Monoclonal Gammopathy Of Undetermined Significance Research Articles

The choice of serum-free light chain analysis method could potentially have clinical consequences for myeloma patients.

Multiple myeloma (MM) is a disease, that at times poses diagnostic and monitoring challenges. Over the last decades laboratory methods have been expanded with serum free light chain (FLC) analysis. Alerted by two index cases with clinical impact due to failure of the FLC analysis to indicate a disease progression, we aimed to identify any clinical consequences due to known differences between FLC analysis methods. We applied two FLC analysis methods (Freelite Binding Site [FBS] and N-Latex Siemens [NLS]) on all patients with MM and monoclonal gammopathy of uncertain significance diagnosed/followed up at Södra Älvsborg Hematology Unit, from April to December 2022. From a total of 123 patients with malignant plasma cell disorder, we identified five cases (4.1%) where solely the FBS method, as opposed to NLS, urine and serum electrophoresis, could support diagnosis or detect progression. The consequences of this discrepancy included not only change of diagnosis or delayed therapy but also change of treatment. Our findings indicate that a stronger awareness of the potential weaknesses of different FLC methods is needed, which calls for a closer collaboration between clinical chemists and hematologists.

Development of a Multivariable Model to Predict the Need for Bone Marrow Sampling in Persons With Monoclonal Gammopathy of Undetermined Significance : A Cohort Study Nested in a Clinical Trial.

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions to multiple myeloma and related disorders. Smoldering multiple myeloma is distinguished from MGUS by 10% or greater bone marrow plasma cells (BMPC) on sampling, has a higher risk for progression, and requires specialist management. To develop a multivariable prediction model that predicts the probability that a person with presumed MGUS has 10% or greater BMPC (SMM or worse by bone marrow criteria) to inform the decision to obtain a bone marrow sample and compare its performance to the Mayo Clinic risk stratification model. iStopMM (Iceland Screens, Treats or Prevents Multiple Myeloma), a prospective population-based screening study of MGUS. (ClinicalTrials.gov: NCT03327597). Icelandic population of adults aged 40 years or older. 1043 persons with IgG, IgA, light-chain, and biclonal MGUS detected by screening and an interpretable bone marrow sample. Monoclonal gammopathy of undetermined significance isotype; monoclonal protein concentration; free light-chain ratio; and total IgG, IgM, and IgA concentrations were used as predictors. Bone marrow plasma cells were categorized as 0% to 4%, 5% to 9%, 10% to 14%, or 15% or greater. The c-statistic for SMM or worse was 0.85 (95% CI, 0.82 to 0.88), and calibration was excellent (intercept, -0.07; slope, 0.95). At a threshold of 10% predicted risk for SMM or worse, sensitivity was 86%, specificity was 67%, positive predictive value was 32%, and negative predictive value was 96%. Compared with the Mayo Clinic model, the net benefit for the decision to refer for sampling was between 0.13 and 0.30 higher over a range of plausible low-risk thresholds. The prediction model will require external validation. This accurate prediction model for SMM or worse was developed in a population-based cohort of persons with presumed MGUS and may be used to defer bone marrow sampling and referral to hematology. International Myeloma Foundation and the European Research Council.

Clinicopathological characteristics and prognosis in patients with monoclonal gammopathy and renal damage in central China: a multicenter retrospective cohort study

Renal involvement is common in monoclonal gammopathy (MG); however, the same patient may have both MG and non-paraprotein-associated renal damage. Accordingly, distinguishing the cause of renal damage is necessary because of the different clinical characteristics and associated treatments. In this multicenter retrospective cohort study, we described the clinicopathological characteristics and prognosis of 703 patients with MG and renal damage in central China. Patients were classified as having MG of renal significance (MGRS), MG of undetermined significance (MGUS), or hematological malignancy. 260 (36.98%), 259 (36.84%), and 184 (26.17%) had MGRS, MGUS, and hematological malignancies, respectively. Amyloidosis was the leading pattern of MGRS (74.23%), followed by thrombotic microangiopathy (8.85%) and monoclonal immunoglobulin deposition disease (8.46%). Membranous nephropathy was the leading diagnosis of MGUS (39.38%). Renal pathological findings of patients with hematological malignancies included paraprotein-associated lesions (84.78%) and non-paraprotein-associated lesions (15.22%). The presence of nephrotic syndrome and an abnormal free light chain (FLC) ratio were independently associated with MGRS. The overall survival was better in patients with MGUS than in those with MGRS or hematological malignancies.

A rare case of crystalline deposits over Descemet’s membrane in a suspected case of monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant disorder that can give way to multiple myeloma and related plasma cell disorders. In patients with MGUS, ocular involvement is rare, although several cases of crystalline deposits in the corneal stroma have been reported which may be unilateral or bilateral.[1-4] Along with stromal deposits, corneal involvement may happen with varied presentations making imperative to be differentiated from corneal degenerations and dystrophies. We report a suspected case of MGUS presenting with uniocular involvement in the form of crystalline deposits over Descemet’s membrane, which is an infrequent manifestation of the occult systemic disorder.

