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.

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.

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.

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.

Quantification of Free Immunoglobulin Light Chains in Urine

BACKGROUND

The serum-free immunoglobulin light chain assay has been recommended as a screening test for monoclonal gammopathy. We evaluated the usefulness of urine free immunoglobulin light concentration for selection of specimens for immunofixation electrophoresis.

METHODS

Using kits from The Binding Site for Freelite ®, we validated examination of urine for measuring free κ and λ light chains. The results of urine free light chain concentrations were evaluated to ascertain if the results could be used to reduce the number of specimens requiring urine protein immunofixation electrophoresis.

RESULTS

In the 515 specimens examined, there was no evidence of monoclonal gammopathy or history of monoclonal gammopathy in 331. Monoclonal κ or λ light chains were detectable in 42 and 30 specimens, respectively. There was history of κ or λ chain associated monoclonal gammopathy in 62 and 50 patients, respectively. In the 38 monoclonal κ positive urine specimens, with light chain data, κ/λ ratio was >5.83 in all specimens. In 27 specimens positive for monoclonal λ light chains, with light chain data, the urine λ/κ ratio was > 0.17 in 24 of 27 specimens and > 0.041 in all specimens. In patients without monoclonal gammopathy all specimens had a κ/λ ratio of >5.83 or λ/κ ratio >0.17.

CONCLUSIONS

The Freelite ® assay from The Binding Site is suitable for quantification of free light chains in urine. In patients with known history of monoclonal gammopathy, urine immunofixation electrophoresis may be omitted in specimens with κ/λ ratio of <5.83 for κ associated lesions and λ/κ ratio of <0.041 for λ associated lesions. However, the results do not support using this test for first-time urine testing for monoclonal light chains as it is not predictive of positive result, nor does it exclude a monoclonal light chain in urine.

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.

Urine Protein Immunofixation Electrophoresis: Free Light Chain Urine Immunofixation Electrophoresis Is More Sensitive than Conventional Assays for Detecting Monoclonal Light Chains and Could Serve as a Marker of Minimal Residual Disease

BACKGROUND

Immunoglobulin monoclonal light chains (MLCs) in serum and urine are markers for monoclonal gammopathy and could serve as markers of minimal residual disease (MRD) in multiple myeloma (MM). Excretion of MLCs in urine is known to result in renal damage and shorter survival in patients with LC-predominant MM.

METHODS

Retrospective review of urine immunofixation in 1738 specimens at 3 medical centers was conducted to assess the utility of urinalysis for diagnosis and monitoring of monoclonal gammopathy. We tested 228 stored urine specimens via the modified urine immunofixation method, using antisera to assay free LCs (FLCs).

RESULTS

Our review of urine immunofixation results and medical records validated the theory that the only meaningful value-added finding was detection of monoclonal free light chains. Examination of 228 urine specimens using our novel method revealed 18.4% additional positive results. The rate of incremental findings for lambda LCs was nearly 3-fold higher than for kappa LCs.

CONCLUSIONS

The new method of urine immunofixation is significantly more sensitive and more efficient than the conventional method for detecting MLCs in urine. The new assay appears to be sensitive enough to prove that MLCs serve as a marker of MRD in MM.

Validation of ELISA assays for the calculation of FLC indices for the diagnosis of intrathecal immunoglobulin synthesis

OBJECTIVES

Define the cutoff thresholds of the Kappa (K) and Lambda (L) free light chains (FLC) indices for the detection of intrathecal immunoglobulin synthesis (IIS) using the new K and L FLC ELISA from SEBIA. The reference technique, which is not readily standardized between laboratories, is based on the demonstration of oligoclonal banding (OCB) in cerebrospinal fluid (CSF) which is absent in serum. For the past 6 years, we have also routinely calculated the K FLC index using The Binding Site (TBS) reagents on an Optilite instrument, an approach increasingly used as an alternative and/or a complement to electrophoretic analysis.

METHODS

We analyzed 391 serum/CSF pairs divided into three groups. The first group were cases without OCB and with normal albumin CSF/serum ratio (n=174). The second group were cases with specific OCB (n=73). The last group included patients with increased albumin CSF/sera ratio without OCB (n=142).

RESULTS

Analysis of the first group determined that the cutoffs for detection of IIS are respectively 2.55 and 1.02 for the K FLC and L FLC indices. Of the 73 cases with IIS, only 2 had a K FLC index below this threshold (sensitivity of 97.26%), while 16 out of 73 cases (78.08%) and 13 out of 72 cases (81.94%) had an IgG and L FLC index below the cutoffs, respectively. Additionally, we illustrate equivalent performances for prediction of the presence of OCB between SEBIA and TBS methods.

