Monoclonal gammopathies of undetermined significance: a review

Elevated Total Serum Immunoglobulin A Levels in Patients with Suspicion for Celiac Disease

Patients with classic symptoms of celiac disease are often initially tested for serum tissue transglutaminase-immunoglobulin A (tTG-IgA) and total serum immunoglobulin A (IgA) levels concurrently, as IgA deficiency can lead to falsely low tTG-IgA. There are no guidelines for incidental findings of elevated total serum IgA when testing for celiac disease. In our study, we described the proportion of patients with suspicion of celiac disease who had elevated total serum IgA and the factors that may be associated with these findings. We studied the management of these patients with incidental findings of elevated total serum IgA to identify its clinical significance. To investigate, we performed a retrospective chart review of patients who underwent celiac disease serologic testing at a single clinic from January 2017 to June 2022. We reported further laboratory workup and follow-up for patients with incidental findings of elevated total serum IgA by board-certified immunologists. In our chart review, 848 patients were identified, 85 (10.0%) of whom were found to be negative for celiac disease but had elevated total serum IgA levels (median IgA 351 mg/dL, interquartile range 324-382). Out of 85 patients, 73 were further evaluated by immunologists, with 55 patients undergoing additional laboratory workup. None were diagnosed with specific immunologic conditions. Male sex was identified as associated with elevated total serum IgA findings, and constipation was found in a statistically significant greater frequency of patients with normal total serum IgA rather than elevated total serum IgA. To provide external validation of our findings, we created a second patient cohort within the Stanford Research Repository database. Out of 33,875 patients identified, a similarly high proportion of patients were negative for celiac disease but had elevated total serum IgA levels (9.3%, 3140 patients). In this separate patient cohort, male sex was also identified as being associated with elevated total serum IgA. Our study also provides preliminary evidence that patients with incidental findings of elevated total serum IgA may not need further management or workup, as these abnormalities may not be clinically relevant without other clinical suspicions.

Multi-trajectory models of serum biomarkers among patients with monoclonal gammopathy of undetermined significance

Understanding the progression of monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM) is needed to identify patients who would benefit from closer clinical surveillance. Given that two of the defining criteria of MM are renal failure and anemia, we described the trajectories of creatinine (Cr) and hemoglobin (Hgb) over time in patients with a diagnosis of MGUS. Patients diagnosed with MGUS (n = 424) were identified by a previously validated case-finding algorithm using health claims and electronic health record data (2007-2015) and followed through 2018. Group-based trajectory modeling identified patients with distinct laboratory value trajectories of Cr (mg/dl) and Hgb (g/dl). Most patients were non-Hispanic White (97.6%) with a mean age of 75 years at MGUS diagnosis. Three multi-trajectory groups were identified: (1) Normal Cr/Hgb (n = 225; 53.1%)-stable serum Cr levels and decreasing, normal Hgb levels; (2) Normal Cr/lower-normal Hgb group (n = 188; 44.3%)-stable, slightly elevated levels of Cr and decreasing levels of Hgb; and (3) High Cr/borderline Hgb group (n = 11; 2.6%)-increased Cr levels and stable low levels of Hgb. Patients with MGUS in Group 2 were older than patients in other groups, and patients in group 3 had more comorbidities than participants in all other groups. Few patients developed MM during the study period. We were able to identify distinct biomarker trajectories in patients with MGUS over time. Future research should investigate how these trajectories may be related to the risk of progression to MM, including M-protein levels.

MYD88L265P Detection in IgM Monoclonal Gammopathies: Methodological Considerations for Routine Implementation

In IgM monoclonal gammopathies MYD88^L265P is a prognostic and predictive biomarker of therapy response. MYD88^L265P detection is mainly performed by allele-specific quantitative PCR (ASqPCR), however recently, droplet digital PCR (ddPCR) has been proved to be suitable for MYD88^L265P screening and minimal residual disease monitoring (MRD). This study compared ASqPCR and ddPCR to define the most sensitive method for MYD88^L265P detection in bone marrow (BM), peripheral blood (PB) sorted or unsorted CD19+ cells, and in plasma cell-free DNA (cfDNA). Overall, the analysis showed a good concordance rate (74%) between the two methods, especially in BM samples, while discordances (26%) were mostly in favor of ddPCR (ddPCR+ vs. ASqPCR-) and were particularly evident in samples with low mutational burden, such as PB and cfDNA. This study highlights ddPCR as a feasible approach for MYD88^L265P detection across different specimen types (including cfDNA). Interestingly, its high sensitivity makes CD19+ selection dispensable. On the other hand, our results showed that MYD88^L265P detection on PB samples, especially with ASqPCR, is suboptimal for screening and MRD analysis. Finally, significantly different MYD88^L265P mutational levels observed between Waldenström Macroglobulinemia and IgM monoclonal gammopathy of undetermined significance patients suggest the need for further studies in order to identify possible correlations between mutational levels and risk of progression to Waldenström.