Decreased neutrophil function in newly diagnosed multiple myeloma patients is restored with lenalidomide therapy.

Bacterial infections are common and a major cause of morbidity and mortality in multiple myeloma (MM). We have investigated the function of polymorphonuclear leukocyte (PMN), the immune system's first line of defense against bacteria, in peripheral blood (PB) and bone marrow (BM) samples from patients with newly diagnosed MM (NDMM), smoldering MM (SMM), monoclonal gammopathy of undetermined significance (MGUS) and healthy controls. Phagocytosis and oxidative burst in PMN cells from patients and healthy donors were investigated using PhagoTest and PhagoBurst assay. PMN from NDMM, SMM, and MGUS patients had reduced phagocytosis and oxidative burst ability compared with healthy controls. The dysfunction was most prominent in BM samples from MM, SMM, and MGUS patients. Importantly the reduced phagocytosis in MM patients was restored in patients on lenalidomide therapy. Consistently the ability of Escherichia coli stimulated oxidative burst in BM was reduced for the MM, SMM, and MGUS cohort in contrast to the healthy controls and the patients on lenalidomide treatment. Our results show that MM patients have neutrophil dysfunction that could contribute to susceptibility for bacterial infections and that lenalidomide therapy was associated with restored PMN function.

Abstract 3455: Prevalence of monoclonal gammopathy of undetermined significance (MGUS) in a Western Nigerian population

Abstract Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant condition characterized by plasma cell production of monoclonal (M) protein and is a requisite precursor to multiple myeloma (MM). African American (AA) individuals have a two-fold higher incidence of MGUS and MM compared to White individuals. However, data are limited on individuals from Africa, especially using sensitive MGUS detection methods. We examined the prevalence of MGUS in a sample of the general population in Nigeria. Individuals aged 40 and over (n=343) were recruited through health promotion events in Ado-Odo Ota Local Government Area of Ogun State, Nigeria, and provided informed consent, a blood sample, and a short questionnaire. Serum was screened at Mayo Clinic for heavy chain (HC)-MGUS using the matrix-assisted laser desorption/ionization-time of flight (Mass-Fix) assay, which has high sensitivity for detection of M-proteins; serum free light chains (FLC) were also measured. FLC was abnormal if the kappa (>0.26 mg/dL) or lambda (>0.33 mg/dL) light chain (LC) was elevated and FLC ratio (kappa/lambda) was outside the reference range (0.26-3.10). LC-MGUS was defined as an abnormal FLC in the absence of a HC. Age- and sex-adjusted prevalence rates were directly standardized to 2010 United States (US) population for comparison to published studies. Logistic regression was used to examine the association of age, sex, and BMI with HC-MGUS. The mean age of participants was 55 years (SD=10.9), and 74.6% were female. Of these, 216 (63%) had both parents from the Yoruba tribe, 89 (26%) from the Igbo tribe and 38 (11%) from other tribes. Overall, 33 participants (9.6%) had HC-MGUS, with 8 (2.3%) having an M-protein above 0.2 g/dL; 6 (1.7%) had LC-MGUS. HC-MGUS was predominantly IgG isotype (48.5%), followed by IgA (27.3%), biclonal (15.2%) and IgM (9.0%). Prevalence of HC-MGUS was 8.3% for ages 40-49, 7.7% ages 50-69 and 22% ages 70 and above. Standardized to the US population, age and sex adjusted MGUS prevalence ages 50 and older was 17.3% (95% CI: 9.8%-24.9%) and HC-MGUS was 14.7% (95% CI: 7.7%-21.8%), similar to previously published rates of HC-MGUS using Mass-Fix screening of AA individuals (16.5%, 95% CI: 12.2%-20.8%) (PMID: 35316833). In models that included age, sex and BMI, older age was positively associated with HC-MGUS (OR=3.1, 95% CI: 1.1-8.7 for ages 70+ compared to <50), while female sex (OR=0.53, 95% CI: 0.24-1.2) and overweight/obesity (OR=0.34, 95% CI: 0.16-0.75 for BMI > 25 vs. <25) were inversely associated with HC-MGUS. We observed similar prevalence of HC-MGUS at ages 50 and above among Western Nigerian and AA populations when screened using mass-spectrometry. Older age was positively associated with HC-MGUS while overweight and obesity were inversely associated. Studies of MGUS in indigenous African populations may provide insight to unique cancer risk factors compared to other populations. Citation Format: Celine M. Vachon, Cristine Allmer, Danelle Moonen, Aaron Norman, Joselle Cook, Susan Slager, Oluwakemi A. Rotimi, Opeyemi C. De Campos, Titilope M. Dokumu, David Murray, Shaji Kumar, Elizabeth Brown, Linda B. Baughn, Solomon Rotimi. Prevalence of monoclonal gammopathy of undetermined significance (MGUS) in a Western Nigerian population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3455.