CONCLUSIONS

Sebia K FLC and L FLC assays are adequate alternative methods for the diagnosis of IIS.

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.

Dual Expression of Immunoglobulin Light Chains in Plasma Cell Myeloma: A Case Report and Literature Review

Typically, myeloma cells express a monoclonal immunoglobulin (Ig), either heavy or light chain. Here, we present a case of multiple myeloma with clonal dual expression of kappa and lambda light chain in a 74-year-old woman. Awareness of rare biphenotypic myeloma is important for proper diagnostic workup. A 74-year-old woman underwent hip replacement with an incidental finding of 20% plasma cells in the femoral head. Subsequent bone marrow biopsy also showed about 30% of plasma cells negative for CD20, CD56, and CD117. Immunohistochemistry (IHC) and in situ hybridization studies showed a mixture of kappa and lambda plasma cells. Flow cytometry showed ambiguous results for cytoplasmic Ig light chains kappa and lambda. However, cyclin D1 was highly expressed by plasma cells, and increased free kappa light chains were identified in serum. Further investigation by double IHC demonstrated co-expression of kappa and lambda light chains in the same cells. Fluoresces in situ hybridization studies were positive for t(11;14)(q13;q32) and the deletion 13q. Since its first description by Taylor and Burns in 1974, the demonstration of restricted cytoplasmic Ig light chain expression by immunohistochemistry is 1 of the basic tools for corroborating clonality of the plasma cells in tissue biopsy. IHC results in myeloma with dual expression of Ig light chains may suggest polyclonal plasma cell population, especially when plasma cells do not form sheets in the bone marrow. In an appropriate clinical setting, other investigations are needed to exclude plasma cell neoplasm, even with seemingly "polytypic" results by IHC.

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.

Rapid detection of serum free light chains by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Introduction: Serum free light chain (FLC) measurements are increasingly prominent for patients with plasma cell disorders (PCDs) in screening, prognostic stratification, and monitoring therapy responses. Objectives: We aimed to develop a sensitive, reliable, and accurate method for diagnosing PCDs that can notably decrease the time and cost of current methods. Methods: Here, we present a novel approach for FLC measurement using immunoenrichment on micro-affinity chromatography in combination with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) detection. In this study, serum free kappa (κ) and free lambda (λ) light chain (LC) levels in the serum of 105 patients were compared between the nephelometric serum FLC quantification and MALDI-TOF MS detection. Results: Cohen's kappa coefficient between the MALDI-TOF MS-based method and the FLC assay revealed an almost perfect agreement in the case of normal (negative) results (κ = 0.92; 95% confidence interval (CI): 0.837 to 0.968) and a good agreement in the case of increased (positive) results (κ = 0.76; 95% CI: 0.608 to 0.870). In Spearman's correlation analysis, the best correlation was found between serum free κ/λ ratios (r = 0.628, 0.496 to 0.732; p <0.0001). Our method showed sensitivity (92.5%) and specificity (76.3%) for discrimination between the κ/λ FLC ratio compared to the serum FLC assay. Conclusion: The proposed method can significantly contribute to diagnosing and monitoring PCDs as it can significantly be time-saving, cost-effective in FLC measurement.

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.

Serum Free Light Chain Reference Intervals in a Local Population in Spain using the Optilite Analyser

BACKGROUND

Our aim was to establish local reference intervals for k and λ free light chains.

METHODS

Fresh sera from 246 healthy blood donors were analyzed to evaluate reference intervals for FLC. CLSI EP28-A3C protocol was applied to establish new RIs.

RESULTS

The 95% reference interval for FLCk was 7.20 - 20.0 mg/L, and that for FLCλ was 6.72 - 20.23 mg/L. The diagnostic interval for the k/λ ratio was 0.5 - 2.11 mg/L. When we analyze the distribution of the k/λ ratio results for the 1,025 pieces of data collected using the diagnostic intervals reported by the manufacturer and those established in this study, we observed that discordant results were reported in 14.5% of patients with MGUS and 16.3% of patients with multiple myeloma.

CONCLUSIONS

Our findings underline the importance of establishing the reference intervals for serum FLCs and the proper diagnostic interval by instrument platform and appropriate to the target study patient population.

