SARS-CoV-2 infection is not associated with the emergence of monoclonal gammopathies

BACKGROUND

Upon infection activated plasma cells produce large quantities of antibodies which can lead to the emergence of a monoclonal component (MC), detectable by serum protein electrophoresis (SPEP). This study aims to investigate any correlation between SARS-CoV-2 infection and MC development and, if identified, whether it persists during follow-up.

METHODS

SPEPs of 786 patients admitted to hospitals between March 01 2020 and March 31 2022 were evaluated. Positive (SARS-CoV-2+) and negative (SARS-CoV-2-) patients to nasopharyngeal swab for SARS-CoV-2 by RT-PCR were included. The persistence/new occurrence of MC was investigated for all patients during follow-up. Patient groups were compared by chi-square analysis.

RESULTS

MC was identified in 12% of all patients admitted to hospital, of which 28.7% were SARS-CoV-2+. The most common immunoglobulin isotype in both groups was IgG-k. There was no correlation between MC development and SARS-CoV-2 infection (p = 0.173). Furthermore, the risk of MC persistence in SARS-CoV-2-negative patients was revealed to be higher than in the SARS-CoV-2+ at follow-up (HR = 0.591, p = 0.05).

CONCLUSIONS

Our study suggests that the detection of MC during SARS-CoV-2 infection is most likely due to the hyperstimulation of the humoral immune system, as also occurs in other viral infections.

Detection of Plasma Cell Disorders by Mass Spectrometry: A Comprehensive Review of 19,523 Cases

OBJECTIVES

To verify the analytical performance of a new mass spectrometry-based method, termed MASS-FIX, when screening for plasma cell disorders in a routine clinical laboratory.

PATIENTS AND METHODS

Results from 19,523 unique patients tested for an M-protein between July 24, 2018, and March 6, 2020, by a combination serum protein electrophoresis (SPEP) and MASS-FIX were examined for consistency with pretest implementation performance. MASS-FIX's ability to verify abnormal results from SPEP and free light chain measurements was then compared with that of immunofixation electrophoresis (IFE) using a separate cohort of 52,586 patients tested by SPEP/IFE during the same period.

RESULTS

Overall, 62.4% of our cohort was negative for an M-protein. Importantly, 7.3% of all specimens had an M spike on SPEP (0.1 to 8.5 g/dL) and MASS-FIX detected an M-protein in all these samples. Of all samples, 30.3% had M-proteins that were detected by MASS-FIX but the SPEP finding was too small for quantification. Of the positive samples, 5.7% contained a therapeutic monoclonal antibody. Of the positive samples, 4.1% had an N-glycosylated light chain (biomarker of high-risk plasma cell disorders). MASS-FIX confirmed a higher percentage of SPEP abnormalities than IFE. MASS-FIX was slightly more sensitive than IFE when confirming an M-protein in samples with an abnormal free light chain ratio. MASS-FIX had a very low sample repeat rate (1.5%). MASS-FIX was highly automatable resulting in a higher number of samples/technologist/day than IFE (∼30% more).

CONCLUSION

Overall, MASS-FIX was successful in maintaining validation characteristics. MASS-FIX was more sensitive in confirming SPEP abnormalities when compared with IFE. Ability to detect therapeutic monoclonal antibodies and glycosylated light chains was distinctly advantageous.

Efficacy of Antiviral Treatment in Hepatitis C Virus (HCV)-Driven Monoclonal Gammopathies Including Myeloma

Multiple myeloma (MM) remains an incurable plasma cell malignancy. While its origin is enigmatic, an association with infectious pathogens including hepatitis C virus (HCV) has been suggested. Here we report nine patients with monoclonal gammopathy of undetermined significance (MGUS) or MM with previous HCV infection, six of whom received antiviral treatment. We studied the evolution of the gammopathy disease, according to anti-HCV treatment and antigen specificity of purified monoclonal immunoglobulin, determined using the INNO-LIA™ HCV Score assay, dot-blot assays, and a multiplex infectious antigen microarray. The monoclonal immunoglobulin from 6/9 patients reacted against HCV. Four of these patients received antiviral treatment and had a better evolution than untreated patients. Following antiviral treatment, one patient with MM in third relapse achieved complete remission with minimal residual disease negativity. For two patients who did not receive antiviral treatment, disease progressed. For the two patients whose monoclonal immunoglobulin did not react against HCV, antiviral treatment was not effective for MGUS or MM disease. Our results suggest a causal relationship between HCV infection and MGUS and MM progression. When HCV was eliminated, chronic antigen-stimulation disappeared, allowing control of clonal plasma cells. This opens new possibilities of treatment for MGUS and myeloma.

Monoclonal free light chain detection and quantification: Performances and limits of available laboratory assays

The detection and quantification of immunoglobulin free light chains in serum and urine is recommended for the diagnosis and monitoring of monoclonal gammopathies according to the guidelines of the International Myeloma Working Group (IMWG). Several tests are currently available in the clinical laboratory to detect and quantify free light chains but although quality, efficiency, and effectiveness have been improved, the results are still variable and poorly harmonized and standardized. The present review article wants to analyze these aspects, with a keen eye on techniques, such as mass spectrometry, that could replace in the practical clinical laboratory the current methods including Bence-Jones protein assay and free light chain immunoassays.

Application of Capillary Electrophoresis in Monoclonal Gammopathies and the Cutoff Value of Monoclonal Protein in Differential Diagnosis of Multiple Myeloma and Other Monoclonal Gammopathies

OBJECTIVE

Monoclonal protein (MP) exists in various diseases, and capillary electrophoresis (CE) has been widely used to detect MP. However, there is not much research on the application value of MP in the differential diagnosis of monoclonal gammopathies. This study aimed to explore MP's cutoff value for the differential diagnosis of multiple myeloma (MM) and other monoclonal gammopathies (MGs).

METHODS

A retrospective analysis of 8167 cases was conducted. Serum MP was detected by CE, and the patients' clinical information was collected from the clinical database of our hospital.

RESULTS

985 cases had MP with high peaks, and 91.1% were diagnosed with malignant diseases. The MP showed small peaks in 471 cases, and only 24.4% were diagnosed with malignant diseases. Among the MPs, the IgG-κ type was the most common type, followed by the IgG-λ, IgA-κ, IgA-λ, free λ light chain, IgM-κ, free κ light chain, double clone, and IgM-λ types. Differences in the MP of the IgG, IgA, IgM, and FLC types between the MM group and MGUS group were statistically different (P<0.01). The MP of the IgG, IgA, and FLC types showed clear specificity and sensitivity in discriminating MM from other monoclonal gammopathies in ROC curve analysis. Serum IgM had statistical significance in the differential diagnosis between WM and other MGs (P<0.01). However, there was no statistical significance in the differential diagnosis between MM and other MGs (P=0.140). The cutoff values of the MP of the IgG, IgA, and FLC types were >18.67g/L, >13.86g/L, and >10.15g/L, respectively, for the differential diagnosis of MM and other MGs. The cutoff value of the MP of IgM for the WM diagnosis was >37.75 g/L.

