Lambda Free Light Chains Research Articles

A Case Report of a Prevertebral Mass in an Elderly Male Post Hodgkin's Lymphoma

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory autoimmune disease characterized by tissue infiltration by dense lymphoplasmacytic infiltrate composed of T cells, activated B-cells, and plasma cells expressing IgG4 and has varied presentations with similar histopathology. It can involve visceral organs, glands, aorta, lymph nodes, and retroperitoneal tissue. In our case, a 68-year-old male with a past history of Hodgkin's lymphoma and in remission presented for investigation of polyclonal gammopathy. Serum electrophoresis showed increased free kappa light chains, free lambda light chains, and kappa lambda ratio; immunoglobulin G (IgG) levels were also increased. A positron emission tomography (PET) scan and magnetic resonance imaging (MRI) thoracic spine suggested a hypermetabolic prevertebral soft tissue density. Biopsy of the mass suggested IgG4-related disease (IgG4-RD). He also had a compression fracture of the T7 vertebra. He was started on intravenous methylprednisolone and rituximab, following which he had a significant decrease in the size of the mass along with a decline in the levels of IgG, kappa, and lambda chains.

Serum Free Light Chain Quantification Testing: Comparison of Two Methods for Disease Monitoring.

Levels of free immunoglobulin light chains in serum and urine are a sensitive measure of dysregulated immunoglobulin synthesis. The development of an assay for free light chains in serum was a major advance in laboratory testing for monoclonal gammopathies. The original assay by The Binding Site, called Freelite®, has been in common use in laboratory monitoring of monoclonal gammopathies. Two clinical entities, myeloma-defining condition and light chain-predominant multiple myeloma, rely on quantitative measurements of serum free light chains. Using polyclonal antisera specific to free light chains, Diazyme Laboratories developed a latex immunoturbidimetric assay for quantification of human kappa and lambda serum free light chains. We evaluated the Diazyme assay by comparing the results of kappa and lambda free light chain quantification, and kappa/lambda ratio with the results on the same specimens by the Freelite method. We also compared the correlation of the 2 methods to evaluate response to treatment and to changes in clinical status of patients with multiple myeloma. The results of Freelite and Diazyme methods are comparable. There was no statistically significant difference in the performance of the 2 assays for quantification of light chains, kappa/lambda ratio, or correlation of clinical parameters from patients with multiple myeloma at various stages of monitoring the disease in 2 geographically diverse laboratory and clinical environments. The Diazyme method is comparable to Freelite and provides an opportunity to add the test to front-end automation and improvement in efficiency of the assay.

Application of cerebrospinal fluid free light chain in diagnosis of primary central nervous system lymphoma and monitoring of associated chemotherapy efficacy

BackgroundCerebrospinal fluid (CSF) free light chain (FLC) detection has been proposed as a tool for diagnosing primary central nervous system lymphoma (PCNSL), but there is no consensus on the appropriate reference range and its value for monitoring chemotherapy efficacy has not been investigated in Chinese PCNSL patients. We assessed the application potential of CSF FLC ratios for diagnosing PCNSL and monitoring associated treatment efficacy. MethodsKappa (κ) and lambda (λ) FLC were measured by nephelometry in CSF samples of patients with PCNSL (n = 45), other neurological diseases (n = 30), and normal controls (n = 60). Results of κ/λ FLC ratios (FLCr) were correlated with patients’ diagnoses and receiver operating characteristic analysis was used to determine accuracy. In PCNSL patients, FLCr analysis was compared between PCNSL before and after treatment. Resultsκ FLC and FLCr concentrations in PCNSL were significantly higher than in patients without PCNSL (P < 0.05). The optimal cut-off for FLCr was 0.35, with diagnostic sensitivity and specificity of 78% and 72%, respectively. FLCr concentrations decreased after chemotherapy. ConclusionCSF FLC is a novel biomarker for diagnosis and chemotherapy efficacy monitoring in PCNSL.