Risk factors for monoclonal gammopathy of undetermined significance: a systematic review

Monoclonal gammopathy of undetermined significance (MGUS), precursor of multiple myeloma, is an asymptomatic plasma cell disorder that overproduces serum monoclonal protein. Older age, male sex, black race, and family history of MGUS increase the risk of MGUS, yet other risk factors are known. We systematically reviewed observational epidemiological studies that examined sociodemographic, clinical, and behavioral risk factors for the development of MGUS. The protocol for this study was registered on the PROSPERO registry for systematic reviews. We identified epidemiological studies from PubMed and Scopus. Articles were limited to those written in English and published before February 2019. Five case-control and three cohort studies were eligible for data extraction. Studies evaluating factors associated with MGUS risk are limited, with conflicting conclusions regarding risk associated with obesity. Despite the limited research, a significant elevated risk for being diagnosed with MGUS was associated with several specific prior infections, inflammatory disorders, and smoking. The sparse existing literature suggests an increased risk of MGUS associated with several risk factors related to immune function. Further research is needed to explore the potential mechanisms underlying the development of MGUS and to confirm risk factors, both modifiable and non-modifiable.

Older Human B Cells and Antibodies

B cells have a number of different roles in the immune response. Their excellent antigen presentation potential can contribute to the activation of other cells of the immune system, and evidence is emerging that specialized subsets of these cells, that may be increased with age, can influence the cell-mediated immune system in antitumor responses. They can also regulate immune responses, to avoid autoreactivity and excessive inflammation. Deficiencies in regulatory B cells may be beneficial in cancer but will only exacerbate the inflammatory environment that is a hallmark of aging. The B cell role as antibody producers is particularly important, since antibodies perform numerous different functions in different environments. Although studying tissue responses in humans is not as easy as in mice, we do know that certain classes of antibodies are more suited to protecting the mucosal tissues (IgA) or responding to T-independent bacterial polysaccharide antigens (IgG₂) so we can make some inference with respect to tissue-specific immunity from a study of peripheral blood. We can also make inferences about changes in B cell development with age by looking at the repertoire of different B cell populations to see how age affects the selection events that would normally occur to avoid autoreactivity, or increase specificity, to antigen.

Evaluation of in vitro effects of various targeted drugs on plasma cells and putative neoplastic stem cells in patients with multiple myeloma

Multiple myeloma (MM) is a malignancy characterized by monoclonal paraproteinemia and tissue plasmocytosis. In advanced MM cytopenia and osteopathy may occur. Although several effective treatment strategies have been developed in recent years, there is still a need to identify new drug targets and to develop more effective therapies for patients with advanced MM. We examined the effects of 15 targeted drugs on growth and survival of primary MM cells and 5 MM cell lines (MM.1S, NCI-H929, OPM-2, RPMI-8226, U-266). The PI3-kinase blocker BEZ235, the pan-BCL-2 inhibitor obatoclax, the Hsp90-targeting drug 17AAG, and the Polo-like kinase-1 inhibitor BI2536, were found to exert major growth-inhibitory effects in all 5 MM cell lines tested. Moreover, these drugs suppressed the in vitro proliferation of primary bone marrow-derived MM cells and induced apoptosis at pharmacologic drug concentrations. Apoptosis-inducing effects were not only seen in the bulk of MM cells but also in MM stem cell-containing CD138⁻/CD20⁺/CD27⁺ memory B-cell fractions. Synergistic growth-inhibitory effects were observed in MM cell lines using various drug combinations, including 17AAG+BI2536 in MM.1S, OPM-2, RPMI-8226, and U-266 cells, 17AAG+BEZ235 in MM.1S, OPM-2, RPMI-8226, and U-266 cells, 17AAG+obatoclax in MM.1S, NCI-H929, OPM-2, and RPMI-8226 cells, BI2536+BEZ235 in MM.1S, NCI-H929, OPM-2, and RPMI-8226 cells, BI2536+obatoclax in MM.1S, OPM-2 and RPMI-8226 cells, and BEZ235+obatoclax in MM.1S and RPMI-8226 cells. Together, our data show that various targeted drugs induce profound and often synergistic anti-neoplastic effects in MM cells which may have clinical implications and may contribute to the development of novel treatment strategies in advanced MM.

Long Non-Coding RNAs in Multiple Myeloma

Multiple myeloma (MM) is an incurable disease caused by the malignant proliferation of bone marrow plasma cells, whose pathogenesis remains largely unknown. Although a large fraction of the genome is actively transcribed, most of the transcripts do not serve as templates for proteins and are referred to as non-coding RNAs (ncRNAs), broadly divided into short and long transcripts on the basis of a 200-nucleotide threshold. Short ncRNAs, especially microRNAs, have crucial roles in virtually all types of cancer, including MM, and have gained importance in cancer diagnosis and prognosis, predicting the response to therapy and, notably, as innovative therapeutic targets. Long ncRNAs (lncRNAs) are a very heterogeneous group, involved in many physiological cellular and genomic processes as well as in carcinogenesis, cancer metastasis, and invasion. LncRNAs are aberrantly expressed in various types of cancers, including hematological malignancies, showing either oncogenic or tumor suppressive functions. However, the mechanisms of the related disease-causing events are not yet revealed in most cases. Besides emerging as key players in cancer initiation and progression, lncRNAs own many interesting features as biomarkers with diagnostic and prognostic importance and, possibly, for their utility in therapeutic terms as druggable molecules. This review focuses on the role of lncRNAs in the pathogenesis of MM and summarizes the recent literature.

