Free Light Chain Levels Research Articles

Biomarkers in HCV-related mixed cryoglobulinemia patients withnon-Hodgkin lymphoma.

Chronic Hepatitis C virus (HCV) infection can cause severe extrahepatic manifestations, such as mixed cryoglobulins (MC), up to the development of B cell nonHodgkin's lymphoma (B-NHL). Mechanisms transforming of HCV infection into lymphoproliferative and/or autoimmune disorders are still poorly understood. In course of HCV infection, the sustained virus-driven antigenic stimulation may probably induce a B-cell clonal expansion. Measurements of serum free light chains (FLCs) levels, considered as a direct marker of B cell activity, are analyzed with increasing interest in clinical practice, for diagnosis, monitoring and follow-up of plasma cell dyscrasia. Syndecan-1 (CD138) is a transmembrane heparan sulfate proteoglycan expressed and actively shed by most myeloma cells. Membrane CD138 represents the major receptor protein for HCV attachment to the hepatocyte surface and high levels of circulating sCD138 levels are detected in patients at early stage of B-cell chronic lymphocytic leukemia. This study is aimed to evaluate sCD138 and FLC levels as diagnostic biomarkers of HCV-related MC with B-NHL. We enrolled 35 HCV-MC-NHL patients, characterized for the specific type of cryoglobulins, and 25 healthy blood donors (HBD) as negative control. Serum sCD138 levels were determined using ELISA kits specific for human sCD138. Serum FLCs were assessed by means of the turbidimetric assay. We found that serum levels of sCD138, as well as FLCs, were significantly higher in patients than in HBD (p<0.001). In agreement with the definition of HCV-driven lymphoproliferative disorders as the consequence of a multifactorial and multistep pathogenetic process, we suggest that sCD138 and FLCs could be considered putative independent markers of worsening progression of the disease.

Free light chain UV quantification compared with immunochemical measurement: How dimers and monomers may influence the results

Serum κ and λ free light chain (FLC) levels are important for the management of plasma cell disorders. Immunochemical measurements on automated platforms with different reagents occasionally return different results that make them not interchangeable. The reasons for this behaviour are not clear and it is not known which result is the most accurate. The aim of the study is to quantify naturally occurring FLCs with a reference method (UV absorbance) in a sample devoid of other sources of UV absorbance. This was possible on a particular urine sample containing only lambda FLC proteins, dialyzed to clear it from low molecular weight UV absorbing compounds. The sample was submitted to Fast Protein Liquid Chromatography separation with a size-exclusion column in order to separate the FLC monomers and dimers. FLCs were also measured with the Freelite and N Latex FLC methods and the results were compared. The results demonstrated that the amount of FLC calculated on the basis of UV absorbance was overestimated by both immunochemical methods, and that the amount measured by the two reagents was affected by the different proportions of dimers or monomers. The present findings may be useful for the comprehension of the immunochemical measurement of FLC.

High κ free light chain is a potential biomarker for double seronegative and ocular myasthenia gravis.

ObjectiveTo investigate the hypothesis that free light chain (FLC) sera levels could serve as a biomarker for myasthenia gravis (MG), especially for the subgroups of seronegative MG and ocular MG.MethodsSera from 73 patients with MG (20 seronegative for antiacetylcholine receptor [AChR] and anti–muscle-specific kinase and 53 positive for anti-AChR, which were clinically divided into 24 patients with ocular type, 45 with generalized type, and 4 with unequivocal clinical manifestation) and 49 healthy controls were studied for κ FLC and λ FLC levels with the Freelite human FLC kits.ResultsThe κ but not the λ levels of FLC were significantly increased in the patients with MG, including those with double seronegative MG and ocular MG, compared with the healthy controls. The specificity for double seronegative MG and ocular MG were both 98.0% when κ FLC was ≥25.0 mg/L. Increased κ FLC levels were not affected by the patient's sex, age at MG onset, the presence of thymic pathology, or different treatments.ConclusionsElevated serum κ FLC may serve as a biomarker for MG in suspected patients who are double seronegative and in those with only ocular manifestations when serology is inconclusive.Classification of evidenceThis study provides Class III evidence that high κ FLC levels distinguished patients with MG, including those who were double seronegative, from healthy controls.

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.

