A rare case of IgA lambda multiple myeloma in a 32-year-old woman with t(14;16) translocation associated with kidney injury and non-albumin proteinuria.

BACKGROUND: Multiple myeloma (MM) is a malignant disorder characterized by monoclonal differentiated plasma cells. While it is more commonly diagnosed in elderly individuals, it can also affect younger populations, though with a lower incidence. CASE PRESENTATION: Here, we present the case of a 32-year-old woman diagnosed with IgA lambda MM. She presented with fatigue, nausea, acute kidney injury (AKI) with a rapid increase in creatinine, and anemia. A kidney biopsy was done to rule out a rapidly progressive glomerular disease and a diagnosis was thus reached. A genetic workup revealed t(14;16) translocation and an extra copy of TP53. The patient received aggressive intravenous steroids and intravenous fluid resuscitation, resulting in an improvement in renal function. Treatment with daratumumab in combination with bortezomib, thalidomide, and dexamethasone was initiated and well tolerated. Despite the generally poor prognosis of IgA MM, our case emphasizes the importance of considering MM in young patients with unexplained kidney injury. CONCLUSION: Early recognition and prompt intervention are essential in managing MM patients, especially in those with high-risk cytogenetic abnormalities. This case serves as a reminder for clinicians to maintain a high index of suspicion for MM, even in younger populations, when presented with unexplained kidney injury.

A case report of biclonal immunoglobulin D lambda/lambda multiple myeloma in patient with liver echinococcosis.

Less than 2% of all symptomatic multiple myeloma (MM) has immunoglobulin D (IgD) as monoclonal protein. Biclonal gammopathy is much rarer. At the time of diagnosis, disease is often in advanced stage, including renal failure, anemia, hypercalcemia and lytic bone lesions. Due to the rarity of myeloma itself, but also due to the fact that anti-IgD antisera is not used in routine practice, there are only a few reports of IgD MM described in the literature. This case report describes a patient with IgD lambda MM with anemia and renal failure. Anemia, renal failure, and > 80 percent plasma cells in bone biopsy in our patient with IgD lambda MM meets International Myeloma Working Group criteria for diagnosis of MM. The patient clinical course was similar to other patients with IgD MM. The final result of serum protein immunofixation (s-IFE) showed IgD lambda and free lambda monoclonal bands. To prevent misdiagnosis, it is necessary to use anti-IgD and anti-IgE antisera whenever the serum protein immunofixation with IgA, IgM, IgG, kappa and lambda antiserums shows a kappa or lambda monoclonal band without monoclonal band in heavy chain.

Serum free light chains among twin siblings: is the kappa/lambda ratio genetically determined?

BACKGROUND: Serum kappa, lambda, the K/λ light chain concentrations are used for screening, diagnosis, and monitoring of patients with multiple myeloma and other plasma cell disorders. Biological variation studies conducted on healthy subjects showed that free light chains have a low within and high between-individual variation. We determined if this variation were genetically linked. METHODS: We obtained a single serum sample from 16 pairs of identical twins, 8 neonate twins, and 19 presumed directly-related siblings children, measured Κ and λ light chains and computed the Κ/λ ratio. RESULTS: As expected, Κ/λ results from each twin neonate were near identical (reflecting maternal/placental transfer). For older children and adult twins, the Κ/λ ratio form a cluster of results that were a subset of the reference range. There was one outlier, a female with a high, different from her twin sister. She likely had a monoclonal gammopathy (no followup was possible). Excluding this pair, results from neonate twins (14.4% ±10.3%) and non-neonate twins (18.0 ± 15.3%) were not significantly different. Results between non-twin siblings were more scattered (53.2%±53.4%) and different from neonate and non-neonate twin adult and children. CONCLUSION: We suggest that the Κ/λ free light chains may be genetically linked.

Primary cerebral immunoglobulin light chain amyloidoma in a patient with multiple sclerosis.