Abstract 6848: Analysis of the bone microenvironment cells by single cell transcriptomics reveals altered features in multiple myeloma patients compared to pre-malignant monoclonal gammopathies

Abstract Multiple myeloma (MM) is a malignant plasma cell dyscrasia that can be preceded by monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM (SMM). How the bone microenvironment (BME) changes and contributes to tumoral progression in MM remains unresolved. Published data on BME are mainly produced in vitro and few data are on MGUS/SMM patients. Up to date, no single-cell RNA sequencing database of the BME cells has been described in MM. The aim of this project was to characterize for the first time at single cell level, the BME in patients with newly diagnosed MM (MMD) and MGUS/SMM to identify alterations involved in tumoral progression. From 15 bone biopsies of MMD, MGUS and SMM patients, we depleted CD235a+, CD45+, CD31+, and CD138+ cells to enrich the rare BME non-hemopoietic cells. The CD45-CD31-CD235a-CD138- cells were analyzed by scRNAseq. Data were generated on Chromium 10X Genomics. Cellranger and Seurat pipeline in R software has been used. Cell identities were assigned by manual curation. The trajectory analysis has been made by Monocle3. Decouple R and FindMarkers were used to compare pathways, and differential gene expression (DGE) of the samples throughout the different conditions. A total of 35723 cells were profiled. We identified 13 BME cell type clusters: 7 mesenchymal stromal cells (MSCs) clusters (proliferating MSC, MSC DDK-OPG-, MSC DKK+, MSC RUNX2-, MSC OPG+, MSC Osteogenic, Perivascular MSC) and 6 osteoblasts (OBs) clusters (OB precursor, OB precursor LEPR+, OB BGLAP+, OB SPP1+, OB NFkB+, OB late). Psdeudotime analyses highlighted a complex trajectory of differentiation from more immature cell clusters (proliferating MSC) to late OB cluster, confirming the ability of the dataset to snapshot the in vivo complexity of BME and we highlighted an alteration of the MSCs clusters trajectories starting in SMM samples till a disruption in MM. Pathway analyses, in MMD compared to MGUS/SMM, revealed an upregulation of VEGF and PI3K activity in proliferating MSC, perivascular MSC and OB clusters. TRAIL pathway activity, known to suppress MM cell proliferation, was upregulated in MSC osteogenic and OB BGLAP+ in MGUS. Finally, DGE analyses revealed the modulation of different genes, many not yet described in MM. MGUS MSCs clusters showed an upregulation of FBLN1, SERPNF1 and MMD MSCs clusters dramatically downregulated WISP2 and upregulated SRGN, involved in MM cell proliferation. Interestingly, in SMM samples, we reported an upregulation of genes involved both in the promotion of osteoblastogenesis (SCARA3, SPON2) and inhibition (GREM1), likely underling the attempt to contrast the establishment of altered BME, characteristic of MM. Our approach is able to dissect the complex organization of the BME and to highlight at single cells level the alterations of the BME in patients with MM compared to MGUS and SMM. Citation Format: Paola Storti, Tommaso Torelli, Cristina Manferdini, Denise Toscani, Alessandro Guidi, Rosanna Vescovini, Nicolas Thomas Iannozzi, Benedetta Dalla Palma, Matteo Scita, Federica Librale, Stefania Ricci, Vincenzo Raimondi, Oxana Lungu, Giannalisa Todaro, Gabriella Sammarelli, Emanuela Aleo, Gina Lisignoli, Luca Agnelli, Nicola Giuliani. Analysis of the bone microenvironment cells by single cell transcriptomics reveals altered features in multiple myeloma patients compared to pre-malignant monoclonal gammopathies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6848.

Abstract 3447: Potential for reduction in invasive cancer incidence by interception of preneoplastic lesions