The Use of Kappa Free Light Chains to Diagnose Multiple Sclerosis

Background: The positive implications of using free light chains in diagnosing multiple sclerosis have increasingly gained considerable interest in medical research and the scientific community. It is often presumed that free light chains, particularly kappa and lambda free light chains, are of practical use and are associated with a higher probability of obtaining positive results compared to oligoclonal bands. The primary purpose of the current paper was to conduct a systematic review to assess the up-to-date methods for diagnosing multiple sclerosis using kappa and lambda free light chains. Method: An organized literature search was performed across four electronic sources, including Google Scholar, Web of Science, Embase, and MEDLINE. The sources analyzed in this systematic review and meta-analysis comprise randomized clinical trials, prospective cohort studies, retrospective studies, controlled clinical trials, and systematic reviews. Results: The review contains 116 reports that includes 1204 participants. The final selection includes a vast array of preexisting literature concerning the study topic: 35 randomized clinical trials, 21 prospective cohort studies, 19 retrospective studies, 22 controlled clinical trials, and 13 systematic reviews. Discussion: The incorporated literature sources provided integral insights into the benefits of free light chain diagnostics for multiple sclerosis. It was also evident that the use of free light chains in the diagnosis of clinically isolated syndrome (CIS) and multiple sclerosis is relatively fast and inexpensive in comparison to other conventional state-of-the-art diagnostic methods, e.g., using oligoclonal bands (OCBs).

Clinical characteristics and outcomes of IgD myeloma: experience across UK national trials

Immunoglobulin D (IgD) myeloma is a subtype often considered to have adverse features and inferior survival, but there is a paucity of data from large clinical studies. We compare the clinical characteristics and outcomes of patients with IgD myeloma from UK phase 3 myeloma trials analyzed in 2 groups: old (1980-2002) and recent (2002-2016) clinical trials, based on the time of adoption of novel myeloma therapies. Patients with IgD myeloma comprised 44 of 2789 (1.6%) and 70 of 5773 (1.2%) of the old and recent trials, respectively. Overall, IgD myeloma was associated with male predominance, low-level paraproteinemia (<10g/L), and λ light chain preference. The frequency of ultra-high-risk cytogenetics was similar in IgD myeloma compared with other subtypes (4.3% vs 5.3%, P > .99). Despite the old trial series being a younger group (median age: 59 vs 63 years, P = .015), there was a higher frequency of bone lesions, advanced stage at diagnosis, worse performance status, and severe renal impairment compared with the recent trials. Furthermore, the early mortality rate was significantly higher for the old trial series (20% vs 4%, P = .01). The overall response rate following induction therapy was significantly higher in the recent trials (89% vs 43%, P < .0001), and this was consistent with improved median overall survival (48 months; 95% confidence interval [CI] 35-67 months vs 22 months; 95% CI, 16-29 months). Survival outcomes for IgD myeloma have significantly improved and are now comparable to other myeloma types because of earlier diagnosis, novel therapies, and improved supportive care. This trial was registered at clinicaltrials.gov as # NCT01554852.

Different roles of urinary light chains and serum light chains as potential biomarkers for monitoring disease activity in systemic lupus erythematosus

Objective

The assessment system for monitoring systemic lupus erythematosus (SLE) disease activity is complex and lacks reliable laboratory indicators. It is necessary to find rapid and noninvasive biomarkers. The aim of this study was to screen and identify the differentially expressed proteins in urine samples between active SLE and stable SLE and to further explore the expression of light chains.

Methods

First, we used a label-free quantitative proteomics approach to establish the urine protein expression profile of SLE, and then screened differentially expressed proteins. Subsequently, the expression of overall light chains was examined by immunofixation electrophoresis and immunoturbidimetric methods, respectively.

Results

Mass spectrometry data analysis found a total of 51 light chain peptides in the urinary protein expression spectrum, of which 27 light chain peptides were differentially expressed between the two groups. The largest difference was IGLV5-45 located in the variable region of the immunoglobulin Lambda light chain. The levels of urinary light chains and serum light chains were both significantly elevated in active SLE, and the levels of urinary light chains increased with the severity of disease activity.

Conclusions

The measurement of light chains would help to monitor SLE disease activity. Serum light chains had better discriminatory capacity than urinary light chains, while urine light chains were closely related to the severity of disease activity and could be used for dynamically monitoring the progress of disease activity.

Defects and countermeasures in laboratory diagnosis of rare IgE multiple myeloma

BACKGROUND

IgE multiple myeloma (MM) is a rare subtype of MM that is easily misdiagnosed. We report a rare case of IgE-MM and investigate the application of the SLiM-CRAB criteria to screen for high-risk smoldering MM (SMM) patients, so as to summarize the causes and methods used to prevent missed diagnosis or misdiagnosis in IgE-MM.

METHODS

The serum monoclonal protein (M-protein) classification and IgE quantification was performed and sent to several individual institutions. The results were collected and the causes of IgE detection defects were analyzed.

