From myeloma precursor disease to multiple myeloma: new diagnostic concepts and opportunities for early intervention

Longitudinal assessment of established risk stratification models in patients with monoclonal gammopathy of undetermined significance

Risk of progression of monoclonal gammopathy of undetermined significance (MGUS) into multiple myeloma and related plasma cell disorders can be determined by three major risk stratification models, namely Mayo2005, Sweden2014, and NCI2019. This retrospective study of 427 patients with MGUS diagnosed according to the 2014 International Myeloma Working Group criteria aimed to describe and analyze the longitudinal applicability of these risk models. In all three models, the majority of patients remained at their baseline risk group, whereas small numbers of patients migrated to a different risk group. Proportions of patients among risk groups remained stable over time (e.g. Mayo2005 model, low-risk group, at baseline: 43%, after 1, 2, 3, 4, 5, and 8 years: 40%, 37%, 37%, 43%, 44%, and 43%). All three risk models reliably distinguished risk of progression at baseline, upon yearly reassessment (e.g. 1 year from diagnosis) and in time-dependent analyses. Upstaging to a high-risk category was associated with an increased risk of progression in all three models (Mayo2005: hazard ratio [HR] = 5.43, 95% confidence interval [95% CI] 1.21-24.39, p = 0.027; Sweden2014: HR = 13.02, 95% CI 5.25-32.28, p < 0.001; NCI2019: HR = 5.85, 95% CI 2.49-13.74, p < 0.001). Our study shows that MGUS risk stratification models can be applied longitudinally to repeatedly determine and improve individual risk of progression. Patient migration to higher risk categories during follow up should prompt more frequent monitoring in clinical routine.

Review of whole-body magnetic resonance imaging in multiple myeloma

Multiple Myeloma (MM) is a hematological malignancy affecting bone marrow, most frequently in elderly men. Imaging has a crucial role in this disease. Recently, whole-body MRI has been introduced and it has gained growing interest due to is high sensitivity and specificity in evaluating bone marrow involvement in MM. Diffusion-weighted sequences (DWI) with apparent diffusion coefficient (ADC) maps have emerged as the most sensitive technique to evaluate patients with MM, both in the pre- and post-treatment setting. Aim of this review is to provide an overview of the role and main imaging findings of whole-body MRI in MM.

Efbalropendekin Alfa enhances human natural killer cell cytotoxicity against tumor cell lines in vitro

IL-15 has shown preclinical activity by enhancing the functional maturation of natural killer (NK) cells. Clinical evaluation of the potential anticancer activity of most cytokines, including IL-15, has been limited by low tolerability and rapid in vivo clearance. Efbalropendekin Alfa (XmAb24306) is a soluble IL15/IL15-receptor alpha heterodimer complex fused to a half-life extended Fc domain (IL15/IL15Rα-Fc), engineered with mutations to reduce IL-15 affinity for CD122. Reduced affinity drives lower potency, leading to prolonged pharmacodynamic response in cynomolgus monkeys. We show that in vitro, human NK cells treated with XmAb24306 demonstrate enhanced cytotoxicity against various tumor cell lines. XmAb24306-treated NK cells also exhibit enhanced killing of 3D colorectal cancer spheroids. Daratumumab (dara), a monoclonal antibody (mAb) that targets CD38 results in antibody-dependent cellular cytotoxicity (ADCC) of both multiple myeloma (MM) cells and NK cells. Addition of XmAb24306 increases dara-mediated NK cell ADCC against various MM cell lines in vitro. Because NK cells express CD38, XmAb24306 increases dara-mediated NK cell fratricide, but overall does not negatively impact the ADCC activity against a MM cell line likely due to increased NK cell activity of the surviving cells. These data show that XmAb24306 increases direct and ADCC-mediated human NK cell cytotoxicity in vitro.

Monoclonal Gammopathy of Undetermined Significance: A Comprehensive Review

Monoclonal Gammopathy of Undetermined Significance (MGUS) is an asymptomatic premalignant plasma cell dyscrasia with a predominate rise of the IgG immunoglobulin fraction without end-organ damage, often diagnosed incidentally. Despite its progression into various subsequent forms of hematological malignancies, MGUS remains underdiagnosed. A literature search was conducted using the Medline, Cochrane, Embase, and Google Scholar databases, including articles published until December 2022. Keywords used encompassed "Monoclonal Gammopathy of Undetermined Significance," "Plasma Cell dyscrasia," "Monoclonal gammopathy of renal significance," and "IgM Monoclonal gammopathy of Undetermined Significance," This study aimed to conduct a critical review to update knowledge regarding the pathophysiology, risk factors, clinical features, diagnostic protocols, complications, and current and novel treatments for MGUS. We recommend a multidisciplinary approach to manage MGUS due to the complexity of the illness's etiology, diagnosis, and therapy. This comprehensive review also highlights future prospects, such as developing screening protocols for at-risk populations, prevention of disease progression by early diagnosis through genome-wide association studies, and management using Daratumumab and NSAIDs.

Prognostic Relevance of Multi-Antigenic Myeloma-Specific T-Cell Assay in Patients with Monoclonal Gammopathies

Multiple Myeloma (MM) typically originates from underlying precursor conditions, known as Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM). Validated risk factors, related to the main features of the clonal plasma cells, are employed in the current prognostic models to assess long-term probabilities of progression to MM. In addition, new prognostic immunologic parameters, measuring protective MM-specific T-cell responses, could help to identify patients with shorter time-to-progression. In this report, we described a novel Multi-antigenic Myeloma-specific (MaMs) T-cell assay, based on ELISpot technology, providing simultaneous evaluation of T-cell responses towards ten different MM-associated antigens. When performed during long-term follow-up (mean 28 months) of 33 patients with either MGUS or SMM, such deca-antigenic myeloma-specific immunoassay allowed to significantly distinguish between stable vs. progressive disease (p < 0.001), independently from the Mayo Clinic risk category. Here, we report the first clinical experience showing that a wide (multi-antigen), standardized (irrespective to patients' HLA), MM-specific T-cell assay may routinely be applied, as a promising prognostic tool, during the follow-up of MGUS/SMM patients. Larger studies are needed to improve the antigenic panel and further explore the prognostic value of MaMs test in the risk assessment of patients with monoclonal gammopathies.

T-Cell-Based Cellular Immunotherapy of Multiple Myeloma: Current Developments

Simple Summary

Over the past two decades, there has been significant progress in the treatment of multiple myeloma. Starting with the approval of bortezomib and lenalidomide, followed by newer agents in the same classes, monoclonal antibodies, and most recently idecabtagene vicleucel and ciltacabtagene autoleucel, which are genetically engineered autologous T-cell-based therapies, our view of this disease has changed from incurable to controllable and potentially curable. In addition to multiple myeloma and B-cell lymphomas, T-cell-based therapies are also actively investigated in various types of hematological and non-hematological malignancies and are considered one of the most impactful evolutions in cancer therapeutics. This review aims to summarize existing data regarding the efficacy, toxicity, and management of unique adverse events in T-cell-based therapies that are both clinically available and under investigation. We will also address undergoing efforts to improve the survival outcomes of multiple myeloma patients through this treatment modality.