Abstract Background: Preneoplastic lesions (PNL) are morphologically identifiable lesions lack the ability to invade surrounding tissue but can progress to invasive cancer. Thus, PNL present an opportunity to identify individuals at elevated cancer risk and identify opportunities for early detection and interception of cancer. Objective: We used published data sources to estimate the impact of intercepting progression of PNL to invasive cancer across multiple anatomic sites. We estimated the hypothetical number of cancers that could be avoided in the United States population if interception was successful in preventing a percentage of individuals with PNL from progressing to invasive cancer. Methods: Estimates of prevalence, latency, and probability of percent progression of PNL to invasive cancer were obtained from literature. We considered PNL associated with invasive tumors of the breast, bladder, cervix, colorectum, esophagus, liver, lung, oropharynx, pancreas, prostate, skin (melanocytes), skin (squamous cells), and stomach as well as precursors to leukemia and myeloma. We modeled a cohort of 100,000 individuals from which we estimated the number of cases that could be avoided if interception of a PNL before it progressed to an invasive cancer case was successful. Results were stratified for race and sex; positive- and negative-predictive values were calculated. Results: For PNL with a higher prevalence and percent progression per year, there were more invasive cancers that could be avoided if interception was successful. Detection of PNL associated with pancreas, stomach, oral, and prostate cancers had the greatest potential to avoid invasive cancers in the US population. For example, if 95% of pancreatic intraepithelial neoplasia lesions were detected, 15% progressed to pancreas cancer, and assuming a 43% prevalence over a 5-year latency period, 1,226 potential invasive pancreatic cancer cases could be avoided per year. Similarly, 998 potential invasive stomach cancer cases could be avoided earlier if 95% of gastric intestinal metaplasia lesions were detected assuming 42% progressed to invasive cancer with a 19% prevalence and a 4-year latency period. Additionally, if we could intercept 5% to 95% of all PNL from becoming invasive cancer, we would avoid between 176 to 8,515 number of invasive cases being diagnosed. When stratified by race, symptomatic multiple myeloma can be avoided in individuals with monoclonal gammopathies of undetermined significance if this condition is detected earlier among Black individuals. Conclusion: By detecting PNL and preventing them from advancing to invasive cancer, we can avoid substantial mortality as well as the costs and morbidities associated with treating more advanced cancers. Citation Format: Pranoti Pradhan, Irene Ghobrial, Catherine Marinac, Betsy O’Donnell, Sapna Syngal, Timothy Rebbeck. Potential for reduction in invasive cancer incidence by interception of preneoplastic lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3447.

Retrospective analysis of multiple myeloma drug use in cutaneous toxicity of monoclonal gammopathy of undetermined significance

Retrospective analysis of multiple myeloma drug use in cutaneous toxicity of monoclonal gammopathy of undetermined significance

Design and Rationale of Prolonged Nightly Fasting for Multiple Myeloma Prevention (PROFAST): Protocol for a Randomized Controlled Pilot Trial.

Obesity is an established, modifiable risk factor of multiple myeloma (MM); yet, no lifestyle interventions are routinely recommended for patients with overweight or obesity with MM precursor conditions. Prolonged nightly fasting is a simple, practical dietary regimen supported by research, suggesting that the synchronization of feeding-fasting timing with sleep-wake cycles favorably affects metabolic pathways implicated in MM. We describe the design and rationale of a randomized controlled pilot trial evaluating the efficacy of a regular, prolonged nighttime fasting schedule among individuals with overweight or obesity at high risk for developing MM or a related lymphoid malignancy. We aim to investigate the effects of 4-month prolonged nightly fasting on body composition and tumor biomarkers among individuals with overweight or obesity with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), or smoldering Waldenström macroglobulinemia (SWM). Individuals with MGUS, SMM, or SWM aged ≥18 years and a BMI of ≥25 kg/m2 are randomized to either a 14-hour nighttime fasting intervention or a healthy lifestyle education control group. Participants' baseline diet and lifestyle patterns are characterized through two 24-hour dietary recalls: questionnaires querying demographic, comorbidity, lifestyle, and quality-of-life information; and wrist actigraphy measurements for 7 days. Fasting intervention participants are supported through one-on-one telephone counseling by a health coach and automated SMS text messaging to support fasting goals. Primary end points of body composition, including visceral and subcutaneous fat (by dual-energy x-ray absorptiometry); bone marrow adiposity (by bone marrow histology); and tumor biomarkers, specifically M-proteins and serum free light-chain concentrations (by gel-based and serum free light-chain assays), are assessed at baseline and after the 4-month study period; changes therein from baseline are evaluated using a repeated measures mixed-effects model that accounts for the correlation between baseline and follow-up measures and is generally robust to missing data. Feasibilityis assessed as participant retention (percent dropout in each arm) and percentage of days participants achieved a ≥14-hour fast. The PROlonged nightly FASTing (PROFAST) study was funded in June 2022. Participant recruitment commenced in April 2023. As of July 2023, six participants consented to the study. The study is expected to be completed by April 2024, and data analysis and results are expected to be published in the first quarter of 2025. PROFAST serves as an important first step in exploring the premise that prolonged nightly fasting is a strategy to control obesity and obesity-related mechanisms of myelomagenesis. In evaluating the feasibility and impact of prolonged nightly fasting on body composition, bone marrow adipose tissue, and biomarkers of tumor burden, this pilot study may generate hypotheses regarding metabolic mechanisms underlying MM development and ultimately inform clinical and public health strategies for MM prevention. ClinicalTrials.gov NCT05565638; http://clinicaltrials.gov/ct2/show/NCT05565638. DERR1-10.2196/51368.

