Free Light Chain Research Articles

The Role of Monoclonal Antibodies in the Treatment of Myeloma Kidney Disease.

Renal failure is one of the most important manifestations of multiple myeloma. It is caused by renal lesions such as cast nephropathy, immunoglobulin deposition disease, AL amyloidosis or other glomerular and/or tubular diseases, mostly due to the toxic effect of free light chains in serum. Renal failure can represent a clinical emergency and is associated with poor outcome in newly diagnosed and relapsed/refractory multiple myeloma patients. Although progression-free survival and overall survival have improved with the introduction of novel agents, renal failure remains a challenge for the treatment of patients with multiple myeloma. Monoclonal antibodies are a component of therapy for newly diagnosed and relapsed/refractory patients and, based on clinical trials and real-world experience, are also safe and effective for subjects with renal failure, even if they are on dialysis. Most of the data are on anti-CD38 and anti-SLAM7 antibodies, but new antibody-drug conjugates such as belantamab mafodotin and bispecific antibodies also appear to be effective in myeloma kidney disease. In the future, we will have to face some challenges, such as defining new criteria for renal response to treatment, defining specific trials for these difficult-to-treat patients and integrating different therapeutic options.

Evaluating the complement C1q levels in serum and cerebrospinal fluid in multiple sclerosis patients: Could it serve as a valuable marker in clinical practice?

Immunohistochemical studies have identified complement component C1q in MS lesions. We aimed to compare serum (sC1q) and CSF (csfC1q) levels in a large cohort of MS patients (pwMS) (n = 222) with those of healthy controls (HC, n = 52), individuals with other immune (IND, n = 14), and non-immune neurological disorders (nIND, n = 15), and to analyze their correlation with other biomarkers.pwMS were divided into three series based on their origin. CSF samples were unavailable for HC. All three pwMS cohorts had lower sC1q levels compared to HC and IND. csfC1q was higher in one pwMS cohort, with a trend in another, and correlated with IgG, Free Kappa Light Chains, GFAP, and Chitinase-3 Like Protein-1 in CSF. Our findings suggest a significant role for C1q in MS pathophysiology, potentially serving as a biomarker for disease identification.

Impact of M-protein detection on the response evaluations of patients undergoing treatment with the IgG-κ monoclonal antibodies daratumumab or isatuximab, and discrepancies between immunofixation electrophoresis (IFE) systems and reagents.

Immunofixation electrophoresis (IFE) is the standard method for confirming the presence of a monoclonal protein (M-protein) at multiple myeloma (MM) diagnosis. IFE is also essential at assessment of complete response (CR) and stringent CR during treatment. As the CR assessment is influenced by daratumumab and isatuximab, HYDRASHIFT assays were developed. Samples from patients under treatment that included daratumumab or isatuximab were tested and monitored by IFE on the HYDRASYS system using HYDRASHIFT assays (HYDRASYS/HYDRASHIFT) and by IFE on the Epalyzer2 system (Epalyzer). The IFE using HYDRASYS/HYDRASHIFT avoided a false positive caused by drug-related IgG-κ and contributed to accurate assessment of CR. Furthermore, HYDRASYS/HYDRASHIFT detected small M-proteins at early relapse and detected free light chains (FLCs) in patients with renal impairment exhibiting high serum FLCs despite being often missed on Epalyzer. Sensitivity and specificity of M-protein detection vary greatly depending on the IFE system and reagents used.

Correlation between Morphological Typing and Monoclonality of Bone Marrow Plasma Cells and Its Diagnostic Value for High-Risk Smoldering Multiple Myeloma