RESULTS

Upon admission to our hospital, the patient's serum free kappa light chain was 1,069.9 mg/L, free lambda light chain was 9.2 mg/L, and free kappa/lambda ratio was 115.9, which met the SLiM criteria, but without CRAB features. Immunofixation electrophoresis (IF) showed "M-like protein aggregation bands" in all lanes. After pretreatment with 1% β-mercaptoethanol to depolymerize the aggregation of monoclonal protein, the "M-like protein aggregation bands disappeared. The other five institutions did not provide the correct typing results. The quantification of serum IgE was as high as 2.06×10⁷ IU/mL, whereas 7 other testing institutions reported IgE levels ranging from 1.0 to 1100 IU/mL.

CONCLUSION

High-risk biomarkers in SLiM criteria can achieve good therapeutic effects in rare IgE-MM patients. Serum immunofixation performed without antisera against IgE, insufficient identification of the lytic bands produced by high macromolecule aggregation in IF, and the absence of a prozone effect avoidance procedure during IgE quantitative detection are the primary causes of missed diagnosis or misdiagnosis in patients with IgE-MM.

Clinicopathologic and Proteomic Analysis of Amyloidomas Involving the Ocular Surface and Adnexa

OBJECTIVES

Ocular amyloidoma is a rare disorder characterized by deposition of insoluble proteinaceous fibrils in the extracellular space of the ocular adnexa. This study details the clinicopathologic features and proteomic characteristics of periocular amyloid deposition.

METHODS

Specimens (1991-2020) were retrieved and reviewed. All available H&E slides and special stains were reviewed. Proteomic analysis was performed using immunohistochemistry (IHC) for IgG, IgG4, IgA, IgD, IgM, CD20, CD3, CD138, and κ/λ, as well as chromatography-electrospray tandem mass spectrometry on formalin-fixed, paraffin-embedded tissue.

RESULTS

There were 14 patients (7 men, 7 women). The depositions involved eyelid (n = 3), conjunctiva (n = 8), and orbit (n = 3). All patients were adults with a median age at diagnosis of 56 (range, 39-88) years. The deposits were predominantly λ light chain restricted (n = 6) and mixed light chains (n = 2), and one case was κ predominant. Two of the cases with a mixture of κ and λ light chains had an excess of transthyretin by mass spectrometry. Four of the cases did not have adequate material for proteomic subtyping.

CONCLUSIONS

Amyloidomas involving ocular adnexa contain a variety of amyloid-related and immunoglobulin-associated peptides. The λ light chain predominates as in other body sites, but mixed patterns and rarely κ light chain restriction may be encountered.

Oligosecretory myeloma with gastrointestinal tract involvement: an unusual presentation and literature review

A woman in her 70s with vague gastrointestinal (GI) symptoms and unintentional weight loss was referred to endoscopy clinic for investigation and consideration of GI malignancy. CT of the thorax, abdomen and pelvis showed a suspicious mass in the oesophago-gastric junction with a lytic lesion on S1-S2 sacrum. A subsequent upper GI endoscopy revealed two raised, ulcerated tumours on the lesser curvature of the stomach. By the time an MRI of the whole spine was done which revealed multiple metastases involving thoracic, lumbar and sacral skeleton, she had developed leg weakness and paraesthesias, consistent with the imaging findings. A positron emission tomography/CT scan further confirmed the above findings. The initial working diagnosis was primary GI tumour with bony metastases. However, she was later referred to the haematology team after the immunohistochemistry of the tumour showed that it was of a plasma cell origin (CD138 positive) associated with lambda light chain deposits. Serum-free light chain showed a raised lambda light chain of 272 mg/L and kappa light chain of 11.3 mg/L and involved/uninvolved light chain ratio of 24. Bone marrow biopsy confirmed a plasma cell myeloma with moderate disease burden. Monoclonal lambda chains were demonstrated on immunofixation but negative on serum protein electrophoresis and hence a diagnosis of oligosecretory myeloma with GI involvement was made. Subsequent management involved physiotherapy, pain management and chemotherapy, where this woman was commenced on Velcade (generically known as bortezomib), thalidomide and dexamethasone and she continued to experience clinical and biochemical improvement.

IgG1 Subclass Restriction and Biochemical Peculiarities of Monoclonal Immunoglobulins in Scleromyxedema

BACKGROUND

Scleromyxedema (SME) is a rare mucinosis associated with monoclonal gammopathy. Several biochemical peculiarities of monoclonal immunoglobulins (Ig) in SME patients were reported in case reports or short series, such as IgGλ over-representation, cationic migration, and partial deletion.

METHODS

Monoclonal immunoglobulins (Ig) from the serum of 12 consecutive patients diagnosed with scleromyxedema (SME) were analyzed using electrophoretic and immunoblotting techniques.