Performance Characteristics and Limitations of the Available Assays for the Detection and Quantitation of Monoclonal Free Light Chains and New Emerging Methodologies.

Light chain measurements form an essential component of the testing strategy for the detection and monitoring of patients with suspected and/or proven plasma cell disorders. Urine-based electrophoretic assays remain at the centre of the international guidelines for response assessment but the supplementary role of serum-free light chain (FLC) assays in response assessment and the detection of disease progression due to their increased sensitivity has been increasingly recognised since their introduction in 2001. Serum FLC assays have also been shown to be prognostic across the spectrum of plasma cell disorders and are now incorporated into risk stratification scores for patients with monoclonal gammopathy of undetermined significance (MGUS), smouldering multiple myeloma, and light chain amyloidosis (AL amyloidosis), as well as being incorporated into the criteria for defining symptomatic multiple myeloma. There are now multiple different commercially available serum FLC assays available with differing performance characteristics, which are discussed in this review, along with the implications of these for patient monitoring. Finally, newer methodologies for the identification and characterisation of monoclonal FLC, including modifications to electrophoretic techniques, mass spectrometry-based assays and Amylite, are also described along with the relevant published data available regarding the performance of each assay.

The Diagnostic Value of Abnormal Bone Marrow Signal Changes on Magnetic Resonance Imaging: Is Bone Marrow Biopsy Essential?

It is essential to determine whether bone marrow signal changes on magnetic resonance imaging (MRI) represent a physiological response or pathology; at present, the clinical significance of these signal changes is unclear. It is unknown whether a bone marrow biopsy is required when bone marrow signal changes are detected incidentally in individuals without suspected malignancy. The primary purpose of this study was to determine whether incidentally detected bone marrow signal changes on MRI performed for various reasons (at the time of admission or during follow-up) are clinically significant. We retrospectively evaluated the bone marrow biopsy clinical and laboratory findings of 42 patients with incidental bone marrow signal changes on MRI between September 2016 and January 2020. We also determined whether the patients were diagnosed with malignancy during admission or follow-up. Of the 42 patients, three (7%) were diagnosed with hematological malignancies during admission, while two were diagnosed with multiple myeloma and one with B-cell acute lymphoblastic leukemia. Of the 42 patients, 35 had a mean follow-up of 40.6 ± 5.3 months. One patient was diagnosed with monoclonal gammopathy of undetermined significance four months after their first admission. In addition to MRI, detailed clinical and laboratory evaluations should be performed to inform the decision for bone marrow biopsy and exclude hematological malignancy. If there is any doubt, a bone marrow biopsy should be performed. Moreover, since bone marrow signal changes may be a preliminary finding, follow-up of these patients is essential.

Enhancing prognostic power in multiple myeloma using a plasma cell signature derived from single-cell RNA sequencing

Multiple myeloma (MM) is a heterogenous plasma cell malignancy, for which the established prognostic models exhibit limitations in capturing the full spectrum of outcome variability. Leveraging single-cell RNA-sequencing data, we developed a novel plasma cell gene signature. We evaluated and validated the associations of the resulting plasma cell malignancy (PBM) score with disease state, progression and clinical outcomes using data from five independent myeloma studies consisting of 2115 samples (1978 MM, 65 monoclonal gammopathy of undetermined significance, 35 smoldering MM, and 37 healthy controls). Overall, a higher PBM score was significantly associated with a more advanced stage within the spectrum of plasma cell dyscrasias (all p < 0.05) and a shorter overall survival in MM (hazard ratio, HR = 1.72; p < 0.001). Notably, the prognostic effect of the PBM score was independent of the International Staging System (ISS) and Revised ISS (R-ISS). The downstream analysis further linked higher PBM scores with the presence of cytogenetic abnormalities, TP53 mutations, and compositional changes in the myeloma tumor immune microenvironment. Our integrated analyses suggest the PBM score may provide an opportunity for refining risk stratification and guide decisions on therapeutic approaches to MM.

