLAMMATORY MARKERS FROM EXPANDED HEMODIALYSIS THERAPY COMPARED TO ONLINE HEMODIAFILTRATION?

Abstract Background and Aims Expanded hemodialysis (HDx) with a medium cut-off dialyzer, Theranova® 500, can achieve a middle molecule clearance but its efficacy or comparison with HDF is still unknown. It is still unknown on how large middle molecules and inflammation markers are affected over time with a medium cut-off dialyzer. This study compared the purifying effectiveness of Theranova® 500 dialyzer with respect to online Hemodiafiltration (OL-HDF). Method Sixty-three patients who were already receiving HDF were evaluated and 43 were randomized by residual renal function. Twenty-one patients received treatment with HDx using Theranova® 500 and 22 patients remained in HDF in post-dilution mode, using a high-flux dialyzer, Polyflux® 170H, for up to 24 weeks. The dialysis time and the adequacy parameters for both arms were the same. Large middle molecules were measured (kappa immunoglobulin free light chains [κ-FLC], lambda immunoglobulin free light chains [λ-FLC], chitinase-3-like protein 1 [YKL-40], fibroblast growth factor 23 [FGF-23] and serum beta-2 microglobulin [β2M]), ; and inflammatory markers (high sensitivity C-reactive protein [hs-CRP], pentraxin - 3 [PTX-3], interleukin-6 [IL-6], interleukin-10 [IL-10]) at 12 weeks of treatment; and its change from baseline to weeks 12 and 24 in mid-week pre-dialysis. The method of measurement was the immunoassay. Siemens immunoassay was used for FLCs. Results HDx with Theranova® 500 demonstrated comparable results to OL-HDF with convective volume 24.4±3.2 L in terms of reduction rate (RR) of middle molecules (κ-FLC, λ-FLC, FGF-23 and β2M) at 12 weeks of treatment. HDx demonstrated similar performance to HDF in mid-week pre-dialysis plasma levels of middle molecules from baseline, at 12 and 24 weeks of treatment. Greater RR of YKL-40 at 12 weeks of treatment was seen in HDx group when compared to HDF (58.1% vs 42.4%; p≤0.0001), and there was a difference in the pre-dialysis β2M change from Baseline values between the groups (-0.60 for HDx arm and +3.28 for HDF arm, p=0.46). HDx with Theranova® 500 demonstrated comparable results to HDF in terms of reduction rate (RR) of inflammatory markers (hs-CRP, PTX-3, IL-6 and IL-10) at 12 weeks of treatment. There were no differences in the parameters of adequacy of dialysis between both arms. Both treatments were effective in maintaining pre-dialysis albumin and fibrinogen levels throughout the study. There were no significant adverse events related to the safety of Theranova. Conclusion HDx with Theranova® 500 is an emergent, effective and safe hemodialysis therapy that showed a purifying efficacy at least comparable to OL-HDF.

Immunoglobulin free light chains as an inflammatory biomarker of heart failure with myocarditis

BackgroundIn this study, we measured immunoglobulin free light chains (FLC), a biomarker of inflammation in the sera of patients with heart failure due to myocarditis. MethodsFLC kappa and FLC lambda were assayed in stored serum samples from patients with heart failure with myocarditis from the US myocarditis treatment trial by a competitive-inhibition multiplex Luminex® assay. ResultsThe median concentration of circulating FLC kappa/lambda ratio was significantly lower in the sera from patients with heart failure with myocarditis than in healthy controls, and FLC kappa/lambda ratio had good diagnostic ability for identification of heart failure with myocarditis. Further, FLC kappa/lambda ratio was an independent prognostic factor for overall survival, and allowed creation of three prognostic groups by combining with N-terminal pro-B-type natriuretic peptide. ConclusionsThis study suggests that FLC kappa/lambda ratio is a promising biomarker of heart failure with myocarditis.

Immunoglobulin free light chains: an inflammatory biomarker of diabetes.