Hemodiafiltration with ultrafiltrate regeneration reduces free light chains without albumin loss in multiple myeloma patients

BackgroundAcute kidney injury (AKI) occurs in 12–20% of multiple myeloma (MM) patients. Several studies have shown a reduction of free light chains (FLC) using hemodialysis with High-Cut-Off membranes. However, this technique entails albumin loss. Hemodiafiltration with ultrafiltrate regeneration is a technique that includes a process of adsorption. The aim of this study was to evaluate the effectiveness of hemodiafiltration with ultrafiltrate regeneration in reducing FLC levels without causing albumin loss.MethodsThis is an observational study (2012 to 2018) including nine patients with MM (5 kappa, 4 lambda) and AKI. All patients were treated with chemotherapy and hemodiafiltration with ultrafiltrate regeneration. Blood Samples (pre and post-dialysis) and ultrafiltrate were collected pre and post-resin at 5 min after initiation of the session and 5 min before the end of the procedure.ResultsThe serum levels of kappa and lambda were reduced by a 57.6 ± 10% and 33.5 ± 25% respectively. Serum albumin concentration remained unchanged after the procedure. In the ultrafiltrate, the mean FLC reduction ratio shortly after initiation of the dialysis procedure was: 99.2 and 97.06% for kappa and lambda respectively, and only 0.7% for albumin; and at the end of the session the percent reduction was: 63.7 and 33.62% for kappa and lambda respectively, and 0.015% for albumin. Patients clinical outcome was: 33.3% recovered renal function, 22.2% died during the first year and 44.4% required maintenance dialysis.ConclusionsHemodiafiltration with ultrafiltrate regeneration reduces FLC levels without producing a significant loss of albumin; and, FLC removal is maintained throughout the session. Therefore, hemodiafiltration with ultrafiltrate regeneration may be considered an effective adjunctive therapy in patients with MM.

P0642EFFECTIVENESS OF HEMADSORPTION IN REDUCING FREE LIGHT CHAINS IN PATIENTS WITH MULTIPLE MYELOMA A.M.FOMIN, A.V.VATAZIN MOSCOW REGIONAL RESEARCH AND CLINICAL INSTITUTE. MOSCOW, RUSSIAN FEDERATION

Abstract Background and Aims Acute kidney injury is a frequent complication of multiple myeloma with unfavorable prognostic significance. The aim of the present study is to evaluate the effectiveness of hemadsorption to reducing free light chains (FLCs) in patients with multiple myeloma without replacement kidney therapy. Method The research was conducted for 6 patients ages 65- 74 with multiple myeloma. All patients were already suffering from a mild degree of renal insufficiency and elevated free light chains (4 kappa, 2 lambda). All patients didn’t have renal replacement therapy. Patients received VMP induction chemotherapy after two sessions of hemadsorption. The level of creatinine was from 198 µmol/l to 289 µmol/l. The glomerular filtration rate (eGFR) was from 34,8 to 21,3 mL/min/1,73 m2. The level of kappa FLC was 1714 – 5600 mg/L. The level of lambda FLC was 1575 – 3220 mg/L. In CytoSorb therapy, the blood is purified by adsorption in a procedure similar to hemoperfusion. The hemadsorption procedures were carried out on the AK10 device (Gambro, Sweden) with use of CytoSorb adsorbent cartridge. The content of the CytoSorb cartridge consists of a highly porous high-tech polymer. The patients were treated with 2 CytoSorb hemoadsorption treatments for 10 hours each separated and from one another by a pause interval of 12-14 hours. The blood flow rate was 130-160 ml/min. Anticoagulation was ensured by washing the bloodlines and a cartridge with a sorbent with normal saline with heparin – 4,000 units of activity per 1 L. 5,000 units of activity of heparin were injected intravenously at the beginning of the procedure. The FLCs, the level of creatinine and coagulogram test results of patients were studied prior to procedure and upon termination of procedure. Results An extracorporeal blood purification methods reduce elevated levels of FLCs. The cartridge with a total surface of&amp;gt;40,000 square meters, an adsorber is able to effectively and over time lower hydrophobic (water-insoluble) molecules that can be removed up to a size of 55kDa. FLC have high molecular weight (monomeric kappa of 22.5 kDa, dimeric lambda of 45 kDa). FLC removal, combined with chemotherapy may be associated with renal function recovery. As a result of hemadsorption after carrying out two procedures, there was a significant decrease in level kappa FLCs by 78.3 %, lambda FLCs by 64,0 %. All patients were dialysis independent. The level of creatinine decreased and the glomerular filtration rate increased. Other blood chemistry parameters did not show any changes. Throughout the treatment, the study did not show a decrease in dynamics of hemoglobin or platelets. There were not negative dynamics in change of INR (international normalized ratio), APTT (activated partial thromboplastin time), level of fibrinogen, prothrombin, or anti-thrombin III. No bleeding complication occurred in any patient during the procedure of hemadsorption. Other biochemical values did not change significantly. Conclusion The research showed that an extracorporeal blood purification method by CytoSorb therapy reduce elevated levels of FLCs in patients with multiple myeloma. The benefits of this modality need confirmation with a randomized controlled trial.