Abstract P06: Characterization of the Immune Tumor Microenvironment in a Diverse Cohort of Patients with Multiple Myeloma

Abstract Multiple myeloma (MM) is the most common blood cancer in African American (AA) individuals. AAs have an increased risk of developing Monoclonal Gammopathy of Undetermined Significance (MGUS) and MM compared to non-Hispanic White (NHW) individuals. While several studies have shown a pivotal role for the immune tumor microenvironment (iTME) in MM pathogenesis, the composition of the iTME in AAs with MM is under investigated. Viably frozen whole bone marrow (BM) aspirates from 128 individuals (53 AA and 75 NHW) with either MM (n=65), MGUS (n=28), smoldering MM (SMM, n=13), or healthy controls (n=22) were evaluated by single cell RNA-sequencing (scRNA-seq) or mass cytometry (CyTOF). We characterized 34 (14 AA and 20 NHW) by scRNA-seq and 94 (39 AA and 55 NHW) by CyTOF. CyTOF samples were stained with Maxpar Direct Immune Profiling Assay Kit (Fluidigm), acquired on a Helios mass cytometer and analyzed in Cytobank. Data were analyzed by logistic equivalent regression model with p&amp;lt;0.05 for significance. ScRNA-seq samples were processed as in Yao, 2022. Data were normalized using scvi-tools and clustered by Uniform manifold approximation and projection (UMAP). Differentially expressed markers between clusters were identified using Model-based Analysis of Single-cell Transcriptomics (MAST) in Seurat R package at FDR &amp;lt; 0.05 and log2 fold change &amp;gt; 0.55. ScRNA-seq of the CD45+ non-tumor lymphocytes revealed 17 immune populations (HSC, erythroblast, MDSC, GMP, CD1c+ DC, CD4+ and CD8+ T cell, CD14+ M1 macrophage, CD16+monocyte, monocyte, pDC, naïve B, pre-B, pro-B, memory B, NK/MAIT). CD3E/D+cells were clustered into naïve/central memory (CCR7+, LEF1+, SELL+), memory (GZMK+), effector (GZMB+, GZMH+, FGFBP2+), g/d (TRDC+), MAIT (SLC4A10+, KLRB1+) and IFN CD8+ T cells (IFIT1+, IFIT2+,IFIT3+). Disease progression was associated with increases in median CD4+ and CD8+ GZMK+ T cells, memory B cells and a reduction in all monocyte clusters. Within the diseased cohort in comparison to NHW patients, AA patients had increased CD3+ T cells (CD4 and CD8+) (AA 57.5% vs. NHW 44.3%) and a reduction in overall monocytes (AA 10.5% vs. 26.5%). These results were validated by CyTOF, which confirmed an increase in CD3+ T cells (AA 53.7% vs. NHW 35.7%, p&amp;lt;0.001) including increases in CD8+ (AA 7.0% vs. NHW 3.2%, p&amp;lt;0.05) and CD4+ terminal effector T cells (AA 5.7% vs. NHW 2.7%, p&amp;lt;0.05) and a reduction in monocytes (AA 18.3% vs. NHW 26.6%) among AAs. After adjusting for age and sex, AAs retained an increase in T cells (OR 1.59 (95%CI 1.2-2.01, p=0.00023)) and a reduction in monocytes (OR 0.88 (95%CI 0.78-1, p=0.045)). Despite the increase in CD8+ T cells in AA patients, we identified reduced GZMK+ T cells and reductions in exhaustion markers (TIGIT, LAG3, TOX) in CD8+ T cells in comparison to NHWs. Nevertheless, the distribution of the immune populations was similar between healthy AA and NHW individuals. Our multiomics approach to characterize the iTME identified significant differences among AA compared to NHW patients with MM. Citation Format: Suganti Shivaram, Hongwei Tang, Huihuang Yan, Shulan Tian, Guyu Qin, Emilie Anderson, Neeraj Sharma, Abiola Bolarinwa, Cinthya Zepeda-Mendoza, Stacey Lehman, Felicia Gomez, Amit Mitra, Surendra Dasari, Taxiarchis Kourelis, Shaji Kumar, Linda Baughn. Characterization of the Immune Tumor Microenvironment in a Diverse Cohort of Patients with Multiple Myeloma [abstract]. In: Proceedings of the Blood Cancer Discovery Symposium; 2024 Mar 4-6; Boston, MA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(2_Suppl):Abstract nr P06.

Genetic alterations in chronic lymphocytic leukemia and plasma cell neoplasms- a practical guide to WHO HAEM5.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours (WHO-HAEM5) provides a revised classification of lymphoid malignancies including chronic lymphocytic leukemia (CLL) and plasma cell myeloma/multiple myeloma (PCM/MM). For both diseases the descriptions of precursor states such as monoclonal B-cell lymphocytosis and monoclonal gammopathy of uncertain significance (MGUS) have been updated including a better risk stratification model. New insights on mutational landscapes and branching evolutionary pattern were embedded as diagnostic and prognostic factors, accompanied by a revised structure for the chapter of plasma cell neoplasms. Thus, the WHO-HAEM5 leads to practical improvements of biological and clinical relevance for pathologists, clinicians, geneticists and scientists in the field of lymphoid malignancies. The present review gives an overview on the landscape of genetic alterations in CLL and plasma cell neoplasms with a focus on their impact on classification and treatment.

RAB22A as a predictor of exosome secretion in the progression and relapse of multiple myeloma.

