Kappa Free Light Chains Research Articles

Prevalence of Clonal Hematopoiesis in Patients with Monoclonal Gammopathy of Undetermined Significance

INTRODUCTION: Clonal hematopoiesis of indeterminate potential (CHIP) is defined by the expansion of progeny derived from hematopoietic stem cells (HSCs) that have acquired somatic mutations at a VAF greater that 2%. CHIP manifests in 10% of patients older than 65 and is associated with an increased risk of progression to hematologic malignancies such as the myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Although the risk factors for developing CHIP remain incompletely defined, they include prior exposure to chemotherapy and a history of smoking. Monoclonal gammopathy of undetermined significance (MGUS) is characterized by the abnormal growth of clonal plasma cells in the bone marrow and carries a risk of 1% for progression to multiple myeloma (MM) per year. Like CHIP, it becomes more prevalent with age and has been associated with smoking. Additionally, patients with MM have been demonstrated to have an increased risk for myeloid malignancies. Thus, an examination for a correlation between CHIP and MGUS promises to reveal a link between these two pre-malignant conditions. However, a recent study did not demonstrate such an association, but this study was performed in a very elderly population and may not be applicable to younger patients. In this study, we aim to assess the relationship between CHIP and MGUS in a population-based cohort of MGUS patients seen at UT Southwestern Medical Center. METHODS: To evaluate an association between CHIP and MGUS, we collected bone marrow samples from 37 patients diagnosed with MGUS at UT Southwestern Medical Center. We employed a hybridization capture-based next generation sequencing assay in order to detect CHIP. We identified 24 genes known to cause CHIP in adults. We also evaluated patients' risk for developing Multiple Myeloma after having been diagnosed with CHIP. RESULTS: The mean age of MGUS patients was 68, ranging between 26-92. 17 patients had IgG, 10 had IgA, five had IgM, and five had light-chain MGUS. We identified 18 mutations to validate the presence of CHIP in 10 (27%) patients, with the most frequent being in DNMT3A and TET2 (Fig. 1). Three out of the 10 patients harbored two mutations and one patient harbored four mutations. History of chemotherapy (n=6) and smoking (n=14) was taken into consideration to determine the relative risk of patients with MGUS developing CHIP. We found that those who had a prior history of smoking and chemotherapy displayed a higher risk of acquiring CHIP (Fig. 2). 54% of patients displayed high levels of serum kappa free light chains at the time of diagnosis. CONCLUSION: There was no significant association between CHIP and MM progression. Our analysis showed one patient with CHIP progression, and two patients without CHIP progression. Because the rates of CHIP and MGUS are positively correlated with characteristics like aging and a history of smoking, we expected to see relatively high rates of CHIP in patients within our cohort. However, our data suggests that CHIP is frequent (27%) in MGUS patients, but larger future cohorts need to be evaluated to validate this association. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Infectious Complications and Their Relationship with Mortality in Patients Newly Diagnosed with Multiple Myeloma

INTRODUCTION. Early mortality after diagnosis of Multiple Myeloma (MM) is common and frequently associated with infections. A Danish study reported a mortality of 22% among the first 180 days with infections being responsible for 50.9% of deaths. Treatment for MM has been related with infections in some studies, but this data is not consistent. Infections typically occur during the first months after MM diagnosis and initiation of treatment. In Latin America there is a lack of information about infections in patients diagnosed with MM, with only one study reporting a prevalence of 35.9% within the first 6 months, and most of them, 67.3%, during the first 3 months. To describe infections and to evaluate potential risk factors associated with them could help to improve the care of patients with MM. METHODS We conducted a retrospective cohort from a tertiary referral center in Mexico City. We included patients diagnosed with MM according to the International Myeloma Working Group criteria, between January 2017 and December 2020. Baseline clinical characteristics, disease parameters and infections at or after the MM diagnosis were collected, as well as the etiologic agents and their outcomes. The primary outcome was to describe the infectious complications of patients with MM in the first 6 months after diagnosis. The secondary outcome was to identify risk factors for early mortality defined as death during the first 6 months after diagnosis. Baseline characteristics and infections were described using mean and standard deviation or median and interquartile ranges. For the secondary outcome, patients were analysed in two groups depending in the presence of infections or not. Comparisons between groups were made by chi square, Fisher's exact test, t-tests, and rank-sum test; multivariate analysis by means of a logistic regression was performed. Two-sided p-values of <0.05 were considered statistically significant. All analysis were performed using STATA version 15.1. RESULTS Eighty-two patients were diagnosed and included in the study in the specific period. Median age was 66.5 and 56% were male. Median follow-up time was 28.6 months; 49/82 (60%) developed > 1 infections, of which 33/49 (67%) were in the first 4 months after MM diagnosis and 16/33 patients (48%) experienced two or more episodes. Distribution of infections was as follows: lower respiratory tract (45%), urinary tract (24%), gastrointestinal tract (9%) and primary bacteriemia (6%). Bacteria were the most common etiologic agents. There were 3 cases of Clostridium difficile infection documented during the second and third episodes of infection. The mortality associated with this infection was very high (66%). High plasma cell infiltration in bone marrow aspirate (p=0.03), increased kappa free light chain concentration (p=0.02), lower hemoglobin concentration (p=0.003), decreased serum albumin (p=0.004) and high serum globulin concentration (p=0.04) were associated with infection. Alkylating agents were the only treatment associated with increased risk of infection (p=0.05). Overall mortality during the first 6 months was 11%. There was a significantly higher cumulative risk (46.4%) of early death in patients who developed infections, compared to those who did not. CONCLUSIONS. Sixty percent newly diagnosed MM developed infections during the first 6 months after diagnosis. The most common affected sites were lower respiratory tract, urinary tract, gastrointestinal tract and primary bacteriemia. Sixty-seven percent of the infectious episodes were developed among the first four months after the diagnosis. The most common etiologic agents were bacteria. There were two episodes of infections caused by candida SPP and three caused by influenza virus. Gram-negative bacteria were the most common bacteria isolated during the second and third episodes, with 3 cases of Clostridium difficile infection. Infections were responsible of 46.4% more early deaths in newly diagnosed MM patients compared to those that did not have infections. High tumor burden characteristics were associated with greater risk of infections. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