Combined Immunoglobulin Free Light Chains Are Novel Predictors of Cardiovascular Events in Patients With Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is characterised by the presence of B cells and immunoglobulins in the aortic wall, mainly in the adventitia. Kappa (κ) and lambda (λ) free light chains (FLCs) are produced from B cells during immunoglobulin synthesis. This study investigated the presence and prognostic value of combined FLCs (cFLCs or summed κ and λ) in patients with AAA. cFLCs were analysed by a turbidimetric specific assay in tissue conditioned media from AAA samples (n = 34) compared with healthy aortas (n = 34) from France and in plasma samples from patients with AAA (n = 434) and age matched controls (n = 104) selected from the Viborg Vascular (VIVA) AAA screening trial in Denmark. t test, logistic regression, and Cox regression were used to test whether plasma cFLCs serve as a marker for AAA presence and whether cFLCs were predictive of death, major adverse cardiovascular events (MACE), or major adverse lower limb events (MALE). Increased cFLC levels were detected in the AAA adventitial layer compared with the AAA medial layer and healthy media layer (13.65 ± 3.17 vs. 6.57 ± 1.01 vs. 0.49 ± 0.09 mg/L, respectively, p < .050). The upper tertile of plasma cFLCs was independently associated with AAA presence after correcting for confounders (odds ratio [OR] 7.596, 95% confidence intervals [CI] 3.117 – 18.513; p < .001). Of 434 patients with AAA, 89 (20.5%) died, 104 (24.0%) suffered MACE, and 63 (14.5%) suffered MALE, during a five year follow up. In univariable analysis, the cFLC upper tertile was associated with a higher risk of death, MACE, and MALE (p < .001 for all). After adjustment for confounders, cFLCs remained an independent predictor of all cause mortality (hazard ratio [HR] 4.310, 95% CI 2.157 – 8.609; p < .001), MACE (HR 2.153, 95% CI 1.218 – 3.804; p = .008), or MALE (HR 3.442, 95% CI 1.548 – 7.652; p = .002) for those in the upper tertile. Increased cFLCs are observed in adventitial tissue of patients with AAA, indicating local activation of B cells. Plasma cFLC levels are an independent predictor of death, MACE, and MALE in patients with AAA.

Defects and countermeasures in laboratory diagnosis of rare IgE multiple myeloma

BackgroundIgE multiple myeloma (MM) is a rare subtype of MM that is easily misdiagnosed. We report a rare case of IgE-MM and investigate the application of the SLiM-CRAB criteria to screen for high-risk smoldering MM (SMM) patients, so as to summarize the causes and methods used to prevent missed diagnosis or misdiagnosis in IgE-MM. MethodsThe serum monoclonal protein (M-protein) classification and IgE quantification was performed and sent to several individual institutions. The results were collected and the causes of IgE detection defects were analyzed. ResultsUpon admission to our hospital, the patient’s serum free kappa light chain was 1069.9 mg/L, free lambda light chain was 9.2 mg/L, and free kappa/lambda ratio was 115.9, which met the SLiM criteria, but without CRAB features. Immunofixation electrophoresis (IF) showed “M-like protein aggregation bands” in all lanes. After pretreatment with 1% β-mercaptoethanol to depolymerize the aggregation of monoclonal protein, the “M-like protein aggregation bands disappeared. The other five institutions did not provide the correct typing results. The quantification of serum IgE was as high as 2.06 × 107 IU/mL, whereas 7 other testing institutions reported IgE levels ranging from 1.0 to 1100 IU/mL. ConclusionHigh-risk biomarkers in SLiM criteria can achieve good therapeutic effects in rare IgE-MM patients. Serum immunofixation performed without antisera against IgE, insufficient identification of the lytic bands produced by high macromolecule aggregation in IF, and the absence of a prozone effect avoidance procedure during IgE quantitative detection are the primary causes of missed diagnosis or misdiagnosis in patients with IgE-MM.

MO174: Proliferative Glomerulonephritis with Monoclonal Immunoglobulin Deposits: Rare Disease with Poor Prognosis?

Abstract BACKGROUND AND AIMS Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMIDs) is a recently described disease among the spectrum of monoclonal gammopathy of renal significance (MGRS). The disease is renal limited and manifests with chronic glomerular disease, altered renal function and albuminuria, sometimes in the nephrotic range. Kidney injury results from direct glomerular deposition of the monoclonal immunoglobulin. Of note, in approximately 70% of the cases of PGNMID, a clone cannot be detected. METHOD Clinical case of PGNMID. RESULTS A 36-year-old woman, with a past history of acute glomerulonephritis, was treated with mycophenolate mofetil 2 g and concomitant methylprednisolone 2 mg from January 2020 to September 2021 (kidney biopsy was not performed). After 3 months, she showed recurrence of nephrotic syndrome: peripheral edema, severe weakness, shortness of breath, decreased diuresis up to oliguria and increased blood pressure. Blood analysis has shown: GFR 127 mL/min/1.73 m2, total protein 44.4 g/L, albumin 16.2 g/L; autoimmune markers—negative; kappa free light chains 182 mg/L (3.3–19.4 mg/L); lambda free light chains 112 mg/L (5.71–26.3 mg/L), ratio of kappa/lambda 1.63 (0.26 to 1.65). Urine analysis has shown: total protein excretion rate 3.5 g/24 h; albuminuria 1000 mg/g; urine microscopy—normal; kappa free light chains ++++; lambda free light chains +++. A kidney biopsy has shown up to 12 glomerulies, which have different sizes, some are enlarged, as due to diffuse proliferation of mesangial cells, oedema and segmental proliferation of endothelial cells, as fibrinoid changes; some of the capillary loops are infiltrated with monocytes, an uneven increase in the mesangial matrix, there are small areas of segmental sclerosis that tend to be nodular in some glomerulies. Degenerative changes (granular, vacuolar, in some areas hyaline-droplet dystrophy), necrosis of epithelial cell groups, areas of epithelial atrophy with thickening of the tubular basement membrane (up to 10% of the biopsy volume) are sharply expressed in the tubules. In the tubules—protein masses, exfoliated epithelium, the lumen of the tubules is sharply reduced and/or absent due to pronounced degenerative changes in the epithelium. In the stroma—edema, areas of interstitial fibrosis, including perivascular (up to 10% of the biopsy volume), focal lymphohistiocytic cell infiltrates. By definition, there is evidence of monoclonal deposits by immunofluorescence: IgA (predominantly), IgG, IgM, С3 deposits; С1q, CD20 (В- lymphocytes), AA amyloidosis -negative expression; kappa free light chains (predominantly) +++; lambda free light chains ++ (Figure 1). Finally, we reached a clinical diagnosis of CKD G1, A3: PGNMIDs (IgM, IgA, IgG; LC Ķ˃λ). Nephrotic syndrome. Light Chain Deposition Disease. At that point (January 2021), we have started clone-targeted chemotherapy following the data sheet, with urinary and haematological response after 2 weeks, and normal kidney function with complete remission of nephrotic syndrome after 4 weeks, as well as a negativization of kappa and lambda free light chains deposits (Table 1). Three months after admission, the patient maintained haematological and kidney remission up to now. CONCLUSION MGRS is not an independent kidney disease, not ‘chronic glomerulonephritis’, but a condition in which kidney damage is secondary to clonal B-cell proliferation. In other words, MGRS is a precancerous disease combined with chronic kidney disease that requires immediate treatment. Renal prognosis is poor, with progression to ESKD in 25% of patients within 30 months and frequent early recurrence on the renal allograft. However, recent studies indicate that clone-targeted chemotherapy may significantly improve renal outcomes, opening future perspectives for the management of this rare disease.