Multiple myeloma (MM) is an incurable malignant plasma cell disease. We explored the role of RAB22A in exosome secretion, epithelial-mesenchymal transition (EMT) and immune regulation. We obtained MM samples from Gene Expression Omnibus (GEO) data sets. We downloaded the "IOBR" package, and used the "PCA" and "ssGSEA" algorithms to calculate the EMT scores and exosome scores. The "CIBERSORT" package was used to analyze the infiltration of immune cells. We extracted the exosomes of mesenchymal stem cell (MSC) to verify the biological function of RAB22A. The expression level of RAB22A in smoldering multiple myeloma (SMM) and MM patients was significantly higher than that in normal people and monoclonal gammopathy of undetermined significance (MGUS) patients, and the expression level of RAB22A in relapse MM patients was significantly higher than that in newly diagnosed patients. The EMT scores and exosome scores of high RAB22A group were significantly higher than those of low RAB22A group, and the exosome scores of MSC in recurrent patients were significantly higher than those of newly diagnosed patients. In addition, the infiltration levels of monocyte, NK cells resting, eosinophils, T cells regulatory and T cells CD4 memory activated were positively correlated with RAB22A. After down-regulating the expression of RAB22A in MM-MSC, the secretion of exosomes decreased. Compared with the exosomes of MSC in si-RAB22A group, the exosomes in control group significantly promoted the proliferation of MM. RAB22A is a potential therapeutic target to improve the prognosis of MM, which is closely related to exosome secretion, EMT and immune cell infiltration.

A Brazilian Rare-Disease Center's Experience with Glucosylsphingosine (lyso-Gb1) in Patients with Gaucher Disease: Exploring a Novel Correlation with IgG Levels in Plasma and a Biomarker Measurement in CSF.

Gaucher disease (GD, OMIM 230800) is one of the most common lysosomal disorders, being caused by the deficient activity of the enzyme acid β-glucocerebrosidase (Gcase). Three clinical forms of Gaucher's disease (GD) are classified based on neurological involvement. Type 1 (GD1) is non-neuronopathic, while types 2 (GD2) and 3 (GD3) are neuronopathic forms. Gcase catalyzes the conversion of glucosylceramide (GlcCer) into ceramide and glucose. As GlcCer accumulates in lysosomal macrophages, it undergoes deacylation to become glycosylsphingosine (lyso-Gb1), which has shown to be a useful and reliable biomarker for the diagnosis and monitoring of treated and untreated patients with GD. Multiple myeloma (MM) is one of the leading causes of cancer-related death among patients with GD and monoclonal gammopathy of undetermined significance (MGUS) is a non-neoplastic condition that can be a telltale sign of a B clonal proliferation caused by the chronic activation of B cells. This study aimed to quantify Lyso-Gb1 levels in dried blood spots (DBS) and cerebrospinal fluid (CSF) as biomarkers for Gaucher disease (GD) and discuss the association of this biomarker with other clinical parameters. This is a mixed-methods study incorporating both cross-sectional and longitudinal elements within a cohort design with a convenience-sampling strategy. Data collection took place from January 2012 to March 2023. Lyso-Gb1 extraction from DBS involved the use of a methanol-acetonitrile-water mixture, followed by incubation and centrifugation. Analysis was performed using UPLC-MS/MS with MassLynx software version 4.2 and the control group for the DBS measurements included general newborns. CSF Lyso-Gb1 was extracted using ethyl acetate, analyzed by UPLC-MS/MS with a calibration curve, and expressed in pmol/L. Lysosomal activity in CSF was assessed by measuring chitotriosidase (Cht), and other lysosomal enzyme activities were assessed as previously described in the literature. Patients with metachromatic leukodystrophy (MLD) were used as controls. Thirty-two treated patients (twenty-nine GD1 and three GD3, all on ERT except for one GD type on SRT with eliglustat) and three untreated patients (one GD1, one GD2, and one GD3) were included. When analyzing only the treated GD1 group, a significant correlation was found between lyso-Gb1 and age (rho = -0.447, p = 0.001), ChT, and IgG levels (rho = 0.73, p < 0.001; and rho = 0.36, p = 0.03, respectively). Five GD1 patients (three females, mean age 40 years) also had their CSF collected and analyzed. The average measurement of lyso-Gb1 in CSF was 94 pmol/L (range: 57.1-157.9 pmol/L) versus <6.2 pmol/L in the control group (MLD). This is the first time, to the best of our knowledge, that lyso-Gb1 has been associated with IgG levels. While this finding reflects a risk for MGUS or MM and not only chronic plasma B-cell activation, it still requires further studies. Moreover, the analysis of CSF lyso-Gb1 levels in GD1 patients was demonstrated to be significantly higher than the control group. This raises the hypothesis that CSF lyso-Gb1 may serve as a valuable indicator for neurological involvement in GD, providing insights into the potential implications for neurological manifestations in GD, including GD1. The correlation between lyso-Gb1 and ChT levels in treated GD1 patients further underscores the interconnectedness of lysosomal markers and their relevance in monitoring.