High TIM-3 Expression May Contribute to the Functional Impairment of Bone Marrow and Circulating Gamma Delta T Lymphocytes during the Progression of Multiple Myeloma

Introduction: The tumor microenvironment (TME) has a significant impact on the development and evolution of multiple myeloma (MM). Understanding the reciprocal interactions between aberrant clonal plasma cells and the TME is required to shed light on the mechanisms behind disease progression from early (monoclonal gammopathy of undetermined significance (MGUS)/smoldering MM (SMM)) to active disease. γδ T cells are among the bone marrow infiltrating cells that have both innate and adaptive immune cell features and play a significant role in cancer immunosurveillance. To date, however, their contribution to the evolution of MM remains unknown. To this aim, we investigated the role of γδ T cells in MM and its early stages, developing the first single-cell (sc) atlas of this population in this disease. Methods: CD3+ cells from the bone marrow of healthy donors (HD; n=3), MGUS/SMM patients (n=5), and active MM patients (n=9) were sorted and seeded into single drops using a Chromium instrument (10X genomics), and 12527 γδ T cells were analyzed using scRNAseq. To validate transcriptomic findings, we next isolated peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMCs) from healthy donors (n=4; PBMCs exclusively), MGUS/SMM (n=8), and MM patients (n=14) by density gradient centrifugation and performed flow cytometric analysis to evaluate the frequency, differentiation/exhaustion profile, and functionality of the two main γδ T cell subsets known as Vδ1+ and Vδ2+ T cells. Results: Bioinformatics workflow enabled us to identify 7 γδ T clusters: 2 naïve subpopulations (CD4-/CD8- and CD4+ γδ T cells), 2 GZMB effector/terminally differentiated subpopulations (CD8+/TIGIT+/LAG3+, TIM3+/CD27- and GNLY+/FTH1+ γδ T cells) and 2 GZMK memory subpopulations (GZMK+ and CXCR3+ γδ T cells). Surprisingly, we observed a decrease in naive γδ T cells (p<0.05), which was coupled with an increase in TIM3 expression as MM evolved (Figure 1). Notably, we found a decrease in Vδ2+ T cells compared to healthy donors (mean 2,3% HD vs 1% MGUS/SMM vs 1,3% MM; p<0.05), as well as an increase in the Vδ1+/Vδ2+ ratio throughout MM progression (mean 0,4 HD vs 4,4 MGUS/SMM vs 4,4 MM). The frequency of Vδ2+ T cells in MM patients was positively correlated with free kappa light chain serum levels (PB: r= 0.8303, p<0.01; BM: r= 0.7455, p<0.05), instead, Vδ1+/Vδ2+ ratio was inversely correlated (PB: r= -0.7455, p<0.05; BM: r= -0.8909, p<0.01). Furthermore, we confirmed by flow cytometry the predominance of effector memory (Vδ1+ T cells: mean 1,4% HD vs 2.2% MGUS/SMM vs 14,4% MM; Vδ2+ T cells: mean 22,1% HD vs 21,4% MGUS/SMM vs 41,7% MM; p<0.05) and terminally differentiated γδ T cells (Vδ1+ T cells: mean 28,2% HD vs 79,2% MGUS/SMM 72,8% MM; Vδ2+ T cells: mean 19,2% HD vs 42,8% MGUS/SMM vs 32,2% MM; p<0.05) in MM patients as compared to healthy donors, where naïve (Vδ1+ T cells: mean 53,7% HD vs 15% MGUS/SMM vs 5,8% MM; Vδ2+ T cells: mean 10,5% HD vs 14,1% MGUS/SMM vs 8,1% MM; p<0.05) and central memory populations predominated (Vδ1+ T cells: mean 16,5% HD vs 3.4% MGUS/SMM vs 6,8% MM; Vδ2+ T cells: mean 48,7% HD vs 42,8% MGUS/SMM vs 17,2% MM; p<0.05). Accordingly, the analysis of exhaustion markers corroborated the progressive increase of TIM3 expression (but not PD1) in both Vδ1+ (mean 5,65% HD vs 34,5% MGUS/SMM vs 36,4% MM; p<0.05) and Vδ2+ T cell subsets (mean 2,1% HD vs 22,8% MGUS/SMM vs 32,6% MM; p<0.05). Finally, we observed that the acquisition of this exhausted phenotype along MM evolution was associated with impaired functions of both Vδ1+ and Vδ2+ T cells with reduced TNF-α (mean 75,1% HD vs 14,4% MGUS/SMM vs 14,5% MM; p<0.01) and IFN-γ (mean 28,8% HD vs 7,02% MGUS/SMM vs 7,24% MM; p<0.05) expression after in vitro stimulation. Conclusions: These findings suggested that the upregulation of the immunosuppressive receptor TIM3 may play a role in destabilizing γδ T cells and inducing their dysfunction throughout the progression of MM. Furthermore, because PB-derived T cells mirrored the bone marrow landscape, monitoring them could provide a potential minimally invasive approach for identifying patients at high risk of progressing to symptomatic MM. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Kappa Free Light Chain Biomarkers Are Efficient for the Diagnosis of Multiple Sclerosis