P1114HA-130 HEMOPERFUSION CARTRIDGE IN THE TREATMENT OF CAST NEPHROPATHY IN A 58-YEAR-OLD MALE WITH MULTIPLE MYELOMA: A CASE REPORT

Abstract Background and Aims Multiple myeloma is a plasma cell neoplasm that results in the production of monoclonal immunoglobulin. Renal failure is a common complication of multiple myeloma, occurring in approximately one-half of patients on initial presentation and is associated with increased mortality. Cast nephropathy in particular, is considered to be one of the major mechanisms of renal failure in multiple myeloma, and is characterized by precipitation of free light chains in the distal nephron, leading to intratubular obstruction, inflammation and fibrosis. Recent studies have demonstrated the use of extracorporeal methods such as plasmapheresis and high-cutoff membrane dialysis as an adjunctive therapy to chemotherapy in the management of cast nephropathy, however currently there are no existing guidelines in the use of extracorporeal therapies in the management of complications of multiple myeloma. Hemoperfusion is an extracorporeal treatment technique which utilizes adsorption in the removal of specific toxins. The HA 130 cartridge in particular has a resin pore size distribution of 500Da- 40 KDa and is able to remove molecules at 5-30kDa. In this case report we describe the use of HA 130 hemoperfusion cartridge in the treatment of cast nephropathy in Multiple Myeloma. Method A 58-year-old male, diabetic, non-hypertensive came in for 5-day history of generalized body weakness, associated with myalgia, lumbar pain and undocumented fever, with 1-day history of loose stools and vomiting. Upon admission blood tests done revealed anemia with a hemoglobin of 7.8g/dl, creatinine of 9.97mg/dL and potassium of 5.5mmol/L. He was diagnosed with acute renal failure and underwent hemodialysis on the second hospital day. On workup he had lytic bone lesions in the spine, pelvis and cranium on CT scan and x-ray. Serum Protein Electrophoresis (SPEP) and Serum Free Light Chain (sFLC) tests showed a monoclonal gammopathy. Serum beta 2 microglobulin was elevated at 12,618ng/ml. Free kappa and lambda light chains were also elevated at 19,250mg/L and 25.7mg/L, respectively. Bone marrow biopsy was done, with findings of markedly hypercellular marrow with 80% plasma cells confirming the diagnosis of Multiple Myeloma. Combined hemodialysis with hemoperfusion were done using HA 130 filter and hi flux dialyzer for 2.5 hours then hemodialysis for three times a week. Patient was also started on chemotherapy using Bortezomib with Dexamethasone for 2 cycles. Results Patient had a total of 14 sessions of combined hemoperfusion with hemodialysis. On repeat free kappa light chains decreased to 212.5mg/L. Patient was maintained on hemodialysis three times a week and was discharged after 55 hospital days. Outpatient hemodialysis was continued three times a week, and after 2 weeks, patient showed signs of renal recovery with a repeat creatinine of 2.1mg/dL. Four weeks after discharge, patient was independent of hemodialysis with a repeat creatinine of 1.3mg/dL. Conclusion This report highlights the use of hemoperfusion using HA 130 cartridge in combination with chemotherapy using Bortezomib in reducing free light chain levels in a 58-year-old male that developed renal failure secondary to cast nephropathy. Patient was able to achieve reduction in free light chain levels, improvement in renal function and eventually independence from hemodialysis four weeks after the last hemoperfusion treatment. Further studies using a randomized control trial on the use of hemoperfusion in directly reducing serum free light chain levels is recommended. The value of hemoperfusion on the rate of independence from hemodialysis, as well as survival rates among patients with renal failure secondary to multiple myeloma may also be worth investigating using larger studies.

P1072COMPARISON OF UREMIC TOXINS, INFLAMMATORY MARKERS AND VEGF LEVEL WITH MEDIUM CUT-OFF MEMBRANES AND HIGH-FLUX MEMBRANES IN HEMODIALYSIS: THERANOVA IN SISLI HAMIDIYE ETFAL (THE SHE) STUDY