RESULTS

All monoclonal Ig from 12 SME were of IgG1 subclass, with an overrepresentation of the lambda-type light chain and a cationic mobility on standard zone electrophoresis, as compared with 21 cases of monoclonal gammopathy of undetermined significance (MGUS) of IgG1 subclass. Reactivity with specific monoclonal antibodies demonstrated no evident deletion of the heavy chain constant domains, which was also confirmed by analysis of Ig heavy chain molecular weight on a purified monoclonal component from one case.

CONCLUSIONS

Significant isotype restriction of both heavy and light chains, and peculiar biochemical properties suggest that monoclonal Ig might be involved in pathophysiological events of SME.

Primary thymic mucosa-associated lymphoid tissue lymphoma complicated with renal amyloidosis: A first case report

INTRODUCTION

Primary mucosa-associated lymphoid tissue (MALT) lymphomas originating in thymus is rare. And, there have been few reports of patients with MALT coexisting with amyloidosis. As far as we know, this was the first case report on MALT lymphoma associated with renal amyloidosis.

PATIENT CONCERNS

A 57-year-old man presented with nephrotic syndrome. Further workup revealed IgM-Lambda type monoclonal gammopathy. Bone marrow biopsy showed 8% clonal plasma cells. Renal biopsy confirmed the diagnosis of Lambda light chain AL amyloidosis. positron emission tomography/computed tomography showed thymic lesions which upon biopsy were diagnosed as MALT lymphoma of the thymus.

DIAGNOSIS

Primary thymic MALT lymphoma complicated with renal amyloidosis.

INTERVENTIONS

The patient underwent surgical resection of the thymus mass and 2 courses of chemotherapy.

OUTCOMES

Follow-up data showed that the patient survived 18 months after surgical excision and chemotherapy.

CONCLUSION

The case highlights the importance of screening for malignancy in patients with renal amyloidosis.

Bilateral Breast Involvement in A 71-Year-Old White Man with Lambda Light Chain Disease. Regression after A new Chemotherapy Combination. A Case Report

A rare case of lambda light chain disease with bilateral breast involvement is described. A complete regression after a new chemotherapy combination (peptichemio + teniposide + dexa-methasone) was obtained. A previous treatment with prednisone + melphalan was ineffective.

Combined Group I and III ABO Discrepancies in Multiple Myeloma with IgG-Lambda Type: A Case Report

OBJECTIVE

To report a case with unusual ABO discrepancies caused by coexistence of the loss of anti-B isoagglutinin and rouleau formation.

CLINICAL PRESENTATION AND INTERVENTION

A 79-year-old female diagnosed as having multiple myeloma (MM) with monoclonal IgG-λ type showed rouleau formation in peripheral blood smear. The ABO and Rh blood type before the diagnosis of MM was A+, but the following ABO grouping was interpreted as AB+. The ABO genotype revealed the subtypes A102 and O101, which confirmed her ABO phenotype as A+.

CONCLUSION

This was a case of combined group I and III ABO discrepancies mimicking blood group AB.

Salivary immunoglobulin free light chains: reference ranges and responses to exercise in young and older adults

BACKGROUND

Free light chains (FLCs) have a range of biological functions and may act as a broad marker of immunesuppression and activation and inflammation. Measurement of salivary FLCs may provide practical advantages in a range of clinical populations. The aim of the present study was to develop normal reference ranges of FLCs in saliva and assess the effects of acute exercise on FLC levels in younger and older adults.

METHODS

Saliva FLC concentrations and secretion rates were measuredin young (n = 88, aged 18-36) and older (n = 53, aged 60-80) adults. To assess FLC changes in response to acute exercise, young adults completed a constant work-rate cycling exercise trial at 60% VO2max (n = 18) or a 1 h cycling time trial (TT) (n = 10) and older adults completed an incremental submaximal treadmill walking exercise test to 75% HRmax (n = 53). Serum FLCs were measured at baseline and in response to exercise.

RESULTS

Older adults demonstrated significantly higher levels of salivary FLC parameters compared with young adults. Median (5-95th percentile) concentrationswere 0.45 (0.004- 3.45) mg/L for kappa and 0.30 (0.08-1.54) mg/L for lambda in young adults; 3.91 (0.75-19.65) mg/L for kappa and 1.00 (0.02-4.50) mg/L for lambda in older ad ults. Overall median concentrations of salivary kappa and lambda FLCs were 10-fold and 20-fold lower than serum, respectively. Reductions in salivary FLC concentrations and secretion rates were observed immediately post- and at 1 h post exercise, but were only significant for the older cohort; FLCs began to recover between post and 1 h post-exercise. No changes in serum FLCs were observed in response to exercise.