Kappa free light chains (KFLC) seem to efficiently diagnose MS. However, extensive cohort studies are lacking to establish consensus cut-offs, notably to rule out non-MS autoimmune CNS disorders. Our objectives were to (1) determine diagnostic performances of CSF KFLC, KFLC index, and KFLC intrathecal fraction (IF) threshold values that allow us to separate MS from different CNS disorder control populations and compare them with oligoclonal bands' (OCB) performances and (2) to identify independent factors associated with KFLC quantification in MS. We conducted a retrospective multicenter study involving 13 French MS centers. Patients were included if they had a noninfectious and nontumoral CNS disorder, eligible data concerning CSF and serum KFLC, albumin, and OCB. Patients were classified into 4 groups according to their diagnosis: MS, clinically isolated syndrome (CIS), other inflammatory CNS disorders (OIND), and noninflammatory CNS disorder controls (NINDC). One thousand six hundred twenty-one patients were analyzed (675 MS, 90 CIS, 297 OIND, and 559 NINDC). KFLC index and KFLC IF had similar performances in diagnosing MS from nonselected controls and OIND (p = 0.123 and p = 0.991 for area under the curve [AUC] comparisons) and performed better than CSF KFLC (p < 0.001 for all AUC comparisons). A KFLC index of 8.92 best separated MS/CIS from the entire nonselected control population, with better performances than OCB (p < 0.001 for AUC comparison). A KFLC index of 11.56 best separated MS from OIND, with similar performances than OCB (p = 0.065). In the multivariate analysis model, female gender (p = 0.003), young age (p = 0.013), and evidence of disease activity (p < 0.001) were independent factors associated with high KFLC index values in patients with MS, whereas MS phenotype, immune-modifying treatment use at sampling, and the FLC analyzer type did not influence KFLC index. KFLC biomarkers are efficient tools to separate patients with MS from controls, even when compared with other patients with CNS autoimmune disorder. Given these results, we suggest using KFLC index or KFLC IF as a criterion to diagnose MS. This study provides Class III evidence that KFLC index or IF can be used to differentiate patients with MS from nonselected controls and from patients with other autoimmune CNS disorders.

A Rare Case of Amyloid Light Chain Amyloidosis with Extensive Hepatic Involvement

Abstract Introduction/Objective Amyloid light chain (AL) amyloidosis is a life-threatening disease entity, with an incidence of 10–15 per million per year in the USA. Amyloidosis is caused by the extracellular deposition of insoluble fibrillary amyloid protein resulting in multiorgan damage. Though amyloidosis is primarily a systemic disease, 10%-20% of cases can be localized. Methods/Case Report We present a case of a 37-year-old male admitted with predominant hepatic manifestations, whose liver biopsy led to the diagnosis of amyloidosis. The patient presented with intermittent abdominal pain, weight loss, persistent hypoglycemia, hepatomegaly, and raised liver enzymes. Imaging studies showed hepatomegaly with a heterogeneous lace like appearance of the liver parenchyma. Liver biopsy revealed an extensive deposition of amyloid protein in peri-sinusoidal spaces. The amyloid protein is highlighted by crystal violet stain and revealed apple- green birefringence on polarized microscopy after Congo red staining. On further evaluation, elevated kappa and lambda free light chains with increased kappa-lambda ratio were identified by serum protein electrophoresis. Subsequent bone marrow aspirate and biopsy identified a monoclonal kappa positive plasma cell neoplasm with an amorphous eosinophilic infiltrate. Liquid chromatography-tandem mass spectrometry on bone marrow biopsy detected a peptide profile consistent with AL (kappa) type amyloid deposition. Results (if a Case Study enter NA) NA. Conclusion AL amyloidosis patients with predominant hepatic involvement have a worse prognosis. Rapid diagnosis and prompt clinical intervention prevents further organ damage. This case study aims to promote awareness of the unusual presentations of amyloidosis.