To investigate the correlation between morphological typing and monoclonality of bone marrow plasma cells, and explore the diagnostic value of plasma cell morphological typing for high-risk smoldering multiple myeloma(HR-SMM). The correlation between the morphological characteristics and the monoclonality of bone marrow plasma cells was analyzed in 84 patients with HR-SMM who treated in our hospital. The consistency of morphologically abnormal bone marrow plasma cells with serum free light chain (sFLC) ratio, next-generation sequencing (NGS) detection results, and its correlation with monoclonal plasma cells detected by flow cytometry (FCM) were further verified. The immunoglobulin types and levels of non-involved immunoglobulins in serum of the patients were detected, and the distribution of plasma cell clusters in patients with different disease was observed. The mean percentage of mature plasma cells were decreased successively in the order of reactive plasmacytosis (RP) group, monoclonal gammopathy of undetermined significance (MGUS) group, smoldering multiple myeloma (SMM) group, HR-SMM group and multiple myeloma (MM) group; while the mean percentage of immature, primitive, reticular and flaming plasma cells were increased successively in the order of RP group, MGUS group, SMM group, and HR-SMM group, and the difference between any two groups was statistically significant (P < 0.05).The average proportion of abnormal plasma cells in the bone marrow of HR-SMM patients was 96.2% of the total plasma cells. The proportion of abnormal plasma cells were in good agreement with the sFLC ratio and the results of NGS detection in HR-SMM patients (kappa=0.879 and kappa=0.891, both >0.75)，and showed good correlation with the monoclonal plasma cells with immunophenotype of CD45-/CD38+/CD138+/CD56+/CD19-( γ=0.825). The levels of non-involved immunoglobulin in IgG, IgA and IgM type HR-SMM patients were all decreased by more than 25% compared with the normal reference range, and the differences were statistically significant (P < 0.05). There was no significant difference in the distribution ratio of plasma cell clusters among different disease groups (P >0.05). In HR-SMM patients, the immature, primitive, reticular and flaming plasma cells in bone marrow are considered as abnormal plasma cells, and they are correlated with monoclonal plasma cells. The proportion of abnormal plasma cells in total plasma cells of bone marrow and the reduction extent of non-involved immunoglobulin level in patients have certain reference value for the diagnosis of HR-SMM.

The Monoclonal Gammopathies of Renal Significance

Abstract As a heterogeneous group of diseases, monoclonal gammopathy is typical for older age and is characterized by the presence of paraprotein in serum and urine. In addition to damage to the bone marrow, other organs are also affected, whereas in the case of monoclonal gammopathy of renal significance (MGRS), the kidneys are dominant. The clinical presentation of MGRS is diverse depending on the type of renal monoclonal gammopathy. The basis of the diagnosis is the detection of free light chains in the serum, along with electrophoresis and subsequent serum immunofixation. The kappa and lambda serum light chain ratio is evaluated in patients with MGRS within modified reference parameters. A kidney biopsy provides information on the extent of renal parenchymal involvement. The basis of therapy is chemotherapeutics with possible autologous stem cell transplantation to preserve kidney function.

Implications of monoclonal gammopathy and isoelectric focusing pattern 5 on the free light chain kappa diagnostics in cerebrospinal fluid.

Oligoclonal bands (OCB) analysis is the reference standard for detecting an intrathecal IgG synthesis. Alongside OCB, free light chains kappa (FLCκ) are considered an additional sensitive biomarker for determining patterns 2 or 3, indicating intrathecal Ig synthesis. However, kFLC IF is not suitable for detecting a monoclonal pattern 5. The primary aim of this study was to evaluate the impact of incorporating FLCκ analysis into routine cerebrospinal fluid (CSF) diagnostics instead of OCB testing on the rate of missed monoclonal IgG detection. A two-center retrospective biomarker study was conducted. OCB were identified using isoelectric focusing in polyacrylamide gels followed by silver staining or in agarose gels followed by immunofixation. FLCκ were quantified using nephelometry and FLCκ assay (Siemens). Out of a combined total of 17,755 OCB analyses conducted between 2011 and 2021, a subset of 269 cases (1.5 %) exhibited pattern 5. 98 samples (36 %), which included 18 samples with intrathecal inflammation as determined by additional OCB pattern 2 were included in the FLCκ analysis. Of those, 16 (89 %) had intrathecal FLCκ synthesis. While FLCκ offers a promising avenue for detecting an intrathecal inflammation, the pattern 5, though rare, remains a valuable additional finding of OCB analysis. A combined approach of FLCκ and OCB analysis is recommended for a comprehensive assessment of the humoral intrathecal immune response.