Distinct lncRNA transcriptional fingerprints characterize progressive stages of multiple myeloma

Although many efforts have recently contributed to improve our knowledge of molecular pathogenesis of multiple myeloma (MM), the role and significance of long non-coding RNAs (lncRNAs) in plasma cells (PC) malignancies remains virtually absent. To this aim, we developed a custom annotation pipeline of microarray data investigating lncRNA expression in PCs from 20 monoclonal gammopathies of undetermined significance, 33 smoldering MM, 170 MM, and 36 extra-medullary MMs/plasma cell leukemia patients, and 9 healthy donors. Our study identified 31 lncRNAs deregulated in tumor samples compared to normal controls; among these, the upregulation of MALAT1 appeared associated in MM patients with molecular pathways involving cell cycle regulation, p53-mediated DNA damage response, and mRNA maturation processes. Furthermore, we found 21 lncRNAs whose expression were progressively deregulated trough the more aggressive stages of PC dyscrasia, suggesting a possible role in the progression of the disease. Finally, in the context of molecular heterogeneity of MM, we identified a transcriptional fingerprint in hyperdiploid patients, characterized by the upregulation of lncRNAs/pseudogenes related to ribosomal protein genes, known to be upregulated in this molecular group. Overall, the data provides an important resource for future studies on the functions of lncRNAs in the pathology.

IgMk paraprotein from gammopathy patient can bind to cardiolipin and interfere with coagulation assay: a case report

Background

The monoclonal gammopathies are a group of plasma-cell proliferative disorders characterized by the secretion of monoclonal immunoglobulin (M protein or paraprotein). Some rare cases have revealed the specific affinity of paraprotein as autoantibody. Here we report a patient with monoclonal gammopathy of undetermined significance (MGUS) accompanied by a remarkable increase of anticardiolipin antibody (aCL) and an extensively decreased coagulation factor activity, however, without any clinical signs of antiphospholipid syndrome (APS) and bleeding.

Results

Our further investigation indicated that IgMκ paraprotein of this patient possessed an antibody activity against phospholipids so as to bind to cardiolipin and interfere with coagulation assay in vitro.

Conclusions

This case might be indicative that an abnormality of coagulation tests, disturbed by IgMκ paraprotein, does not predict a risk of bleeding in this patient.

Electrophysiologic features of POEMS syndrome compared with MGUS-related neuropathy

INTRODUCTION

Polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome and monoclonal gammopathy of undetermined significance (MGUS) are paraproteinemic disorders that can cause demyelinating polyneuropathy. Herein we assessed the findings of nerve conduction studies (NCS) in patients with POEMS syndrome and MGUS-related neuropathy to determine whether the NCS characteristics can help differentiate between these conditions.

METHODS

We enrolled 24 POEMS and 37 MGUS-related neuropathy patients. NCS parameters, including compound muscle action potential (CMAP), motor conduction velocity (MCV), and terminal latency index (TLI), were evaluated.

RESULTS

Compared with MGUS-related neuropathy patients, POEMS syndrome patients demonstrated a greater reduction in both the upper and lower limb CMAPs and a greater reduction in the median and ulnar MCVs. The TLIs were significantly higher in POEMS patients.

DISCUSSION

NCS can help distinguish POEMS syndrome from MGUS-related neuropathy. Reduced CMAPs, slow MCVs, and high TLIs are indicative of POEMS syndrome rather than MGUS-related neuropathy. Muscle Nerve 56: E73-E77, 2017.

Potential prognostic long non-coding RNA identification and their validation in predicting survival of patients with multiple myeloma

Multiple myeloma, a typical hematological malignancy, is characterized by malignant proliferation of plasma cells. This study was to identify differently expressed long non-coding RNAs to predict the survival of patients with multiple myeloma efficiently. Gene expressing profiles of diagnosed patients with multiple myeloma, GSE24080 (559 samples) and GSE57317 (55 samples), were downloaded from Gene Expression Omnibus database. After processing, survival-related long non-coding RNAs were identified by Cox regression analysis. The prognosis of multiple myeloma patients with differently expressed long non-coding RNAs was predicted by Kaplan–Meier analysis. Meanwhile, stratified analysis was performed based on the concentrations of serum beta 2-microglobulin (S-beta 2m), albumin, and lactate dehydrogenase of multiple myeloma patients. Gene set enrichment analysis was performed to further explore the functions of identified long non-coding RNAs. A total of 176 long non-coding RNAs significantly related to the survival of multiple myeloma patients (p < 0.05) were identified. In dataset GSE24080 and GSE57317, there were 558 and 55 patients being clustered into two groups with significant differences, respectively. Stratified analysis indicated that prediction of the prognoses with these long non-coding RNAs was independent from other clinical phenotype of multiple myeloma. Gene set enrichment analysis–identified pathways of cell cycle, focal adhesion, and G2-M checkpoint were associated with these long non-coding RNAs. A total of 176 long non-coding RNAs, especially RP1-286D6.1, AC008875.2, MTMR9L, AC069360.2, and AL512791.1, were potential biomarkers to evaluate the prognosis of multiple myeloma patients. These long non-coding RNAs participated indispensably in many pathways associated to the development of multiple myeloma; however, the molecular mechanisms need to be further studied.