Abstract Background and Aims Mortality in hemodialysis have not changed since last 30 years which may be caused by inflammation and accumulation of middle and large uremic toxins. Medium cut-off (MCO) membranes are able to perform hemodialysis as effective as hemodiafiltration. Their effect on inflammatory molecules and vascular endothelial growth factor-C (VEGF), an independent factor effective on mortality, are not well known. The aim of the study was to compare intra and inter dialyzer performances of MCO and high-flux dialyzers regarding middle and large uremic toxin, inflammatory marker, VEGF and serum albumin level. Method This is a randomized, prospective, open-label, cross-over study (ClinicalTrials.gov: NCT03836508) approved by local ethic committee. Patients had hemodialysis with either 36 sessions of high-flux dialyzer followed by 36 sessions of medium cut-off dialyzer or vice versa. Pre and postdialysis levels for urea, creatinine, albumin, total protein, free kappa light chain, free lambda light chain, beta-2 microglobulin, myoglobulin levels were determined at first and last sessions of every dialyzer. Postdialysis level of middle and large uremic molecules have been determined by a formula to prevent hemoconcentration effect. Reduction rate for uremic toxins were calculated. Serum level of human VEGF, fibroblast growth factor-23 (FGF-23), interferon gamma (IFN-g), interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-17A (IL-17A) levels were determined at first and last session of the each dialyzer. Results Fifty-two patients were enrolled to the study. Median age of patients was 56.40 (43.87-67.39) years. Median dialysis vintage was 4.77 (3.08-10.09) years. Reduction rates and postdialysis levels of free kappa and lambda light chain, myoglobulin, beta-2 microglobulin were lower both at first and last sessions in medium cut-off dialyzers compared to high-flux dialyzers (p&amp;lt;0.05 for all) (Table 1). Last session predialysis free kappa, free lambda, beta-2 microglobulin level was lower than first session predialysis levels in medium cut-off dialyzers (p&amp;lt;0.05 for all) (Table 2). Last session IL-6, IL-10, IL-17, IFN-gamma levels did not differ between dialyzers (p&amp;gt;0.05 for all). Vascular endothelial growth factor levels were 500.91 (363.80-679.15) pg/ml in medium cut-off group and 610.60 (450.63-1021.93) pg/ml in high-flux group (p=0,043). Predialysis serum albumin level at first session for MCO and high-flux groups were 3.88 (3.71-4.04) g/L and 3.75 (3.59-3.95) g/L, respectively (p=0.086) (Figure 1). After 3 months of hemodialysis, it was 3.62 (3.45-3.88) g/L in MCO group and 3.78 (3.58-4.02) g/L in high-flux group (p=0.04). Serum albumin level has decreased from 3.88 (3.71-4.04) g/L to 3.62 (3.45-3.88) g/L in 3 months during hemodialysis with MCO dialyzers (p=0.0001). It did not change significantly in high-flux group in the same time period (p=0.861). Conclusion MCO membranes not only decrease post dialysis levels of free kappa, free lambda, beta-2 microglobulin, myoglobulin but also decrease the third month predialysis levels of free kappa, free lambda, beta-2 microglobulin. They do not let the increase in myoglobulin level as seen in high-flux dialyzers. Even though the IL-6, IL-10, IL-17, IFN-gamma, FGF-23 levels did not differ, VEGF levels were lower in MCO dialyzer. The most important side effect of hemodialysis with MCO membranes is decreased serum albumin level.

P0631COMPLICATIONS OF TREATMENT WITH HIGH CUT OFF FILTERS FOR ACUTE KIDNEY INJURY SECONDARY TO MULTIPLE MYELOMA

Abstract Background and Aims Acute kidney injury is a frequent complication of MM that can affect 18 to 56% of patients and more than 10% end up needing dialysis. One of the drawbacks associated with the technique is attributed to the albumin loss. The other complications are related with the dialysis technique itself, especially infections, as highlighted by the Eulite study. The objective of the study is to check that there are no more complications in dialysis with High Cut Off filters than in conventional Hemodialysis. Method We are the referral hospital in our community in the treatment of acute kidney injury secondary to myeloma. We have performed 28 treatments of hemodialysis with High cut off filters (HD-HCO). The HD-HCO protocol includes daily dialysis session of 6 hours during the first 6 days to subsequently switch to dialysis every other dayuntil free light chains levels below 500 mg/L, or until the recovery of renal function allows the independence of dialysis. All these patients have a chemotherapy regimen based on Bortezomib (25 of the 28 treatments) and Dexamethasone (28 treatments). A retrospective analysis of the 28 treatments that are performed with HD-HCO after 8 years of experience (July 2011 to May 2019) to demostrate the presence of the same complications as the conventional Hemodialysis. Results Loss of albumin is one of the main drawbacks of the technique. Our patients had no changes in albumin levels due to the fact that our protocol includes the infusion of 2 vials of 20% albumin of 50 ml. at the end of each HD-HCO session. Figure 2 Another concern is intradialytic complications. We have reviewed this topic and our results show that patients in HD-HCO do not present a greater number of complications than those who dialyze with HD-HD or other conventional dialysis. The total number of sessions was 298. 21 patients developed hypotension (7%). The number of sessions in which the patient presented fever was 6 (2%), coagulation of the circuit occurred in 23 sessions (7,7%). The catheter dysfunction (when it does not allow to reach 250 ml/min of blood flow) in 26 times(8.7%) and only 13 times the replacement of the catheter (4.26%) was necessary, consequently, in those who required a greater number of dialysis sessions. In only 1 case (patient who required 27 sessions) to place a permanent Tesio catheter was necessary. Figure 1 In referring to complications of dialysis for AKI secondary to myeloma, few studies consider them. These studies focus on quantifying the reduction of light chains and the efficiency of the treatment, but don’t keep in mind the record of the complications. In the EuLITE study, authors observed a greater number of lung infections in the HD-HCO group (12 vs 3) p = 0.014 and attributed this difference to extended dialysis and albumin loss.We have not observed this problem. The levels of albumin are stable with our infusion protocol of 2 vials of 20% human albumin of 50 ml at the end of each HD-HCO. There’s no more complications than conventional dialysis, even infection ones. 13 febrile episodes occurred in 6 patients (more than 37,5ºC). Blood cultures were collected in all patients, being positive in only 4 patients. Germs found were: Escherichia coli (treated with Amoxicilin/clavulanic), Staphylococcus aureus (treated with Daptomycin), Staphylococcus epidermidis (treated with Meropenem) and Klebsiella pneumoniae (treated with Meropenem too). This 4 patients were the ones who required the replacement of the catheter. Conclusion 1. - Our findings indicate that the HD-HCO has the same safety profile as the conventional Hemodialysis. 2.- There is no serious infectious complications in our patients despite of the fact that all of them are immunosuppressed patients (AKI secondary to Multiple Myeloma in patients treated with chemotherapy)