MO646: Effect of a High-Flux Dialyzer Applied to HFR Supra on the Removal of Large Uraemic Toxins in Haemodialysis Patients: Results from a Randomized Controlled Study

Abstract BACKGROUND AND AIMS HFR-Supra (haemodiafiltration with the regeneration of the ultrafiltrate) is a highly biocompatible dialysis technique characterized by an adsorptive resin cartridge with high protein-bound toxin adsorption capacity without removal of albumin, mimicking both glomerular and tubular functions. However, the low-flux dialyzer contained in the second diffusive stage of the HFR Supra system may hamper the removal of large uraemic toxins. This study assessed the large uraemic toxin removal ability of a new HFR system (HFR-H) which combines adsorption such as in HFR-Supra, with a high-efficiency high-flux haemodialysis membrane. METHOD In an open, randomized, cross-over, single-center, controlled study, 16 adult chronic haemodialysis patients were treated by haemodiafiltration with the regeneration of the ultrafiltrate with the HFR-Supra or the HFR-H system. All other dialysis parameters were kept constant in both study arms. All the treatments were delivered with Flexya dialysis monitor (Medtronic) in the middle-week session, lasting 4-h. The reduction rate (RR) of urea, creatinine, phosphate, β2-microglobulin, kappa (κFLC) and lambda (λFLC) free light chains and albumin, was intra-individually compared for the two dialysis types with linear mixed models. RESULTS The RRs for β2-microglobulin, κFLC and λFLC were significantly higher with the HFR-H system than those obtained with HFR-Supra (Figure). There were no significant differences in the RR for urea, creatinine, phosphate, interleukin-6 and albumin. CONCLUSION This study demonstrates that treating patients with an HFR-H instead of an HFR-Supra system significantly increases the elimination of middle and large molecules.

MO661: Elimination of Middle and Large Uraemic Toxins in Short Daily Home Haemodialysis with Low Dialysate Volume: A Randomized Crossover Clinical Trial

Abstract BACKGROUND AND AIMS Portable haemodialysis (HD) systems with a low dialysate flow rate in a short frequent schedule have become an attractive option for patients on home HD (HHD). Although these systems have been demonstrated to be effective for removing low weight molecular uraemic toxins, there are few data on their removal ability of higher molecular weight toxins. This study assessed the uraemic toxin removal ability of the portable Physidia S3 Monitor in a short, frequent, 5 days/week, low-dialysate flux HHD versus 3 days/week, in centre online haemodiafiltration (OL-HDF). METHOD In an open, randomized, cross-over, single-centre, controlled, prospective study, 40 adult chronic HD patients were treated by a 2.5-h low flux dialysate HD session or a 4-h post-dilution OL-HDF. All other dialysis parameters including dialyzer (polysulfone high-flux dialyzer NS 1.8, Toray®) were kept constant in both the study arms. The weekly reduction rate (RR) and the weekly eliminated mass into dialysate (EM) of urea, creatinine, phosphate, β2-microglobulin, kappa (κFLC) and lambda (λFLC) free light chains and albumin, were intra-individually compared for the two dialysis types with linear mixed models. RESULTS There were no significant differences in the RR for urea, phosphate, κFLC and albumin, whereas the weekly RRs for creatinine and β2-microglobulin were significantly higher with the Physidia S3 system than those obtained with OL-HDF (Table). Only the λFLC RR was significantly higher with OL-HDF. Similar results were observed when weekly EMs were compared (data not shown). CONCLUSION This study demonstrates that treating patients with low flow dialysate HHD in a short frequent schedule with Physidia S3 system, instead of 3 days/week, in-centre OL-HDF, significantly increases the weekly elimination of β2-microglobulin, enabling an adequate clearance of small and large uraemic toxins.