Neoplastic and non-neoplastic complications of solid organ transplantation in patients with preexisting monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) occurs in 3-7% of the elderly population, with higher prevalence in renal failure patients, and is associated with a 25-fold increased lifetime risk for plasma cell myeloma (PCM), also known as multiple myeloma. Using the California State Inpatient, Emergency Department, and Ambulatory Surgery Databases components of the Healthcare Cost and Utilization Project (HCUP), we sought to determine whether patients with MGUS who undergo solid organ allograft (n = 22,062) are at increased adjusted relative risk (aRR) for hematologic malignancy and other complications. Among solid organ transplant patients, patients with preexisting MGUS had higher aRR of PCM (aRR 19.46; 95% CI 7.05, 53.73; p < 0.001), venous thromboembolic events (aRR 1.66; 95% CI 1.15, 2.41; p = 0.007), and infection (aRR 1.24; 95% CI 1.06, 1.45; p = 0.007). However, when comparing MGUS patients with and without solid organ transplant, there was decreased aRR for PCM with transplant (aRR 0.34; 95% CI 0.13, 0.88; p = 0.027), and increased venous thromboembolic events (aRR 2.33; 95% CI 1.58, 3.44; p < 0.001) and infectious risks (aRR 1.44; 95% CI 1.23, 1.70; p < 0.001). While MGUS increased the risk of PCM overall following solid organ transplantation, there was lower risk of PCM development compared to MGUS patients who did not receive a transplant. MGUS should not preclude solid organ transplant.

Acute adult-onset still's disease presenting as pulmonary hemorrhage, urticaria, angioedema and leukemoid reaction: a case report and literature review

INTRODUCTION

Adult-onset Still's disease is a rare systemic inflammatory disorder of unknown aetiology characterized by the classic triad of persistent high spiking fevers, joint pain and a distinctive salmon-colored bumpy rash however, the multiorgan involvement can be present.

CASE DESCRIPTION

A 40-year-old woman previously healthy was referred to our hospital with 7 days of high fever and generalized arthralgia, The physical exam revealed angioneurotic edema detected on soles, palms and tongue and widespread red, urticated plaques in a symmetrical distribution affecting the arms, dorsal hands, upper and lower chest and back. Followed 5 days later by fever, the patient presented dyspnea, cough and hypoxemia, the imaging studies showed unilateral consolidation and pleural effusion. The bronchoscopy with bronchoalveolar lavage and skin biopsy were consistent with neutrophilic urticarial. The hematological disorders, infections and other autoimmune diseases were excluded.

DISCUSSION AND EVALUATION

The diagnosis of adult-onset Still's disease can be very difficult. There are no specific tests and reliance is usually placed on a symptom complex and the well described typical rash seen in most patients. In recent years, however, other cutaneous manifestations of Adult-onset Still's disease have been reported but these are not so well known.

CONCLUSIONS

The evidence of rare manifestations is growing and the early clinical presentation of Adult-onset Still's is extremely variable, making diagnosis difficult. For this reason, data on early clinical presentation of the disease are of interest. We reported the first case of acute Adult-onset Still's disease with the association of pulmonary hemorrhage, urticaria and angioedema including a rare systemic manifestation as leukemoid reaction.

Ocular manifestations of monoclonal copper-binding immunoglobulin

The dense accumulation of copper in Descemet membrane and lens capsule is the characteristic manifestation of a circulating monoclonal antibody with strong affinity for copper. The overproduction of this monoclonal immunoglobulin may be associated with either multiple myeloma or a benign monoclonal gammopathy. Despite prolonged exposure to elevated serum copper, no other tissues in the body are adversely affected by this redox metal. We describe the clinical and pathological findings in a 46-year-old woman with this disorder.

Molecular profiling of multiple myeloma: from gene expression analysis to next-generation sequencing

INTRODUCTION

Multiple myeloma is a fatal malignant proliferation of clonal bone marrow Ig-secreting plasma cells, characterized by wide clinical, biological, and molecular heterogeneity.

AREAS COVERED

Herein, global gene and microRNA expression, genome-wide DNA profilings, and next-generation sequencing technology used to investigate the genomic alterations underlying the bio-clinical heterogeneity in multiple myeloma are discussed.