A novel and robust approach to defining population-based reference ranges for a serum free light chain assay in a clinical laboratory

Abstract Serum protein electrophoresis and immunofixation are used to detect the presence of monoclonal heavy and light immunoglobulin chains for the diagnosis of plasma cell neoplasms (PCN). In conjunction, the Freelite® assay has been used to detect excess free kappa and lambda light chains produced by PCN, where the kappa:lambda free light chain ratio (KLR) serves as a surrogate marker of clonality and disease. The manufacturer-defined KLR reference range of 0.26-1.65 is used in internationally recognized criteria for PCN diagnosis and monitoring, and KLR results affect clinical decision making, disease categorization, and response assessment. Our laboratory has verified the manufacturer-defined Freelite® KLR reference range three times using healthy control sera since assay implementation in 2006. Despite this, high percentages of abnormal KLR have consistently been observed among immunofixation-defined monoclonal-negative specimens. We therefore retrospectively interrogated 48,012 serum free light chain clinical results reported at our institution between 2010-2020 by extracting results from our laboratory information system and analyzing population distributions using the R programming language. For all specimens, the distribution of KLR values was shifted towards the towards the upper limit of the manufacturer-defined reference range, indicating that it poorly describes both our monoclonal-negative and monoclonal-positive patient populations. Furthermore, &amp;gt;80% of monoclonal-negative specimens exhibited KLR above the median of the manufacturer-defined reference range (0.26-1.65), while 24% (1,226/5,057) unexpectedly exhibited KLR &amp;gt;1.65. We found that this phenomenon has been present consistently since 2010 and is not affected by patient sex or age, impaired renal function, lot-to-lot variation, or assay drift. We therefore sought to establish an institution-appropriate KLR reference range by defining a reference population from within our existing dataset. We leveraged International Classification of Diseases codes, estimated glomerular function data, and serum/urine immunofixation results to exclude specimens from individuals with PCN- or renal-related diagnoses, impaired renal function, and prior, current, or subsequent monoclonal components. The resultant 1,536 monoclonal-negative reference specimens were then classified according to the manufacturer-defined KLR reference range, where 13% remained abnormally elevated, consistent with the published false positive rate in healthy volunteers. Lastly, we determined a new KLR reference range of 0.66-2.21 using the central 95% of KLR values from these reference specimens. When applied to our dataset, this institution-specific KLR reference range improved the accurate classification of specimens containing monoclonal free light chains by immunofixation, while reducing the false-positive rate in monoclonal-negative specimens. Together, our findings support the use of historical KLR and immunofixation data from routine clinical testing to derive institution-appropriate KLR reference ranges, which can then be used for continuous quality improvement. Implementation of this more-accurate KLR reference range should improve subsequent test utilization by non-specialist providers, reduce concern for/over-diagnosis of kappa-involved disease, and improve the detection and monitoring of lambda-involved disease.

Alpha Heavy Chain Disease Post-Diffuse Large B-cell Lymphoma Remission: A Series of Two Cases

Abstract Introduction/Objective Heavy chain disease is the production of abnormal monoclonal immunoglobulin heavy chains. Alpha heavy chain disease is typically identified in mucosa-associated lymphoid tissue lymphomas and is secreted due to chronic infection. The alpha heavy chain can manifest as hypogammaglobulinemia or a normal serum protein electrophoresis (SPEP). Broadband may appear in the alpha-2 or beta mobility regions. Methods/Case Report We describe two cases in which a monoclonal alpha heavy chain was detected in a 60-year-old female with diffuse large B-cell lymphoma (DLBCL) of the thoracic spine and a 71-year-old female with mediastinal DLBCL. Both patients achieved clinical and radiological remission. Results (if a Case Study enter NA) A distinct IgA band without an associated light chain was detected on the first patient's serum immunofixation essay (SIFE) one year later. For the second case, there was a distortion of the beta-2 region, elevated kappa free light chain (230.6 mg/dL), and a kappa to lambda free light chain ratio of 14.23, suggesting alpha heavy chain disease and a possible monoclonal gammopathy of unknown significance. Interestingly, even with a monoclonal IgA, the patients remained symptom-free, without any gastrointestinal manifestations, and concurrent PET scans show no recurrence. Conclusion To the best of our knowledge, these are the first two cases describing the presence of alpha heavy chain disease in association with DLBCL. The significance of alpha heavy chain secretion in patients with a history of DLBCL needs to be further assessed and we need to identify the possible presence of a non-clonally related paraprotein post-treatment for DLBCL.