CONCLUSION

CE has good clinical application value in the diagnosis of monoclonal gammopathies, and MP can be used in the differential diagnosis of MM and other monoclonal gammopathies.

Acquired hemophagocytic lymphohistiocytosis as initial manifestation of multiple myeloma: A case report and literature review

INTRODUCTION

Hemophagocytic lymphohistiocytosis (HLH) is a condition characterized by a hyperinflammatory state and persistent macrophage activation, resulting in reactive phagocytosis of the hematopoietic elements. In children, it is usually a hereditary disorder, while in adults it is usually acquired secondary to viral infections, collagenoses, or tumors. Although accounting for 10% of hematologic malignancies, HLH is rarely associated with multiple myeloma (MM) and other plasmacytic dyscrasias.

PATIENT CONCERNS

A 64-year-old Brazilian man seeked medical care with a 3-month history of intermittent fever, weight loss, night sweats, and progressive anemic symptoms.

DIAGNOSIS

Total blood count showed severe bicytopenia (normocytic-normochromic anemia and thrombocytopenia), biochemical exams showed elevation of creatinine, as well as monoclonal peak in serum protein electrophoresis, high IgA dosage, and serum immunofixation with IgA kappa paraprotein. Bone marrow biopsy showed 30% of monoclonal and phenotypically anomalous plasmocytes, confirming the diagnosis of MM. Diagnosis of HLH was established by the presence of clinical and laboratory criteria: fever, splenomegaly, cytopenias, hypofibrinogenemia, hyperferritinemia, elevation of triglycerides, and several figures of erythrophagocytosis in bone marrow aspirate.

INTERVENTIONS

The patient experienced pulse therapy with methylprednisolone for hemophagocytic lymphohistiocytosis, followed by initial therapy for multiple myeloma with cyclophosphamide and dexamethasone.

OUTCOMES

Once the diagnosis of MM and secondary hemophagocytic syndrome was established, the patient had a rapid clinical deterioration despite the established therapeutic measures, evolving with cardiovascular failure, acute liver failure, acute disseminated intravascular coagulation, worsening renal dysfunction requiring dialysis support, respiratory dysfunction, and lowering of consciousness, characterizing rapid multiple organ dysfunction, ultimately leading to the death of the patient.

INNOVATION

Here, we aimed to describe the sixth reported case of HLH associated with MM, according to cases cataloged in the PubMed database, and the first case evaluated by 18-fluordeoxyglucose positron emission tomography (18-FDG-PETCT).

CONCLUSION

Our case report seeks to provide support for a better clinical and laboratory characterization of this rare paraneoplastic entity associated with MM, and aims to call the attention of hematologists and intensivists to this condition that falls within the scope of the differential diagnosis of rapid onset multiple organ failure in patients with plasmacytic neoplasms.

Enhancing the Role of the Medical Technologist in Serum Protein Electrophoresis Interpretation: A Pattern Recognition Approach to Identifying Obvious and Potentially Significant Subtle Alterations

Medical technologists who perform serum protein electrophoresis can provide valuable input and assistance in the interpretation of the electrophoretic pattern. Recognition of common alterations in conjunction with the utilization of standardized interpretation comments expedites the final interpretation performed by the clinical pathologist. Improved understanding of the clinical utility of the electrophoretic interpretation enhances the role and satisfaction of the medical technologists.

Crystalglobulin-associated nephropathy presenting as MGRS in a case of monoclonal B-cell lymphocytosis: a case report

BACKGROUND

Crystalglobulin-associated nephropathy (CAN), a rare subtype of monoclonal gammopathy, usually associated with multiple myeloma and occasionally monoclonal gammopathy of uncertain significance (MGUS), is characterized by occluding monoclonal pseudothrombi within renal glomerular capillaries and/or interstitial arterioles. Ultrastructurally, these pseudothrombi are unique for having a crystalline substructure. We describe a case of an adult patient with monoclonal B-cell lymphocytosis (MBL) and acute renal failure whose kidney biopsy revealed a rare diagnosis of CAN.

CASE PRESENTATION

A 63-year old male presented with a 2-month history of edema, arthralgia and malaise. He had acute kidney injury with hematoproteinuria on urine analysis. Serum and urine protein electrophoresis were both negative. A renal biopsy however revealed features of CAN. Organomegaly, bone pain and lymphadenopathy were absent. A repeat serum electrophoresis was positive for IgA kappa and a free light chain assay showed elevated free kappa light chains. Flow cytometry done subsequently revealed a diagnosis of MBL, chronic lymphocytic leukemia (CLL) type.

CONCLUSION

CAN in association with MBL/CLL has not been previously described in literature, and our case highlights yet another instance of monoclonal gammopathy of renal significance (MGRS) where a small B-cell clone resulted in extensive renal pathology without systemic manifestations.

Effects of Long-Term Storage on Serum Free Light Chain Stability

BACKGROUND

Determination and quantification of serum free light chains (FLC) is essential for the diagnosis and monitoring of patients with monoclonal gammopathies. Currently, the Freelite assay (The Binding Site, United Kingdom) and the N Latex FLC assay (Siemens Healthineers, Germany) are available for FLC determination. Data concerning stability of FLC following long-term storage are limited. Therefore, the aim of the present study is to investigate the stability of FLC in frozen samples determined by the N latex FLC assay.

METHODS

One hundred eighty-eight serum samples from 47 patients with monoclonal gammopathies were analyzed at the beginning and after long-term storage (-20°C, 193 - 568 days). Serum free light chain kappa (κFLC) and lambda (λFLC) concentrations were measured, and the corresponding kappa/lambda (κ/λ FLC) ratios were calculated. All samples were analyzed with the N latex FLC assay on a single BNII System.

RESULTS

Comparison analyses between fresh and stored samples revealed very strong correlations for the determination of κFLC (r = 0.993), λFLC (r = 0.998) and the calculated κ/λ FLC ratio (r = 0.997). Median percentage changes of κFLC (-0.5%) and λFLC (-0.8%) measurements and the calculated κ/λ FLC ratios (-3.7%) were within the calculated analytical imprecision of the FLC assay. Changes of κFLC (r = 0.17, p = 0.02) and λFLC (r = 0.28, p < 0.01) concentrations and of the κ/λ FLC ratio (r = 0.18, p = 0.01) over time were very weak, but statistically significant.

CONCLUSIONS

Serum free light chains in serum samples are sufficiently stable following long-term frozen storage and are therefore suitable to be measured with the N Latex FLC assay.

Fibrogenesis Imperfecta Ossium

Fibrogenesis imperfecta ossium (FIO) is an extremely uncommon fatal bone disorder of poorly understood etiology. The pathogenesis of FIO is not well known. The fundamental skeletal defect appears to be an abnormality in organic matrix of bone characterized by defective mineralization of the abnormal collagen. FIO clinically manifests in middle-aged adults presenting with fracture and bone pain. Elevated serum alkaline phosphatase is the only and the most consistent biochemical abnormality. Although paraproteinemia is observed in one-third of cases, the pathogenic link to the disease process is unclear. Limited information on FIO and its close resemblance to many metabolic bone disorders leads to delayed or missed diagnoses and management. Prednisolone, bisphosphonates, melphalan and steroids have been tried previously with variable success. Recently, a trial of recombinant growth hormone therapy was found to be effective. Further research focused on the pathogenetic mechanisms of FIO is needed to identify and develop targeted therapeutic options.