MO889: High Flux Dialyzer 2.6 M2 is Promising for Free Light Chains Removal in High Flux Hemodialysis and Hemodiafiltration

Abstract BACKGROUND AND AIMS Immunoglobulin light chains are classified as middle molecule uremic toxins and its removal through effective dialyzer is needed with less albumin loss. This study assessed the free light chains removal using dialyzer surface area (SA) 2.6m2 in high flux dialysis (HD) versus hemodiafiltration (HDF) and its relation to cumulative albumin loss. METHOD A cross-over study included 25 patients who underwent hemodialysis using dialyzer surface area 2.6 m2 in high flux HD followed by online post-dilution hemodiafiltration with washout period 2 weeks using high flux dialyzers (max 2.0 m2 SA). All patients were subjected to single session measurement of dialysate albumin every hour and pre-post dialysis Free light chains (FLC) kappa and Lambda by ELISA. RESULTS Dialyzer (SA) 2.6m2 showed significant reduction in post-dialysis kappa and lambda in comparison to pre-dialysis level in high flux hemodialysis and hemodiafiltration (P &amp;lt; 0.001). HDF showed higher kappa and lambda FLC reduction ratio (45.16 ± 6.53 ng/mL), (28.68 ± 4.36 ng/mL), respectively compared with high flux HD (29.52 ± 6.38 ng/mL), (19.48 ± 1.96 ng/mL), respectively (P &amp;lt; 0.001). HDF/HD fold change of kappa and lamda were (1.56 ± 0.23) and (1.48 ± 0.26), respectively. Patients on HDF dialysis had significant total albumin loss in dialysate [median (IQR) 2.47 (1.16) gm/dL] compared with high flux dialysis [median (IQR) 0.65 (0.64) gm/dL] with (P &amp;lt; 0.001). Maximum albumin loss in patients on HDF was in the first hour [median (IQR) 1.22 (0.59)] gm/dL with lower albumin loss in the next hours reaching median {0.17 (0.15) gm/dL} in the fourth hour. Trans-membrane pressure was positively correlated with total albumin loss in high flux hemodialysis and hemodiafiltration (r 0.443, p 0.027, r 0.745, P = 0.001), respectively. CONCLUSION High flux dialyzer 2.6 m2 (SA) is effective for free light chains removal especially with online post-dilution hemodiafiltration with acceptable albumin loss.

Effects of Medium Cut-Off Polyarylethersulfone and Polyvinylpyrrolidone Blend Membrane Dialyzers in Hemodialysis Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The use of medium cut-off (MCO) polyarylethersulfone and polyvinylpyrrolidone blend membrane is an emerging mode in hemodialysis. Recent studies have shown that MCO membranes exhibit a middle high molecular weight uremic toxin clearance superior to standard high flux hemodialysis. We conducted a systematic literature review and meta-analysis of randomized controlled trials to investigate whether MCO membranes efficiently increase the reduction ratio of middle molecules, and to explore the potential clinical applications of MCO membranes. We selected articles that compared beta 2-microglobulin (β2M), kappa free light chain (κFLC), lambda free light chain (λFLC), interleukin-6 (IL-6), and albumin levels among patients undergoing hemodialysis. Five randomized studies with 328 patients were included. The meta-analysis demonstrated a significantly higher reduction ratio of serum β2M (p < 0.0001), κFLC (p < 0.0001), and λFLC (p = 0.02) in the MCO group. No significant difference was found in serum IL-6 levels after hemodialysis. Albumin loss was observed in the MCO group (p = 0.04). In conclusion, this meta-analysis study demonstrated the MCO membranes’ superior ability to clear β2M, κFLC, and λFLC. Serum albumin loss is an issue and should be monitored. Further studies are expected to identify whether MCO membranes could significantly improve clinical outcomes and overall survival.