Abstract

T-cell-based cellular therapy was first approved in lymphoid malignancies (B-cell acute lymphoblastic leukemia and large B-cell lymphoma) and expanding its investigation and application both in hematological and non-hematological malignancies. Two anti-BCMA (B cell maturation antigen) CAR (Chimeric Antigen Receptor) T-cell therapies have been recently approved for relapsed and refractory multiple myeloma with excellent efficacy even in the heavily pre-treated patient population. This new therapeutic approach significantly changes our practice; however, there is still room for further investigation to optimize antigen receptor engineering, cell harvest/selection, treatment sequence, etc. They are also associated with unique adverse events, especially CRS (cytokine release syndrome) and ICANS (immune effector cell-associated neurotoxicity syndrome), which are not seen with other anti-myeloma therapies and require expertise for management and prevention. Other T-cell based therapies such as TCR (T Cell Receptor) engineered T-cells and non-genetically engineered adoptive T-cell transfers (Vγ9 Vδ2 T-cells and Marrow infiltrating lymphocytes) are also actively studied and worth attention. They can potentially overcome therapeutic challenges after the failure of CAR T-cell therapy through different mechanisms of action. This review aims to provide readers clinical data of T-cell-based therapies for multiple myeloma, management of unique toxicities and ongoing investigation in both clinical and pre-clinical settings.

Novel immunotherapies in multiple myeloma

For a substantial period, options for the treatment of multiple myeloma (MM) were limited; however, the advent of novel therapies into clinical practice in the 1990s resulted in dramatic changes in the prognosis of the disease. Subsequently, new proteasome inhibitors and immunomodulators with innovations in efficacy and toxicity were introduced; yet there remains a spectrum of patients with poor outcomes with current treatment strategies. One of the causes of disease progression in MM is the loss of the ability of the dysfunctional immune environment to control virulent cell clones. In recent years, therapies to overcome the immunosuppressive tumor microenvironment and activate the host immune system have shown promise in MM, especially in relapsed and refractory disease. Clinical use of this approach has been approved for several immunotherapies, and a number of studies are currently underway in clinical trials. This review outlines three of the newest and most promising approaches being investigated to enhance the immune system against MM: (1) overcoming immunosuppression with checkpoint inhibitors, (2) boosting immunity against tumors with vaccines, and (3) enhancing immune effectors with adoptive cell therapy. Information on the latest clinical trials in each class will be provided, and further developments will be discussed.

Pathogenic signaling in multiple myeloma

Multiple myeloma is a common hematological malignancy of plasma cells, the terminally differentiated B cells that secrete antibodies as part of the adaptive immune response. Significant progress has been made in treating multiple myeloma, but this disease remains largely incurable, and most patients will eventually suffer a relapse of disease that becomes refractory to further therapies. Moreover, a portion of patients with multiple myeloma present with disease that is refractory to all treatments from the initial diagnosis, and no current therapeutic approaches can help. Therefore, the task remains to advance new therapeutic strategies to help these vulnerable patients. One strategy to meet this challenge is to unravel the complex web of pathogenic signaling pathways in malignant plasma cells and use this information to design novel precision medicine strategies to assist these patients most at risk.

Feasibility of artificial intelligence–supported assessment of bone marrow infiltration using dual-energy computed tomography in patients with evidence of monoclonal protein — a retrospective observational study

Objectives

To demonstrate the feasibility of an automated, non-invasive approach to estimate bone marrow (BM) infiltration of multiple myeloma (MM) by dual-energy computed tomography (DECT) after virtual non-calcium (VNCa) post-processing.

Methods

Individuals with MM and monoclonal gammopathy of unknown significance (MGUS) with concurrent DECT and BM biopsy between May 2018 and July 2020 were included in this retrospective observational study. Two pathologists and three radiologists reported BM infiltration and presence of osteolytic bone lesions, respectively. Bone mineral density (BMD) was quantified CT-based by a CE-certified software. Automated spine segmentation was implemented by a pre-trained convolutional neural network. The non-fatty portion of BM was defined as voxels > 0 HU in VNCa. For statistical assessment, multivariate regression and receiver operating characteristic (ROC) were conducted.

Results

Thirty-five patients (mean age 65 ± 12 years; 18 female) were evaluated. The non-fatty portion of BM significantly predicted BM infiltration after adjusting for the covariable BMD (p = 0.007, r = 0.46). A non-fatty portion of BM > 0.93% could anticipate osteolytic lesions and the clinical diagnosis of MM with an area under the ROC curve of 0.70 [0.49–0.90] and 0.71 [0.54–0.89], respectively. Our approach identified MM-patients without osteolytic lesions on conventional CT with a sensitivity and specificity of 0.63 and 0.71, respectively.

Conclusions

Automated, AI-supported attenuation assessment of the spine in DECT VNCa is feasible to predict BM infiltration in MM. Further, the proposed method might allow for pre-selecting patients with higher pre-test probability of osteolytic bone lesions and support the clinical diagnosis of MM without pathognomonic lesions on conventional CT.

Key Points

• The retrospective study provides an automated approach for quantification of the non-fatty portion of bone marrow, based on AI-supported spine segmentation and virtual non-calcium dual-energy CT data.

• An increasing non-fatty portion of bone marrow is associated with a higher infiltration determined by invasive biopsy after adjusting for bone mineral density as a control variable (p = 0.007, r = 0.46).

• The non-fatty portion of bone marrow might support the clinical diagnosis of multiple myeloma when conventional CT images are negative (sensitivity 0.63, specificity 0.71).

Harnessing the Immune System to Fight Multiple Myeloma

Multiple myeloma (MM) is a heterogeneous plasma cell malignancy differing substantially in clinical behavior, prognosis, and response to treatment. With the advent of novel therapies, many patients achieve long-lasting remissions, but some experience aggressive and treatment refractory relapses. So far, MM is considered incurable. Myeloma pathogenesis can broadly be explained by two interacting mechanisms, intraclonal evolution of cancer cells and development of an immunosuppressive tumor microenvironment. Failures in isotype class switching and somatic hypermutations result in the neoplastic transformation typical of MM and other B cell malignancies. Interestingly, although genetic alterations occur and evolve over time, they are also present in premalignant stages, which never progress to MM, suggesting that genetic mutations are necessary but not sufficient for myeloma transformation. Changes in composition and function of the immune cells are associated with loss of effective immune surveillance, which might represent another mechanism driving malignant transformation. During the last decade, the traditional view on myeloma treatment has changed dramatically. It is increasingly evident that treatment strategies solely based on targeting intrinsic properties of myeloma cells are insufficient. Lately, approaches that redirect the cells of the otherwise suppressed immune system to take control over myeloma have emerged. Evidence of utility of this principle was initially established by the observation of the graft-versus-myeloma effect in allogeneic stem cell-transplanted patients. A variety of new strategies to harness both innate and antigen-specific immunity against MM have recently been developed and intensively tested in clinical trials. This review aims to give readers a basic understanding of how the immune system can be engaged to treat MM, to summarize the main immunotherapeutic modalities, their current role in clinical care, and future prospects.