C3 glomerulopathy associated with monoclonal Ig is a distinct subtype

Monoclonal immunoglobulins (MIg) may play a causal role in C3 glomerulopathy (C3G) by impairing regulation of the alternative pathway of complement. Ninety-five patients with C3G were tested for MIg of which 36 were positive. Their mean age at diagnosis was 60 years and among patient 50 years and older, 65.1% had a MIg. At presentation, median serum creatinine and proteinuria were 1.9 mg/dL and 3.0 g/24 hours. Hematuria was present in 32 (88.9%) patients. Twelve (34.3%) patients had low C3 levels. C3 nephritic factor was detected in 45.8% patients; pathogenic variants in complement protein genes were rare. Hematologic evaluation revealed monoclonal gammopathy of renal significance in 26 patients, multiple myeloma in five, smoldering multiple myeloma in two, and chronic lymphocytic leukemia, lymphoma, or type I cryoglobulin each in one patient. After a median follow-up of 43.6 months, the median serum creatinine and proteinuria were 1.4 mg/dL and 0.8g/24 hours. Nine patients developed ESRD. Sixteen patients received MIg-targeted treatment, 17 patients received non-targeted treatment while three patients were managed conservatively. Of the 16 patients receiving MIg-targeted treatment, ten achieved complete/very good/partial hematologic response. Of these, seven achieved a complete/partial/stable renal response. Five patients receiving targeted treatment did not achieve hematologic response, none had a renal response. Patients receiving targeted treatment were more likely to have multiple myeloma/smoldering multiple myeloma. Patients receiving non-targeted treatment were more likely to have monoclonal gammopathy of renal significance. Thus, C3G with MIg is seen in older patients, C3 nephritic factor is the most common autoantibody detected, and MIg-targeted treatment may result in remission and stabilization of kidney function in a subset of these patients.

[A case of neurolymphomatosis presented as cauda equine syndrome accompanied with M-proteinemia]

A 63-year-old man developed a syndrome of cauda equine, with the numbness which is a left lower extremity from the left buttocks, weakness of left leg, and a dysfunction of bladder and bowel. Enhanced MRI revealed the enhancement of lower cauda equine, and a nerve conduction test revealed decreased F-wave persistency in the tibial nerve and increased F-wave latency in the peroneal nerve on the both sides. M-proteinemia was admitted and myeloma was suspected. By a biopsy of a vertebral arch, we diagnosed with diffuse large B-cell lymphoma. We treated with dexamethasone and R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin, prednisone (prednisolone)), then the symptom was improved. In case of caude equine syndrome with M-proteinemia, a possibility of the malignant lymphoma should also be considered.

Serum Thymidine Kinase and Beta-2 Microglobulin in Monoclonal Gammopathies

We evaluated the serum thymidine kinase (TK) and β-2 microglobulin (β-2) levels of 22 patients with monoclonal gammopathy of undetermined significance (MGUS) and of 29 patients with multiple myeloma (MM). Both parameters were significantly lower in MGUS than in MM patients and in early (stage I+II) than in advanced (stage III) MM. TK was also lower in MGUS than in stage I MM (p < 0.025). A seven-fold increase of TK level was documented in one patient who developed a full blown picture of MM 6 years after a diagnosis of MGUS. In 3 patients with stage III MM, a sharp decrease in TK (40–77%) and in β-2 (29–53%) levels at remission was evident with respect to the levels measured at diagnosis. Patients with high levels of TK or [3-2 had a shorter survival than those with low levels; however, this was statistically significant only for β-2 levels (p < 0.02). Serum TK as well as β-2 levels appear to be of clinical value in monoclonal gammopathies and related to the course of the disease.

Biobanking strategy and sample preprocessing for integrative research in monoclonal gammopathies

AIMS

Some types of monoclonal gammopathies are typified by a very limited availability of aberrant cells. Modern research use high throughput technologies and an integrated approach for detailed characterisation of abnormal cells. This strategy requires relatively high amounts of starting material which cannot be obtained from every diagnosis without causing inconvenience to the patient. The aim of this methodological paper is to reflect our long experience with laboratory work and describe the best protocols for sample collection, sorting and further preprocessing in terms of the available number of cells and intended downstream application in monoclonal gammopathies research. Potential pitfalls are also discussed.

METHODS

Comparison and optimisation of freezing and sorting protocols for plasma cells in monoclonal gammopathies, followed by testing of various nucleic acid isolation and amplification techniques to establish a guideline for sample processing in haemato-oncology research.

RESULTS

We show the average numbers of aberrant cells that can be obtained from various monoclonal gammopathies (monoclonal gammopathy of undetermined significance/light chain amyloidosis/multiple myeloma (MM)/MM circulating plasma cells/ minimal residual disease MM-10 123/22 846/305 501/68 641/4000 aberrant plasma cells of 48/30/10/16/37×106 bone marrow mononuclear cells) and the expected yield of nucleic acids provided from multiple isolation kits (DNA/RNA yield from 1 to 200×103 cells was 2.14-427/0.12-123 ng).

CONCLUSIONS

Tested kits for parallel isolation deliver outputs comparable with kits specialised for just one type of molecule. We also present our positive experience with the whole genome amplification method, which can serve as a very powerful tool to gain complex information from a very small cell population.

Circulating Plasma Cells in Monoclonal Gammopathies

BACKGROUND

Monoclonal gammopathies are characterized by presence of clonal plasma cells in the bone marrow, although peripheral blood circulating plasma cells can be found in a significant proportion of patients. The number of circulating plasma cells is an independent prognostic marker associated with shorter survival, but it can also help to predict early relapse. The reason and mechanism of plasma cell expansion from the bone marrow to enter peripheral blood is still not entirely clear, but possible changes in the expression of adhesion molecules are probably involved. Multiparametric flow cytometry allows simple and exact enumeration of circulating plasma cells in different types of cell suspensions, even in their low quantity. The phenotype profile and confirmation of clonality regarding to their bone marrow clonal counterparts should be verified as well. There is no uniform method used in clinical laboratories for circulating plasma cells analyses at this moment.

AIM

Review is focused on use of multiparametric flow cytometry for circulating plasma cells analysis in peripheral blood. It is comparing possibilities of their detection by different methods and on clinical relevance of that assessment. The standardization of analyses is the main goal.

CONCLUSION

Multiparametric flow cytometry is a very sensitive method for detection of circulating plasma cells, so using a standardized approach can lead to determination and implementation of the flow cytometry diagnostic threshold in plasma cell leukemia suspicious cases as well as in prognostication of monoclonal gammopathies patients. Moreover, analysis of plasma cells phenotypic profile could probably clarify their future behaviour.Key words: monoclonal gammopathies - circulating plasma cells - plasma cell leukemia - flow cytometry.