Clinic-pathological characteristics of rare tubulointerstitial diseases.

Tubulointerstitial diseases is one of the common causes of renal dysfunction. Some rare pathological types are easy to be misdiagnosed and missedly diagnosed because of their low prevalence and relatively insufficient understanding, which affects the treatment and prognosis of patients. This study aims to explore clinical manifestations and pathological characteristics of several rare tubulointerstitial diseases, and therefore to improve their diagnosis and treatment. A total of 9 363 patients diagnosed by renal biopsy in the Department of Nephrology, Second Xiangya Hospital, Central South University from November 2011 to September 2021 were selected. Six cases of light chain cast nephropathy (LCCN), 2 cases of light chain proximal tubulopathy (LCPT), 1 case of LCCN with LCPT, 4 cases of genetic tubulointerstitial disease, and 6 cases of non-genetic related tubulointerstitial lesion were screened out, and their clinical manifestations and renal biopsy pathological results were collected, compared, and analyzed. Patients with LCCN presented with mild to moderate anemia, microscopic hematuria, and mild to moderate proteinuria. Compared with patients with LCPT, proteinuria and anemia were more prominent in patients with LCCN. Five patients with LCCN and 2 patients with LCPT had elevated serum free kappa light chain. Five patients with LCCN presented clinically with acute kidney injury (AKI). Two patients with LCPT and 1 patient with LCCN and LCPT showed CKD combined with AKI, and 1 LCPT patient presented with typical Fanconi syndrome (FS). Five patients with LCCN, 2 patients with LCPT, and 1 patient with LCCN and LCPT were diagnosed with multiple myeloma. Five patients with LCCN had kappa light chain restriction in tubules on immunofluorescence and a "fractured" protein casts with pale periodic acid-Schiff (PAS) staining on light microscopy. Immunohistochemical staining of 2 LCPT patients showed strongly positive kappa light chain staining in the proximal tubular epithelial cells. And monoclonal light chain crystals in crystalline LCPT and abnormal lysosomes and different morphological inclusion bodies in noncrystalline LCPT were observed under the electron microscope. Six patients with LCCN were mainly treated by chemotherapy. Renal function was deteriorated in 1 patient, was stable in 4 patients, and was improved in 1 patient. Two patients with LCPT improved their renal function after chemotherapy. Four patients with genetic tubulointerstitial disease were clinically presented as CKD, mostly mild proteinuria, with or without microscopic hematuria, and also presented with hyperuricemia, urine glucose under normal blood glucose, anemia, polycystic kidneys. Only 1 case had a clear family history, and the diagnosis was mainly based on renal pathological characteristics and genetic testing. Compared with patients with non-genetic related tubulointerstitial lesion, patients with genetic tubulointerstitial disease had an earlier age of onset, higher blood uric acid, lower Hb and estiated glomemlar fitration (eGFR), and less edema and hypertension. Renal pathology of genetic tubulointerstitial disease presented tubular atrophy and interstitial fibrosis, abnormal tubular dilation, glomerular capsuledilation, and glomerular capillary loop shrinkage. Glomerular dysplasia and varying degrees of glomerular sclerosis were observed. Genetic tubulointerstitial disease patients were mainly treated with enteral dialysis, hypouricemic and hypoglycemic treatment. Two genetic tubulointerstitial disease patients had significantly deteriorated renal function, and 2 patients had stable renal function. Patients with AKI or FS, who present serum immunofixation electrophoresis and/or serum free kappa light chain abnormalities, should be alert to LCCN or LCPT. Renal biopsy is a critical detection for diagnosis of LCCN and LCPT. Chemotherapy and stem cell transplantation could delay progression of renal function in patients with LCCN and LCPT. If the non-atrophic area of the renal interstitium presents glomerular capsule dilatation, glomerular capillary loop shrinkage, and abnormal tubular dilatation under the light microscopy, genetic tubulointerstitial disease might be considered, which should be traced to family history and can be diagnosed by genetic testing.