EXPERT OPINION

High-throughput technologies have undoubtedly allowed a better comprehension of the molecular basis of the disease, a fine stratification, and early identification of high-risk patients, and have provided insights toward targeted therapy studies. However, such technologies are at risk of being affected by laboratory- or cohort-specific biases, and are moreover influenced by high number of expected false positives. This aspect has a major weight in myeloma, which is characterized by large molecular heterogeneity. Therefore, meta-analysis as well as multiple approaches are desirable if not mandatory to validate the results obtained, in line with commonly accepted recommendation for tumor diagnostic/prognostic biomarker studies.

Paraproteinemic neuropathies

The term paraproteinemic neuropathy refers to a heterogeneous group of neuropathies, which share the common feature of a homogeneous immunoglobulin in the serum. The presence of a monoclonal gammopathy indicates an underlying clonal B-cell expansion, which may appear in the context of a lymphoproliferative disorder. If a neoplastic origin of the gammopathy is identified, the treatment should be targeted to the neoplasm. In most patients, however, the monoclonal gammopathy is not associated with malignant haematological disorders, and is defined as monoclonal gammopathy of undetermined significance.

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.

Prevalence and type of monoclonal gammopathy of undetermined significance in an apparently healthy Nigerian population: a cross sectional study

Background

The prevalence of monoclonal gammopathy of undetermined significance (MGUS), a premalignant plasma-cell disorder has not been determined in our geographic area Nigeria.

Methods

A cross sectional survey was carried on apparently healthy Nigerians selected by multistage sampling technique from the cosmopolitan city of Lagos, Nigeria. Subjects enrolled into the study had 2-step screening for the presence, type and concentration of monoclonal band. Agarose-gel electrophoresis was performed on all serum samples, and any serum sample with a discrete band of monoclonal protein or thought to have a localized band was subjected to Immunofixation. Subjects were also evaluated for Bence jones proteinuria, haematological and biochemical parameters.

Results

Four hundred and ten subjects with a mean age of 45.68 ± 10.3 years, a median of 45.00 years and a range of 20 to 80 years were enrolled into the study. MGUS was identified in only one (0.24 percent) of the 410 study subject. This subject was demonstrated to have a double monoclonal gammopathy; IgGλ at 16.9 g/L and IgAκ at 8.5 g/L. None of them including the sole subject with MGUS had a monoclonal urinary light chain.

Conclusion

Among residents of Lagos, Nigeria, MGUS was found in only 0.24% percent of apparently normal persons with a median age of 45 years. This suggests that MGUS which represents the earliest stage of monoclonal plasma/lymphoid cell proliferation is not a common finding in the relatively young population of Nigeria. Future epidemiologic studies dealing with plasma cell disorders in older people are required to carefully examine the relationship between environmental factors and prevalence of MGUS and its ultimate progression to MM.

Consensus guidelines for the conduct and reporting of clinical trials in systemic light-chain amyloidosis

This manuscript summarizes the recommendations that emerged from the first Roundtable on Clinical Research in Immunoglobulin Light-chain Amyloidosis (AL), a meeting sponsored by the Amyloidosis Foundation (Clarkston, MI, USA) to develop a consensus of experts on a modern framework for clinical trial design and drug development in AL. Recent diagnostic and technical advances in AL, and updated consensus guidelines for assessing hematologic and organ responses, enable us to define study populations, appropriate end points, and other criteria for all phases of clinical research. This manuscript provides a framework for the design and conduct of systematic collaborative clinical research in AL to encourage more rapid testing of therapies and to expedite new drug development and approval.

Advances in understanding monoclonal gammopathy of undetermined significance as a precursor of multiple myeloma

Monoclonal gammopathy of undetermined significance (MGUS) affects at least 3% of the population above the age of 50 and is the precursor to multiple myeloma (MM), an incurable malignancy of plasma cells. Recent advances in MGUS include: an improved understanding of the pathogenesis of MGUS and its progression to MM, involving molecular events intrinsic to the malignant plasma cell as well as the microenvironment; novel techniques to assess risk for progression to MM using serum-free light-chain analysis and immunophenotyping; and a renewed interest in chemoprevention of MM. In the future, continued improvement in our understanding of MGUS will lead to the development of better biomarkers for prognosis and therapies for chemoprevention of MM.

The role of sulfoglucuronosyl glycosphingolipids in the pathogenesis of monoclonal IgM paraproteinemia and peripheral neuropathy

In IgM paraproteinemia and peripheral neuropathy, IgM M-protein secretion by B cells leads to a T helper cell response, suggesting that it is antibody-mediated autoimmune disease involving carbohydrate epitopes in myelin sheaths. An immune response against sulfoglucuronosyl glycosphingolipids (SGGLs) is presumed to participate in demyelination or axonal degeneration in the peripheral nervous system (PNS). SGGLs contain a 3-sulfoglucuronic acid residue that interacts with anti-myelin-associated glycoprotein (MAG) and the monoclonal antibody anti-HNK-1. Immunization of animals with sulfoglucuronosyl paragloboside (SGPG) induced anti-SGPG antibodies and sensory neuropathy, which closely resembles the human disease. These animal models might help to understand the disease mechanism and lead to more specific therapeutic strategies. In an in vitro study, destruction or malfunction of the blood-nerve barrier (BNB) was found, resulting in the leakage of circulating antibodies into the PNS parenchyma, which may be considered as the initial key step for development of disease.