POEMS Syndrome with IgG-λ/IgA-κ Biclonal Gammopathy and Abnormal Serum Free Light Chain Ratio: a Case Report

BACKGROUND

POEMS syndrome is a rare paraneoplastic disorder with atypical plasma cell proliferation. Cases of POEMS syndrome presented with either biclonal gammopathy or an abnormal serum free light chain ratio are considered uncommon. The present authors encountered a case of POEMS syndrome with IgG-λ/IgA-κ biclonal gammopathy with dominant κ free light chain and abnormal serum free light chain ratio.

CASE

A 56-year-old man with a history of Castleman disease was suspected with POEMS syndrome and admitted for further evaluation for B-cell proliferative disease to rule out multiple myeloma. He also had a sustained tingling sensation on both feet and gait disturbance, which were compatible with diffuse peripheral sensorimotor polyneuropathy with demyelinating features. His laboratory findings revealed hyperlipidemia and hypothyroidism, and he had hypertrichosis. The results of the serum and urine protein electrophoresis seemed normal, except a very weak band at the end of the serum gamma region. Serum immunofixation electrophoresis confirmed IgG-λ and IgA-κ biclonal gammopathy, with an increased serum IgA concentration and normal levels of IgG, IgM, and IgD. Both serum free light chain κ and λ values were increased, and the κ/λ ratio was higher than normal.

CONCLUSIONS

The finding of IgG-λ/IgA-κ biclonal gammopathy and abnormal serum free light chain ratio with dominant κ clonality in our case was definitely rare. However, a primary pathogenic role of the different paraproteinemia in POEMS syndrome remains unclear. Further studies to identify better management modalities for POEMS syndrome is needed.

Unusual myelomas: a review of IgD and IgE variants

Immunoglobulin D multiple myeloma (IgD MM) accounts for almost 2% of all myeloma cases. It is associated with an increased frequency of undetectable or small monoclonal (M)-protein levels on electrophoresis; osteolytic lesions; extramedullary involvement; amyloidosis; a lambda (lambda) light chain predilection; renal failure; hypercalcemia; and, often, advanced disease at diagnosis. Immunoglobulin E (IgE) MM is rare, with fewer than 50 cases reported in the literature. IgE MM presents with features similar to those of IgD MM, along with a higher incidence of plasma cell leukemia. The hallmark of IgE MM is t(11;14) (q13;q32). IgD and IgE levels are generally very low and hence may escape detection; thus, it is important that, when myeloma is suspected, patients be screened for the presence of IgD and IgE if they have an apparently free monoclonal immunoglobulin light chain in the serum. Although survival of patients with IgD MM or IgE MM is shorter in comparison to those with immunoglobulin G (IgG) MM or immunoglobulin A (IgA) MM, the outcome for patients with IgD and IgE subtypes is improving with the use of novel agents and autologous transplantation.

Lambda light chain myeloma with oliguric cast nephropathy and remission with bortezomib, doxorubicin and dexamethasone

Cast nephropathy is one of the major causes of renal failure in patients with multiple myeloma resulting from precipitation of free light chains inside the tubules. Timely diagnosis and treatment confers a better prognosis though around 10% of patients with cast nephropathy remain dialysis dependent in spite of treatment. We report the clinical course and outcome of a patient presenting with acute kidney injury and oliguria, preceded by acute gastroenteritis and intake of Chinese medications and dialysis dependent state for eight weeks. Kidney biopsy revealed cast nephropathy with lambda light chain restriction and severe tubular injury. Serum protein electrophoresis was normal with no "M spike" but serum free light chain ratio was altered with very high lambda and normal kappa light chain levels. Bone marrow biopsy showed >85% atypical plasma cells. Haemodialysis was continued and chemotherapy with bortezomib, doxorubicin and dexamethasone was started. Kidney function gradually improved with discontinuation of dialysis after 1 month and complete remission of acute kidney injury and myeloma in 4 months of chemotherapy.

[A comparative analysis of three diagnostic criteria for multiple myeloma]

OBJECTIVE

To compare the sensitivity among three diagnostic criteria for multiple myeloma.

METHODS

A total of 220 patients with multiple myeloma were studied retrospectively to compare the sensitivity, as well as their clinical manifestations, cell morphology in bone marrow and immunophenotype.

RESULTS

(1) The sensitivity of domestic diagnostic criterion in 1975 was 79.1% (174/220) and there were some drawbacks in type identify. The sensitivity of WHO diagnostic criterion in 2001 was 97.3% (214/220) and the sensitivity of domestic diagnostic criteria in 2011 was 100%. (2) Immunoglobulin level in 12.7% (28/220) patients was < 30 g/L, plasma cells count in bone marrow in 13.6% (30/220) was < 10%; 2.7% (6/220) patients had not met the standard in immunity globulin and bone marrow plasma cells count. (3) The immunophenotype was CD(38) positive (100%), restricted light chain (kappa/lambda) and CD(19)100%, CD(138) (98.2%, 216/220) negative.