Combined Immunoglobulin Free Light Chains Are Novel Predictors of Cardiovascular Events in Patients With Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is characterised by the presence of B cells and immunoglobulins in the aortic wall, mainly in the adventitia. Kappa (κ) and lambda (λ) free light chains (FLCs) are produced from B cells during immunoglobulin synthesis. This study investigated the presence and prognostic value of combined FLCs (cFLCs or summed κ and λ) in patients with AAA. cFLCs were analysed by a turbidimetric specific assay in tissue conditioned media from AAA samples (n= 34) compared with healthy aortas (n= 34) from France and in plasma samples from patients with AAA (n= 434) and age matched controls (n= 104) selected from the Viborg Vascular (VIVA) AAA screening trial in Denmark. t test, logistic regression, and Cox regression were used to test whether plasma cFLCs serve as a marker for AAA presence and whether cFLCs were predictive of death, major adverse cardiovascular events (MACE), or major adverse lower limb events (MALE). Increased cFLC levels were detected in the AAA adventitial layer compared with the AAA medial layer and healthy media layer (13.65 ± 3.17 vs. 6.57 ± 1.01 vs. 0.49 ± 0.09 mg/L, respectively, p < .050). The upper tertile of plasma cFLCs was independently associated with AAA presence after correcting for confounders (odds ratio [OR] 7.596, 95% confidence intervals [CI] 3.117 - 18.513; p < .001). Of 434 patients with AAA, 89 (20.5%) died, 104 (24.0%) suffered MACE, and 63 (14.5%) suffered MALE, during a five year follow up. In univariable analysis, the cFLC upper tertile was associated with a higher risk of death, MACE, and MALE (p < .001 for all). After adjustment for confounders, cFLCs remained an independent predictor of all cause mortality (hazard ratio [HR] 4.310, 95% CI 2.157 - 8.609; p < .001), MACE (HR 2.153, 95% CI 1.218 - 3.804; p= .008), or MALE (HR 3.442, 95% CI 1.548 - 7.652; p= .002) for those in the upper tertile. Increased cFLCs are observed in adventitial tissue of patients with AAA, indicating local activation of B cells. Plasma cFLC levels are an independent predictor of death, MACE, and MALE in patients with AAA.

Synchronous plasma cell neoplasm and B lymphoblastic leukemia/lymphoma at initial presentation: first report of an unusual association with a good outcome.

A synchronous diagnosis of a plasma cell neoplasm (PCN) and a non-plasma cell hematologic malignancy is very rare. We report what we believe is the first instance of a synchronous PCN and B lymphoblastic leukemia/lymphoma (B-ALL) diagnosed at initial presentation. The patient underwent laboratory evaluation for an underlying plasma cell neoplasm, including immunology studies, bone marrow biopsy, and flow cytometry immunophenotyping. Serum lambda free light chain and serum IgG were elevated, with an IgG lambda M-protein identified by serum protein electrophoresis and immunofixation. The clinical working diagnosis was plasma cell myeloma. Bone marrow biopsy was positive for a composite PCN and B-ALL. The patient received treatment with VDT-PACE chemotherapy followed by autologous stem cell transplant and maintenance therapy with bortezomib/daratumumab and is in complete remission for both diseases 3.5years after diagnosis. This case not only adds to the known repertoire of hematologic neoplasms that can occur in association to a PCN, but also demonstrates that patients presenting with this rare combination of hematopoietic neoplasms can be effectively treated simultaneously with excellent responses. Additional research is warranted to understand the pathophysiology, to identify potential prognostic factors, and to develop specific therapeutic plans for these patients.

Эффективность адаптированного протокола комплексной иммуносупрессивной терапии «флударабин-циклофосфамид- дексаметазон-ритуксимаб» при лечении синдрома CLIPPERS (клиническое наблюдение)

CLIPPERS (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids) syndrome is a chronic lymphocytic inflammation of the pons with perivascular accumulation of contrast agent responding to glucocorticosteroid therapy (GCS). This immune- mediated brainstem lesion syndrome requires extensive differential diagnosis. The literature provides descriptions of CLIPPERS with delayed response to GCS or refractory to GCS. Such cases require a customized treatment tactics. In the clinical case of CLIPPERS presented by the authors, it was possible to achieve disease remission using an adapted chemotherapeutic protocol regimen "fludarabine-cyclophosphamide- dexamethasone-rituximab". During the follow-up, the patient did not have any disease relapses. Persistent immunosuppressive effect a year after therapy according to flow cytometry indicated effective inhibition of proinflammatory phenotypes of cellular components. The stabilization of the condition with the improvement of parameters according to the rating scales was noted. The study of cerebrospinal fluid 12 months after nonselective immune depletion indicated a decrease in the myelin basic protein content, normalization of lambda free light chains, the blood-brain barrier permeability and a change in the synthesis type from oligoclonal to polyclonal. The authors conclude that using this method, a long-term clinical, radiological and immunological remission of potentially any autoimmune process can be achieved. KEYWORDS: CLIPPERS, immunosuppressive therapy, fludarabine, rituximab, cyclophosphamide, immunosuppression, autoimmune disease. FOR CITATION: Polushin A.Yu., Zalyalov Yu.R., Tsynchenko A.A. et al. Efficacy of the adapted protocol of complex immunosuppressive therapy regimen "fludarabine-cyclophosphamide-dexamethasone-rituximab" in CLIPPERS syndrome (clinical case). Russian Medical Inquiry. 2022;6(10):580–588 (in Russ.). DOI: 10.32364/2587-6821-2022-6-10-580-588.

Transgelin-2 in Multiple Myeloma: A New Marker of Renal Impairment?