Inflammation is increasingly understood as playing an important role in type 2 diabetes mellitus (T2D) development. A critical mechanism of the inflammatory cascade in developing T2D is nuclear factor-kappa B (NF-kB) activation. As immunoglobulin free light chains (FLC) could be a biomarker of activation of NF-kB, we measured FLC in patients with T2D. The age range of the 77 patients with T2D and the 75 healthy control participants were 45-87years (median 60) and 25-72years (median 51), respectively. Serum FLC kappa and lambda were assayed by a competitive-inhibition multiplex Luminex assay. The concentration of circulating FLC the kappa/lambda ratio was lower in patients with T2D than in healthy volunteers. The area under the receiver operating curve (ROC-AUC) of the FLC kappa/lambda ratio showed the largest ROC-AUC compared with other FLC variables and hemoglobin A1c (HbA1c). The diagnostic performance for distinguishing between T2D and healthy control was a sensitivity of 0.96 and a specificity of 1. The odds ratio was 0.000018. These results suggest that FLC kappa/lambda may be more specific and sensitive for the diagnosis of T2D than HbA1c, and thus represents a potentially promising biomarker of inflammation.

MON-279 Correlation Between Haemolitic Complement Activity (CH50) and Growth Hormone Response to Stimulation in Adult Growth Hormone Deficiency: Preliminary Data

It is known that GH, directly or via IGF-1 activity, influences many aspects of immune response; both humoral and cellular branches are modulated, but no data are available about complement function. CH50 is a screening assay for the activation of the classical complement pathway and it is sensitive to the reduction, absence and/or inactivity of any component of the pathway. The CH50 tests the functional capability of serum complement components of the classical pathway to lyse sheep red blood cells (SRBC) pre-coated with rabbit anti-sheep red blood cell antibody (haemolysin). On the other hand, a low inflammation is present in GH deficiency (GHD) and it is related to cardiovascular risk of such situation, also in partial forms.Therefore, we performed a cohort study in a group of adult GHD patients evaluating CH50 levels to further explore the pattern of inflammatory markers in this condition.We included 17 patients with total GHD (GH peak after stimulation with GHRH+arginine <9 ng/ml with BMI<30 or <4 ng/ml with BMI≥30 Kg/m2; n=15) or partial GHD (peak between 9 and 16 ng/ml with BMI<30 Kg/m2 n=2) with mean±SEM BMI 27.7±2.6 kg/m2 and mean±SEM age 52.5±2.6 ys. The etiology of GHD, assessed by MRI, was: primary empty sella (n=7); post-surgical (n=1) pituitary adenoma (n=4); idiopathic (n=4), pineal cyst (n=1); CH50 has been assayed by turbidimetric method. Mean±SEM CH50 of entire cohort was 50.75±2.5 U/l (normal range 12.5-100 U/ml); however, a significant inverse correlation was observed between GH AUC and CH50 levels (Spearman r=-0.49; p=0.04).This datum joint to our previous observations about increased free light chains of immunoglobulins in GHD, substantiating the hypothesis of chronic low-grade inflammation affecting this condition, which in turn could negatively influence GH secretion. These data could be of interest especially in patients recognized as “idiopathic” GHD, where no pituitary morphologic alterations or anamnestic information (previous surgery, trauma or irradiation) were found. However, these data cannot be conclusive and further studies are needed to establish the causal relationships between these parameters, also in a greater cohort of patients.