CONCLUSIONS

Among the three diagnostic criteria, the highest was 2011 domestic diagnostic criteria. Comprehensive analysis include clinical manifestations, cell morphology, immunophenotype will contribute to the diagnosis for multiple myeloma.

Elevated serum free light chains are associated with event-free and overall survival in two independent cohorts of patients with diffuse large B-cell lymphoma

PURPOSE

The serum free light chain (FLC) assay quantitates free kappa (κ) and free lambda (λ) immunoglobulin light chains. This assay has prognostic value in plasma cell proliferative disorders. There are limited data on serum FLC in B-cell malignancies.

PATIENTS AND METHODS

The association of pretreatment FLC with event-free survival (EFS) and overall survival (OS) in diffuse large B-cell lymphoma (DLBCL) was evaluated in 76 patients from the North Central Cancer Treatment Group trial N0489 (NCT00301821) and 219 patients from the University of Iowa/Mayo Clinic Specialized Program of Research Excellence Molecular Epidemiology Resource (MER). Published reference ranges were used to define an elevated FLC or an abnormal κ:λ FLC ratio.

RESULTS

Elevated FLC or abnormal κ:λ FLC ratio was present in 32% and 14% of patients, respectively. Patients with elevated FLC had an inferior OS and EFS in both cohorts compared with patients with normal FLC (N0489: EFS hazard ratio [HR], 3.06; OS HR, 3.16; both P < .02; MER: EFS HR, 2.42; OS HR, 3.40; both P < .001; combined EFS HR, 2.57; OS HR, 3.74; both P < .001). All associations remained significant for EFS and OS after adjusting for the International Prognostic Index (IPI). Abnormal κ:λ FLC ratio was modestly associated with outcome in the combined group (EFS HR, 1.61; OS HR, 1.67; both P = .07), but not in patients without corresponding elevated κ or λ. Elevated FLC was the strongest predictor of outcome in multivariable models with the IPI components.

CONCLUSION

Increased serum FLC is an independent, adverse prognostic factor for EFS and OS in DLBCL and warrants further evaluation as a biomarker in DLBCL.

[Factors affecting the response of thalidomide therapy for patients with multiple myeloma]

Factors that affect the response of multiple myeloma patients to thalidomide were evaluated in 40 patients who were not eligible for chemotherapy (untreated: 14, relapse/refractory: 26). The complete response (CR) rate was 2.5%; partial response (PR) 50.0%; minimal response (MR) 25.0%; no change (NC) 12.5%; and progressive disease 10.0%. The response to thalidomide could be evaluated after four weeks of treatment. Significantly higher responses were associated with untreated patients, patients with combined use of thalidomide plus dexamethasone, and patients with kappa light chain. Patients who responded well to thalidomide showed a significantly higher progression-free survival (PFS) rate. In patients with kappa light chain, PFS and overall survival rates were significantly higher than those with lambda light chain. Frequent adverse reactions were numbness (47.5%), constipation (32.5%), and eruption (30.0%). In patients previously treated with vincristine, numbness occurred in a significantly higher percentage of patients.

Molecular analysis of light-chain switch and acute lymphoblastic leukemia transformation in two follicular lymphomas: Implications for lymphomagenesis

We observed novel transformations of follicular lymphoma (FL), first, a switch in immunoglobulin (Ig) light chain, and second, transformation of FL to acute lymphoblastic leukemia (ALL). Each set of tumors shared a common clonal origin, as demonstrated by expression of identical, unique CDR IIIH sequences, shared somatic mutations in JH, and identical bcl-2 translocation breakpoints of microdissected ALL cells. Molecular analysis of lambda V-gene expression demonstrated lambda-bearing cells in the original kappa tumor, while expansion of the lambda subclone at relapse occurred after active immunotherapy targeting the Ig receptor. These exceptional cases are compatible with a more contemporary model of lymphomagenesis in which critical events originate from genetic mechanisms which normally occur in germinal center (GC) B cells and challenge the current paradigm of parallel generation of subclones from an early, pre-GC precursor. It is also possible that the outgrowth of these variants was a consequence of immunoselection.

Follicular Lymphoma in Staging Bone Marrow Specimens: Correlation of Histologic Findings With the Results of Flow Cytometry Immunophenotypic Analysis

Context.—Bone marrow (BM) examination is part of the staging workup of lymphoma patients. Few studies have compared BM histologic findings with results of flow cytometric immunophenotyping analysis in follicular lymphoma (FL) patients.