Clinical disorders responsible for plasma hyperviscosity and skin complications

In this brief review, we have examined some clinical disorders which are associated to an altered hemorheological profile and at times accompanied by skin ulcers. This skin condition may be, in fact, observed in patients with primary plasma hyperviscosity such as multiple myeloma, Waldenstrom macroglobulinemia, cryoglobulinemia, cryofibrinogenemia, dysfibrinogenemia and connective tissue diseases. It must be underlined that the altered hemorheological pattern is not the only responsible for this skin complication but, as it worsens the microcirculatory flow, it contributes to determine the occurrence of the skin ulcers.

Laboratory testing in monoclonal gammopathy of renal significance (MGRS)

Recently, monoclonal gammopathy of renal significance (MGRS) reclassified all monoclonal (M) gammopathies that are associated with the development of a kidney disease but do not meet the definition of symptomatic multiple myeloma (MM) or malignant lymphoma. The purpose was to distinguish the M gammopathy as the nephrotoxic agent independent from the clonal mass. The diagnosis of MGRS obviously depends on the detection of the M-protein. More importantly, the success of treatment is correlated with the reduction of the M-protein. Therefore, familiarity with the M-protein tests is a must. Protein electrophoresis performed in serum or urine is inexpensive and rapid due to automation. However, poor sensitivity especially with the urine is an issue particularly with the low-level M gammopathy often encountered with MGRS. Immunofixation adds to the sensitivity and specificity but also the cost. Serum free light chain (sFLC) assays have significantly increased the sensitivity of M-protein detection and is relatively inexpensive. It is important to recognize that there is more than one assay on the market and their results are not interchangeable. In addition, in certain diseases, immunofixation is more sensitive than sFLC. Finally, novel techniques with promising results are adding to the ability to identify M-proteins. Using the time of flight method, the use of mass spectrometry of serum samples has been shown to dramatically increase the sensitivity of M-protein detection. In another technique, oligomeric LCs are identified on urinary exosomes amplifying the specificity for the nephrotoxic M-protein.

Strengths and weaknesses of methods for identifying monoclonal free light chains of Ig: examples from two cases with renal disease

BACKGROUND

Serum free light chain (FLC) analysis with ratio and urine immunofixation electrophoresis (IFE) are both available for routine use in helping to detect plasma cell dyscrasia and related diseases.

CASES

Case reports showing one serum positive for serum FLC but that showed a hook effect and overestimated the amount of monoclonal FLC while urine IFE was negative for Bence Jones protein, and a second serum that showed elevated FLC κ and λ but a normal κ/λ ratio, while urine IFE was positive for Bence Jones protein.

CONCLUSIONS

These two techniques complement one another. Neither of the techniques is truly quantitative, and both exhibit methodological defects.

Vitamin D and plasma cell dyscrasias: reviewing the significance

Monoclonal gammopathy of undetermined significance (MGUS) is a clonal plasma cell disorder and precursor disease to multiple myeloma and other related cancers. While MGUS is considered a benign disorder, with a low risk of disease progression, patients have altered bone microarchitecture and an increased risk of bone fracture. In addition, alterations in immune function are regularly found to correlate with disease activity. Vitamin D, an important hormone for bone and immune health, is commonly deficient in multiple myeloma patients. However, vitamin D deficiency is also prevalent in the general population. The purpose of this review is to highlight the current understanding of vitamin D in health and disease and to parallel this with a review of the abnormalities found in plasma cell dyscrasias. While some consensus statements have advocated for vitamin D testing and routine supplementation in MGUS, there is no clear standard of care approach and clinical practice patterns vary. Further research is needed to better understand how vitamin D influences outcomes in MGUS patients.

Analysis of Monoclonal Antibodies in Human Serum as a Model for Clinical Monoclonal Gammopathy by Use of 21 Tesla FT-ICR Top-Down and Middle-Down MS/MS

With the rapid growth of therapeutic monoclonal antibodies (mAbs), stringent quality control is needed to ensure clinical safety and efficacy. Monoclonal antibody primary sequence and post-translational modifications (PTM) are conventionally analyzed with labor-intensive, bottom-up tandem mass spectrometry (MS/MS), which is limited by incomplete peptide sequence coverage and introduction of artifacts during the lengthy analysis procedure. Here, we describe top-down and middle-down approaches with the advantages of fast sample preparation with minimal artifacts, ultrahigh mass accuracy, and extensive residue cleavages by use of 21 tesla FT-ICR MS/MS. The ultrahigh mass accuracy yields an RMS error of 0.2-0.4 ppm for antibody light chain, heavy chain, heavy chain Fc/2, and Fd subunits. The corresponding sequence coverages are 81%, 38%, 72%, and 65% with MS/MS RMS error ~4 ppm. Extension to a monoclonal antibody in human serum as a monoclonal gammopathy model yielded 53% sequence coverage from two nano-LC MS/MS runs. A blind analysis of five therapeutic monoclonal antibodies at clinically relevant concentrations in human serum resulted in correct identification of all five antibodies. Nano-LC 21 T FT-ICR MS/MS provides nonpareil mass resolution, mass accuracy, and sequence coverage for mAbs, and sets a benchmark for MS/MS analysis of multiple mAbs in serum. This is the first time that extensive cleavages for both variable and constant regions have been achieved for mAbs in a human serum background. Graphical Abstract ᅟ.

Analytical interference by monoclonal immunoglobulins on the direct bilirubin AU Beckman Coulter assay: the benefit of unsuspected diagnosis from spurious results

BACKGROUND

Monoclonal (M) components can interfere with the direct bilirubin (D-Bil) assay on the AU Beckman Coulter instrumentation and produce spurious results, such as D-Bil values greater than total bilirubin (T-Bil) or very low/negative D-Bil values. If properly detected, this interference may uncover undiagnosed patients with monoclonal gammopathy (MG).

METHODS

We investigated the interference rate on the D-Bil AU assay in serum samples known to contain M proteins along with their isotype and described the protocol set up in our laboratory to help with the diagnosis of MG based on D-Bil spurious results as first indication.

RESULTS

During a period of 4 years, 15.4% (345 of 2235) of serum samples containing M immunoglobulins produced erroneous D-Bil results, although no clear relationship between the magnitude or isotype of the M component and interference could be found. In total 22 new patients were diagnosed with MG based on the analytical artefact with the D-Bil as first indication.

CONCLUSIONS

The D-Bil interference from MG on the Beckman AU analysers needs to be made known to laboratories in order to prevent clinical confusion and/or additional workup to explain the origin of anomalous results. Although this information may not add to the management of existing patients with serum paraproteins, it can benefit patients that have not been diagnosed with MG by triggering follow up testing to determine if M components are present.

[Macro-AST and myeloma: An incidental association?]