Hemato-Renal Profile of Proliferative Glomerulonephritis with Monoclonal Immunoglobulin Deposits

Background Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is a rare entity classified under the umbrella of monoclonal gammopathy of renal significance. The clinical implications of circulating monoclonal immunoglobulin (MIg), light chain restriction on immunofluorescence (IF) microscopy, histopathological pattern, and type of therapy on renal outcomes are not clearly defined. Materials and Methods Sixteen patients of PGNMID diagnosed between 2013 and 2020 were included from a biopsy registry of 11,459 patients at a single center. Follow-up data was collected from electronic medical records until June 2021. Results The mean age of the cohort was 41.7 ± 13.5 years. Forty-four (7/16) percent showed monoclonal protein on serum or urine electrophoresis, 25% (3/12) had IgG kappa by serum immunofixation electrophoresis (IFE) and 38% (5/13) had abnormal kappa: lambda free light chain (FLC) ratio. The predominant light microscopy pattern, membranoproliferative glomerulonephritis (MPGN) was seen in 7/16 (43.7%) patients. The predominant heavy chain detected by IF microscopy was IgG (13/16, 81.3%). Kappa and lambda light chain restriction were seen in 56.3 (9/16) and 43.8 (7/16) percent of patients respectively. Circulating monoclonal kappa light chains were detected in 50 and 29% of kappa-PGNMID patients by IFE and FLC assay respectively. None of the lambda-PGNMID patients had detectable circulating monoclonal lambda light chains. Patients with circulating MIg had more proteinuria, lower estimated glomerular filtration rate, and a higher percentage of plasma cells on bone marrow biopsy. Thirty-eight percent of our cohort (5/13) progressed to kidney failure over a median (range) period of 3 (IQR, 1-7) months. Of these, 4/5 received immunosuppression, and 1/5 were treated with plasma cell-targeted chemotherapy. Conclusion PGNMID is a rare disease with a biopsy incidence of 0.1%. Only a quarter of patients with PGNMID have circulating MIg. Presence of circulating MIg, type of monoclonal light chain restriction in kidney biopsy, and type of therapy did not predict renal outcomes. Patients with MPGN pattern had favorable renal outcomes despite a higher degree of proteinuria at presentation.

Reference interval of free light chains ratio in patients with end-stage renal disease on chronic hemodialysis.

Not available.

Kappa index in the diagnostic work-up of autoimmune encephalitis

BackgroundThe presence of inflammatory changes in the cerebrospinal fluid (CSF), including immunoglobulin intrathecal synthesis (IS), can support the diagnosis of autoimmune encephalitis (AE) and allow prompt treatment. The main aim of our study was to calculate the Kappa index as a marker of IS, in patients with AE. MethodsCharts of patients undergoing a diagnostic work-up for suspected AE between 2009 and 2023 were reviewed and the Graus criteria applied. CSF and serum kappa free light chains were determined using the Freelite assay (The Binding Site Group) and the turbidimetric Optilite analyzer. ResultsWe identified 34 patients with “definite” AE (9 anti-NMDAR AE and 25 limbic AE) and nine patients with “possible” AE. Five patients (15%) with definite AE had pleocytosis and twelve (34%) showed CSF-restricted oligoclonal bands (OCB) at isoelectric focusing. The Kappa index was >6 in 29.4% and > 3 in 50% of the definite AE patients. It was elevated (>3) in 36.4% of patients with definite AE who resulted negative to OCB testing and was the only altered parameter suggestive of an ongoing inflammatory process in the CNS in three definite AE patients with otherwise normal CSF findings (i.e. normal cell count and protein levels, no OCBs). In the possible AE group, one patient had a Kappa index >3 in the absence of OCB. ConclusionsThe Kappa index could be useful, as a more sensitive marker of IS and as a supportive marker of neuroinflammation, in the diagnostic work-up of suspected AE.

Primary Sjögren syndrome specific B cells induced aberrant surface aggregation of B cell receptors (BCRs) and signalling

Primary Sjögren’s syndrome (pSS) is a systematic autoimmune manifestation of the exocrine glands caused by impaired lymphocytic infiltration, leading to dry eyes and xerostomia. The pathologic hallmark of this disease is the dysfunction of the exocrine glands, which results in dry eyes and mouth. Clinical observations suggest that B cells contribute to the pathogenesis of pSS through the enhanced secretion of autoantibodies, hypergammaglobulinemia, reduced free light chains, and a higher B cell lymphoma. Despite increased evidence of B cell hyperactivation and dysregulated B cell interactions in pSS, detailed speculations into the mechanism by which pSS-specific B cells exhibited abnormal BCR signaling repertoires and the magnitude of downstream signaling responses remain limited. Upon encountering antigens, B lymphocytes produce neutralizing antibodies by phosphorylating immune receptor tyrosine activation motifs (ITAMs). Despite these advancements, we still do not understand how pSS-specific B cells influence the surface clustering of BCRs and subsequent downstream immune responses. This paper hypothesizes that pSS-specific B cells encountering surrogate antigens will undergo a coordinated series of events that initiate B cell activation and spatiotemporal dynamics of BCRs. Additionally, we assume that pSS individuals have aberrant BCR repertoire and clonal expansion. In the future, these studies can provide detailed therapeutic entanglements for B cell-linked autoimmune and other hypersensitive disorders.