Objective.—To correlate histologic findings with immunophenotypic data in staging BM biopsy and aspiration specimens of FL patients.

Design.—Bone marrow biopsy specimens of untreated FL patients were reviewed. Histologic findings were correlated with 3-color flow cytometric immunophenotyping results on corresponding BM aspirates.

Results.—Bone marrow biopsy specimens (with or without aspirates) of 114 patients with histologic evidence of FL in BM were reviewed. There were 76 bilateral and 38 unilateral biopsies performed, resulting in 190 specimens: 187 involved by FL and 3 negative (in patients with a positive contralateral specimen). The extent of BM involvement was &lt;5% in 32 (17.1%), ≥5% and ≤25% in 102 (54.6%), &gt;25% and ≤50% in 27 (14.4%), and &gt;50% in 26 (13.9%) specimens. The pattern of involvement was purely paratrabecular in 81 (43.3%), mixed in 80 (42.8%), and purely nonparatrabecular in 26 (13.9%). Immunophenotyping was only performed unilaterally, on BM aspirates of 92 patients, and was positive for a monoclonal B-cell population in 53 (57.6%) patients. Immunophenotyping was more often negative when biopsy specimens showed FL with a purely paratrabecular pattern. For comparison, we assessed 163 FL patients without histologic evidence of FL in BM also analyzed by flow cytometric immunophenotyping. A monoclonal B-cell population was identified in 5 patients (3%).

Conclusions.—Our data suggest that 3-color flow cytometric immunophenotyping adds little information to the evaluation of staging BM specimens of FL patients.

Cytopathologic findings in “POEMS” syndrome associated with Castleman disease

A 34-year-old man with a history of a scorpion bite followed by increasing polyneuropathy and IgG lambda monoclonal gammopathy was referred for fine-needle aspiration of a lytic bone lesion and an enlarged axillary lymph node. The findings in the bone lesion were consistent with a plasmacytoma. The FNA of the lymph node showed a peculiar capillary proliferation in a background of polymorphous mature lymphocytes. Flow cytometric analysis showed a mixed lymphoid population. The lymph node was originally signed out descriptively, but review of the case showed features consistent with Castleman disease. After the pathologic findings and clinical features were discussed with the clinical team, the diagnosis of POEMS syndrome was established. Subsequent surgical excision of the lymph node was diagnosed as hyaline vascular-variant Castleman disease.

[Bullous amyloïdis revealing a light chains lambda myeloma]

INTRODUCTION

Although rare, skin lesions are regularly reported in patients with systemic amyloidosis. The existence of bullous skin lesions however is very rare; only thirty cases have been previously reported. We report a new case of bullous amyloidosis revealing a light chains lambda myeloma, and underline the usual characteristics of this type of systemic amyloidosis.

EXEGESIS

An 85-year-old man was hospitalised for a bullous eruption associated with a general asthenia. Bullous amyloidosis revealing a light chains lambda myeloma was diagnosed and confirmed by histopathological examination of a skin biopsy specimen. The patient died of a severe congestive heart failure, 15 days later, due to cardiac involvement of the amyloidosis.

CONCLUSION

Bullous amyloidosis lesions can be an early manifestation of occult dysglobulinemia. Early diagnosis would allow rapid treatment, before onset of systemic amyloidosis, which is often lethal.

High-dose melphalan with autologous stem cell transplantation after VAD induction chemotherapy for treatment of amyloid light chain amyloidosis: a single centre prospective phase II study

Amyloid light chain (AL) amyloidosis is the result of a clonal plasma cell expansion, in which monoclonal light chains transform to amyloid deposit in various tissues and can lead to organ dysfunction and organ failure. The median survival of patients with AL amyloidosis without therapy is 10-14 months. With high-dose melphalan (HDM) and autologous stem cell transplantation (ASCT), haematological and clinical remission rates of up to 50% of treated patients have been reported from phase II studies. HDM followed by ASCT appears to prolong survival in patients, if haematological remission can be reached. In this phase II study, we evaluated vincristine, adriamycin and dexamethasone (VAD) as induction chemotherapy prior to stem cell mobilization and HDM with ASCT. The regimen was, in general, feasible in patients with AL amyloidosis, but VAD chemotherapy had a considerable World Health Organization (WHO) grade III-IV toxicity (25%) and mortality (7%) rate. VAD pretreatment did not interfere with stem cell mobilization and HDM with ASCT was possible in 86% of patients. The overall treatment efficacy was comparable with reported results of HDM and ASCT without preceding chemotherapy. We could not show an additional benefit of VAD induction in terms of increasing haematological response rate; however the 13% mortality rate after HDM and ASCT in our series was lower than the previous report.