INTRODUCTION

Macro-AST is recognized as a classical aetiology of isolated and persistent increase of serum aspartate aminotransferase (AST) levels. Macro-AST are high molecular weight complexes associating AST and a macromolecule, often an immunoglobulin. Although those macroenzymes of unknown pathogenesis are usually non-pathogenic, association with several diseases, including autoimmune diseases and liver diseases has been described.

CASE REPORT

We report here the case of a 45-year-old patient with previously normal liver enzymes in whom an AST elevation and an IgA monoclonal gammopathy were discovered concomitantly. Following the diagnosis of multiple myeloma, we could evidence in the patient's serum a complex between AST and the monoclonal IgA. AST levels course followed closely the progression of monoclonal gammopathy.

CONCLUSION

This is the first report demonstrating a clear link between macro-AST and a monoclonal gammopathy.

The Hematologic Definition of Monoclonal Gammopathy of Undetermined Significance in Relation to Paraproteinemic Keratopathy (An American Ophthalmological Society Thesis)

PURPOSE

To determine if paraproteinemic keratopathy (PPK) in the setting of monoclonal gammopathy of undetermined significance (MGUS) causes distinct patterns of corneal opacification that can be distinguished from hereditary, immunologic, or inflammatory causes.

METHODS

A retrospective, interventional study of patients showed distinct bilateral opacity patterns of the cornea at the eye clinics of Hanau, Mainz, Helsinki, Marburg, and Berlin between 1993 and 2015. Data on patient characteristics and clinical features on ophthalmic examination were collected, and serum protein profiles were evaluated. A literature review and analysis of all published studies of MGUS with PPK is also presented.

RESULTS

The largest group of patients diagnosed with MGUS-induced PPK is analyzed in this study. We studied 22 eyes of 11 patients (6 male, aged 43 to 65, mean age 54; 5 female, aged 49 to 76, mean age 61) with distinct corneal opacities and visual impairment who were first suspected of having hereditary, inflammatory, or immunologic corneal entities. Subsequently, serum protein electrophoresis revealed MGUS to be the cause of the PPK. Literature review revealed 72 patients with bilateral PPK (34 male, mean age 57; 38 female, mean age 58) in 51 studies of MGUS published from 1934 to 2015 and disclosed six additional corneal opacity patterns.

CONCLUSIONS

This thesis shows that MGUS is not always an asymptomatic disorder, in contrast to the hematologic definition, which has no hint of PPK. The MGUS-induced PPK can mimic many other diseases of the anterior layer of the eye. A new clinical classification for PPK in MGUS is proposed.

Low Levels of Serum Cholesterol/Phospholipids are Associated with the Antiphospholipid Antibodies in Monoclonal Gammopathy

A decrease in cholesterol blood level, not due to a decrease synthesis by the liver, has been observed in patients suffering from tumors. In this work cholesterol blood was evaluated in patients affected by monoclonal gammopathy who were not subjected to any treatment. The blood of 25 patients were analyzed for protein and lipid content. Patients were divided according to the gamma protein content into three groups, and it was demonstrated that the group with high levels of gamma proteins presented a strong decrease in blood cholesterol and phospholipids. In these patients the presence of antibodies against phospholipids by using cardiolipin and phosphatidylinositol as antigens has also been demonstrated. The antibodies were rare in patients with a low content of gamma proteins and normal level of lipids, but the frequency was more than 80% in patients with low blood lipid levels.

Lenalidomide as a novel treatment for refractory acquired von Willebrand syndrome associated with monoclonal gammopathy

Essentials Treatment options are limited for refractory bleeding in acquired von Willebrand Syndrome (AVWS). Lenalidomide therapy was studied in two patients with AVWS due to monoclonal gammopathy (MG). Lenalidomide increased von Willebrand factor (VWF), lowered VWF clearance and resolved bleeding. Lenalidomide is a potential treatment option for refractory bleeding in AVWS secondary to MG.

SUMMARY

Background Acquired von Willebrand syndrome (AVWS) is associated with lymphoproliferative disorders, including monoclonal gammopathy (MG) of undetermined significance (MGUS) and multiple myeloma. Patients commonly present with significant bleeding complications that are difficult to manage, owing to a markedly reduced von Willebrand factor (VWF) half-life. Objectives To investigate the use of the immunomodulatory drug lenalidomide in two patients with severe refractory bleeding caused by AVWS associated with MGs. Results In both patients, lenalidomide treatment resulted in significant clinical improvement, and marked increases in plasma VWF antigen (VWF:Ag) and VWF ristocetin cofactor levels. This normalization in plasma VWF levels was sustained for > 2 years in both patients. Furthermore, in one patient, plasma VWF levels remain normal for at least 14 months following discontinuation of lenalidomide treatment. To investigate the molecular mechanisms underlying these observations, VWF propeptide (VWFpp)/VWF:Ag ratios were analyzed to assess VWF clearance. At enrolment, plasma VWFpp/VWF:Ag ratios were significantly elevated in both patients. Importantly, lenalidomide treatment resulted in normalization of VWFpp/VWF:Ag ratios in both patients. These novel data suggest that lenalidomide functions to attenuate enhanced VWF clearance in AVWS. Interestingly, in a patient with MGUS, lenalidomide treatment was associated with a significant increase in plasma VWF levels, despite no major change in paraprotein level. Conclusions Collectively, our findings suggest that lenalidomide constitutes a novel therapeutic option for the management of AVWS associated with MG. The biological mechanism(s) through which lenalidomide causes a sustained increase in plasma VWF levels in AVWS independently of paraprotein level requires further study, but is in part modulated through inhibition of enhanced VWF clearance.

Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to detect monoclonal immunoglobulin light chains in serum and urine

RATIONALE

Use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to monitor serum and urine samples for endogenous monoclonal immunoglobulins. MALDI-TOFMS is faster, fully automatable, and provides superior specificity compared to protein gel electrophoresis (PEL).

METHODS

Samples were enriched for immunoglobulins in 5 min using Melon Gel™ followed by reduction with dithiothreitol for 15 min to separate immunoglobulin light chains and heavy chains. Samples were then desalted using C4 ZipTips, mixed with sinapinic acid matrix, and analyzed on a Bruker Biflex III MALDI-TOF mass spectrometer.

RESULTS

Monoclonal immunoglobulin light chains were identified in serum and urine samples from patients with a known monoclonal gammopathy using MALDI-TOFMS with minimal sample preparation.

CONCLUSIONS

MALDI-TOFMS can identify a monoclonal immunoglobulin in serum and urine samples. The molecular mass of the monoclonal immunoglobulin light chain is obtained providing unprecedented specificity compared to PEL. In addition, the methodology can be automated, making it a practical alternative to PEL.

Lymphoplasmacytic Lymphoma with IgA Paraproteinemia

BACKGROUND

Lymphoplasmacytic lymphoma is a type of B-cell Non-Hodgkin's lymphoma. The monoclonal immunoglobulin of IgA type is rarely seen in the clinical practice.

METHODS

We report a patient with anemia, thrombocytopenia, hepatomegaly, and splenomegaly. Serum immuno-electrophoresis, bone marrow morphology, and flow cytometry assays were used for the diagnosis of this patient.