NK cell surveillance of hematological malignancies. Therapeutic implications and regulation by chemokine receptors

NK cells are circulating innate lymphoid cells that constantly move from bloodstream into tissues, exerting several functions including tumor surveillance. For this reason, NK cells are considered attractive target for cancer immunotherapy. Several strategies are employed to harness NK cell efficacy especially in hematological tumors, including adoptive transfer, genetic manipulation to overexpress chimeric antigen receptors and cytokine or immunomodulatory drug treatments of ex-vivo cultivated and expanded NK cells. Several chemokine receptors support NK cell tissue homing and are required for efficient tumor infiltration. Nevertheless, chemokine receptor expression is often insufficient, or their respective ligands may not be expressed in the tumor microenvironment, thus limiting NK cell localization at the tumor site. Therefore, strategies to implement expression or promote the function of the correct chemokine receptor/ligand axes have been employed in the last years with promising results in preclinical models. In this review, we discuss how chemokine receptors and their ligands regulate the trafficking and localization of NK cells in hematological tumors and how the chemokine function can be manipulated to improve current therapeutic approaches.

Myeloma cells induce the accumulation of activated CD94low NK cells by cell-to-cell contacts involving CD56 molecules

Natural killer (NK) cells represent innate effector cells potentially able to play a role during the immune response against multiple myeloma (MM). To better define the distribution and the specific properties of NK cell subsets during MM disease, we analyzed their features in the bone marrow and peripheral blood of newly diagnosed MM patients. Our findings revealed that, in both compartments, NK cells were more abundant than in healthy donors. Among total MM-NK cells, a significant increase of CD94lowCD56dim NK cell subset was observed, which already appears in clinical precursor conditions leading to MM, namely monoclonal gammopathy of undetermined significance and smoldering MM, and eventually accumulates with disease progression. Moreover, a consistent fraction of CD94lowCD56dim NK cells was in a proliferation phase. When analyzed for their killing abilities, they represented the main cytotoxic NK cell subset against autologous MM cells. In vitro, MM cells could rapidly induce the expansion of the CD94lowCD56dim NK cell subset, thus reminiscent of that observed in MM patients. Mechanistically, this accumulation relied on cell to cell contacts between MM and NK cells and required both activation via DNAM-1 and homophilic interaction with CD56 expressed on MM cells. Considering the growing variety of combination treatments aimed at enhancing NK cell-mediated cytotoxicity against MM, these results may also be informative for optimizing current immunotherapeutic approaches.

Quantitative, Dynamic 18F-FDG PET/CT in Monitoring of Smoldering Myeloma: A Case Report

We report on a 52-year-old patient with an initial diagnosis of smoldering myeloma (SMM), who was monitored by means of dynamic and static positron emission tomography/computed tomography (PET/CT) with the radiotracer ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG). Baseline PET/CT revealed no pathological signs. Six months later, a transition to symptomatic, multiple myeloma (MM) was diagnosed. The transition was not accompanied by focal, hypermetabolic lesions on PET/CT. However, a diffusely increased ¹⁸F-FDG uptake in the bone marrow, accompanied by a marked increase of semi-quantitative (standardized uptake value, SUV) and quantitative, pharmacokinetic ¹⁸F-FDG parameters, was demonstrated. After successful treatment, including tandem autologous transplantation, the diffuse uptake in the bone marrow as well as the semi-quantitative and quantitative parameters showed a marked remission. This response was also confirmed by the clinical follow-up of the patient. These findings suggest that in MM a diffuse ¹⁸F-FDG uptake in the bone marrow may indeed reflect an actual bone marrow infiltration by plasma cells. Moreover, SUV values and kinetic parameters, not only from myeloma lesions but also from random bone marrow samples, may be used for MM monitoring. This could be particularly helpful in the follow-up of myeloma patients negative for ¹⁸F-FDG-avid focal lesions.

Game of Bones: How Myeloma Manipulates Its Microenvironment

Multiple myeloma is a clonal disease of long-lived plasma cells and is the second most common hematological cancer behind Non-Hodgkin's Lymphoma. Malignant transformation of plasma cells imparts the ability to proliferate, causing harmful lesions in patients. In advanced stages myeloma cells become independent of their bone marrow microenvironment and form extramedullary disease. Plasma cells depend on a rich array of signals from neighboring cells within the bone marrow for survival which myeloma cells exploit for growth and proliferation. Recent evidence suggests, however, that both the myeloma cells and the microenvironment have undergone alterations as early as during precursor stages of the disease. There are no current therapies routinely used for treating myeloma in early stages, and while recent therapeutic efforts have improved patients' median survival, most will eventually relapse. This is due to mutations in myeloma cells that not only allow them to utilize its bone marrow niche but also facilitate autocrine pro-survival signaling loops for further progression. This review will discuss the stages of myeloma cell progression and how myeloma cells progress within and outside of the bone marrow microenvironment.

Therapeutic Strategies for Targeting IL-1 in Cancer

Since its discovery, interleukin-1 has been extensively studied in a wide range of medical fields. Besides carrying out vital physiological functions, it has been implicated with a pivotal role in the progression and spreading of different cancer entities. During the last years, several clinical trials have been conducted, shedding light on the role of IL-1 blocking agents for the treatment of cancer. Additionally, recent developments in the field of immuno-oncology have implicated IL-1-induced signaling cascades as a major driver of severe chimeric antigen receptor T cell-associated toxicities such as cytokine release syndrome and immune effector cell-associated neurotoxicity. In this review, we summarize current clinical trials investigating the role of IL-1 blockade in cancer treatment and elaborate the proposed mechanism of these innovative treatment approaches. Additionally, we highlight cutting-edge developments utilizing IL-1 blocking agents to enhance the safety and efficacy of adoptive T cell therapy.