P0463KIDNEY INVOLVEMENT IN PARAPROTEINEMIC DISEASES - ANALYSIS OF THE SINGLE CENTER REGISTER OF KIDNEY BIOPSIES

Abstract Background and Aims Kidneys are often damaged in paraproteinemic conditions. Paraproteins are monoclonal immunoglobulins or immunoglobulin fractions that are produced by a clonal population of B- or plasma cell lineage and can cause a variety of histological patterns of kidney injury, such as light chain (AL) amyloidosis or light chain cast nephropathy (LCCN). Monoclonal gammopathy of renal significance (MGRS) represents a group of disorders in which a monoclonal immunoglobulin secreted by B- or plasma cell clone causes renal damage. By definition, these disorders do not meet diagnostic criteria for overt, symptomatic multiple myeloma or a lymphoproliferative disorder, but in contrast to monoclonal gammopathy of undetermined significance (MGUS) there is evidence of end-organ damage that can warrant therapy. Method All patients with paraproteinemic kidney disease were identified by retrospective review of the Hospital Register of kidney biopsies done at Department of Nephrology and Dialysis, in Dubrava University Hospital, Zagreb, from 2009 until 2018. Every kidney biopsy was analyzed by light, immunofluorescent and electron microscopy. Laboratory findings, including serum protein electrophoresis, serum free light chain level and immunofixation of serum proteins, were done for every patient. Clinical and histologic features of patients and features of underlying hematological conditions were analyzed. Results We identified 47 patients (3,28% of all biopsies that were done in that period) with kidney disease with clear hematological background. The mean patients' age at the time of the biopsy was 63 years and 27 of them were females. Two patients had signs of direct infiltration of kidneys with malignant lymphomic cells (non-Hodgkin lymphoma) and were excluded from the analysis. Clinical presentation of the patients at the time of biopsy were: proteinuria in 85% of patients, full nephrotic syndrome in 55%, azotemia in 66% of patients (80% had acute kidney injury of unclear etiology) and hematuria in 12,7%. Most common histologic patterns of kidney injury were AL amyloidosis (45%) and LCCN (30%) but additionally 7 different histological patterns were found: light chain depostion disease, light chain proxymal tubulopathy, fibrillary and imunotactoid glomerulopathy, proliferative glomerulonephritis with monoclonal immunoglobulin deposition, crioglobulinemic glomerulopathy type I and tubulointerstitial damage caused by immunoglobulin deposition. Figure 1 shows main features of patients with AL amyloidosis and cast LCCN. Conclusion Kidney disease can be initial presentation of an underlying paraproteinemia and, as our data showed, can clinicaly present with acute kidney injury, nephrotic or subnephrotic range proteinuria or full nephrotic syndrome. Variety of histologic patterns of kidney injury were described and AL amyloidosis and LCCN were the most common histological findings. Detailed hematologic workup should follow kidney biopsy in order to determine the exact nature and extension of the disease and therefore the most appropriate therapy.