Transgelin is a 22-kDa protein involved in cytoskeletal organization and expressed in smooth muscle tissue. According to animal studies, it is a potential mediator of kidney injury and fibrosis, and moreover, its role in tumorigenesis is emerging in a variety of cancers. The study included 126 ambulatory patients with multiple myeloma (MM). Serum transgelin-2 concentrations were measured by enzyme-linked immunoassay. We evaluated associations between baseline transgelin and kidney function (serum creatinine, estimated glomerular filtration rate—eGFR, urinary markers of tubular injury: cystatin-C, neutrophil gelatinase associated lipocalin—NGAL monomer, cell cycle arrest biomarkers IGFBP-7 and TIMP-2) and markers of MM burden. Baseline serum transgelin was also evaluated as a predictor of kidney function after a follow-up of 27 months from the start of the study. Significant correlations were detected between serum transgelin-2 and serum creatinine (R = 0.29; p = 0.001) and eGFR (R = −0.25; p = 0.007). Transgelin significantly correlated with serum free light chains lambda (R = 0.18; p = 0.047) and serum periostin (R = −0.22; p = 0.013), after exclusion of smoldering MM patients. Patients with decreasing eGFR had higher transgelin levels (median 106.6 versus 83.9 ng/mL), although the difference was marginally significant (p = 0.05). However, baseline transgelin positively correlated with serum creatinine after the follow-up period (R = 0.37; p < 0.001) and negatively correlated with eGFR after the follow-up period (R = −0.33; p < 0.001). Moreover, higher baseline serum transgelin (beta = −0.11 ± 0.05; p = 0.032) significantly predicted lower eGFR values after the follow-up period, irrespective of baseline eGFR and follow-up duration. Our study shows for the first time that elevated serum transgelin is negatively associated with glomerular filtration in MM and predicts a decline in renal function over long-term follow-up.

188 Disarming the bomb in AL amyloidosis: a case report

Abstract Aims Light-chain amyloidosis (AL) is a rapidly progressive systemic disease commonly involving also the myocardium, with poor outcome if lately diagnosed and treated. Clinical presentation can be widely varied, ranging from unapparent disease with soft symptoms to acute heart failure syndromes, requiring urgent therapies and supports. Methods and results A 52-year-old women came to our outpatient cardiomyopathy clinic because of hypertrophic cardiomyopathy (HCM) suspicion. Family history included a paternal cousin with diagnosis of unspecified cardiomyopathy and cardiac arrest. Her medical history was unremarkable until few months ago, when she started to complain with palpitations and asthenia. Given that both electrocardiogram and echocardiogram had previously showed signs of left ventricular (LV) hypertrophy, she was referred to us for HCM evaluation. Our physical examination was unremarkable, in particular there were no signs of central or peripheral venous congestion. Electrocardiogram showed a diffuse strain pattern with inferolateral ST-depression and T-wave inversion. Echocardiogram showed a thicked interventricular septum (17 mm), a pseudo-normal transmitral filling pattern with mild increase of LV filling pressure (E/E′ 11), a severely dilated left atrium (51 ml/mq). To complete the diagnostic path for HCM, we asked for a cardiac magnetic resonance (CMR), which two months later gave to us the diagnosis of myocardial amyloid infiltration. The diagnosis was quite surprising, because the patient was fine, 6 min walking test assessed a good functional capacity (500 m), no heart failure signs were recorded. So, we sent the patient to perform bone scintigraphy, which showed Perugini 0 uptake, and blood exam, showing, instead, rise of lambda free light chains, cardiac troponin (41.5 ng/l) and NTproBNP (5318 ng/l). Patient was urgently referred to haematologists, who using bone marrow and fat pad biopsy diagnosed a multiple myeloma with stage IV sec. Mayo AL amyloidosis. (Cy)BorD therapy was started, reaching a complete response in 4 months. Conclusions Diagnosis of AL amyloidosis is tricky due to heterogeneous clinical onset and multi-organ involvement. Cardiologist community should be aware of this condition, phenotypically mimicking HCM, but with very different management, in order to favour early diagnosis, prompt referral and treatment initiation. This case teaches that only 1. clinical awareness and 2. multidisciplinary approach can lead to disarm the bomb in AL amyloidosis.

A Rare Case of Mild COVID-19 Disease Associated with Type 1 Cryoglobulinemia and Thrombotic Thrombocytopenic Purpura