Changing paradigms in diagnosis and treatment of monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM)

Multiple myeloma (MM) is a highly heterogenous disease that exists along a continuous disease spectrum starting with premalignant conditions monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) that inevitably precede MM. Over the past two decades, significant progress has been made in the genetic characterization and risk stratification of precursor plasma cell disorders. Indeed, the clinical introduction of highly effective and well-tolerated drugs begs the question: would earlier therapeutic intervention with novel therapies in MGUS and SMM patients alter natural history, providing a potential curative option? In this review, we discuss the epidemiology of MGUS and SMM and current models for risk stratification that predict MGUS and SMM progression to MM. We further discuss genetic heterogeneity and clonal evolution in MM and the interplay between tumor cells and the bone marrow (BM) microenvironment. Finally, we provide an overview of the current recommendations for the management of MGUS and SMM and discuss the open controversies in the field in light of promising results from early intervention clinical trials.

Advancements in nanotechnology for the diagnosis and treatment of multiple myeloma

Multiple myeloma (MM), known as a tumor of plasma cells, is not only refractory but also has a high relapse rate, and is the second-most common hematologic tumor after lymphoma. It is often accompanied by multiple osteolytic damage, hypercalcemia, anemia, and renal insufficiency. In terms of diagnosis, conventional detection methods have many limitations, such as it is invasive and time-consuming and has low accuracy. Measures to change these limitations are urgently needed. At the therapeutic level, although the survival of MM continues to prolong with the advent of new drugs, MM remains incurable and has a high recurrence rate. With the development of nanotechnology, nanomedicine has become a powerful way to improve the current diagnosis and treatment of MM. In this review, the research progress and breakthroughs of nanomedicine in MM will be presented. Meanwhile, both superiorities and challenges of nanomedicine were discussed. As a new idea for the diagnosis and treatments of MM, nanomedicine will play a very important role in the research field of MM.

Identification of patients with smouldering multiple myeloma at ultra-high risk of progression using serum parameters: the Czech Myeloma Group model

Smouldering multiple myeloma (SMM) presents without MM defining symptoms. We aimed to identify patients with SMM with an 80% risk of progression within 2 years using only serum parameters. In total, 527 patients with SMM were included and divided into a training group (287 patients from the Czech Myeloma Group [CMG]) and an independent validation group (240 patients from Heidelberg). The median follow-up was 2·4 and 2·5 years, respectively. Progression to MM occurred in 51·9% of the CMG and 38·8% of the Heidelberg patients, respectively. The median risk of progression was 11·0% (CMG) and 9·7% (Heidelberg) per year, during the 5 years after diagnosis. A serum involved/uninvolved free light-chain ratio of >30, immunoparesis, and serum monoclonal (M) protein of ≥2·3 g/dl emerged as powerful predictors of 2-year progression rate with a hazard ratio (HR) of 2·49 (95% confidence interval [CI] 1·49-4·17), HR of 2·01 (95% CI 1·36-2·96) and HR of 2·00 (95% CI 1·44-2·79) (P < 0·001) in univariate Cox regression analysis, respectively. Based on this, the CMG model identified patients with SMM with a 2-year risk of progression of 78·7% (95% CI 53·1-95·7; HR 6·8; P < 0·001, CMG) and 81·3% (95% CI 47·1-98·8; HR 38·63; P < 0·001, Heidelberg). Serum parameters in the CMG model allow identification of patients with SMM with an 80% risk of progression to symptomatic MM within 2 years.

Identifying monoclonal gammopathy of undetermined significance in electronic health data

PURPOSE

Monoclonal gammopathy of undetermined significance (MGUS) is a prevalent yet largely asymptomatic precursor to multiple myeloma. Patients with MGUS must undergo regular surveillance and testing, with few known predictors of progression. We developed an algorithm to identify MGUS patients in electronic health data to facilitate large-scale, population-based studies of this premalignant condition.

METHODS

We developed a four-step algorithm using electronic health record and health claims data from men and women aged 50 years or older receiving care from a large, multispecialty medical group between 2007 and 2015. The case definition required patients to have at least two MGUS ICD-9 diagnosis codes within 12 months, at least one serum and/or urine protein electrophoresis and one immunofixation test, and at least one in-office hematology/oncology visit. Medical charts for selected cases were abstracted then adjudicated independently by two physicians. We assessed algorithm validity by positive predictive value (PPV).

RESULTS

We identified 833 people with at least two MGUS diagnosis codes; 429 (52%) met all four algorithm criteria. We randomly selected 252 charts for review, including 206 from patients meeting all four algorithm criteria. The PPV for the 206 algorithm-identified charts was 76% (95% CI, 70%-82%). Among the 49 cases deemed to be false positives (24%), 33 were judged to have multiple myeloma or another lymphoproliferative condition, such as lymphoma.

CONCLUSIONS

We developed a simple algorithm that identified MGUS cases in electronic health data with reasonable accuracy. Inclusion of additional steps to eliminate cases with malignant disease may improve algorithm performance.

Positron Emission Tomography (PET) Radiopharmaceuticals in Multiple Myeloma

Multiple myeloma (MM) is a plasma cell disorder, characterized by clonal proliferation of malignant plasma cells in the bone marrow. Bone disease is the most frequent feature and an end-organ defining indicator of MM. In this context, imaging plays a pivotal role in the management of the malignancy. For several decades whole-body X-ray survey (WBXR) has been applied for the diagnosis and staging of bone disease in MM. However, the serious drawbacks of WBXR have led to its gradual replacement from novel imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT). PET/CT, with the tracer ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG), is now considered a powerful diagnostic tool for the detection of medullary and extramedullary disease at the time of diagnosis, a reliable predictor of survival as well as the most robust modality for treatment response evaluation in MM. On the other hand, ¹⁸F-FDG carries its own limitations as a radiopharmaceutical, including a rather poor sensitivity for the detection of diffuse bone marrow infiltration, a relatively low specificity, and the lack of widely applied, established criteria for image interpretation. This has led to the development of several alternative PET tracers, some of which with promising results regarding MM detection. The aim of this review article is to outline the major applications of PET/CT with different radiopharmaceuticals in the clinical practice of MM.

Association of Immune Marker Changes With Progression of Monoclonal Gammopathy of Undetermined Significance to Multiple Myeloma

IMPORTANCE

Multiple myeloma is consistently preceded by monoclonal gammopathy of undetermined significance (MGUS). Risk models that estimate the risk of progression from MGUS to multiple myeloma use data from a single time point, usually the initial workup.

OBJECTIVE

To longitudinally investigate the alterations of serum immune markers with stable vs progressive MGUS.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cross-sectional cohort study included 77 469 adult participants aged 55 to 74 years in the screening arm of the National Cancer Institute Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial who had a diagnosis of progressing MGUS (n = 187) or stable MGUS (n = 498), including light-chain subtype, from November 1993, through December 2011. For each participant, all available serially stored prediagnostic serum samples (N = 3266) were obtained. Data analysis was performed from April 2018, to December 2018.