Pharmacodynamic (PD) responses drive dose/schedule selection of CC-92480, a novel CELMoD agent, in a phase 1 dose-escalation study in relapsed/refractory multiple myeloma (RRMM).

8531 Background: CC-92480 is a novel cereblon (CRBN) E3 ligase modulator (CELMoD) agent under investigation in a first-in-human phase 1 study (NCT03374085) in RRMM patients (pts). In preclinical studies, CC-92480 demonstrated efficient and sustained degradation of Ikaros/Aiolos leading to broad antiproliferative effects and induction of apoptosis in MM cell lines, and enhanced immune stimulatory effects. Methods: Eligible RRMM pts received escalating doses of CC-92480 + dexamethasone. Several dosing schedules were evaluated in parallel; more continuous with 4-day or 7-day breaks and intensive with longer breaks in a 28-day cycle. Peripheral blood and bone marrow aspirates (BMA) were taken before and during treatment at multiple time points. Levels of Ikaros/Aiolos in T cells, and effects on immunomodulation were assessed by flow cytometry. Weekly levels of free light chain (sFLC) and B-cell maturation antigen (sBCMA) were determined in serum during the first 2 cycles of treatment. BMA clots were analyzed by immunohistochemistry for CRBN, Ikaros, Aiolos, ZFP91, c-Myc, and IRF-4. Results: The rate and depth of Ikaros/Aiolos degradation in T cells increased with dose and reached maximal at ≥0.6 mg QD with sustained degradation over 24 hrs. Substrate recovery occurred during drug holidays with faster recovery at lower doses, and reached full recovery with ≥7-day break for all dose levels tested. B cells decreased with increasing dose, and T-cell proliferation was demonstrated at all doses/schedules. Substrate degradation was also evident in bone marrow plasma cells including in the setting of low CRBN levels. In these heavily pretreated, including triple-class-refractory, RRMM pts, CC-92480 dosing periods led to rapid and sustained decreases in sFLC and sBCMA. This was dose and schedule dependent and correlated with plasma exposure; the longer breaks in the intensive schedules led to rapid rebound of these markers, while the more continuous schedules maintained the depth of suppression. Conclusions: PD responses correlated with dose and schedule. PD samplings at multiple time points during treatment allowed dynamic changes and kinetics of each biomarker in all schedules to be followed and to inform next steps. Ikaros/Aiolos degradation and recovery, coupled with changes in sFLC and sBCMA, guided the adjustment of the dosing schedule during dose escalation in order to optimize efficacy and tolerability. The study is ongoing and selection of the recommended phase 2 dose is pending.

Biomarkers of minimal residual disease in rituximab-treated patients with mixed cryoglobulinemia.

Hepatitis C virus (HCV) represents the major risk factor for mixed cryoglobulinemia (MC), a small-vessel vasculitis that may evolve into an overt B-cell non-Hodgkin's lymphoma. Here, we aimed to identify a biomarker signature for the early diagnosis of minimal residual disease (MRD). We assessed free light chains (FLCs), IgM k,and IgM λ heavy/light chain (HLC) pairs, and vascular endothelial growth factor (VEGF) in sera from 34 patients with MC vasculitis (32 HCV- and 2 HBV-related), treated with low-dose rituximab (RTX). FLCs and IgM HLCs were measured by turbidimetric assay; VEGF by an enzyme-linked immunosorbent assay. After RTX, the positive (complete+partial) clinical and laboratory responses were of 85.29% and 50%, respectively; in contrast, the mean levels of FLCs, IgM HLCs, and VEGF were substantially unaffected in most patients and still above the normal range. In those achieving a reduction of FLCs and IgM k and λ chains values within the range of normality, we found that post-treatment free λ chains and IgM k values correlated with clinical and laboratory response. Our results suggest that high levels of FLCs, IgM HLCs, and VEGF could represent the signature of "dormant" B cell clones' activity that could be very useful to identify MRD indicative of possible relapse or worsening outcome.

The predictive value of serum free light chain level early after allogeneic hematopoietic stem cell transplantation for chronic graft-versus-host disease, a preliminary study.

Serum free light chain (FLC) level is closely associated with the functional state of B lymphocytes, and many studies have shown that delayed reconstitution of B lymphocytes contributed to chronic graft-versus-host disease (cGVHD). This study assessed the predictive value of FLC levels in serum collected early after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for cGVHD. Sixty-two patients who had undergone allo-HSCT were retrospectively reviewed. The correlations between the FLC levels and the development of cGVHD were explored. Of the 62 patients, 33 cases developed cGVHD, with the prevalence of 53.2%. With Seattle classification, 19 cases had limited cGVHD while 14 cases contracted extensive cGVHD. While with NIH classification, 17 cases had mild cGVHD, 6 cases moderate cGVHD, and 10 cases severe cGVHD. Multivariant statistical analysis showed that the FLC levels were not associated with all severities of cGVHD but were correlated with the development of extensive or moderate to severe cGVHD (P=.01 and .038, respectively). Serum FLC levels early after HSCT may reflect the functional state of B-cell reconstitution. Patients with low serum FLC Level early post-allo-HSCT tend to develop extensive cGVHD or moderate to severe cGVHD.