A man in his 60s, known with multiple sclerosis, presented with seizures and paresis of the left arm and leg. Brain imaging showed a white matter lesion, right parietal, which was progressive over the last 6 years and not typical for multiple sclerosis. Brain biopsy showed a B-cell infiltrate with IgA lambda monotypic plasma cell differentiation and amyloid deposits, typed as lambda immunoglobulin light chain (AL). Bone marrow biopsy and PET/CT ruled out a systemic lymphoma. Extended history taking, blood and urine testing (including cardiac biomarkers) identified no evidence of systemic amyloidosis-induced organ dysfunction.Primary cerebral AL amyloidoma is a very rare entity where optimal treatment is difficult to assess. The patient was treated with locally applied volumetric modulated arc radiotherapy, 24 Gy, divided in 12 fractions. Afterwards, the paresis of the left arm partially resolved, and the function of the left leg improved. Seizures did not occur anymore.

Defect in Automated Antigen Excess Detection Discovered after Reviewing Serum Free Light Chain Results in Context with Clinical Findings.

Serum κ and λ free light chains can be markedly elevated in monoclonal gammopathies; consequently, serum free light chain (sFLC) immunoassays are susceptible to inaccuracies caused by antigen excess. As a result, diagnostics manufacturers have attempted to automate antigen excess detection. A 75-year-old African-American woman had laboratory findings consistent with severe anemia, acute kidney injury, and moderate hypercalcemia. Serum and urine protein electrophoresis and sFLC testing were ordered. The sFLC results initially showed mildly elevated free λ light chains and normal free κ. The pathologist noted that sFLC results were discrepant with the bone marrow biopsy, electrophoresis, and immunofixation results. After manual dilution of the serum, repeat sFLC testing revealed significantly higher λ sFLC results. Antigen excess causing falsely low sFLC quantitation may not be detected by immunoassay instruments as intended. Correlation with clinical history, serum and urine protein electrophoresis results, and other laboratory findings is essential when interpreting sFLC results.

Amino acid sequence homology of monoclonal serum free light chain dimers and tissue deposited light chains in AL amyloidosis: a pilot study.

OBJECTIVES: Diagnosis of light chain amyloidosis (AL) requires demonstration of amyloid deposits in a tissue biopsy followed by appropriate typing. Previous studies demonstrated increased dimerization of monoclonal serum free light chains (FLCs) as a pathological feature of AL. To further examine the pathogenicity of FLC, we aimed at testing amino acid sequence homology between circulating and deposited light chains (LCs). METHODS: Matched tissue biopsy and serum of 10 AL patients were subjected to tissue proteomic amyloid typing and nephelometric FLC assay, respectively. Serum FLC monomers (M) and dimers (D) were analyzed by Western blotting (WB) and mass spectrometry (MS). RESULTS: WB of serum FLCs showed predominance of either κ or λ type, in agreement with the nephelometric assay data. Abnormal FLC M-D patterns typical of AL amyloidosis were demonstrated in 8 AL-λ patients and in one of two AL-κ patients: increased levels of monoclonal FLC dimers, high D/M ratio values of involved FLCs, and high ratios of involved to uninvolved dimeric FLCs. MS of serum FLC dimers showed predominant constant domain sequences, in concordance with the tissue proteomic amyloid typing. Most importantly, variable domain sequence homology between circulating and deposited LC species was demonstrated, mainly in AL-λ cases. CONCLUSIONS: This is the first study to demonstrate homology between circulating FLCs and tissue-deposited LCs in AL-λ amyloidosis. The applied methodology can facilitate studying the pathogenicity of circulating FLC dimers in AL amyloidosis. The study also highlights the potential of FLC monomer and dimer analysis as a non-invasive screening tool for this disease.

Clinical specificity of two assays for immunoglobulin kappa and lambda free light chains.