MAIN OUTCOMES AND MEASURES

Serum protein and monoclonal immunoglobulin levels, serum free light chains, and serum light chains within each immunoglobulin class were measured.

RESULTS

Of 685 individuals included in the study, 461 (67.3%) were men; the mean (SD) age was 69.1 (5.6) years. In cross-sectional modeling, risk factors associated with progressive MGUS were IgA isotype (adjusted odds ratio [OR], 1.80; 95% CI, 1.03-3.13; P = .04), 15 g/L or more monoclonal spike (adjusted OR, 23.5; 95% CI, 8.9-61.9; P < .001), skewed (<0.1 or >10) serum free light chains ratio (adjusted OR, 46.4; 95% CI, 18.4-117.0; P < .001), and severe immunoparesis (≥2 suppressed uninvolved immunoglobulins) (adjusted OR, 19.1; 95% Cl, 7.5-48.3; P < .001). Risk factors associated with progressive light-chain MGUS were skewed serum free light chains ratio (adjusted OR, 44.0; 95% CI, 14.2-136.3; P < .001) and severe immunoparesis (adjusted OR, 48.6; 95% CI, 9.5-248.2; P < .001). In longitudinal analysis of participants with serial samples prior to progression, 23 of 43 participants (53%) had high-risk MGUS before progression; 16 of these 23 (70%) experienced conversion from low-risk or intermediate-risk MGUS within 5 years. Similar results were found for light-chain MGUS.

CONCLUSIONS AND RELEVANCE

The findings of evolving risk patterns support annual blood testing and risk assessment for patients with MGUS or light-chain MGUS.

Plasticity of High-Density Neutrophils in Multiple Myeloma is Associated with Increased Autophagy Via STAT3

In both monoclonal gammopathy of uncertain significance (MGUS) and multiple myeloma (MM) patients, immune functions are variably impaired, and there is a high risk of bacterial infections. Neutrophils are the most abundant circulating leukocytes and constitute the first line of host defense. Since little is known about the contribution of autophagy in the neutrophil function of MGUS and MM patients, we investigated the basal autophagy flux in freshly sorted neutrophils of patients and tested the plastic response of healthy neutrophils to soluble factors of MM. In freshly sorted high-density neutrophils obtained from patients with MGUS and MM or healthy subjects, we found a progressive autophagy trigger associated with soluble factors circulating in both peripheral blood and bone marrow, associated with increased IFNγ and pSTAT3S727. In normal high-density neutrophils, the formation of acidic vesicular organelles, a morphological characteristic of autophagy, could be induced after exposure for three hours with myeloma conditioned media or MM sera, an effect associated with increased phosphorylation of STAT3-pS727 and reverted by treatment with pan-JAK2 inhibitor ruxolitinib. Taken together, our data suggest that soluble factors in MM can trigger contemporary JAK2 signaling and autophagy in neutrophils, targetable with ruxolitinib.

Immune marker changes and risk of multiple myeloma: a nested case-control study using repeated pre-diagnostic blood samples

Biomarkers reliably predicting progression to multiple myeloma (MM) are lacking. Myeloma risk has been associated with low blood levels of monocyte chemotactic protein-3 (MCP-3), macrophage inflammatory protein-1 alpha (MIP-1α), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), fractalkine, and transforming growth factor-alpha (TGF-α). In this study, we aimed to replicate these findings and study the individual dynamics of each marker in a prospective longitudinal cohort, thereby examining their potential as markers of myeloma progression. For this purpose, we identified 65 myeloma cases and 65 matched cancer-free controls each with two donated blood samples within the Northern Sweden Health and Disease Study. The first and repeated samples from myeloma cases were donated at a median 13 and 4 years, respectively, before the myeloma was diagnosed. Known risk factors for progression were determined by protein-, and immunofixation electrophoresis, and free light chain assays. We observed lower levels of MCP-3, VEGF, FGF-2, and TGF-α in myeloma patients than in controls, consistent with previous data. We also observed that these markers decreased among future myeloma patients while remaining stable in controls. Decreasing trajectories were noted for TGF-α (P=2.5 × 10⁻⁴) indicating progression to MM. Investigating this, we found that low levels of TGF-α assessed at the time of the repeated sample were independently associated with risk of progression in a multivariable model (hazard ratio = 3.5; P=0.003). TGF-α can potentially improve early detection of MM.

Guidelines for Acquisition, Interpretation, and Reporting of Whole-Body MRI in Myeloma: Myeloma Response Assessment and Diagnosis System (MY-RADS)

Acknowledging the increasingly important role of whole-body MRI for directing patient care in myeloma, a multidisciplinary, international, and expert panel of radiologists, medical physicists, and hematologists with specific expertise in whole-body MRI in myeloma convened to discuss the technical performance standards, merits, and limitations of currently available imaging methods. Following guidance from the International Myeloma Working Group and the National Institute for Clinical Excellence in the United Kingdom, the Myeloma Response Assessment and Diagnosis System (or MY-RADS) imaging recommendations are designed to promote standardization and diminish variations in the acquisition, interpretation, and reporting of whole-body MRI in myeloma and allow response assessment. This consensus proposes a core clinical protocol for whole-body MRI and an extended protocol for advanced assessments. Published under a CC BY 4.0 license. Online supplemental material is available for this article.

Development of Multiple Myeloma of the IgA Type in a Patient with Cold Agglutinin Disease: Transformation or Coincidence?

Cold agglutinin disease (CAD) is an autoimmune hemolytic anemia and a distinct, clonal bone marrow lymphoproliferative disorder, characterized in most cases by a monoclonal IgMκ serum protein. We describe a CAD patient presenting with a monoclonal immunoglobulin of the IgAλ class. For years, she remained asymptomatic apart from the hemolytic anemia until eventually she developed multiple myeloma (MM) of the IgAλ phenotype. Prior to the development of MM, her hemolytic anemia responded to rituximab monotherapy. After she was diagnosed with MM, both conditions responded well to bortezomib-based therapy. We performed further investigations to determine whether her MM represented a progression/transformation of CAD or an independent disease. Flow cytometry and biopsy findings convincingly confirmed two unrelated clonal B-cell disorders. On this background, we also discuss previously published reports on cold agglutinin activity in patients with IgA gammopathy. In conclusion, cold agglutinins of the IgA class do probably not result in CAD. If a monoclonal immunoglobulin other than IgMκ is found in a patient with CAD, the coexistence of two unrelated B-cell clones should be suspected.