Long-term monitoring of Epstein-Barr virus DNA load and humoral parameter abnormalities in pediatric liver transplant recipients before development of malignancy

EBV loads and abnormalities of humoral responses were monitored in 51 pediatric liver transplant recipients as a proposed non-invasive laboratory tool for early detection of changes preceding severe clinical complications. EBV DNA load, concentrations of IgM, IgG, IgA, and monoclonal proteins were determined in each blood sample. EBV DNA was detected in 70.6% of the children, dysgammaglobulinemia of one or more Ig isotype was present in 41.2% of them. MG detected in 43.1% of patients correlated with the presence of EBV DNA (p = 0.003) and was usually preceded by hypergammaglobulinemia. The median maximum EBV load was significantly higher in EBV DNA+/MG+ patients than in EBV DNA+/MG- patients (p = 0.04), although there was no correlation between current viral load and appearance of MG. Four of 15 EBV DNA-negative patients developed MG, preceded by hypergammaglobulinemia in two. Minimization or cessation of immunosuppression in 42 patients, in whom abnormal biomarkers and/or clinical symptoms raised suspicion of disease progression, permitted complete resolution of abnormalities in all but one patient who developed B-NHL and died. Simultaneous monitoring of protein profiles and EBV DNA load together with thorough physical evaluation of children after LTx is important for early implementation of suitable preemptive therapy.

A case of multiple myeloma presenting as a bullous dermatosis

Multiple myeloma is a malignant plasma cell proliferative disorder that produces a monoclonal immunoglobulin protein. The skin involvement and the development of bullous disease are rarely seen features in multiple myeloma. We present a 55-year-old man with a longstanding, large, tense bullous eruption and hypertrophic scars over his body accompanied recently with weight loss and fatique. He had no response to the previous treatments, which included oral glucocorticoids and dapsone. Histologic examination of the lesions revealed subepidermal bullae, while no immunoflourescence staining was observed. In a further detailed labarotory examination, multiple myeloma was detected. After the treatment of multiple myeloma with chemotherapy, the lesions regressed. Patients with longstanding, recurrent, unusual bullous eruption should be investigated for the development of multiple myeloma.

Crystal-storing histiocytosis and crystalline keratopathy caused by monoclonal gammopathy of undetermined significance

PURPOSE

The purpose of this study was to report the occurrence of crystalline keratopathy and of orbital infiltrative disease resulting from crystal-storing histiocytosis (CSH) in a patient with monoclonal gammopathy of undetermined significance.

METHODS

The authors conducted a review of a medical record and immunohistopathologic studies.

RESULTS

A 66-year-old man presented with a 3-year history of unilateral progressive ptosis, proptosis, and external ophthalmoplegia. Magnetic resonance imaging showed orbital fat expansion and extraocular muscle thickening with gadolinium enhancement. The patient also had bilateral crystalline keratopathy and had undergone penetrating keratoplasty in one eye. The urine and serum showed elevated levels of immunoglobulin, but the bone marrow aspirate was normal. The systemic evaluation was consistent with monoclonal gammopathy of undetermined significance. An orbital fat biopsy revealed histiocytes engorged with lambda light chain crystals. The corneal stroma also showed positive immunostaining for lambda light chains. The patient was diagnosed with orbital CSH and with lambda light chain crystalline keratopathy.

CONCLUSIONS

CSH is characterized by the accumulation of reactive histiocytes filled with immunoglobulin crystals in various tissues and is frequently associated with systemic hyperglobulinemic states. For unknown reasons, in this patient, a systemic immunologic disorder led to lambda light chain abnormalities with histiocyte infiltration of the orbit and corneal deposition. Although CSH is rare, it should be part of the differential diagnosis of orbital infiltrative disease with or without crystalline keratopathy.

Systemic capillary leak syndrome resulting in compartment syndrome and the requirement for a surgical airway

We report on a case of systemic capillary leak syndrome associated with a monoclonal band on plasma electrophoresis. In our patient hospital admission was precipitated by ischaemic pain in the left lower limb, associated with polycythaemia, renal failure and hypovolaemic shock. Fluid resuscitation, venesection and renal replacement therapy were instituted but a compartment syndrome developed necessitating surgery. Failure of tracheal intubation resulted in the requirement for a surgical airway. Despite surgical and resuscitative efforts the outcome was fatal from hypovolaemia and hyperkalaemia. We aim to highlight the difficulties in managing this condition and to remind healthcare workers to include it in the differential diagnoses for patients presenting with polycythaemia; in particular polycythaemic patients with a monoclonal band on plasma electrophoresis.