Introduction:Type I cryoglobulinemia (Type I CG) usually develops in the setting of protein-secreting monoclonal gammopathies [1,2]. The estimated frequency of renal involvement is 30% in Type 1 CG. Thrombotic Thrombocytopenic Purpura (TTP) is a life-threatening disease in which there is a deficiency in ADAMTS13, a protease which normally functions to cleave von Willebrand factor (vWF). A deficiency leads to persistence of large vWF multimers and the formation of platelet-rich thrombi in the microvasculature. We present a case of 52 years old female with Type 1 CG and acquired autoimmune TTP secondary to mild Covid-19 disease.Case Report:A 52-year-old woman with medical history significant for CKD stage 2, with baseline creatinine (Cr) of 2.5, Diffuse Large B-Cell Gastric Lymphoma (DLBCL), in complete remission, and recent diagnosis with COVID-19 presented to the ED for evaluation of three days of a petechial rash on her bilateral extremities. Significant labs on arrival included hemoglobin (Hgb) 8.9, platelet count 65, Cr of 3.65, and K+ 6.6, meeting criteria for acute kidney injury (AKI). Peripheral blood smear showedthrombocytopenia and normochromic normocytic anemia with no schistocytes or microangiopathic changes. ADAMTS13 was 43% and there was no clinical suspicion for TTP. The patient's Cr continued to worsen up to 8.1 during admission, prompting renal biopsy. Renal biopsy showed Type 1 cryoglobulinemic glomerulonephritis with vasculitis and 30 to 40% fibrosis of glomeruli. The patient was started on systemic steroids, plasma exchange every 2-3 day (completed 6 sessions) and hemodialysis. Her platelet counts steadily increased to 212 but had a significant drop to 32 when rechecked seven days later, prompting further investigation. ADAMTS13 was rechecked and found to be 5% with presence of inhibitor, Hgb was 7.7, haptoglobin was <20, and a diagnosis of TTP was made. The patient was started on daily plasmapheresis, rituximab, Caplacizumab and high dose systemic steroid therapy. Our patient had prior history of DLBCL and was treated with radiation therapy. Restaging PET/CT and EGD with biopsy showed no evidence of recurrence. Bone marrow biopsy was negative for evidence of lymphoma. Several serologic tests were used to rule out other etiologies of Type I CG and came back negative including: SLE, HIV, hepatitis C, multiple myeloma, and Waldenstrom's macroglobulinemia. The patient had elevations in multiple immune markers including IgG, IgM, free kappa light chains, and free lambda light chains. She also had hypocomplementemia of both C3 and C4.Discussion:The relationship of Type I CG and COVID-19 is unclear, though viral infections can trigger autoimmune diseases [3]. Previously, all patients with Type I CG had either ahematologic malignancy, solid-organ malignancy, infection, or autoimmune syndromes. Interestingly, in our patient, several serologic tests were performed and negative, which ruled out these etiologies of Type I CG. Our patient's manifestation of Type I CG was petechial rash on extremities and acute on chronic renal disease. Specific treatment of CG can include plasma exchange, corticosteroids, rituximab, and hemodialysis, depending on underlying cause. Our patient was started on systemic steroids, plasma exchange every 2-3 days, and hemodialysis due to worsening renal functions. Despite cases of covid-19 and TTP being reported, the relationship between the disease processes remains unclear. COVID-19 infection can cause disproportionate activation of the complement system and lead to excessive coagulation and thrombotic events. Systemic infection can decrease ADAMTS-13 activity, and this has also been noted in COVID studies. ADAMTS-13 deficiency has no pathophysiologic relevance specific to Type 1 CG. Our patient developed anemia and thrombocytopenia, and ADAMTS13 activity testing was found to be 5% with presence of an inhibitor. Considered as high-risk disease, our patient was started on steroids, rituximab, Caplacizumab and daily plasmapheresis. Repeated weekly ADAMTS13 level was 26% and platelets were stabilized at 69k/microL.Conclusion:Suggests that Covid-19 virus has the capability to induce cryoglobulinemia through an unknown mechanism• There are two other case reports of an association between Covid-19 and TTP.• May be the first case indicating a possible association of Covid-19 with cryoglobulinemia. DisclosuresNo relevant conflicts of interest to declare.

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.

Lambda monoclonal free light chain abnormalities detected by a serum immunofixation electrophoresis assay are underrepresented by quantitative serum free light chain results