Myeloma light chain cast nephropathy, a review

Multiple Myeloma is a plasma cell proliferative disorder that commonly involves the kidney. Renal impairment is a serious complication during the course of the disease that is associated with increased morbidity and mortality. Light chain cast nephropathy is the predominant pattern of renal injury in Multiple Myeloma. This review article focuses on the pathophysiology and diagnostic approach of myeloma cast nephropathy. The management of precipitating factors as well as anti-plasma cell treatment modalities in the context of renal impairment are also discussed.

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.

Shall we treat smoldering multiple myeloma in the near future?

In recent years, several new drugs have been approved for the treatment of multiple myeloma. Many of these newer drugs are highly efficacious and less toxic than older chemotherapy drugs. In 2014, the diagnostic criteria for multiple myeloma were revised. The intent with the new criteria was to identify patients who require therapy at an earlier stage than at manifestation of organ complications. A subset of patients who were previously defined as having high-risk smoldering multiple myeloma was redefined as having multiple myeloma. In this context, it is logical to raise questions regarding the optimal clinical management of patients who are diagnosed with smoldering multiple myeloma in the current era. When is the optimal time to start therapy? Do the clinical trajectories for patients suggest there are distinct sub-entities hidden in the current category of smoldering multiple myeloma? How can we move the field forward from here? This paper reviews and dissects data and models on the topics of clinical features, underlying biology, and early treatment trials in smoldering multiple myeloma. The text highlights assumptions, facts, and gaps in the literature. As indicated in the title of the paper, the recurrent theme of the text is this: shall we treat smoldering multiple myeloma in the near future?

Multiple Myeloma Presenting as Acute Renal Failure in the Absence of Other Characteristic Features

This case report describes a 54-year-old, asymptomatic man who presented with hyperkalemia on routine lab testing who was later found to have acute renal failure, unresponsive to fluid resuscitation, with minimal improvement after hemodialysis. After a comprehensive evaluation ruled out common causes of acute renal failure, the patient underwent testing with a bone survey, urine protein electrophoresis (UPEP), serum protein electrophoresis (SPEP), and immunoelectrophoresis for suspected plasma cell dyscrasia and received plasmapheresis for hyperviscosity syndrome and nephrotoxicity, which resulted in improved renal function. Lab results showed monoclonal gammopathy, elevated serum free light chains, and Bence Jones protein in the urine with a follow-up bone marrow biopsy indicating plasma cell dyscrasia. The patient received a diagnosis of multiple myeloma (MM) and was started on chemotherapy and immunosuppression. In patients presenting with acute renal failure with an evaluation ruling out prerenal and postrenal causes, multiple myeloma should be considered.

Dynamic contrast-enhanced magnetic resonance imaging parameters correlate with advanced revised-ISS and angiopoietin-1/angiopoietin-2 ratio in patients with multiple myeloma

The aim of the study was to assess the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with newly diagnosed multiple myeloma (MM) who were treated with novel anti-myeloma agents. We studied 60 previously untreated MM patients at diagnosis, 14 with smoldering MM (SMM) and 5 with MGUS. All patients underwent MRI of the thoracolumbar spine and pelvis before the administration of any kind of therapy, and DCE-MRI was performed. The MRI perfusion parameters evaluated were wash-in (WIN), washout (WOUT), time-to-peak (TTPK), time-to-maximum slope (TMSP), and the WIN/TMSP ratio. The following serum levels of angiogenic cytokines were measured on the day of MRI: VEGF, angiogenin (Ang), angiopoietin-1 (Angp-1), and -2 (Angp-2). Symptomatic MM patients had increased WIN compared to SMM (p < 0.05) and MGUS patients (p = 0.001). TTPK was decreased, and WIN/TMSP was increased in both symptomatic and SMM patients compared to MGUS patients (p < 0.05). Symptomatic MM patients had decreased TMSP compared to MGUS patients. The Angp-1/Angp-2 ratio was reduced in symptomatic MM compared to SMM (p = 0.017) and MGUS patients (p < 0.001). TTPK correlated with Angp-1/Angp-2 ratio and importantly with R-ISS. Patients with R-ISS-3 had lower TTPK median value (23 s, range 18-29 s) compared to patients with R-ISS-2 (48 s, range 27-68 s) and patients with R-ISS-1 MM (54 s, range 42-76 s; p ANOVA = 0.01). A subset of patients with low TTPK (lower quartile) had shorter time to progression compared to all other patients. These data suggest that certain DCE-MRI parameters correlate with R-ISS and adverse prognostic features of angiogenesis, such as the ratio of Angp-1/Angp-2.

Combined proximal tubulopathy, crystal-storing histiocytosis, and cast nephropathy in a patient with light chain multiple myeloma

Background

The diagnosis of myeloma, a plasma dyscrasia, often results from the workup of unexplained renal disease. Persistent renal failure in myeloma is commonly caused by tubular nephropathy due to circulating immunoglobulins and free light chains. Myeloma cast nephropathy is characterized by crystalline precipitates of monoclonal light chains within distal tubules. Immunoglobulin crystallization rarely occurs intracellularly, within proximal tubular cells (light chain proximal tubulopathy) and interstitial histiocytes (crystal-storing histiocytosis). We present a case report of a rare simultaneous occurrence of light chain proximal tubulopathy, crystal-storing histiocytosis, and myeloma cast nephropathy in a patient with κ light chain multiple myeloma.

Case presentation

A 48-years-old man presented with uremia and anemia. Laboratory examination revealed low levels of serum IgG, IgA, and IgM. Serum and urine immunofixation electrophoresis showed a free κ monoclonal band. Bone marrow aspiration and biopsy revealed hypercellularity with marked plasmacytosis. Light microscopy revealed eosinophilic cuboid- and rhomboid-shaped crystals in the cytoplasm of proximal tubular epithelial cells, diffuse large mononuclear and multinuclear cells in the interstitium, and obstructed distal tubules with cast and giant cell reaction. Immunohistochemical examination indicated intense staining for κ light chains within casts, histiocytes, and tubular epithelial cells. Electron microscopy revealed electro-dense cuboid-, rhomboid-, or needle-shaped crystalline inclusions in proximal tubular epithelial cells and interstitial histiocytes. According to these results, we confirmed that this patient with myeloma exhibited simultaneous light chain proximal tubulopathy, crystal-storing histiocytosis, and myeloma cast nephropathy, which were attributed to monoclonal κ light chains. In addition to dialysis, the patient received induction chemotherapy with a combination of bortezomib, cyclophosphamide, and dexamethasone, followed by maintenance therapy with thalidomide. However, the patient did not regain renal function even when less than 5% plasma cells were detected in the bone marrow.

Conclusion

To the best of our knowledge, this is the first report of simultaneous light chain proximal tubulopathy, crystal-storing histiocytosis, and myeloma cast nephropathy in κ light chain multiple myeloma.