RESULTS

The monoclonal gammopathy was detected in the serum protein electrophoresis. The serum immunoelectrophoresis was of IgA-λ type and serum IgA level was high. The bone marrow aspiration exhibited a large number of prominent lymphoplasmacytoid lymphocytes. Immunophenotype of lymphoplasmacytoid lymphocytes showed: CD38+, CD138+, CD19+, CD20+. The patient was diagnosed as Lymphoplasmacytic Lymphoma with IgA paraproteinemia.

CONCLUSIONS

For patients whose bone marrow aspiration reveals lymphoplasmacytoid lymphocytes while the monoclonal immunoglobulin is not of IgM type, further diagnosis should be performed to determine the characteristic of the tumor cells, in order to diagnose if it is a rare type of LPL.

Combined light chain immunofixation to detect monoclonal gammopathy: a comparison to standard electrophoresis in serum and urine

BACKGROUND

The purpose of this study was to evaluate a combined κ and λ light chain immunofixation (CLIF) as a screening tool to detect monoclonal immunoglobulins in serum and urine. A secondary aim was to investigate the impact on workflow and reagent utilisation of a systematic implementation of CLIF in addition to routine protein electrophoresis (PE) on all samples.

METHODS

Light chain antisera (κ and λ) were mixed in a 1:1 ratio and loaded in the same sequence as the PE to create a superimposable image.

RESULTS

The CLIF procedure agreed significantly better with standard immunofixation procedures in the serum and urine. In 33 (22%) new patients and in 114 (15%) follow-up patients CLIF detected a band missed by PE in serum. In 34 (4.5%) of previously categorised cases the monoclonal band was below the detection limit of CLIF in serum, but still detectable by conventional immunofixation electrophoresis. In one case (0.7%) a band in a urine specimen was missed by CLIF compared to 70 (49%) missed by PE. After the systematic introduction of CLIF turn-around-times (TATs) and utilisation of laboratory consumables decreased significantly (p<0.001).

CONCLUSIONS

A systematic implementation of CLIF led to the detection of monoclonal bands missed by PE with an improvement in TATs and a decrease in cost.

Japanese POEMS syndrome with Thalidomide (J-POST) Trial: study protocol for a phase II/III multicentre, randomised, double-blind, placebo-controlled trial

INTRODUCTION

Polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome is a fatal systemic disorder associated with plasma cell dyscrasia and the overproduction of the vascular endothelial growth factor (VEGF). Recently, the prognosis of POEMS was substantially improved by introduction of therapeutic intervention for myeloma. However, no randomised clinical trial has been performed because of the rarity and severity of the disease.

METHODS AND ANALYSIS

The Japanese POEMS syndrome with Thalidomide (J-POST) Trial is a phase II/III multicentre, double-blinded, randomised, controlled trial that aims to evaluate the efficacy and safety of a 24-week treatment with thalidomide in POEMS syndrome, with an additional 48-week open-label safety study. Adults with POEMS syndrome who have no indication for transplantation are assessed for eligibility at 12 tertiary neurology centres in Japan. Patients who satisfy the eligibility criteria are randomised (1:1) to receive thalidomide (100-300 mg daily) plus dexamethasone (12 mg/m(2) on days 1-4 of a 28-day cycle) or placebo plus dexamethasone. Both treatments were administered for 24 weeks (six cycles; randomised comparative study period). Patients who complete the randomised study period or show subacute deterioration during the randomised period participate in the subsequent 48-week open-label safety study (long-term safety period). The primary end point of the study is the reduction rate of serum VEGF levels at 24 weeks.

ETHICS AND DISSEMINATION

The protocol was approved by the Institutional Review Board of each hospital. The trial was notified and registered at the Pharmaceutical and Medical Devices Agency, Japan (No. 22-1716). The J-POST Trial is currently ongoing and is due to finish in August 2015. The findings of this trial will be disseminated through peer-reviewed publications and conference presentations and will also be disseminated to participants.

TRIAL REGISTRATION NUMBER

UMIN000004179 and JMA-IIA00046.

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.

Analytical performance and diagnostic potential of immunoassays determining intact immunoglobulin kappa/lambda ratios in monoclonal gammopathies

BACKGROUND

Hevylite chain (HLC) assays with specificity for epitopes at the junction between heavy and light chains of intact immunoglobulins (Ig) allow quantification of Ig kappa/lambda ratios of the three major Ig classes. Calculated Ig kappa/lambda ratios outside the reference range indicate a monoclonal background. The primary aim of the present study was to analytically validate HLC assays and to investigate their diagnostic potential in relation to immunofixation electrophoresis (IFE) as the standard method for identification of monoclonal proteins (MPs). A second aim was to investigate the diagnostic potential of HLC assays in disease monitoring.

METHODS

Precision, linearity, accuracy, sensitivity, and specificity of HLC assays for Ig classes A, G, and M were determined as parameters of analytical performance. The diagnostic performance of HLC assays in the detection of MPs was investigated in patient sera revealing monoclonal bands in IFE (n = 156). The utility of the assays in disease monitoring was investigated in a proof of principal approach by quantification of HLC ratios in subsequent sera from stem cell transplanted (ScTx) myeloma patients (n = 4).

RESULTS

All six HLC assays revealed analytical performances suitable for application in routine diagnostics. With regard to diagnostic performance, all samples with IgA MPs in IFE (n = 54) could be identified in the HLC IgA assay. Of sera showing IgG MP in IFE (n = 69), 57 could be identified in the HLC IgG assay, whereas 12 had normal IgG kappa/lambda ratios. Of sera showing IgM MP in IFE (n = 26), 25 could be identified in the HLC IgM assay, 1 serum revealed a normal IgM kappa/lambda ratio. ScTx patients achieving IFE-negative remission had normal HLC ratios. Those who failed to achieve IFE-negative remission showed normalization of conventional monitoring parameters but revealed HLC ratios never reaching reference range.

CONCLUSIONS

HLC assays exhibit analytical performances suitable for clinical routine application. Our preliminary data from ScTx patients suggest a diagnostic potential especially of HLC IgA assay in disease monitoring. Other than that, combined application of HLC assays does not represent an alternative to IFE in first line diagnostics, in particular due to the limited diagnostic performance of the HLC IgG assay.

A Case of Type I Cryoglobulinemia Associated with a Monoclonal Gammopathy of Undetermined Significance (MGUS)

A 79-year-old Japanese male who had been suffering from renal insufficiency of unknown causes visited us with reddish papules and purpura on both forearms of a month's duration. A skin biopsy was performed from the right forearm, and the histopathology showed an obstruction of superficial blood vessels with eosinophilic amorphous materials suggesting cryoglobulins. Although further investigations revealed the presence of monoclonal immunoglobulin (Ig) G-kappa type I cryoglobulin, a bone marrow biopsy demonstrated that there was 7.6% proliferation of plasmacytoid cells, and the serum level of Ig G was less than 3 g/dl. The diagnosis was type I cryoglobulinemia associated with monoclonal gammopathy of undetermined significance as the possible cause of chronic renal failure. Therefore, purpuric changes on extremities of the elderly, especially those complaining of renal failure should, be taken seriously and not regarded simply as an age-related phenomenon.