[Monoclonal gammopathy and primary colonic mantle cell lymphoma]

The association of a monoclonal gammopathy (MG) with a B cell non-Hodgkin's lymphoma (NHL) is a well-known phenomenon. It has been recognized in many subtypes of primary gastrointestinal lymphoma but its association with primary colonic mantle cell lymphoma has never been yet described. We report a 65-year-old man who presented with an exudative ascites and constipation. Serum electrophoresis showed a monoclonal peak in the gamma region of 45g/L and immunoelectrophoresis confirmed the presence of monoclonal gammopathy of IgM kappa type. Bone marrow aspirate was normal. Radiologic and endoscopic investigations evidenced a primary colonic mantle cell lymphoma. Although the association of an MG with an NHL and, in particular, to a primitive digestive location appears a rare phenomenon, endoscopic investigations in patients with MG appears legitimate in the presence of any digestive sign.

Characterization of gp120 hydrolysis by IgA antibodies from humans without HIV infection

Antibody hydrolysis of the superantigenic gp120 site and HIV-1 neutralization was studied as a potential anti-HIV mechanism in uninfected humans. gp120 hydrolysis by purified serum and salivary antibodies was determined by electrophoresis and peptide sequencing, the proteolytic mechanism was analyzed using electrophilic peptide analogs, and viral neutralization was studied using peripheral blood mononuclear cells as hosts. Polyclonal and monoclonal IgA but not IgG preparations selectively catalyzed the cleavage of HIV gp120 at rates sufficient to predict biologically relevant protection against the virus. The IgA hydrolytic reaction proceeded by noncovalent recognition of gp120 residues 421-433, a component of the superantigenic site of gp120, coordinated with peptide bond cleavage via a serine protease-like mechanism. The Lys-432-Ala-433 bond was one of the cleavage sites. Infection of peripheral blood mononuclear cells by a primary isolate of HIV was neutralized by the IgA but not IgG fractions. The neutralizing activity was specifically inhibited by an electrophilic inhibitor of the catalytic activity. The existence of catalytic IgAs to gp120 in uninfected humans suggests their role in resistance to HIV.

Intérêt du dosage des chaînes légères libres d'immunoglobulines sériques pour le diagnostic et le suivi des gammapathies monoclonales

PURPOSE

Monoclonal immunoglobulin free light chains (FLC) are present in the serum and urine of many patients with monoclonal gammopathies. In this review, we discuss the usefulness of serum FLC determination for diagnostic, prognostic and monitoring of multiple myeloma (MM), AL amyloidosis and monoclonal gammopathies of undetermined significance (MGUS).

CURRENT KNOWLEDGE AND KEY POINTS

Serum FLC assay is a useful laboratory test for management of light chain MM, non-secretory MM and AL amyloidosis. Currently, serum FLC testing cannot be recommended for monitoring intact immunoglobulin multiple myeloma. Even though serum FLC determination give a better risk stratification for MGUS, systematic serum FLC assay should not be used in routine because of high MGUS occurrence in the general population.

FUTURE PROSPECTS AND PROJECTS

Further prospective studies with large cohorts of patients should provide additional evidence for the role of serum FLC measurement in patients with intact immunoglobulin multiple myeloma.

Lower bone mineral density in geriatric patients with monoclonal gammopathy of undetermined significance

The aim of this study was to investigate the prevalence of monoclonal gammopathy of undetermined significance (MGUS) in a geriatric population in Turkey and compare bone mineral densities and related laboratory parameters of MGUS patients with those who do not have MGUS. Among 1,012 patients enrolled, monoclonal band was detected in serum samples of 22 patients (2.17%), most of which were IgG type. Further tests revealed multiple myeloma and lung carcinoma in two patients. The remaining 20 patients were diagnosed with MGUS (1.97%). The clinical and laboratory parameters of patients with and without MGUS were mostly comparable; however, bone mineral density measurements of patients with MGUS were significantly lower than those without MGUS (p = 0.007). We suggest evaluation of geriatric patients with MGUS for the presence of osteopenia/osteoporosis considering the high frequency observed in this study.

Schnitzler syndrome: beyond the case reports: review and follow-up of 94 patients with an emphasis on prognosis and treatment

OBJECTIVE

Schnitzler syndrome is a rare disorder characterized by a chronic urticarial rash and monoclonal gammopathy, accompanied by intermittent fever, arthralgia or arthritis, bone pain, and lymphadenopathy. Our objectives are to systematically review disease characteristics of Schnitzler syndrome and collect follow-up information to gain insight into treatment efficacy and long-term prognosis.

METHODS

PubMed and MEDLINE databases (1966-2006) were searched, using the key words "Schnitzler syndrome," and the combination of "urticaria" with "monoclonal gammopathy," "immunoglobulin M (IgM)," or "paraproteinemia," as well as secondary references. Data on a total of 94 patients who met the criteria for Schnitzler syndrome were reviewed. Questionnaires sent to all authors retrieved additional follow-up data on 43 patients, resulting in a mean follow-up of 9.5 years after onset of symptoms, and a follow-up of 20 years or more in 10 patients.