Prognostic Value of Left Ventricular 18F-Florbetapir Uptake in Systemic Light-Chain Amyloidosis

BackgroundPositron emission tomography/computed tomography (PET/CT) with 18F-florbetapir, a novel amyloid-targeting radiotracer, can quantify left ventricular (LV) amyloid burden in systemic light-chain (AL) amyloidosis. However, its prognostic value is not known. ObjectivesThe authors’ aim was to evaluate the prognostic value of LV amyloid burden quantified by 18F-florbetapir PET/CT, and to identify mechanistic pathways mediating its association with outcomes. MethodsA total of 81 participants with newly diagnosed AL amyloidosis underwent 18F-florbetapir PET/CT imaging. Amyloid burden was quantified using 18F-florbetapir LV uptake as percent injected dose. The Mayo stage for AL amyloidosis was determined using troponin T, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and free light chain levels. Major adverse cardiac events (MACE) were defined as all-cause death, heart failure hospitalization, or cardiac transplantation within 12 months. ResultsAmong participants (median age, 61 years; 57% males), 36% experienced MACE, increasing from 7% to 63% across tertiles of LV amyloid burden (P < 0.001). LV amyloid burden was associated with MACE (HR: 1.46; 95% CI: 1.16-1.83; P = 0.001). However, this association became nonsignificant when adjusted for Mayo stage. In mediation analysis, the association between LV amyloid burden and MACE was mediated by NT-proBNP (P < 0.001), a marker of cardiomyocyte stretch and heart failure, and a component of Mayo stage. ConclusionsIn this first study to link cardiac 18F-florbetapir uptake to subsequent outcomes, LV amyloid burden estimated by percent injected dose predicted MACE in AL amyloidosis. This effect was not independent of Mayo stage and was mediated primarily through NT-proBNP. These findings provide novel insights into the mechanism linking myocardial amyloid deposits to MACE.

Comparison of 2 Serum Free Light Chain Assays with Creatinine Normal and Abnormal Populations Demonstrates the Need for Standardization.

The objective of this study was to compare The Binding Site's Freelite on Optilite and Diazyme's Kappa/Lambda free light chains (K/L FLC) on Abbott Architect c8000 with healthy and renal insufficient populations and to evaluate their respective reference intervals for serum free light chains (sFLCs). Two hundred sixty serum samples were measured for creatinine and sFLCs by both assays and a subset by immunofixation electrophoresis. Verification of manufacturer-defined reference intervals was assessed. Kappa free light chains (KFLC) showed excellent correlation of 0.998 R2 with a slope of 0.73. For Lambda free light chains (LFLC), an acceptable correlation of 0.953 R2 was found with a slope of 1.50 as well as a skewness-based difference with a -12.70 intercept. Healthy estimated glomerular filtration rate (eGFR) ≥60 reference interval verification of central 95% could not be confirmed for either Freelite or Diazyme although LFLC was much closer than KFLC for both assays with Freelite KFLC recovering only 37% of values within reference interval claims. The K/L FLC ratio did not meet 100% claim for both Freelite (91%) and Diazyme (95%) among those with eGFR ≥60. Samples with eGFR ≤59 had increasingly higher levels of KFLC and LFLC for both assays. When comparing worsening eGFR status, Freelite recovered increasingly higher ratios while Diazyme recovered increasingly lower ratios. Healthy reference intervals could not be verified for either Freelite or Diazyme. Renal reference intervals for Freelite are currently warranted while they are not recommended for Diazyme. The differences between these 2 assays can be minimized by standardization efforts such as recalibration.