Poor performance of the total kappa/lambda light chain quantification in the diagnosis and follow-up of patients with multiple myeloma

BACKGROUND

The gold standard for paraproteinemia screening in plasma cell disorders has been serum protein electro- phoresis (SPE) with immunofixation electrophoresis (IFx); serum total and free light chain quantifications have also been used.

OBJECTIVE

To define the role of SPE, IFx and serum total light chain (sLC) determinations in patients with multiple myeloma (MM), both at diagnosis and at maximum response during treatment follow-up.

MATERIAL AND METHODS

These serological studies were performed in a group of 62 patients with MM at diagnosis, and in a subset of 29 patients at the point of maximum response to treatment.

RESULTS

At diagnosis, we found an abnormal SPE in 58%, an abnormal IFx in 92% and an abnormal sLC in 45% of the 62 patients; 64% had simultaneously abnormal results in all three serological studies. IFx alone proved to be the most sensitive of all three assays, followed by SPE, which was redundant in most instances with sLC and IFx. At maximum response, the abnormal SPE normalized in 7 cases, the abnormal IFx in 7 cases and the abnormal sLC in 7 cases. There were 12 instances in which an abnormal IFx was found despite normal sLC, and one case in which a normal IFx was found in the presence of abnormal sLC. The association between IFx and sLC was highly significant (r = 0.9274611, p < 0.000001), despite instances where a positive result for IFx was associated to a normal sLC.

CONCLUSION

All three serological methods should ideally be simultaneously performed in patients with MM both at diagnosis and throughout therapy. In this series, the total sLC assay was not more sensitive than IFx neither at diagnosis nor during follow-up.

Thrombosis in multiple myeloma

Multiple myeloma, as with other malignancies, has been associated with the development of venous thromboembolic events. Chemotherapy or steroids in combination with antiangiogenic agents can further enhance this risk. The identification of measurable factors associated with this prothrombotic state could help in the selection of patients who need antithrombotic prophylaxis. Malignancy-associated thrombophilic state, paraprotein-specific mechanisms and treatment-induced changes can explain the high rate of thrombosis in this cancer population. While the release of inflammatory cytokines induces high levels of factor VIII, von Willebrand factor and downregulate the protein C system, elevated plasma immunoglobulin can impair fibrinolysis. Strategies of thromboprophylaxis with low molecular weight heparin, warfarin or aspirin in patients treated with thalidomide/chemotherapy or lenalidomide and dexamethasone have shown efficacy. Early data indicate that the effect of low molecular weight heparin on multiple myeloma is not confined to the anticoagulant effect but could extend to survival; a similar positive trend in overall survival has also been reported in patients treated with aspirin.

C-src enriched serum microvesicles are generated in malignant plasma cell dyscrasia

Plasma cell dyscrasias are immunosecretory disorders that can lead to hematological malignancies such as Multiple Myeloma (MM). MM accounts for 15% of all hematologic cancers, and those diagnosed with MM typically become severely ill and have a low life expectancy. Monoclonal immunoglobulin Free Light Chains (FLC) are present in the serum and urine of many patients with plasma cell diseases. The biological differences between monoclonal FLCs, produced under malignant or benign dyscrasias, has not yet been characterized. In the present study, we show that endothelial and heart muscle cell lines internalize kappa and lambda FLCs. After internalization, FLCs are rerouted in the extracellular space via microvesicles and exosomes that can be re-internalized in contiguous cells. Only FLCs secreted from malignant B Lymphocytes were carried in Hsp70, annexin V, and c-src positive vesicles. In both MM and AL Amyloidosis patients we observed an increase in microvesicle and exosome production. Isolated serum vesicles from MM, AL Amyloidosis and monoclonal gammopathy of undetermined significance (MGUS) patients contained FLCs. Furthermore MM and AL amyloidosis vesicles were strongly positive for Hsp70, annexin V, and c-src compared to MGUS and control patients. These are the first data implying that FLCs reroute via microvesicles in the blood stream, and also suggest a potential novel mechanism of c-src activation in plasma cell dyscrasia.

Oligosecretory biclonal multiple myeloma

Among the plasma cell dyscrasias, non-secretory myeloma is one of the rarest. This diagnosis is based on the absence of monoclonal proteins in the serum and urine. When serum free light chains are trace and the kappa: lambda ratio normal, clonality may however be established by PCR. We present a case of an oligosecretory myeloma confirmed by PCR, which would have hitherto been classified as non-secretory.

Interpretation and clinical significance of small monoclonal peaks in capillary electrophoresis

BACKGROUND

Although the testing mechanism and interpretation criteria for capillary electrophoresis differ from those for gel-based electrophoresis, there are not that many reports on the efficacy of capillary electrophoresis.

MATERIALS AND METHODS

We performed a retrospective analysis, using the Laboratory Information System (LIS) to review a total of 163 capillary electrophoresis results from 117 different patients treated in our hospital between March and August 2012. Capillary electrophoresis was performed on capillary2 (Sebia, Lysse, France).

RESULTS

Among the patients' group, 4 patients presented very small M-peaks in capillary electrophoresis. By using the zoom function in capillary electrophoresis, two of them were confirmed to have monoclonality, but the remaining two required reconfirmation in gel electrophoresis, leading to confirmation of a discrete monoclonal band.

CONCLUSION

In this study, we found that small peaks in capillary electrophoresis accompanying a skewed K/L ratio deserve particular attention as they can grow into larger peaks within a few months. We suggest that any trivial M-peak in capillary electrophoresis should not be overlooked and that a combination of platform tests such as gel electrophoresis or FLC assay be implemented in order to confirm monoclonality.

[Morphological and immunochemical features of nephropathies in multiple myeloma and severe renal failure]

AIM

To study the pathomorphology of kidneys in patients with multiple myeloma (MM) and severe renal failure (RF) and to compare the results of morphological, immunohistochemical, and electron microscopic examinations of nephrobiopsy specimens with the pattern of monoclonal secretion and the type of proteinuria and paraproteinuria.

SUBJECTS AND METHODS

A study group comprised 25 patients with MM and severe RF; 22 of them underwent programmed hemodialysis. Immunochemical study of serum and urine proteins, renal puncture biopsy with light, immunofluorescence and electron microscopy examination of its specimens were performed in all the patients.

RESULTS

Cast nephropathy (CN) is the most common type of renal impairment in patients with MM and severe RF. CN concurrent with monoclonal immunoglobulin deposition disease was identified in 32% of cases. In the mixed lesion, it is CN that is a determinant in the development of acute and chronic RF. Rare variants of nephropathies as fibrillary glomerulonephritis, immunotactoid nephropathy, and crystalline histiocytosis were found in 16% of cases. In most cases, severe RF in MM develops in case of low monoclonal secretion. However, there are a larger number of secreted and excreted monoclonal light chains in CN than in other variants of kidney lesion. Urinary paraprotein G excretion suggests that the glomerular filter is damaged. Degenerative changes in the podocytes and a reduction in their small processes were detected in the majority of cases. In glomerular or mixed proteinuria, there were also unorganized and organized deposits in the glomerular basement membrane.