Immunoglobulin light chain amyloidosis: 2020 update on diagnosis, prognosis, and treatment

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light or heavy chain are deposited in tissues. Clinical features depend on organs involved but can include heart failure with preserved ejection fraction, nephrotic syndrome, hepatic dysfunction, peripheral/autonomic neuropathy, and "atypical smoldering multiple myeloma or MGUS." Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for diagnosis. Invasive organ biopsy is not required in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory. The gold standard is laser capture mass spectroscopy. N-terminal pro-brain natriuretic peptide (NT-proBNP), serum troponin T, and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four groups of similar size; median survivals are 94.1, 40.3, 14.0, and 5.8 months. All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure. Stem cell transplant (SCT) is preferred, but only 20% of patients are eligible. Requirements for safe SCT include systolic blood pressure >90mmHg, troponin T <0.06 ng/mL and serum creatinine ≤1.7 mg/dL. Nontransplant candidates can be offered cyclophosphamide-bortezomib-dexamethasone or daratumumab containing regimens as it appears to be highly active in AL amyloidosis. Delayed diagnosis remains a major obstacle to initiating effective therapy prior to the development of end-stage organ failure. This article is protected by copyright. All rights reserved.

Defining biomarkers to predict symptoms in subjects with and without allergy under natural pollen exposure

Pollen exposure induces local and systemic allergic immune responses in sensitized individuals, but nonsensitized individuals also are exposed to pollen. The kinetics of symptom expression under natural pollen exposure have never been systematically studied, especially in subjects without allergy. We monitored the humoral immune response undernatural pollen exposure to potentially uncover nasal biomarkers for in-season symptom severity and identify protective factors. We compared humoral immune response kinetics in a panel study of subjects with seasonal allergic rhinitis (SAR) and subjects without allergy and tested for cross-sectional and interseasonal differences in levels of serum and nasal, total, and Betula verrucosa 1-specific immunoglobulin isotypes; immunoglobulin free light chains; cytokines; and chemokines. Nonsupervised principal component analysis was performed for all nasal immune variables, and single immune variables were correlated with in-season symptom severity by Spearman test. Symptoms followed airborne pollen concentrations in subjects with SAR, with a time lag between 0 and 13 days depending on the pollen type. Of the 7 subjects with nonallergy, 4 also exhibited in-season symptoms whereas 3 did not. Cumulative symptoms in those without allergy were lower than in those with SAR but followed the pollen exposure with similar kinetics. Nasal eotaxin-2, CCL22/MDC, and monocyte chemoattactant protein-1 (MCP-1) levels were higher in subjects with SAR, whereas IL-8 levels were higher in subjects without allergy. Principal component analysis and Spearman correlations identified nasal levels of IL-8, IL-33, and Betula verrucosa 1-specific IgG4 (sIgG4) and Betula verrucosa 1-specific IgE (sIgE) antibodies as predictive for seasonal symptom severity. Nasal pollen-specific IgA and IgG isotypes are potentially protective within the humoral compartment. Nasal levels of IL-8, IL-33, sIgG4 and sIgE could be predictive biomarkers for pollen-specific symptom expression, irrespective of atopy.

Biochemical and biophysical characterisation of immunoglobulin free light chains derived from an initially unbiased population of patients with light chain disease.

In light chain (LC) diseases, monoclonal immunoglobulin LCs are abundantly produced with the consequence in some cases to form deposits of a fibrillar or amorphous nature affecting various organs, such as heart and kidney. The factors that determine the solubility of any given LC in vivo are still not well understood. We hypothesize that some of the biochemical properties of the LCs that have been shown to correlate with amyloid fibril formation in patients also can be used as predictors for the degree of kidney damage in a patient group that is only biased by protein availability. We performed detailed biochemical and biophysical investigations of light chains extracted and purified from the urine of a group of 20 patients with light chain disease. For all samples that contained a sufficiently high concentration of LC, we quantified the unfolding temperature of the LCs, the monomer-dimer distribution, the digestibility by trypsin and the formation of amyloid fibrils under various conditions of pH and reducing agent. We correlated the results of our biophysical and biochemical experiments with the degree of kidney damage in the patient group and found that most of these parameters do not correlate with kidney damage as defined by clinical parameters. However, the patients with the greatest impairment of kidney function have light chains which display very poor digestibility by trypsin. Most of the LC properties reported before to be predictors of amyloid formation cannot be used to assess the degree of kidney damage. Our finding that poor trypsin digestibility correlates with kidney damage warrants further investigation in order to probe a putative mechanistic link between these factors.