OBJECTIVES: Free light chain (FLC) assays and the ratio of κ/λ are recommended for diagnosis, prognosis and monitoring of plasma cell dyscrasias (PCD). Limited data exists on FLC clinical specificity in patients diagnosed with other conditions. METHODS: We assessed the κ, λ, and κ/λ FLC ratio using the FreeLite assay and the Sebia FLC ELISA assay in 176 patients with clinical presentations of fatigue, anemia, polyclonal hypergammaglobulinemia, joint disorders, kidney disease and non PCD-cancers with no monoclonal protein observed on serum protein electrophoresis or MASS-FIX immunoglobulin isotyping. Manufacturer defined reference intervals (RI) and glomerular filtration rate (GFR) specific RI (renal RI) were utilized. RESULTS: For the κ/λ ratio, 68.7 % (121/176) of specimens on the FreeLite and 87.5 % (154/176) of specimens on the Sebia assay were within RI. For κ, 68.2 % (120/176) and 72.2 % (127/176) of results were outside RI for FreeLite and Sebia respectively. For λ, 37.5 % (66/176) and 84.1 % (148/176) of FreeLite and Sebia results were outside RI. With FreeLite and Sebia, patients with kidney disease (n=25) had the highest κ/λ ratios. 44 patients (25.0 %) had GFR <60 mL/min/BSA. When renal RI were applied, 13.6 % had a FLCr outside the renal RI with FreeLite, and 4.5 % with Sebia. CONCLUSIONS: In a cohort of patients with signs and symptoms suggestive of PCDs, but ultimately diagnosed with other conditions, Sebia FLC had improved clinical specificity relative to FreeLite, if one was using an abnormal κ/λ ratio as a surrogate for monoclonality.

Values of Immunoglobulin and Complements for Evaluating Treatment Outcomes of Patients with Multiple Myeloma.

BACKGROUND: The goal was to detect the levels of immunoglobulin (Ig) and complements (C) in patients newly diagnosed as multiple myeloma (MM) and to analyze their value in evaluating the efficacy of bortezomib and the impact on survival time. METHODS: A total of 125 patients newly diagnosed as MM admitted to our hospital were included into the research group, while another 118 healthy volunteers were recruited into the control group. The effectiveness of Ig and C in efficacy evaluation after treatment with bortezomib and the influencing factors for the survival rate were analyzed. Moreover, survival analysis was conducted. RESULTS: The response rate was 78.51% in the research group. The sensitivity and area under the curve (AUC) of combination of serum IgG, κ light chain, λ light chain, C3 and C4 levels in efficacy evaluation were 97.89% and 0.791, respectively, which were superior to those of any single indicator (p < 0.05). The proportion of stage III cases and the levels of serum IgG, κ light chain, λ light chain, C3 and C4 among the dead patients were higher than those among the surviving patients (p < 0.05). Stage III, serum IgG, κ light chain, λ light chain, C3 and C4 were all the risk factors for death in the research group. The increase in the above indicators was associated with the death of patients (p < 0.05). CONCLUSIONS: The combination of serum IgG, κ light chain, λ light chain, C3 and C4 levels can be more effective than any single indicator in efficacy evaluation of bortezomib.

Functional analysis of tumor-derived immunoglobulin lambda and its interacting proteins in cervical cancer.