Diagnostic Utility of Free Kappa Light Chain Index in Egyptian Multiple Sclerosis Patients

Abstract Background Multiple sclerosis (MS) is a chronic autoimmune-mediated demyelinating disease of the central nervous system (CNS) that is usually associated with varying degrees of progressive disability. Free Kappa light chain (FKLC) has attracted growing attention as a significant diagnostic marker of MS. Aim of the Work The aim of this work was to study the diagnostic utility of free kappa light chain index in a sample of Egyptian MS patients versus IgG oligo clonal bands (OCBs) in CSF and serum in an attempt to throw light on a new simpler non subjective potential diagnostic marker in MS. Patients and Methods This was a case control study of MS patients carried at Ain Shams University Hospitals during the period from January 2021 till January 2022. Subjects included in this study were 30 patients with symptoms suggestive of MS yet undiagnosed and 20 controls, on the basis of their MRI findings, clinical presentation and according to the revised McDonald criteria 2017. Accordingly, patients were diagnosed as MS including 4 CIS patients, 18 RRMS patients and 3 PPMS patients and non-MS including 2 NMO patients, 1 ADEM patient, 1 APS and 1 SLE patient. They were 8 males and 22 female patients, their age ranged from 20 to 40 years old with mean 30.13 ± 6.85 SD. The control group included 5 males and 15 females; their ages ranged from 20 to 40 years with mean 30.13 ± 6.85 SD. Results We found a statistically significantly higher FKLC index and FKLC IF among MS patients in comparison to both control and non-MS group. it could be used for diagnosis of MS with a diagnostic sensitivity of 100 % and a diagnostic specificity of 100 %. Conclusion The significant association between FKLC index and MS led us to conclude FKLC index can be used as a promising diagnostic marker of MS.

Internalisation of immunoglobulin light chains by cardiomyocytes in AL amyloidosis: what can biopsies tell us?

Background Cardiac involvement in systemic light chain amyloidosis (AL) leads to chronic heart failure and is a major prognosis factor. Severe cellular defects are provoked in cardiac cells by tissue-deposited amyloid fibrils of misfolded free immunoglobulin light chains (LCs) and their prefibrillar oligomeric precursors. Objective Understanding the molecular mechanisms behind cardiac cell cytotoxicity is necessary to progress in therapy and to improve patient management. One key question is how extracellularly deposited molecules exert their toxic action inside cardiac cells. Here we searched for direct evidence of amyloid LC uptake by cardiomyocytes in patient biopsies. Methods We immunolocalized LCs in cardiac biopsies from four AL cardiac amyloidosis patients and analysed histopathological images by high resolution confocal microscopy and 3D image reconstruction. Results We show, for the first time directly in patient tissue, the presence of LCs inside cardiomyocytes, and report their proximity to nuclei and to caveolin-3-rich areas. Our observations point to macropinocytosis as a probable mechanism of LC uptake. Conclusions Internalisation of LCs occurs in patient cardiomyocytes. This event could have important consequences for the pathogenesis of the cardiac disease by enabling interactions between amyloid molecules and cellular organelles inducing specific signalling pathways, and might bring new insight regarding treatment.

A patient with AL amyloidosis presenting with refractory tuberculosis, chest tightness and hypotension: case report

IntroductionImmunoglobulin light chain (AL) amyloidosis presents a clinical spectrum characterized by diverse manifestations and involvement of multiple organs, posing a significant diagnostic challenge for physicians.Methods and resultsWe present a case of a patient admitted to our hospital due to recurrent cough and sputum, which was initially diagnosed as refractory tuberculosis. Throughout his hospitalization, the patient experienced distressing symptoms, including uncontrollable chest tightness, hypotension, and fever. Noteworthy observations included a persistent elevation in cardiac biomarkers, indicative of cardiac damage. Bronchoalveolar lavage revealed the presence of various pathogenic microorganisms, while bone marrow flow cytometry demonstrated the existence of clonal plasma cells. Additionally, the urine free light chain assay detected the presence of M protein, and the positive congo red staining of the abdominal wall fat biopsy confirmed amyloid deposition in the tissues. Taking into account the patient’s clinical presentation and the examination findings, we reached a conclusive diagnosis of immunoglobulin light chain (AL) amyloidosis.ConclusionThis case serves as a reminder for physicians to consider rare diseases like AL amyloidosis when patients present with symptoms involving multiple organ systems such as heart, lung and kidney that are unresponsive to conventional treatment options.