Impact of renal impairment on light chain amyloidosis outcomes after autologous hematopoietic stem cell transplantation

Light chain amyloidosis (AL) is a rare clonal plasma cell neoplasm characterized by the deposition of amyloid fibrils derived from the aggregation of misfolded immunoglobulin light chains in vital organs such as heart and kidneys resulting in irreversible organ damage (1). The severity of organ damage is the most important determinant of outcome. Both cardiac and renal staging systems have been proposed and validated as predictors of outcome. Cardiac staging system, initially developed and then revised by the Mayo Group, utilizes cardiac biomarkers (NT-proBNP, troponin T and I) and serum free light chain levels to stratify the patients (2,3). Renal staging system, developed by the Pavia Group, depends on the degree of proteinuria and glomerular filtration rates (GFRs) (4). Cardiac stage in general is a predictor of non-relapse mortality and overall survival, while renal stage is a predictor of renal recovery and dialysis dependence (2-4). Renal involvement is seen in approximately 70% of patients with AL (5). However, there are limited data on the impact of baseline renal dysfunction on the outcomes of AL after autologous stem cell transplantation (ASCT).

Serum free light chain level at diagnosis in myeloma cast nephropathy\u2014a multicentre study

Myeloma cast nephropathy (MCN) is a common cause of severe renal impairment in multiple myeloma (MM). The level of free light chain (FLC) that causes MCN varies substantially and there is uncertainty about the threshold level that should be used to inform clinical practice. In a multicentre cohort study of 103 patients with a diagnosis of MM and biopsy-confirmed MCN made between 2002–2014, we report prospectively measured levels of serum FLC at diagnosis obtained using a single nephelometric assay (Freelite®) and we explore the relationship between serum FLC level at diagnosis with renal outcome and patient survival. Using a landmark approach, overall survival (OS) was compared between patients who achieved independence from dialysis compared to those who remained dialysis dependent at 3-month, 6-month, 9-month, and 12-month time points. The median serum FLC level at diagnosis was 7531 mg/L (range 107–114600). Serum creatinine was 535 μmol/L (range 168–2993) and eGFR 7 ml/min/1.73 m2 (range 1–34). Six patients (5.8%) had an FLC level <1500 mg/L, which is the International Myeloma Working Group threshold for MCN and two patients were below the International Kidney and Monoclonal Gammopathy working group threshold of 500 mg/L; one was hypercalcaemic, and one had high-normal serum calcium level and had received a non-steroidal anti-inflammatory agent. Sixty-nine (67%) patients required haemodialysis treatment of whom 36 (52.1%) recovered independent renal function. Sixty-six (64%) patients died with a median OS of 2.5 years (95% CI 1.8–3.3). A landmark analysis revealed that independence from dialysis was associated with improved survival at 3-months (P = 0.003), 6-months (P = 0.035) and 9-months (P = 0.014); there was no survival benefit observed beyond 12 months (P = 0.146). Serum FLC level at diagnosis was neither associated with renal function recovery nor with OS. This is the largest reported cohort of patients with biopsy-confirmed MCN and prospectively measured serum FLC levels. These results indicate that a serum monoclonal FLC > 500 mg/L should be considered the threshold level associated with the development of MCN.

Outcome and characteristics of non-measurable myeloma: A cohort study with population-based data from the Swedish Myeloma Registry.

We describe survival in patients with oligo- and non-secretory multiple myeloma (MM). We refer to the whole group as non-measurable MM and compare it with secretory MM. Oligo-secretory MM was defined as M protein in serum <10g/L and M protein in urine <200 measured as mg/day, mg/liter or mg/mmol creatinine. If patients had no M protein, they were defined as non-secretory. The groups were also subdivided by Free Light Chains (SFLC) level and ratio. Out of 4325 patients with symptomatic MM in the Swedish Myeloma Registry during 2008-2016 eligible for the study, 389 patients (9%) had non-measurable MM. Out of these, 253 patients (6%) had oligo-secretory and 136 (3%) had non-secretory MM. Median survival for secretory MM was 42.7months, non-measurable MM 40.2months, oligo-secretory MM 38.6months, and non-secretory MM 44.6months. Difference in overall observed survival was non-significant for all groups when compared with secretory MM. Within non-secretory MM, stem cell transplantation (SCT), 95% being auto-SCT, was significant for superior survival in multivariate analysis (HR 0.048. P=.0015). In this population-based study, we found no difference in survival between oligo- or non-secretory MM when compared with secretory MM. SCT appears to be important also for patients with non-secretory disease.