BACKGROUND: Immunoglobulin lambda (Igλ) has been reported to be expressed in many normal and tumor tissues and cells. However, the function and clinical significance of tumor-derived Igλ remain unclear. METHODS: The differential expressions of Immunoglobulin Lambda Constants (IGLCs) in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) were examined with The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Human Protein Atlas (HPA) databases. The effects of IGLCs on patient clinical phenotypes and prognosis were explored via bioinformatics analyses based on the TCGA databases. We used the bioinformatics analyses based on the TCGA and GTEx databases to elucidate the correlations among IGLC expressions, immunomodulator expressions, tumor stemness, and infiltration scores of tumor infiltrating immune cells. Co-immunoprecipitation (Co-IP) and silver staining combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to obtain potential tumor-derived Igλ-interacting proteins. Functional annotation of candidate proteins identified by LC-MS/MS was performed in Database for Annotation, Visualization and Integrated Discovery (DAVID). The bioinformatics analyses of 7 IGLCs in CESC and normal cervical tissues were performed based on TCGA, GTEx, and Gene Expression Profiling Interactive Analysis 2 (GEPIA2) databases. Protein-protein interaction (PPI) network was analyzed based on tumor-derived Igλ-interacting proteins in Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database. Immunohistochemistry (IHC) was used to validate the expressions of IGLCs in CESC. RESULTS: We found that the expressions of the majority of IGLCs (IGLC1, IGLC2, IGLC3, IGLC4, IGLC5, IGLC6, and IGLC7) were upregulated in CESC tissues, compared with those in normal cervical tissues. The expressions of IGLC5 and IGLC7 had significant difference in different pathologic metastasis (M), one of tumor, node, and metastasis (TNM) staging system, categories of CESC. Except for disease-free interval (DFI), 4 IGLC (IGLC1, IGLC2, IGLC3, and IGLC7) expression levels were positively associated with patient overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) respectively in CESC tissues. 5 IGLC (IGLC1, IGLC2, IGLC3, IGLC6, and IGLC7) expressions were positively correlated with the expressions of a majority of immunomodulators respectively in CESC tissues. Tumor stemness was negatively correlated with the expressions of 4 IGLCs (IGLC1, IGLC2, IGLC3, and IGLC7) respectively in CESC tissues. Except for IGLC4, IGLC5, and IGLC7, 4 IGLC (IGLC1, IGLC2, IGLC3, and IGLC6) expressions were positively correlated with infiltration scores of 6 tumor-infiltrating immune cells (B cell, T cell CD4, T cell CD8, neutrophil, macrophage, and DC). After analyses of the above bioinformatics data of tumor-derived Igλ, Co-IP and LC-MS/MS were used to confirm that 4 proteins (RPL7, RPS3, H1-5, and H1-6) might interact with tumor-derived Igλ in cervical cancer cells. Functional analyses of these candidate proteins showed that they interacted with many proteins and were involved in various cellular biological processes. Finally, IHC was used to further confirm the above bioinformatics results, it was indicated that the expression level of Igλ in cervical adenocarcinoma and cervical squamous cell carcinoma was higher than that in normal cervical tissue. CONCLUSION: This study comprehensively investigated the functions of tumor-derived Igλ and its interacting proteins based on bioinformatics analysis and the potential value of Igλ as a prognostic and therapeutic marker for CESC, providing new direction and evidence for CESC therapy.

Investigation of the Diagnostic Value of sFLC and Other Indicators in the Detection of M Protein in LCMM.

BACKGROUND: The aim was to explore the diagnostic value of serum free light chain (sFLC) and other laboratory indicators for the patients with light chain multiple myeloma (LCMM). METHODS: We performed a retrospective study including 82 LCMM cases and 43 healthy subjects as the observation and control groups, respectively. The observation group was further divided into two subgroups: κ- and λ-type LCMM. Sixteen quantitative indicators were collected and the difference among groups was compared. We also evaluated the positive detection rate (PDR) of four qualitative indicators for M protein detection. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of sixteen indicators. RESULTS: Fourteen indicators showed statistical differences between the control group and κ- or λ-type LCMM subgroup. The κ and λ sFLC ratio (rFLC) and the difference between κ and λ FLC (dFLC) showed differences among the three groups. Among the four qualitative indicators of M protein detection, rFLC showed the highest PDR for both κ- and λ-type LCMM. Among the three combinations with rFLC or uIFE did not show statistical differences. ROC curve analysis indicated a relatively high diagnostic value of dFLC for both κ- and λ-type LCMM. CONCLUSIONS: We should be vigilant about the missed diagnosis by observing the changes of MM-related indicators, particularly dFLC and the six other indicators with high diagnostic value. rFLC can improve the diagnostic ability of LCMM.

Reference Intervals for Plasma Free Kappa and Lambda Chains and Kappa/Lambda Ratio using PENIA.

BACKGROUND: Determination of free light chains is used increasingly for patients with multiple myeloma and other plasma cell dyscrasias. The aim of the present study was to define reference intervals for free kappa and lambda chains and kappa/lambda ratio in lithium heparin plasma and compare the test results with cystatin C based estimated glomerular filtration rate. METHODS: Free kappa and lambda chains were measured in Liheparin plasma from 222 healthy blood donors using free light chain reagents and a BNII nephelometer from Siemens Diagnostics. RESULTS: Calculated reference intervals for kappa chain, free was 4.73 mg/L (90% confidence interval 4.00 - 5.45) - 22.66 mg/L (20.33 - 24.98), for lambda chain, free was 4.33 mg/L (3.70 - 4.95) - 29.28 mg/L (26.96 - 31.59), and for Kappa/Lambda Chain ratio 0.59 (0.56 - 0.62) - 1.46 (1.37 - 1.56). There was no need for gender or age specific reference intervals. Cystatin C based estimated glomerular filtration rate had a significant effect on the levels of free light chains. CONCLUSIONS: The study presents reference intervals for plasma free light chains and compared results of estimated glomerular filtration rate with free light chains of kappa and lambda.