Accuracy of determination of free light chains (Kappa and Lambda) in plasma and serum by Swedish laboratories as monitored by external quality assessment

BackgroundFree light chain (FLC) measurements are important in diagnosing monoclonal gammopathies. As FLC are heterogeneous, different reagents and instruments for measuring FLC concentrations may give diverging results that affect assessment of patients with monoclonal gammopathies. Here we investigated agreement between different FLC methods using data from the Swedish external quality assurance (EQA) programme. MethodsThe two main FLC assays, N Latex FLC (Siemens) and Serum Freelite (The Binding Site), using four nephelometric or turbidimetric instrument platforms, were compared. Results from 27 EQA rounds distributed to 11–16 Swedish hospital laboratories during 2015–2020 were investigated. ResultsThe kappa (κ) FLC measurements deviated significantly over time, but when only nephelometry was used, deviation from the mean was lower (median ranges: −5% to 13 %). The CV was significantly higher for the Freelite assay (mean CV = 8.7) than for the N latex assay (mean CV = 5.7) (p < 0.0001). The coefficient of determination between all combinations of reagents and instrument platforms used was generally good (r2 = 0.76–0.87), and the correlation slope acceptable (0.81–1.2). For lambda (λ) FLC measurements, no concordance between combinations of instruments and reagents is apparent, deviating between −40 % to + 48 % from the mean. The CV was significantly higher for the combination with nephelometry and the Freelite assay (CV mean = 13.9 %) than nephelometry and the N latex assay (CV mean = 9.9 %) (p <0.001). The coefficient of determination varied between combinations of reagents and instrument platforms (r2 = 0.59–0.89) and the slope ranged between 0.48 and 1.5. Significant differences between the two reagents used were sometimes noted. ConclusionsImprecision in λFLC affects the κFLC/λFLC ratio. This may be important in clinical assessment of patients, especially differentiating between monoclonal and polyclonal gammopathies.

Saliva Free Light Chains in Patients with Neuro-Sjögren.

Background: Sjögren’s syndrome (SS) is an autoimmune disease characterized by sicca symptoms and various extra-glandular manifestations. The diagnosis of SS requires sicca symptoms, anti-SSA(Ro)-antibody positivity, and/or pathological focus scores on a minor salivary gland biopsy. Previous studies have investigated different biomarkers in order to avoid invasive diagnostic procedures. It was found that kappa and lambda free light chains (KFLC and LFLC) in saliva are specific for SS. Methods: FLC concentrations in saliva and serum were determined in 130 patients—50 with SS and neurological involvement (Neuro-Sjögren) and 80 neurological controls. The EULAR SS disease activity index and patient reported index (ESSPRI) were determined in patients with SS. Results: Patients with SS revealed increased pain and decreased saliva production according to the ESSPRI and Saxon test, respectively, with increasing FLC concentrations in the saliva. No significant differences in serum and salivary protein concentrations were observed between patients with SS and controls. Conclusion: KFLC and LFLC concentrations in saliva are not suitable to distinguish patients with Neuro-Sjögren and neurological control subjects, thus a diagnostic biopsy is still required. The association of salivary KFLC and LFLC concentrations with saliva production and ESSPRI pain score suggests a complex relationship between dryness and pain in patients with SS.

A CASE OF TYPE 1 CRYOGLOBULINEMIA PRESENTING WITH DIFFUSE ALVEOLAR HEMORRHAGE

A CASE OF TYPE 1 CRYOGLOBULINEMIA PRESENTING WITH DIFFUSE ALVEOLAR HEMORRHAGE

S3143 Rare Case of Plasma Cell Infiltration-Induced Cirrhosis

Introduction: Multiple myeloma (MM) is a type of malignancy that arises from the unorganized replication of plasma cells within the bone marrow. The overproduction of these cells damages systems throughout the body leading to early asymptomatic symptoms that can rapidly progress to systemic signs of disease. Liver involvement with MM is less common and generally occurs through plasma cell infiltration, light chain/amyloid deposition, and biliary obstruction. Though it can occur, the probability of it presenting near the time of diagnosis of MM is very rare and associated with poorer outcomes. Case Description/Methods: A 59-year-old male presented with generalized weakness, shortness of breath and weight gain. Physical exam showed sign of ascites and hepatomegaly. PMH was significant for esophageal cancer and a recent diagnosis of MM. No history of acute or chronic liver disease or cirrhosis risk factors. CT scan showed cardiomegaly, bilateral pleural effusions, pulmonary edema, and cirrhosis with abdominal ascites. Labs was unremarkable other than normocytic anemia. An echocardiogram showed mild reduced ejection fraction (47%) with speckle tracking suggestive of cardiac amyloidosis. Abdominal ultrasound confirmed appearance of cirrhosis, ascites, and right pleural effusion. Cirrhosis work up revealed negative hepatitis panel, normal alpha-1 antitrypsin, and normal ceruloplasmin. EGD was performed and ruled out extracellular vesicles (EV) but noted type I isolated gastric varices. Liver biopsy confirmed cirrhosis and showed portal tract damage with severe extensive plasma cell infiltration. Additionally, fragments of hepatic parenchymal showed disrupted lobular architecture by septal fibrosis and nodular formation. Immunohistochemistry was positive for CD3, CD20, CD5, BCL2, CD79a, and CD138 as well as increased lambda light chain compared to free kappa light chain. Despite extensive treatment including repeated thoracentesis and paracentesis, patient eventually developed in to decompensating liver cirrhosis (Figure 1). Discussion: In previous studies, plasma cell infiltration of the liver was seen in about 40% of cases of MM, but rarely lead to cirrhosis. This case is unique in that the patient had liver failure caused by cirrhosis and that it was some of the presenting symptoms. Whether due to masked signs or aggressive onset, the outcome for this diagnosis is poor and more specific factors observing liver function could have provided a more favorable outcome.Figure 1.: Cirrhosis secondary to plasma cell infiltration. Table 1. - Total Protein 5.0 g/dL Serum Ascites Albumin Gradient (SAAG) 1.9 g/dL Left Hepatic Vein Pressure 25 Hg Left Portal Vein Pressure 29 Hg Portosystemic Pressure Gradient 5 Hg EUS Guided Shear Wave Elastography of Liver 27 kPa