Abstract Protein and immunofixation (IFIX) electrophoresis are used to diagnose and monitor monoclonal gammopathies. While IFIX detects clonal production of intact immunoglobulins and free light chains (FLC), the latter can also be quantified using a serum free light chain (SFLC) assay, in which polyclonal antisera detects epitopes specific for free kappa (KFLC) or lambda light chains (LFLC). An abnormal KFLC: LFLC ratio (KLR) serves as a surrogate for clonality. While the SFLC assay is highly sensitive, normal LFLC (&amp;lt;2.63mg/dL) and KLR results (&amp;gt;0.26 &amp; &amp;lt;1.65) were found in samples with distinct lambda monoclonal free light chains visualized by IFIX (X-LMFLC). To investigate this discordance, contemporaneous SFLC or KLR values were evaluated for their ability to accurately classify monoclonal FLCs identified by IFIX. We performed a retrospective analysis of serum and urine IFIX (Sebia Hydrasys) and SFLC (Freelite®, Binding Site) results from our institution between July 2010 through December 2020, using R 4.0.2 and Tidyverse packages. From among 9,594 encounters in which a single monoclonal component was initially identified by IFIX, 157 X-LMFLC and 131 X-KMFLC samples were analyzed. Elevated LFLC with normal KFLC was identified in 105/157 X-LMFLC samples (67%), while both LFLC and KFLC were elevated in 42/157 samples (27%). Concordance between X-KMFLC and KFLC was markedly higher, where 122/131 samples (93%) displayed elevated kappa FLC (&amp;gt;1.94mg/dL) with normal LFLC, and only 7/131 X-KMFLC samples (5%) possessed both elevated KFLC and LFLC. The use of KLR to identify pathogenic monoclonal free light chains improved lambda concordance to 85%; however, 19/157 (12%) of X-LMFLC samples still exhibited normal KLR. High concordance of 98% was again observed for X-KMFLC with abnormal KLR. When samples were segregated according to normal or impaired renal function (eGFR &amp;gt; or ≤60mL/min/1.73m², respectively), this disparate identification of X-LMFLC and X-KMFLC by the SFLC assay persisted, suggesting that renal dysfunction (as measured by eGFR) does not underlie this phenomenon. Lastly, we corroborated the above findings in a larger sample population by examining patients with urine Bence Jones FLC identified by IFIX who had free or intact monoclonal components in serum (N=724), grouped by lambda or kappa light chain involvement. The cause(s) of the discrepant performance by the Freelite® SFLC assay, relative to the Sebia Hydrasys IFIX assay, for identifying lambda FLC components is currently unclear. Possible contributory factors include assay reference range cutoffs, other patient disease parameters, and differences in assay-specific polyclonal antisera. Future analyses of these factors will help to further characterize SFLC assay performance and elucidate how interpretation of composite serum FLC test results can be improved to better guide patient management.

Development of second primary multiple myeloma five years after treatment for limited-stage small cell lung cancer: a rare case report

Introduction. The development of a second primary malignancy (SPM) following small cell lung cancer (SCLC) has been previously reported in the literature. Especially smoking-related malignancy coupling is well known. The development of multiple myeloma (MM) in long-term survivors after treatment for SCLC is unknown. Here, we report the first case in the literature who developed MM 5 years after treatment for limited-stage SCLC. Case report. A 67-year-old male patient was diagnosed with limited-stage SCLC. After he received chemotherapy and radiotherapy, he was followed up without medication. He was admitted to the hospital with back pain and dyspnea 5 years after the diagnosis of small cell lung cancer. MRI revealed osteolytic lesions in the vertebrae. Laboratory testing revealed a markedly elevated serum IgA and an elevated serum beta-2 microglobulin level. Serum immunofixation revealed IgA lambda-type M-protein. Lambda excretion in urine immunofixation electrophoresis was observed. Bone marrow aspiration revealed the frequency of plasma cells to be 80% of all nucleated cells. Hence, the final diagnosis revealed IgA lambda free light chain MM. Treatment was given for multiple myeloma. In the follow-up, the patient experienced increased dyspnea and developed bilateral pleural effusion. The cytology sent from thoracentesis sampling was reported as plasmocyte-rich material. The patient fell into a coma and died in an intensive care unit. Conclusion. We presented the development of MM 5 years after treatment in a patient with SCLC who were treated for one year and then followed up with stable findings. It should be kept in mind that a patient with SCLC who is a long-term survivor and presents with back pain may have developed a primary malignancy originating from bone marrow rather than a bone metastasis. Patients should be advised smoking cessation after the treatment and diagnosis of SCLC. Also, the patients with SCLC who are long-term survivors should be closely monitored for the development of SPM.

Multiple myeloma: Detection of free monoclonal light chains by modified immunofixation electrophoresis with antisera against free light chains

IntroductionNeoplastic monoclonal gammopathies are frequently associated with production of excess free monoclonal light chains. A sensitive method for detecting free monoclonal light chains in serum could provide a marker for residual/minimal residual disease and as an adjunct to serum protein electrophoresis to serve as a screening method for monoclonal gammopathies. MethodsConventional serum immunofixation electrophoresis was modified by applying undiluted serum samples, and staining for serum free light chains with antisera specific to free light chains. Washing/blotting of gels was enhanced to remove residual proteins that did not bind to the antibodies including intact monoclonal immunoglobulins. Results from this modified immunofixation electrophoresis were compared with results from commercially available MASS-FIX/MALDI assay. ResultsMonoclonal free kappa light chains could be detected to a concentration of about 1.78 mg/L and monoclonal free lambda light chains to a concentration of about 1.15 mg/L without the need for special equipment. Comparison of these thresholds with parallel results from a commercially available MASS-FIX/MALDI assay revealed the modified electrophoretic method to be more sensitive in the context of free monoclonal light chains. ConclusionsModified serum immunofixation electrophoresis has been shown to detect low levels of monoclonal free light chains at a sensitivity suitable for the method to be used in detecting minimal residual disease, and potentially in a screening assay for monoclonal gammopathies. The disparity in the results with commercially available MASS-FIX/MALDI assay is postulated to be due to limited repertoire of reactivity of nanobodies of camelid origin.