Myocardial Characteristics, Cardiac Structure, and Cardiac Function in Systemic Light-Chain Amyloidosis

BackgroundIn systemic light-chain (AL) amyloidosis, cardiac involvement portends poor outcomes. ObjectivesThe authors’ objectives were to detect early myocardial alterations, to analyze longitudinal changes with therapy, and to predict major adverse cardiac events (MACE) in participants with AL amyloidosis using cardiac magnetic resonance imaging (MRI). MethodsRecently diagnosed participants were prospectively enrolled. AL amyloidosis with and without cardiomyopathy (AL-CMP, AL-non-CMP) were defined based on abnormal cardiac biomarkers and wall thickness. MRI was performed at baseline, 6 months in all participants, and 12 months in participants with AL-CMP. MACE were defined as all-cause death, heart failure hospitalization, and cardiac transplantation. Mayo stage was based on troponin T, N-terminal pro–B-type natriuretic peptide, and difference in free light chains. ResultsThis study included 80 participants (median age 62 years, 58% men). Extracellular volume (ECV) was abnormal (>32%) in all participants with AL-CMP and in 47% of those with AL-non-CMP. ECV tended to increase at 6 months (median +2%; AL-CMP P = 0.120; AL-non-CMP P = 0.018) and returned to baseline values at 12 months in participants with AL-CMP. Global longitudinal strain (GLS) improved at 6 months (median −0.6%; P = 0.048) and 12 months (median −1.2%; P < 0.001) in participants with AL-CMP. ECV and GLS were strongly associated with MACE (P < 0.001) and improved the prognostic value when added to Mayo stage (P ≤ 0.002). No participant with ECV ≤32% had MACE, while 74% of those with ECV >48% had MACE. ConclusionsIn patients with systemic AL amyloidosis, ECV detects subclinical myocardial alterations. With therapy, ECV tends to increase at 6 months and returns to values unchanged from baseline at 12 months, whereas GLS improves at 6 and 12 months in participants with AL-CMP. ECV and GLS offer additional prognostic performance over Mayo stage. (Molecular Imaging of Primary Amyloid Cardiomyopathy [MICA]; NCT02641145)

Outcomes of therapeutic plasma exchange for the treatment of patients with multiple myeloma cast nephropathy.

Current treatment guidelines of myeloma cast nephropathy (MCN) recommend the institution of plasma cell-directed therapy and consideration of therapeutic plasma exchange (TPE), with the goal of rapid reduction of the serum free light chain (sFLC). However, the role of TPE continues to remain a subject of debate. The goal of this retrospective bi-institutional study was to evaluate the clinical outcomes of TPE in combination with systemic therapy. Eighty patients were included in this analysis, of whom 72.5% had ≥50% drop in their initial involved sFLC. At 3months from TPE initiation, the overall hematologic response rate (ORR) was 67.5% with a very good partial response or better (≥VGPR) rate of 40%. At 6months, ORR was 57.5%, with ≥VGPR rate of 49%. The renal response rate at 3 and 6months was 47.5% and 43.75%, respectively; the overall renal response rate was 48.75%. On multivariable analysis, every one unit increase in baseline creatinine (odds ratio [OR] 0.76, p=0.006), and achievement of ≥VGPR (OR 21.7 p<0.0001) were significantly associated with renal response. Also, a ≥50% drop in sFLC was favorably associated with renal response (OR 3.39, p=0.09). With a median follow-up of 36.4months, the median overall survival (OS) was 11months. On multivariable analysis, achievement of renal response (hazard ratio [HR]0.3, p<0.0001) and newly diagnosed disease (NDMM; HR 0.43, p=0.0055) were associated with improved OS. Among NDMM patients, those treated with daratumumab-based regimens had a trend for better OS (p=0.15), compared to other regimens, but the difference was not significant. At the end of follow-up, an estimated 40.4% of patients who were on dialysis were able to become dialysis independent. In conclusion, our study highlights the poor survival of patients with MCN. Achievement of early renal response is crucial for prolonged OS, with daratumumab-based therapies showing promise.

Expression and diagnostic value of serum free light chain in lung cancer.