A skewed ratio of free light chains is more common in patients with late-onset than early-onset myasthenia gravis.

Myasthenia gravis (MG) is an autoantibody-mediated neuromuscular disease with an unpredictable clinical course. Serum free light chains (FLCs) have risen as a promising biomarker for MG, but their role in different subtypes of MG and in predicting disease progression is still uncharted. We investigated plasma from 58 generalized MG patients during post-thymectomy follow-up to determine κ and λ FLC and κ/λ ratio. In a subcohort of 30 patients, we examined the expression of 92 proteins associated with immuno-oncology using Olink. We further studied the ability of FLCs or proteomic markers to differentiate disease severity. Patients with late-onset MG (LOMG) displayed significantly higher mean κ/λ ratio than patients with early-onset MG (P = 0.004). Inducible T-cell co-stimulator ligand (ICOSLG), matrix metalloproteinase 7 (MMP7), hepatocyte growth factor (HGF), and arginase 1 (ARG1) were differentially expressed in MG patients compared to healthy controls. There were no significant associations between clinical outcomes and FLCs or the assayed proteins. In conclusion, an elevated κ/λ ratio suggests long-lasting aberrant clonal plasma cell function in LOMG. Immuno-oncology-related proteomic analysis showed alterations in immunoregulatory pathways. Our findings pinpoint the FLC ratio as a biomarker for LOMG and call for further investigation of the immunoregulatory pathways in MG.

Some structural features of the peptide profile of myelin basic protein-hydrolyzing antibodies in schizophrenic patients.

The antibodies of schizophrenic patients that hydrolyze myelin basic protein (MBP) have been actively studied recently, but the mechanism of the catalytic properties of immunoglobulin molecules remains unknown. Determination of specific immunoglobulin sequences associated with the high activity of MBP proteolysis will help to understand the mechanisms of abzyme catalysis. In the course of comparative mass spectrometric analysis of IgG peptides from the blood serum of patients with acute schizophrenia and healthy people, 12 sequences were identified, which were found only in antibodies that hydrolyze MBP. These sequences belong to IgG heavy chains and κ- and λ-type light chains, with eight of them belonging to variable domains. The content of peptides from the variable regions of the light chains does not correlate with the proteolytic activity of IgG to MBP in patients with schizophrenia, whereas for two sequences from the variable regions of the heavy chains (FQ(+0.98)GWVTMTR and *LYLQMN(+0.98)SLR), an increase in activity with increasing their concentration. The results suggest that these sequences may be involved in one way or another in MBP hydrolysis.

Free Light Chains κ and λ as New Biomarkers of Selected Diseases.

Diagnostic and prognostic markers are necessary to help in patient diagnosis and the prediction of future clinical events or disease progression. As promising biomarkers of selected diseases, the free light chains (FLCs) κ and λ were considered. Measurements of FLCs are currently used in routine diagnostics of, for example, multiple myeloma, and the usefulness of FLCs as biomarkers of monoclonal gammopathies is well understood. Therefore, this review focuses on the studies concerning FLCs as new potential biomarkers of other disorders in which an inflammatory background has been observed. We performed a bibliometric review of studies indexed in MEDLINE to assess the clinical significance of FLCs. Altered levels of FLCs were observed both in diseases strongly connected with inflammation such as viral infections, tick-borne diseases or rheumatic disorders, and disorders that are moderately associated with immune system reactions, e.g., multiple sclerosis, diabetes, cardiovascular disorders and cancers. Increased concentrations of FLCs appear to be a useful prognostic marker in patients with multiple sclerosis or tick-borne encephalitis. Intensive synthesis of FLCs may also reflect the production of specific antibodies against pathogens such as SARS-CoV-2. Moreover, abnormal FLC concentrations might predict the development of diabetic kidney disease in patients with type 2 diabetes. Markedly elevated levels are also associated with increased risk of hospitalization and death in patients with cardiovascular disorders. Additionally, FLCs have been found to be increased in rheumatic diseases and have been related to disease activity. Furthermore, it has been suggested that inhibition of FLCs would reduce the progression of tumorigenesis in breast cancer or colitis-associated colon carcinogenesis. In conclusion, abnormal levels of κ and λ FLCs, as well as the ratio of κ:λ, are usually the result of disturbances in the synthesis of immunoglobulins as an effect of overactive inflammatory reactions. Therefore, it seems that κ and λ FLCs may be significant diagnostic and prognostic biomarkers of selected diseases. Moreover, the inhibition of FLCs appears to be a promising therapeutical target for the treatment of various disorders where inflammation plays an important role in the development or progression of the disease.