MGUS to myeloma: a mysterious gammopathy of underexplored significance

All cases of multiple myeloma (MM) are preceded by precursor states termed monoclonal gammopathy of undetermined significance (MGUS) or smoldering myeloma (SMM). Genetic analyses of MGUS cells have provided evidence that it is a genetically advanced lesion, wherein tumor cells carry many of the genetic changes found in MM cells. Intraclonal heterogeneity is also established early during the MGUS phase. Although the genetic features of MGUS or SMM cells at baseline may predict disease risk, transition to MM involves altered growth of preexisting clones. Recent advances in mouse modeling of MGUS suggest that the clinical dormancy of the clone may be regulated in part by growth controls extrinsic to the tumor cells. Interactions of MGUS cells with immune cells, bone cells, and others in the bone marrow niche may be key regulators of malignant transformation. These interactions involve a bidirectional crosstalk leading to both growth-supporting and inhibitory signals. Because MGUS is already a genetically complex lesion, application of new tools for earlier detection should allow delineation of earlier stages, which we term as pre-MGUS Analyses of populations at increased risk of MGUS also suggest the possible existence of a polyclonal phase preceding the development of MGUS. Monoclonal gammopathy in several patients may have potential clinical significance in spite of low risk of malignancy. Understanding the entire spectrum of these disorders may have broader implications beyond prevention of clinical malignancy.

Autoimmune manifestations in patients with multiple myeloma and monoclonal gammopathy of undetermined significance

Background

Multiple myeloma (MM) and its precursor, monoclonal gammopathy of undetermined significance (MGUS), have been linked with several autoimmune conditions in the medical literature. Yet, significance of these associations is not well understood.

Methods

Herein, we provide a comprehensive literature review on autoimmune disorders identified in patients with MM and MGUS. Most relevant papers were identified via searching the PubMed/Medline and EMBASE databases for articles published from inception until May 1, 2016.

Findings

Scientific literature on autoimmune conditions in patients with MM and MGUS consists of several case series and a multitude of case reports. Our analysis suggests an increased prevalence of autoimmune conditions in patients with MM and monoclonal gammopathy of undetermined significance (MGUS), including various autoimmune hematologic and rheumatologic conditions among other entities. Conversely, persons with various autoimmune conditions tend to have a higher prevalence of MGUS and MM than the general population.

Conclusions

Future research is required to explore further the link between MGUS/MM and autoimmune disorders. Inflammation in the setting of autoimmunity may serve as a trigger for MGUS and MM. In addition, a common genetic susceptibility for developing both an autoimmune disease and MM/MGUS might also exist. Autoimmune hematologic and rheumatologic diseases may pose important clinical problems for the MM patients. Therefore, a catalogue of these problems is important so that physicians are able to consider, identify and address them promptly.

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A comprehensive review linking MM and MGUS with autoimmune disorders

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There is increased prevalence of autoimmune conditions in patients with MM and MGUS

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Most autoimmune disorders precede the development of plasma cell dyscrasias

Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) magnetic resonance imaging as a biomarker for symptomatic multiple myeloma

Introduction

To evaluate the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) magnetic resonance imaging (MRI) to discriminate between symptomatic and asymptomatic myeloma in lumbar bone marrow without visible focal lesions.

Materials and Methods

The lumbar spine was examined with 3-T MRI in 11 patients with asymptomatic myeloma and 24 patients with symptomatic myeloma. The fat-signal fraction was calculated from the ratio of the signal intensity in the fat image divided by the signal intensity of the corresponding ROI in the in-phase IDEAL image. The t test was used to compare the asymptomatic and symptomatic groups. ROC curves were constructed to determine the ability of variables to discriminate between symptomatic and asymptomatic myeloma.

Results

Univariate analysis showed that β2-microglobulin and bone marrow plasma cell percent (BMPC%) were significantly higher and fat-signal fraction was significantly lower with symptomatic myeloma than with asymptomatic myeloma. Areas under the curve were 0.847 for β₂;-microglobulin, 0.834 for fat-signal fraction, and 0.759 for BMPC%.

Conclusion

The fat-signal fraction as a biomarker for multiple myeloma enables discrimination of symptomatic myeloma from asymptomatic myeloma. The fat-signal fraction offers superior sensitivity and specificity to BMPC% of biopsy specimens.

TPL2 kinase regulates the inflammatory milieu of the myeloma niche

Targeted modulation of microenvironmental regulatory pathways may be essential to control myeloma and other genetically/clonally heterogeneous cancers. Here we report that human myeloma-associated monocytes/macrophages (MAM), but not myeloma plasma cells, constitute the predominant source of interleukin-1β (IL-1β), IL-10, and tumor necrosis factor-α at diagnosis, whereas IL-6 originates from stromal cells and macrophages. To dissect MAM activation/cytokine pathways, we analyzed Toll-like receptor (TLR) expression in human myeloma CD14(+) cells. We observed coregulation of TLR2 and TLR6 expression correlating with local processing of versican, a proteoglycan TLR2/6 agonist linked to carcinoma progression. Versican has not been mechanistically implicated in myeloma pathogenesis. We hypothesized that the most readily accessible target in the versican-TLR2/6 pathway would be the mitogen-activated protein 3 (MAP3) kinase, TPL2 (Cot/MAP3K8). Ablation of Tpl2 in the genetically engineered in vivo myeloma model, Vκ*MYC, led to prolonged disease latency associated with plasma cell growth defect. Tpl2 loss abrogated the "inflammatory switch" in MAM within nascent myeloma lesions and licensed macrophage repolarization in established tumors. MYC activation/expression in plasma cells was independent of Tpl2 activity. Pharmacologic TPL2 inhibition in human monocytes led to dose-dependent attenuation of IL-1β induction/secretion in response to TLR2 stimulation. Our results highlight a TLR2/6-dependent TPL2 pathway as novel therapeutic target acting nonautonomously through macrophages to control myeloma progression.

Myeloma-related kidney disease

Multiple myeloma is a malignant plasma cell disorder characterized by the overproduction of monoclonal proteins. The kidney is 1 of the major target organs of multiple myeloma. Most often, this is the result of the monoclonal proteins, which can injure the kidney via several mechanisms. In some cases, direct invasion by myeloma cells and/or bone marrow cells can also result in kidney injury. A kidney biopsy can help distinguish the various myeloma-related kidney diseases and aid in the treatment plan.