CONCLUSION

The pattern of nephropathy does not determine a renal response after chemotherapy. The reversibility of CN in MM depends on the magnitude of interstitial fibrosis and podocyte changes. The pronounced changes in the podocytes as a reduction in their small processes serves as a poor sign in achieving renal responses following chemotherapy.

Neuropathy and monoclonal gammopathy

The association of neuropathy with monoclonal gammopathy has been known for several years, even if the clinical and pathogenetic relevance of this association is not completely defined. This is not a marginal problem since monoclonal gammopathy is present in 1-3% of the population above 50 years in whom it is often asymptomatic, and in at least 8% of patients is associated with a symptomatic neuropathy, representing one of the leading causes of neuropathy in aged people. Monoclonal gammopathy may result from malignant lymphoproliferative diseases including multiple myeloma or solitary plasmocytoma, Waldenström's macroglobulinemia (WM), other IgM-secreting lymphoma or chronic lymphocytic leukemia, and primary systemic amyloidosis (AL). In most instances it is not associated with any of these disorders and is defined monoclonal gammopathy of undetermined significance (MGUS) for its possible, though infrequent, evolution into malignant forms. Several data support the pathogenetic role of the monoclonal gammopathy in the neuropathy particularly when of IgM isotype where IgM reactivity to several neural antigens has been reported. Increased levels of VEGF have been implicated in POEMS syndrome. However, there are as yet no defined therapies for these neuropathies, as their efficacy has not been confirmed in randomized trials.

[Case of pseudohypercreatininemia associated with monoclonal IgM gammopathy]

An 80-year-old man with well controlled hypertension for eight years and monoclonal IgM gammopathy was referred to our hospital in May 2010 due to persistent elevation of serum creatinine(s-Cr). At our hospital, urine and blood tests showed no abnormal findings as BUN and Cr were 15.0 mg/dL and 0.91 mg/dL, respectively. In contrast the referring hospital had obtained values of 10.4 mg/dL and 4.8 mg/dL, respectively. This discrepancy was replicated when s-Cr was measured in another sample from this patient using the enzyme assay kits employed by the referring hospital and our hospital. High-performance liquid chromatography (HPLC), which is the standard method for measuring s-Cr, gave a value in the normal range. After removing high molecular weight proteins (>3,000 D)from the serum sample, the s-Cr levels measured with the respective kits were similar. Since elevation of s-Cr was linked to that of IgM at the referring hospital, we diagnosed the patient as having pseudohypercreatininemia with monoclonal IgM gammopathy.

Indications for bone marrow examination in autoimmune disorders with concurrent haematologic alterations

OBJECTIVES

The aim of this study was to evaluate the aetiology of 'unexplained' cytopenias in patients with autoimmune disorders, as well as to identify parameters that should alert clinicians to the need for bone marrow examination.

METHODS

During the study period (2005-2010), 110 consecutive patients with an underlying systemic autoimmune disease, excluding Sjogren's syndrome, were referred for haematological consultation and bone marrow examination, due to cytopenias without evident cause including blood loss, haemolysis, nutritional deficiencies and haemoglobin disorders.

RESULTS

Systemic lupus erythaematosus was the most frequent underlying condition (38/110, 34.5%), and anaemia (haemoglobin<12gr/dl) the most common haematologic abnormality (81/110, 74%). Prior to evaluation, more than half of the patients received cytotoxic or immunosuppressive drugs, with methotrexate being the most commonly administrated agent (29/110, 26.4%). Evaluation was informative in 31 (28.2%) of the cases. Twenty-four (21.8%) cases of haematologic clonal disease were diagnosed; 11 myelodysplastic syndromes, 6 lymphoproliferative disorders, 6 plasma cell dyscrasias and one myeloproliferative neoplasm. Seven cases (6.4%) with bone marrow toxicity were also noted. Male gender, serum iron >90 μg/dl, mean corpuscular volume (MCV) >90fl, and serum monoclonal band were significant predictors of specific diagnosis including clonal haematologic disorder or bone marrow toxicity. All other correlations were insignificant.

CONCLUSIONS

Clonal haematologic disorders and toxicity are frequent findings in patients with autoimmunity referred for haematologic consultation, owing to otherwise unexplained cytopenias. Patients with high serum iron, high MCV and presence of serum monoclonal band should undergo bone marrow examination to exclude haematologic malignancy or bone marrow toxicity.

Extremely high parathyroid hormone concentrations associated with pityriasis rubra pilaris and monoclonal gammopathy of unknown significance: a clinical dilemma

We present a case with extremely high parathyroid hormone (PTH) concentrations in the order of hundred thousands accompanied by dermatological and hematological diseases. After several diagnostic interventions, no malignancy could be demonstrated except monoclonal gammopathy of unknown significance. The dermatological findings were taken to be manifestations of the hematological disease. Since the first serum intact PTH concentration of the patient was found to be higher than 2500 pg/ml, dilution study was performed and found to be 215,977 pg/ml. The high concentration of serum PTH was taken to be falsely high due to assay interference. This concentration was checked from three different paths; a test for linear dilution was performed, the test was repeated with another method and the sample was treated to remove or inhibit interfering substances. The results were compatible with endogenous antibody interference, presumed to be a result of monoclonal gammopathy. The extremely high PTH concentrations were not only due to assay interference, but also secondary hyperparathyroidism, which was evident by the decrease in PTH concentrations with calcium and vitamin D treatments.

Monoclonal B-cell lymphocytosis (MBL) with normal lymphocyte counts is associated with decreased numbers of normal circulating B-cell subsets

Monoclonal B-cell lymphocytosis (MBL) with normal lymphocyte counts is associated with decreased numbers of normal circulating B-cell subsets.Little is known about the distribution of normal lymphoid cells and their subsets in the peripheral blood (PB) of subjects with monoclonal B-cell lymphocytosis (MBL). In our study, we compared the absolute number of PB lymphoid cells and their subpopulations in 95 MBL cases with normal lymphocyte counts vs. 617 age-/sex-matched non-MBL healthy subjects (controls), using highly sensitive flow cytometry. MBL cases showed significantly reduced numbers of normal circulating B-cells, at the expense of immature and naive B-cells; in addition, CD4+CD8+ double-positive T-cells and CD8+ T-cells were significantly lower and higher vs. controls, respectively. Moreover, most normal B-cell subsets were significantly decreased in PB at >1% MBL-counts, vs. "low-count" MBL cases, and lower amounts of immature/naive B-cells were detected in biclonal (particularly in cases with coexisting CLL-like- and non-CLL-like B-cell clones) vs. monoclonal MBL subjects. In summary, our results show imbalanced (reduced) absolute numbers of recently produced normal circulating B-cells (e.g., immature and naıve B-cells) in MBL, which becomes more pronounced as the MBL cell count increases.