Evaluation of Free Light Chains (FLCs) Synthesis in Response to Exposure to SARS-CoV-2.

The aim of this study is to assess the synthesis of kappa (κ) and lambda (λ) free light chains (FLCs) in the serum of patients with COVID-19. All the 120 serum samples were collected from patients with COVID-19 and from healthy controls (vaccinated and non-vaccinated against SARS-CoV-2). FLCs, IgG total, IgG4, IgG anti-Nucleocapsid (N), anti-spike S1 receptor binding domain (S-RBD) antibodies and IL-6 were measured according to the manufacturers’ instructions. The concentrations of anti-N IgG, IgG total, IgG4 and IL-6 were elevated in the COVID-19 group in comparison to the vaccinated and non-vaccinated controls. The levels of anti-S-RBD IgG and κFLC were increased in COVID-19 and healthy vaccinated patients when compared to non-vaccinated controls. λFLC concentration was higher in the COVID-19 group than in the non-vaccinated group. The κ:λ ratio was lower in both COVID-19 and non-vaccinated groups in comparison to vaccinated controls. κFLC correlated with all tested parameters (anti-S-RBD IgG, anti-N IgG, λFLC, κ:λ ratio, IgG total, IgG4 and IL-6) except CRP, whereas λFLC correlated with all examined parameters except IgG4. Elevated levels of FLCs in COVID-19 and healthy vaccinated against SARS-CoV-2 patients, as well as the correlation between free light chains with specific anti-SARS-CoV-2 antibodies and IL-6, reflect hyperactivation of the immune system after contact with coronavirus. Furthermore, it seems that serum levels of FLCs might be used as predictive markers of COVID-19. Our findings suggest that free light chains are involved in SARS-CoV-2 infection. However, understanding the exact mechanism requires further investigation.

A method to obtain purified free light chain monomers and dimers from urine samples of patients with multiple myeloma

Antibody light chains are synthesized in excess by plasma cells, and this excess can be secreted into biological fluids as dimers or monomers in various proportions. Structural differences between monomers or dimers of free light chains (FLC) can affect their biological functions and possibly their pathogenicity. They also may exhibit differential immune reactivity, perhaps explaining discrepant quantifications when measured by different immunoreagents. Having purified FLC monomers and dimers available can be useful for studying their properties. Here we propose a simple preparatory procedure to purify FLC monomers and dimers from urine samples of patients with plasma cell disorders. Two representative urine samples containing lambda or kappa FLC were loaded into a nonreducing sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). The gel strips containing separate monomers and dimers were excised, electroeluted, and the FLC recovered. The FLC were recovered from SDS-PAGE gel in sufficient amounts to be quantified by UV and two automated nephelometric assays immunochemical. The procedure was found to be simple, reproducible, and with a high yield, thus offering the opportunity to compare different assays. Not all urine samples are suitable for this procedure, but this approach allows for the purification of FLC monomers and dimers from many selected urine samples which maintain their oligomeric organization.

Defining new reference intervals for serum free light chains in individuals with chronic kidney disease: Results of the iStopMM study

Serum free light chain (FLC) concentration is greatly affected by kidney function. Using a large prospective population-based cohort, we aimed to establish a reference interval for FLCs in persons with chronic kidney disease (CKD). A total of 75422 participants of the iStopMM study were screened with serum FLC, serum protein electrophoresis and immunofixation. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine. Central 99% reference intervals were determined, and 95% confidence intervals calculated. Included were 6461 (12%) participants with measured FLCs, eGFR < 60 mL/min/1.73 m2, not receiving renal replacement therapy, and without evidence of monoclonality. Using current reference intervals, 60% and 21% had kappa and lambda FLC values outside the normal range. The FLC ratio was outside standard reference interval (0.26–1.65) in 9% of participants and outside current kidney reference interval (0.37–3.10) in 0.7%. New reference intervals for FLC and FLC ratio were established. New reference intervals for the FLC ratio were 0.46–2.62, 0.48–3.38, and 0.54–3.30 for eGFR 45–59, 30–44, and < 30 mL/min/1.73 m2 groups, respectively. The crude prevalence of LC-MGUS in CKD patients was 0.5%. We conclude that current reference intervals for FLC and FLC ratio are inaccurate in CKD patients and propose new eGFR based reference intervals to be implemented.