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

Diagnostic significance of intrathecally synthesized immunoglobulins against neurotropic viruses (MRZ-reaction) in diagnosis of multiple sclerosis

Multiple sclerosis is chronic demyelinating disease of the central nervous system with autoimmune inflammation and accretive neurodegeneration. One of the characteristics of autoimmune inflammation in multiple sclerosis is a polyspecific intrathecal humoral immune response against neurotropic viruses (Measles, Rubella and varicella Zoster) called MRZ-reaction. This immune response is based on polyclonal activation of mature B lymphocytes in the central nervous system and intrathecal synthesis of antibodies to anamnestic antigens unrelated to viral replication in the central nervous system as well as serum antibody release. Immunoglobulins produced against neurotropic viruses are an integral part of the oligoclonal antibody pool in the cerebrospinal fluid. Because immunoglobulins can penetrate the blood brain barrier, not only serum and cerebrospinal fluid specific antibody indices are calculated, but also blood-brain barrier antibody permeability (Qalbumin, QIgG) are taken into account to assess their intrathecal synthesis. The aim of the study was to assess the informative value of the intrathecal antibodies against neurotropic viruses (MRZ-reaction) in multiple sclerosis. There were enrolled 60 patients divided into 2 groups: group 1 — 35 patients diagnosed with multiple sclerosis, group 2 — 25 patients with inflammatory and non-inflammatory disоrders of the central nervous system. Paired cerebrospinal fluid and serum samples were collected from all patients to measure level of oligoclonal IgG, immunoglobulin free kappa and lambda light chains, IgG index and specific antibodies indices, followed by assessing magnitude of MRZ-reaction. We found that the MRZ-reaction was the most specific test to diagnose multiple sclerosis. Intrathecally produced antibodies against neurotropic viruses were detected in 3 of 35 multiple sclerosis patients with lacking oligoclonal IgG antibodies. In addition, a relationship between MRZ-reaction and degree of EDSS disability was found in MS patients: peak EDSS score was reported in patients with intrathecally synthesized antibodies against 3 viral agents, whereas the minimum EDSS score — among MRZ-negative patients. Thus, assessing MRZ-reaction seems rational for confirming MS diagnosis in case of other negative laboratory tests (oligoclonal immunoglobulins and free kappa/lambda light chains in cerebrospinal fluid) allowing to improves diagnostic accuracy and evaluation of MS severity.

Immunoglobulin Free Light Chains: A Biomarker of Diabetes

Background: Inflammation is increasingly understood as playing an important role in type 2 diabetes mellitus (T2D) development. A critical mechanism of the inflammatory cascade in developing T2D is nuclear factor-kappa B (NF-kB) activation. As immunoglobulin free light chains (FLC) could be a biomarker of activation of NF-kB, we measured FLC in patients with T2D. Methods: The age range of the 77 patients with T2D and the 75 healthy control participants were 45 to 87 years (median 60) and 25 to 72 years (median 51), respectively.Serum FLC kappa and lambda were assayed by a competitive-inhibition multiplex Luminex assay. Findings: The concentration of circulating FLC kappa and the kappa/lambda ratio was lower, while in contrast, FLC lambda was higher, in patients with T2D than in healthy volunteers (p<0.0001).The area under the receiver operating curve (ROC-AUC) of the FLC kappa/lambda ratio showed the largest ROC-AUC compared with other FLC variables and hemoglobin A1c (HbA1c). With an optimal cutoff value of 1.3 for the FLC kappa/lambda ratio, the diagnostic performance for distinguishing between T2D and healthy control was a sensitivity of 0.96, a specificity of 1, a positive predictive value of 1, and a negative predictive value of 0.96. The odds ratio was 0.000018. Interpretation: These results suggest that FLC kappa/lambda may be more specific and sensitive for the diagnosis of T2D than HbA1c, and thus represents a potentially promising biomarker of inflammation which may reflect activation of NF-kB. Funding Statement: There was no specific funding for the study. Declaration of Interests: The authors declare that they have no conflict of interest. Ethics Approval Statement: The Institutional Review Boards reviewed, and all study participants granted their consent to, the investigative use of blood specimens.