The expression of serum free light chain (FLC) is abnormal in various diseases, but its role in lung cancer remains unclear. This study aims to investigate the expression and diagnostic value of serum FLC in lung cancer. A total of 80 lung cancer patients treated at Xiangdong Hospital, Hunan Normal University from January to December 2021 were selected as the lung cancer group. Another 80 healthy individuals undergoing routine physical examinations during the same period were chosen as the control group. General information and serum κFLC and λFLC levels were collected for all subjects. Clinical indicators such as serum carcinoembryonic antigen (CEA), cytokeratin fragment antigen 21-1 (CYFRA21-1) levels, tumor diameter, histological type, TNM stage, and lymph node metastasis status were recorded for lung cancer patients. The expression levels of serum FLC [κFLC, λFLC, and FLC (κ+λ)] were compared between the lung cancer group and the control group. Lung cancer patients were grouped based on gender, age, smoking history, tumor diameter, TNM stage, histological type, and lymph node metastasis to compare differences in serum κFLC and λFLC levels. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic value of serum FLC alone and in combination with other indicators in lung cancer. The expression levels of serum FLC (κ+λ) and κFLC were significantly higher in the lung cancer group than those in the control group (both P<0.001), while there was no significant difference in serum λFLC levels between the 2 groups (P>0.05). There were no significant differences in serum κFLC levels among lung cancer patients with different tumor diameters, histological types, or TNM stages (all P>0.05); however, serum κFLC levels were higher in lung cancer patients with lymph node metastasis than in those without, with statistical significance (P=0.033). There were no significant differences in serum λFLC levels based on tumor diameter or histological type (both P>0.05), but serum λFLC levels were higher in stage III+IV and lymph node metastatic lung cancer patients compared to stage I+II and non-metastatic patients, with statistical significance (P=0.033 and P=0.019, respectively). The area under the curve (AUC) for κFLC and CEA in diagnosing lung cancer showed no significant difference (P=0.333). The combination of κFLC+CYFRA21-1 had the highest diagnostic efficacy (AUC=0.875) and sensitivity (71.3%). The AUC for the combined diagnosis of κFLC+λFLC+CEA+CYFRA21-1 was 0.915 (95% CI 0.860 to 0.953, P<0.001). Serum FLC is highly expressed in lung cancer and is associated with its invasion and metastasis. Serum FLC, particularly κFLC, has diagnostic value for lung cancer, and the combined detection of FLC, CEA, and CYFRA21-1 offers the best diagnostic efficacy.

Multiple myeloma: 2024 update on diagnosis, risk-stratification, and management.

Multiple myeloma accounts for approximately 10% of hematologic malignancies. The diagnosis requires ≥10% clonal bone marrow plasma cells or a biopsy proven plasmacytoma plus evidence of one or more multiple myeloma defining events (MDE): CRAB (hypercalcemia, renal failure, anemia, or lytic bone lesions) attributable to the plasma cell disorder, bone marrow clonal plasmacytosis ≥60%, serum involved/uninvolved free light chain (FLC) ratio ≥100 (provided involved FLC is ≥100 mg/L and urine monoclonal protein is ≥200 mg/24 h), or >1 focal lesion on magnetic resonance imaging. The presence of del(17p), t(4;14), t(14;16), t(14;20), gain 1q, del 1p, or p53 mutation is considered high-risk multiple myeloma. Presence of any two high risk factors is considered double-hit myeloma; three or more high risk factors is triple-hit myeloma. In patients who are candidates for autologous stem cell transplantation, induction therapy consists of anti-CD38 monoclonal antibody plus bortezomib, lenalidomide, dexamethasone (VRd) followed by autologous stem cell transplantation (ASCT). Selected standard risk patients can delay transplant until first relapse. Frail patients who not candidates for transplant are treated with VRd for approximately 8-12 cycles followed by maintenance or alternatively with daratumumab, lenalidomide, dexamethasone (DRd) until progression. Standard risk patients need lenalidomide maintenance, while bortezomib plus lenalidomide maintenance is needed for high-risk myeloma. A triplet regimen is usually needed at relapse, with the choice of regimen varying with each successive relapse. Chimeric antigen receptor T (CAR-T) cell therapy and bispecific antibodies are additional options.

Concentration of immunoglobulin free light chains in cerebrospinal fluid in the diagnosis of multiple sclerosis

Concentration of immunoglobulin free light chains in cerebrospinal fluid in the diagnosis of multiple sclerosis