Evidence for an Intrathecal Immunoglobulin Synthesis by Kappa Free Light Chains in Neurological Patients with an Isolated Band in Isoelectric Focusing.

The gold standard for detecting intrathecal immunoglobulin synthesis is the determination of the oligoclonal band (OCB) in the cerebrospinal fluid (CSF) using isoelectric focusing (IEF). Controversy still exists regarding the significance of an isolated band in the CSF. A highly promising alternative method for the assessment of intrathecal inflammation is the quantification of kappa free light chains (k-FLC). Our aim was to evaluate the clinical significance of quantitative k-FLC in patients with an isolated band in the CSF. Using the Human Kappa Freelite Mx Kit on a turbidimetric Optilite®, we quantified the k-FLCs in paired CSF and serum samples in 47 patients with a single band in IEF. We classified patients into 27× inflammatory neurological disorders (IND), 2× peripheral inflammatory neurological disorders (PIND), 9× non-inflammatory neurological disorders (NIND) and 9× symptomatic controls (SC) based on their medical diagnosis. k-FLC were below the lower measurement limit of the analyser (LML) in all SC and PIND, as well as in 8 out of 9 NIND and 11 IND. Only 1 NIND and 16 IND were above the LML, and of these, only 14 IND were above the upper discrimination limit (Qlim). A neuroinflammatory nature of the diseases can be indicated in many cases by positive k-FLC in patients with an isolated band in IEF. The measurement of k-FLC can support the diagnosis of neurological diseases if they are included in the routine work-up.

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.

Comparison of four medium cut-off dialyzers.

Recently, several pharmaceutical companies have developed new medium cut-off (MCO) dialyzers for expanded hemodialysis (HDx). This study aimed to compare the safety and efficacy of four MCO dialyzers, against each other and versus high-flux hemodialysis (HD) and post-dilution hemodiafiltration (HDF). A prospective study was carried out on 23 patients who underwent six dialysis sessions: two sessions with the FX80 Cordiax in HD and HDF, and four HDx sessions with the Phylther 17-SD, Vie-18X, Elisio HX19 and Theranova 400 dialyzers. The reduction ratios (RRs) of urea, creatinine, β2-microglobulin, myoglobin, kappa free immunoglobulin light chain (κFLC), prolactin, α1-microglobulin, α1-acid glycoprotein, lambda (λFLC) and albumin were compared. Dialysate albumin loss was also measured. The differences in efficacy between the evaluated dialyzers were minimal in small molecules and even up to the size of β2-microglobulin. The main differences were found between myoglobin, κFLC, prolactin, α1-microglobulin and λFLC RRs, in which all four MCO dialyzers, with similar efficacy, were clearly superior to HD and slightly inferior to HDF treatment. Albumin losses in the dialysate with HD dialyzers were <1 g and between 1.5 and 2.5 g in HDx and HDF. The global removal score values were similar in all four HDx treatments, and again significantly higher than those with HD. The results of the four MCO dialyzers evaluated in this study showed good efficiency, with no significant performance differences between them while being completely safe in terms of albumin loss. Likewise, the study confirms the superiority of HDx over high-flux HD with an efficacy close to that of post-dilution HDF.

Diagnostic Cerebrospinal Fluid Biomarker in Early and Late Onset Multiple Sclerosis.

Background: The intrathecal humoral response is the characteristic diagnostic finding in the cerebrospinal fluid (CSF) analysis of patients with multiple sclerosis (MS). Although the average age of MS patients increases, little is known about the sensitivity of diagnostic markers in elderly MS patients. Methods: In this retrospective two-center study, intrathecal free light chains kappa fraction (FLCk IF) and oligoclonal bands (OCB) were studied in a large cohort of patients with early and late onset relapsing (RMS) and progressive (PMS) MS. Furthermore, the humoral immune profile in CSF was analyzed, including the polyspecific intrathecal immune response measured as the MRZ reaction. Results: While the frequency of CSF-specific OCB did not differ between early and late onset RMS and PMS, the sensitivity of positive FLCk IF and absolute FLCk IF values were lower in PMS. The positivity of the MRZ reaction was equally frequent in early and late onset RMS and PMS. PMS patients had higher local IgA concentrations than RMS patients (p = 0.0123). Conclusions: OCB are slightly superior to FLCk IF in progressive MS in terms of sensitivity for detecting intrathecal immunoglobulin synthesis. The MRZ reaction, as the most specific parameter for MS, is also applicable in patients with late onset and progressive MS.