Paraproteinemia‐associated neuropathy with or without anti‐myelin‐associated glycoprotein antibody

AbstractParaproteinemia‐associated neuropathy (PAN) develops with paraproteinemia and is mainly caused by the monoclonal proliferation of mature B cells, especially monoclonal gammopathy of undetermined significance (MGUS). PAN tends to increase with age, and in a super‐aging society, its frequency is expected to increase. Among paraproteinemias, the immunoglobulin (Ig)G type is most common, but the frequency of PAN is reported to be higher for the IgM type. IgG/IgA‐type PAN includes MGUS, plasma cell myeloma, and polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes syndrome. IgM‐type PAN includes anti‐myelin‐associated glycoprotein antibody‐associated neuropathy, chronic ataxic neuropathy with IgM antibody that recognizes disialosyl ganglioside and IgM‐type PAN without anti‐nerve antibodies. Light chain‐type PAN includes immunoglobulin‐related amyloidosis. PAN has the characteristics of a blood disease, as well as an immune‐mediated disease, and is treated by immunotherapy. As an example, anti‐myelin‐associated glycoprotein antibody‐associated neuropathy is treated with rituximab, plasmapheresis and intravenous immunoglobulin therapy, but their effectiveness has not been established. As novel treatments, lenalidomide, Bruton tyrosine kinase inhibitors, B‐cell lymphoma 2 inhibitors and mimetic human natural killer‐1 epitope polymers have been investigated. By analyzing the human natural killer‐1‐related sugar chain structure as an antigen, the selective removal of pathological antibodies might be a new therapeutic target.

Laboratory reflex testing strategy for the early identification of primary care patients with multiple myeloma

ObjectivesOur objective was to shorten the screen for multiple myeloma (MM), through reflex testing. Design and MethodsThe clinical laboratory in the public University Hospital of San Juan (Alicante, Spain), serves 234,551 inhabitants. Through an intervention agreed with general practitioners, the Laboratory Information System (LIS) automatically registered serum immunoglobulins (Ig) when serum total proteins (STP) > 80 g/L for the first time in primary care patients. When concomitantly one Ig presented a value above and one below its reference interval, the LIS automatically registered a serum protein electrophoresis (SPEP). When a monoclonal peak in SPEP, immunofixation electrophoresis (IFE) for the typification of monoclonal bands (MB) was performed. If MB were present, a comment in the report explained the intervention. The number of additionally registered Ig, SPEP, IFE, and new diagnosis of MM were counted. The number of days elapsed from the report of elevated STP result to the final MM diagnosis was also counted as median and interquartile range (IQR), and compared to a pre intervention period. Results2071 cases of hyperproteinemia were identified, and had 91 a monoclonal peak, confirmed by IFE. In 35 patients it was a new finding, and 9 were diagnosed with MM, 3 Waldestrom macroglobulinemia, 2 lymphoplasmacytic lymphoma and 21 monoclonal gammopathy of undetermined significance. The number of days elapsed from hyperproteinemia to diagnosis was lower in the intervention period (21.5 vs 119.4) (P < 0.01). As our results show, in addition to shortening the time to diagnosis, an increased rate of detection of plasma cell disorders was observed when using our algorithm. ConclusionsThe above laboratory interventions agreed with clinicians, making use of laboratory technology resulted in early identification of MM.

Natural killer cells affect the natural course, drug resistance, and prognosis of multiple myeloma.

Multiple myeloma (MM), a stage-developed plasma cell malignancy, evolves from monoclonal gammopathy of undetermined significance (MGUS) or smoldering MM (SMM). Emerging therapies including immunomodulatory drugs, proteasome inhibitors, monoclonal antibodies, chimeric antigen-T/natural killer (NK) cells, bispecific T-cell engagers, selective inhibitors of nuclear export, and small-molecule targeted therapy have considerably improved patient survival. However, MM remains incurable owing to inevitable drug resistance and post-relapse rapid progression. NK cells with germline-encoded receptors are involved in the natural evolution of MGUS/SMM to active MM. NK cells actively recognize aberrant plasma cells undergoing malignant transformation but are yet to proliferate during the elimination phase, a process that has not been revealed in the immune editing theory. They are potential effector cells that have been neglected in the therapeutic process. Herein, we characterized changes in NK cells regarding disease evolution and elucidated its role in the early clinical monitoring of MM. Additionally, we systematically explored dynamic changes in NK cells from treated patients who are in remission or relapse to explore future combination therapy strategies to overcome drug resistance.