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.

OP201: A Phase 1/2 Study of Melflufen and Dexamethasone in Patients with Immunoglobulin Light Chain (AL) Amyloidosis

OP201: A Phase 1/2 Study of Melflufen and Dexamethasone in Patients with Immunoglobulin Light Chain (AL) Amyloidosis

Re: Acute Renal Colic Due to Immunoglobulin Free Light Chain Kidney Stones: A Case Report of an Unusual Complication of Multiple Myeloma.

Re: Acute Renal Colic Due to Immunoglobulin Free Light Chain Kidney Stones: A Case Report of an Unusual Complication of Multiple Myeloma.

Silver Nanoparticle-Based Assay for the Detection of Immunoglobulin Free Light Chains.

There is a wide spectrum of malignant diseases that are connected with the clonal proliferation of plasma cells, which cause the production of complete immunoglobulins or their fragments (heavy or light immunoglobulin chains). These proteins may accumulate in tissues, leading to end organ damage. The quantitative determination of immunoglobulin free light chains (FLCs) is considered to be the gold standard in the detection and treatment of multiple myeloma (MM) and amyloid light-chain (AL) amyloidosis. In this study, a silver nanoparticle-based diagnostic tool for the quantitation of FLCs is presented. The optimal test conditions were achieved when a metal nanoparticle (MNP) was covered with 10 particles of an antibody and conjugated by 5–50 protein antigen particles (FLCs). The formation of the second antigen protein corona was accompanied by noticeable changes in the surface plasmon resonance spectra of the silver nanoparticles (AgNPs), which coincided with an increase of the hydrodynamic diameter and increase in the zeta potential, as demonstrated by dynamic light scattering (DLS). A decrease of repulsion forces and the formation of antigen–antibody bridges resulted in the agglutination of AgNPs, as demonstrated by transmission electron microscopy and the direct formation of AgNP aggregates. Antigen-conjugated AgNPs clusters were also found by direct observation using green laser light scattering. The parameters of the specific immunochemical aggregation process consistent with the sizes of AgNPs and the protein particles that coat them were confirmed by four physical methods, yielding complementary data concerning a clinically useful AgNPs aggregation test.

Urine and Free Immunoglobulin Light Chains as Analytes for Serodiagnosis of Hantavirus Infection.

Rapid point-of-care testing is a megatrend in infectious disease diagnosis. We have introduced a homogeneous immunoassay concept, which is based on the simultaneous binding of antigen and protein L to a given immunoglobulin molecule. The complex formation is detected utilizing time-resolved Förster resonance energy transfer between antigen-attached donor and acceptor-labeled protein L, hence the name LFRET. Here, we demonstrate that urine can be used as a sample matrix in LFRET-based serodiagnostics. We studied urine samples collected during the hospitalization and recovery of patients with acute Puumala orthohantavirus (PUUV) infection. We compared PUUV antibody-specific LFRET signals in urine to those in plasma, and found excellent correlation in the test outcomes The LFRET test from urine was positive in 40/40 patients with acute PUUV infection. PUUV causes a mild form of hemorrhagic fever with renal syndrome, characterized by acute kidney injury and proteinuria. Immunofluorescence and western blotting demonstrated PUUV-IgG and -IgA in urine, however, the presence of intact immunoglobulins did not fully explain the LFRET signals. We purified free light chains (FLCs) from both urine and serum of healthy volunteers and patients with acute PUUV infection, and verified the presence of antigen-specific FLCs. Antigen-specific FLCs provide a new means for non-invasive antibody detection and disease diagnosis.

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.