Mass spectrometric-based assessment of the serum kappa to lambda immunoglobulin light chain ratio (κ:λ) in dogs with immunoglobulin secretory diseases.

The ratio of κ light chains to λ light chains (κ:λ) in serum is used as a biomarker of immunoglobulin secreting neoplasia in humans but has not been evaluated in dogs. A mass-spectrometry based method for determining the canine serum κ:λ was developed and used to evaluate samples from control dogs, dogs with an infectious aetiology, dogs with secretory plasma cell tumours (sPCT) and dogs with non-secretory B cell neoplasia. A human-targeted immunoturbidometric κ:λ assay and immunofixation using antisera targeting human κ light chain or λ light chain was also performed on all samples. Using whole serum samples, the MS-based κ:λ method identified 5 sPCT as κ-predominant (mean κ:λ = 3.307) and 5 sPCT as λ-predominant (mean κ:λ = 0.023) and documented differences between these groups and all other groups (p < 0.05 for all). The infectious aetiology group had a lower mean κ:λ ratio (mean κ:λ = 0.069) than control samples (mean κ:λ = 0.103, p = 0.035). Similar results were obtained when samples were enriched for proteins between 10 and 50 kDa using size exclusion chromatography, except for the statistical difference between the control and infectious aetiology group. All λ-predominant cases had only anti-human λ light chain labelling by immunofixation. Three κ-predominant cases had only anti-human κ-light chain labelling and the remaining two cases did not label with either antisera by immunofixation. The immunoturbidometric method had high analytical CV% (λ light chain CV = 13%, κ light chain CV = 50%), was unable to measure light chains in 20.5% of samples and did not distinguish groups. The data suggests that the human-targeted immunoturbidometric method would not be diagnostically useful and that the MS-derived serum κ:λ may be a useful biomarker of canine immunoglobulin secretory neoplasia which may have the ability to distinguish neoplasia from infectious causes of immunoglobulin secretion.

The presence of two light chain bands on immunofixation is associated with poor outcomes in newly diagnosed multiple myeloma patients.

We aimed to describe the clinical and biological characteristics and the prognosis of patients presenting with an additional light chain (LC) band along with a complete monoclonal protein on immunofixation (IF).An 8-year descriptive study was conducted to assess all cases with confirmed monoclonal gammopathies (MG). We studied those with an entire M-protein with 2 bands of LC of the same isotype based on the results of IF. Data were collected from patients' files.Among 548 cases of MG, we found 32 cases (5.8%) with an additional LC band. We included 28 patients (5%) with a confirmed diagnosis of multiple myeloma (MM). The m/f ratio was 2.5 with a median age of 63 years [32-80 years]. All MM patients had anemia, 16 (57%) had renal failure, 14 (50%) had lytic lesions, 9 (32%) received hemodialysis, and 7 (25%) had hypercalcemia. The free-kappa-lambda ratio was abnormal in all cases: median = 0.07 [0.002-58.57]. The mean overall survival (OS) was 22 months ± 38.76.Fifteen MM patients (48%) received chemotherapy, and 7 (22%) autologous stem cell transplants (SCT). Patients who received SCT had an OS higher than those who received other treatments (p = 0.038). OS was low in patients with high ß2microglobulin levels (rho = -0.791; p = 0.001), and abnormally low free-kappa-lambda ratio (rho = -0.852;p = 0.04).The presence of an additional LC band with a complete monoclonal protein seems to identify newly diagnosed MM patients with poor outcomes and frequent renal impairment.