Extracellular matrix remodeling by bone marrow fibroblast-like cells correlates with disease progression in multiple myeloma

The pathogenesis of multiple myeloma (MM) is regarded as a multistep process, in which an asymptomatic stage of monoclonal gammopathy of undetermined significance (MGUS) precedes virtually all cases of MM. Molecular events characteristic for the transition from MGUS to MM are still poorly defined. We hypothesized that fibroblast-like cells in the tumor microenvironment are critically involved in the pathogenesis of MM. Therefore, we performed a comparative proteome profiling study, analyzing primary human fibroblast-like cells isolated from the bone marrow of MM, of MGUS, as well as of non-neoplastic control patients. Thereby, a group of extracellular matrix (ECM) proteins, ECM receptors, and ECM-modulating enzymes turned out to be progressively up-regulated in MGUS and MM. These proteins include laminin α4, lysyl-hydroxylase 2, prolyl 4-hydroxylase 1, nidogen-2, integrin α5β5, c-type mannose receptor 2, PAI-1, basigin, and MMP-2, in addition to PDGF-receptor β and the growth factor periostin, which are likewise involved in ECM activities. Our results indicate that ECM remodeling by fibroblast-like cells may take place already at the level of MGUS and may become even more pronounced in MM. The identified proteins which indicate the stepwise progression from MGUS to MM may offer new tools for therapeutic strategies.

Indolent mantle cell lymphoma

Over the past decade, it has become increasingly clear that mantle cell lymphoma (MCL) is a more heterogeneous disease than originally recognized. Several groups have reported on a subgroup of patients with a less aggressive course than expected resulting in the term "indolent MCL". Unlike the recognized histologic variants, the definition of indolent mantle cell lymphoma is unclear, and patients with indolent MCL are often identified only after having undergone prolonged periods of observation. In this review, we will discuss clinical and biologic features and provide a framework for the approach in identifying patients with indolent MCL.

Monoclonal gammopathy of undetermined significance: a new proposal of workup

OBJECTIVE

Diagnostic criteria for monoclonal gammopathy of undetermined significance (MGUS) require quantification of bone marrow plasma cells (BMPCs) and skeletal survey to discriminate between MGUS and multiple myeloma (MM). By contrast, recent published guidelines suggest that these procedures could be avoided in the presence of serum monoclonal spike (M-spike) of small amount (≤1.5 g/dL). Aim of this study is to better quantify the risk of missing a diagnosis of MM, not performing bone marrow aspirate and skeletal survey in patients with M-spike ≤ 1.5 g/dL asymptomatic for bone pain.

METHODS

We reviewed data of 2282 patients consecutively observed from January 1974 to December 2010 in our single hematology department. We considered eligible for this study 1271 patients with grade <2 NCI bone pain, confirmed to have an MGUS or an MM after extensive standardized diagnostic workup including bone marrow biopsy, skeletal bone survey and laboratory tests.

RESULTS

The risk of finding a BMPC infiltration ≥10% in patients with an M-spike ≤ 1.5 g/dL was very low (7.3%), although significantly different according to IgH isotype (4.7% for IgG vs. 20.5% for IgA). The risk of finding bone lesions with M-spike ≤ 1.5 g/dL was negligible (2.5%), regardless of IgH isotype.

CONCLUSION

In asymptomatic patients with M-spike of small amount (≤1.5 g/dL): (i) BMPC evaluation may be reasonably avoided in patients with IgG M-spike, while should always be part of diagnostic workup in the presence of IgA M-spike and (ii) skeletal survey, less predictive for MM, should not be routinely indicated irrespective of IgH isotype.

Modeling progression risk for smoldering multiple myeloma: results from a prospective clinical study

The risk of progression to multiple myeloma (MM) from the precursor condition smoldering MM (SMM) varies considerably among individual patients. Reliable markers for progression to MM are vital to advance the understanding of myeloma precursor disease and for the development of intervention trials designed to delay/prevent MM. The Mayo Clinic and Spanish PETHEMA have proposed models to stratify patient risk based on clinical parameters. The aim of our study was to define the degree of concordance between these two models by comparing the distribution of patients with SMM classified as low, medium and high risk for progression. A total of 77 patients with SMM were enrolled in our prospective natural history study. Per study protocol, each patient was assigned risk scores based on both the Mayo and the Spanish models. The Mayo Clinic model identified 38, 35 and four patients as low, medium and high risk, respectively. The Spanish PETHEMA model classified 17, 22 and 38 patients as low, medium and high risk, respectively. There was significant discordance in overall patient risk classification (28.6% concordance) and in classifying patients as low versus high (p < 0.0001), low versus non-low (p = 0.0007) and high versus non-high (p < 0.0001) risk. There is a need for prospectively validated models to characterize individual patient risk of transformation to MM.

Frequent occurrence of highly expanded but unrelated B-cell clones in patients with multiple myeloma

Clonal diversity in multiple myeloma (MM) includes both MM-related and MM-unrelated clonal expansions which are subject to dominance exerted by the MM clone. Here we show evidence for the existence of minor but highly expanded unrelated B-cell clones in patients with MM defined by their complementary determining region 3 (CDR3) peak. We further characterize these clones over the disease and subsequent treatment. Second clones were identified by their specific IgH-VDJ sequences that are distinct from those of dominant MM clones. Clonal frequencies were determined through semi-quantitative PCR, quantitative PCR and single-cell polymerase chain reaction of the clone-specific sequence. In 13/74 MM patients, more than one dominant CDR3 peak was identified with 12 patients (16%) being truly biclonal. Second clones had different frequencies, were found in different locations and were found in different cell types from the dominant MM clone. Where analysis was possible, they were shown to have chromosomal characteristic distinct from those of the MM clone. The frequency of the second clone also changed over the course of the disease and often persisted despite treatment. Molecularly-defined second clones are infrequent in monoclonal gammopathy of undetermined significance (MGUS, 1/43 individuals or 2%), suggesting that they may arise at relatively late stages of myelomagenesis. In further support of our findings, biclonal gammopathy and concomitant MM and CLL (chronic lymphocytic leukemia) were confirmed to originate from two unrelated clones. Our data supports the idea that the clone giving rise to symptomatic myeloma exerts clonal dominance to prevent expansion of other clones. MM and second clones may arise from an underlying niche permissive of clonal expansion. The clinical significance of these highly expanded but unrelated clones remains to be confirmed. Overall, our findings add new dimensions to evaluating related and unrelated clonal expansions in MM and the impact of disease evolution and treatment on clonal diversity.

Can NKT cells extinguish smoldering myeloma?

One of the greatest challenges in all of medicine is to improve on the life of an asymptomatic patient; however, in this issue of Blood, Richter and colleagues share provocative new data taking steps toward accomplishing this goal.

Etiology of Waldenström macroglobulinemia: genetic factors and immune-related conditions

Epidemiologic studies provide an insight into the etiology of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia, which indicates that repetitive immune stimulation and genetic factors play an important role. Here, the current understanding on the causes of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia are reviewed. Recent studies of the literature are discussed, and future population-based studies are proposed to further elucidate the molecular mechanisms that underlie these associations. Finally, the clinical implications of these data are outlined, and perspectives on clinical follow-up and counseling are provided.