RESULTS

Symptoms, signs, and laboratory findings as found in the 94 patients are reviewed in detail. There have been promising developments in therapeutic options, especially antiinterleukin-1 treatment, which induced complete remission in all 8 patients treated so far. To date, no spontaneous complete remissions have been reported. Patients with Schnitzler syndrome showed no increased mortality during the present follow-up. However, they had a 10-year risk of 15% of developing a lymphoproliferative disorder, most notably Waldenström's macroglobulinemia. Three cases of type amyloid A (AA) amyloidosis associated with Schnitzler syndrome were reported.

CONCLUSIONS

Schnitzler syndrome is a disabling disorder which affects multiple systems and which can be considered as an autoinflammatory syndrome. There are new, effective treatment options, but close monitoring remains warranted because of the increased risk of lymphoproliferative disease.

[Malignant transformation of monoclonal gammopathy of undetermined significance]

Monoclonal gammopathy of undetermined significance (MGUS) is found in approximately 3% of the general population aged 50 years or older. MGUS is a premalignant state. The risk of malignant transformation is about 1% per year. Some factors predictive of malignant transformation have been identified: type of serum monoclonal protein, monoclonal protein value, bone marrow plasmocytosis and serum free light chain ratio. Predictive scores combining these factors have recently been proposed and make it possible to identify groups of patients with significantly different rates of transformation. These scores require validation. These scores will probably allow individualization of management and monitoring.

Retrospective study of monoclonal gammopathies detected in the clinical laboratory of a Spanish healthcare district: 14-year series

BACKGROUND

We studied the incidence, classification and isotype distribution of monoclonal gammopathies and M-protein detected between 1992 and 2005 inclusive in the clinical laboratory of a healthcare district in Madrid (Spain) with an average population of 280,574 inhabitants.

METHODS

Serum electrophoresis was carried out on a cellulose acetate support up until 1997, and then using capillary zone electrophoresis systems, with M-protein identification carried out by agarose gel immunofixation. The age-adjusted incidences were standardized with respect to the WHO World Standard Population Distribution, based on the world average population between 2000 and 2025. The clinical diagnosis was recorded from the patient case history.

RESULTS

M-protein was detected in a total of 537 patients; of these, 42 had been diagnosed before 1992, representing a 0.19% prevalence in our population. The mean age-adjusted incidence of monoclonal gammopathy was 10.72 per 100,000 inhabitants/year (SE 1.31), ranging from 4.85/100,000 in 1992 to 14.28/100,000 in 2003 and 2004. The median patient age at diagnosis was 73 years (range 25-96 years), with males accounting for 46.8% of all cases of monoclonal gammopathy, and 57.8% of all malignant monoclonal gammopathies. A total of 54.1% of the patients were clinically defined as presenting monoclonal gammopathy of undetermined significance, 31.3% presented multiple myeloma, and the remaining 14.6% presented malignant gammopathies. The most frequent M-protein isotype was IgG (55.8%), followed by IgA (20.8%) and IgM (13.6%). A total of 88% of the light chain M-proteins, 54% of isotype IgM, 51% of isotype IgA and 36% of isotype IgG were associated with B lymphoproliferative diseases.

CONCLUSIONS

We conclude that the clinical laboratory should play an important role in the study of monoclonal gammopathies, since it is the only location where all M-protein patients are observed. On the other hand, studies of this type should be carried out over long-term periods, owing to the variations we have noted in the detection of M-proteins.

Molecular Characterization of Waldenstrom's Macroglobulinemia Reveals Frequent Occurrence of Two B-Cell Clones Having Distinct IgH VDJ Sequences

PURPOSE

Malignant B lineage cells in Waldenstrom's macroglobulinemia (WM) express a unique clonotypic IgM VDJ. The occurrence of biclonal B cells and their clonal relationships were characterized.

EXPERIMENTAL DESIGN

Bone marrow and blood from 20 WM patients were analyzed for clonotypic VDJ sequences, clonal B-cell frequencies, and the complementary determining region 3 profile.

RESULTS

Two different clonotypic VDJ sequences were identified in 4 of 20 WM. In two cases, partner clones had different VDJ rearrangements, with one clonotypic signature in bone marrow and a second in blood. For both cases, the bone marrow clone was hypermutated, whereas the blood clone was germ line or minimally mutated. In two other cases, partner clones shared a common VDJ rearrangement but had different patterns of somatic mutations. They lacked intraclonal diversity and were more abundant in bone marrow than in blood. VDJ mutation profiles suggested they arose from a common IgM progenitor. Single-cell analysis in one case indicated the partner clones were reciprocally expressed, following rules of allelic exclusion.

CONCLUSIONS

The existence of two B-cell clones having distinct VDJ sequences is common in WM, suggesting that frequent transformation events may occur. In two cases, the partner clones had distinct tissue distributions in either blood or bone marrow, were of different immunoglobulin isotypes, and in one case exhibited differential response to therapy. The contributions of each clone are unknown. Their presence suggests that WM may involve a background of molecular and cellular events leading to emergence of one or more malignant clones.