Withdrawal from Hemodialysis in a Patient with IgD Type Multiple Myeloma: A Case-based Review.

Several previous case reports have shown that patients with immunoglobulin D (IgD) multiple myeloma (MM) can be withdrawn from hemodialysis, however, the characteristics that can predict withdrawal in these patients have not yet been elucidated. A 57-year-old Japanese woman required hemodialysis because of renal dysfunction due to IgD-λ and Bence Jones protein-λ MM. Bortezomib-based chemotherapy nine days after admission led to her withdrawal from hemodialysis on Day 50. In our case-based review, younger age and early initiation of bortezomib-based chemotherapy emerged as possible predictors of successful hemodialysis withdrawal.

Atypical Migration in Serum Immunofixation of Immunoglobulin A with Masked kappa Light Chains: a Case Report and Review of the Literature.

BACKGROUND: We report a case of a patient with immunoglobulin A multiple myeloma associated with a masked kappa light chain. Serum immunofixation showed a monoclonal band in the IgA heavy chain lane without corre-spondence with the light chain and a monoclonal band in total kappa light chain lane without correspondence with the heavy chain. METHODS: To distinguish between heavy chain disease and immunoglobulin with "masked" light chains, two tubes containing the patient's serum were incubated with a very high concentration of anti-total kappa and anti-total lambda antisera for 48 hours at 4°C in order to facilitate immunoprecipitation of the involved light chain. After centrifugation, the supernatant was analyzed by using the IFs method on the Hydrasys 2 Scan Focusing Sebia® without dilution. Then we applied the anti-IgA, anti-total kappa and anti-total lambda antisera. RESULTS: The serum immunofixation test of the sample treated with a high concentration of anti-total kappa showed the disappearance of the monoclonal bands corresponding to IgA heavy chain lane and kappa light chain lane, indicating that precipitation had occurred and that the IgA did have kappa light chains that could not be detected by the standard immunofixation protocol. The serum immunofixation test of the sample treated with anti-total lambda showed the disappearance of the polyclonal background in lambda light chain lane, confirming that the precipitation with lambda light chains according to the previously mentioned protocol has done well. CONCLUSIONS: This case illustrates some of the difficulties encountered and the corrective actions that can be taken for the detection of immunoglobulins with masked light chains.

Clinical implication by differential analytical performances of serum free light chain quantitation analysis using fully automated analyzers.

OBJECTIVES: Free light chain (FLC) is used for the diagnosis and prediction with regard to the progression risk of plasma cell disorders and Freelite reagent using the SPAplus analyzer (The Binding Site) has been one of the widely used option. However, N Latex FLC reagent with the Atellica CH 930 analyzer (Siemens Healthineers) has shown the advantages of automation and high throughput. We aimed to evaluated clinical implication by differential analytical performances of two assays. METHODS: A total of 322 serum samples were collected from 193 patients requested for FLC analysis including 131 multiple myeloma patients. The precision, linearity, dilution recovery of N Latex FLC assay was evaluated. We compared the two assays and analyzed the monomer-dimer pattern for discrepant results. RESULTS: The precision, linearity, and dilution recovery performance was appropriate for the routine use in clinical laboratories. Despite the good correlation within normal range, proportional bias up-to 170% was observed in samples with high concentrations especially for lambda. The higher value samples with N Latex FLC assay contained more monomer forms than controls. All opposite changes of FLC burden by the N Latex FLC assay proved to present concordant dynamic changes when assessed by serum protein electrophoresis. CONCLUSIONS: Clinical laboratories should be aware of the inter-assay variability of FLC quantitative measurements using different platforms, especially for high concentrations of both kappa and lambda measurements, possibly due to monomer/dimer ratio diversity. Clinical interpretations for multiple myeloma disease status might not be dramatically affected only when the same assay is utilized during follow-up periods.