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。

UTILITY OF SERUM AND URINARY FREE LIGHT CHAINS AS NON-INVASIVE BIOMARKERS OF ACTIVITY IN LUPUS NEPHRITIS

BACKGROUND: Current laboratory biomarkers for lupus nephritis like proteinuria, urine protein to creatinine ratio, creatinine clearance, anti-ds DNA and complement levels lack sensitivity and specificity for predicting disease activity and damage. Free light chains (FLCs) released in circulation during antibodies production play a key role in the pathogenesis of autoimmune diseases. Expression of serum and urinary FLCs in lupus nephritis can act as non-invasive diagnostic and prognostic indicators and alleviate the dependency on the invasive procedure of biopsy to guide management. AIMS & OBJECTIVES: Present study intends to adjudge the implications of serum and urinary FLCs as non-invasive biomarkers of disease activity in lupus nephritis. MATERIALS & METHODS: Histomorphological diagnosis of lupus nephritis was done as per ISN-RPS classification. Cases were divided into 2 subgroups, classes I/II and III/IV in accordance with low to high histological grades and activity/chronicity scores. Concurrent serum and urinary FLCs levels were estimated by immunonephelometry and correlated with clinical presentation and histological grades of lupus nephritis. Control cases were selected from a pool of other native renal diseases with a non-immunological basis. RESULTS: Urinary kappa and lambda FLCs were significantly elevated in lupus nephritis class III/IV as compared to class I/II and controls. Serum kappa FLCs exhibited significant/near significant increments on comparison of classes III/IV and I/II with controls, however, intra-comparison of classes I/II and III/IV was insignificant. Serum lambda FLCs showed significance only for the comparison of class III/IV with controls. CONCLUSION: Urine FLCs have definite potential to be established as a non-invasive biomarker of activity in lupus nephritis. The role of serum FLCs needs further validation.

The prognostic impact of monoclonal immune globulin and free light chain secretion in diffuse large B cell lymphoma (DLBCL)

We analyzed the prognostic impact of levels of free light chains (FLC) in 106 patients with DLBCL, selecting 61 patients with a monoclonal (M) protein in serum, and 45 patients without a M protein as an IPI-matched control group. Patients with a M protein had higher levels of FLC, but these were not of prognostic significance in this group. The presence of a M protein nullified associations of κ-FLC with several laboratory parameters indicating immune system activation observed in patients without a M protein. Patients without M protein and κ-FLC >50 mg/L had a significant inferior event-free survival (p = .004). The presence of M protein of an IgM type at diagnosis was a negative outcome predictor (p = .008), while a non-IgM M protein did not significantly impact on prognosis. In conclusion, the prognostic performance of the FLC assay is altered by the presence of a M protein.

Cerebrospinal fluid kappa and lambda free light chains in oligoclonal band-negative patients with suspected multiple sclerosis.

Cerebrospinal fluid (CSF) kappa free light chains (FLCs) may be a more sensitive marker of intrathecal immunoglobulin (Ig)G synthesis compared with oligoclonal bands (OCBs). Our aim was to retrospectively determine the additional value of the kappa and lambda index (CSF FLC/serum FLC)/(CSF albumin/serum albumin) in predicting a multiple sclerosis (MS) diagnosis in a group of OCB-negative patients with suspected MS. The CSF and serum kappa and lambda FLCs were tested using the Freelite kit (serum) and Freelite Mx (CSF) assay (The Binding Site Group, Bimingham, UK) in 391 OCB-negative patients with suspected/possible MS and in 54 OCB-positive patients with MS. The CSF kappa FLC levels were below the detection limit (0.27 mg/L) in 61% of patients. Using quantitative data, we found the best kappa index cut-off value for the prediction of MS to be 5.8. A kappa index ≥5.8 was present in 25% of OCB-negative MS (23/92) and in 98% of OCB-positive patients with MS. Using a qualitative approach and a kappa index cut-off of 5.9, based on literature data, we likewise found that 24% of OCB-negative patients with MS had a kappa index ≥5.9, compared with 5.4% of OCB-negative patients without MS (P<0.001). No reliable data could be obtained for the lambda index; lambda FLCs were below the detection limit (0.68mg/L) in 90% of CSF samples. The kappa index could contribute to the identification of OCB-negative patients with a high probability of an MS diagnosis. Using more sensitive techniques might even improve the diagnostic performance of the kappa index and better define the role of the lambda index.