Multiple Myeloma Plasma Cells Research Articles

“Synchronous Development of Acute Myeloid Leukemia and Multiple Myeloma: A Rare Case Presentation”

Abstract Introduction/Objective The co-occurrence of acute myeloid leukemia (AML) and multiple myeloma (MM) presents a diagnostic challenge, particularly when it arises without prior chemotherapy exposure. This study aims to elucidate the clinical characteristics, diagnostic approach, and management implications of such synchronous hematologic malignancies through a detailed case report. Methods/Case Report A 64-year-old female with no previous medical history presented with chest pain, shortness of breath, and hematologic abnormalities. Clinical evaluation revealed severe pancytopenia, cystic liver mass, enlarged retroperitoneal lymph nodes, and hypercalcemia. Peripheral blood smear indicated hematologic malignancy, prompting further investigation. Bone marrow aspirate analysis, including flow cytometry and immunohistochemical stains, was performed to confirm the dual cell populations of AML blasts and MM plasma cells. Results (if a Case Study enter NA) Flow cytometric analysis and immunohistochemical stains of the bone marrow aspirate confirmed the presence of distinct cell populations: blasts expressing markers consistent with AML and abundant plasma cells indicative of MM. Monotypism of plasma cells was established, with kappa predominance. Notably, there was no coexpression of markers between the AML blasts and MM plasma cells. Conclusion This case highlights the rare occurrence of synchronous AML and MM in a patient without prior chemotherapy exposure. The diagnostic approach involving flow cytometry and immunohistochemical stains proved essential in confirming the dual hematologic malignancies. Clinicians should be vigilant for such presentations, as timely diagnosis and appropriate management are crucial for optimizing patient outcomes in these complex cases.

Flower-Shaped Plasma Cells in Multiple Myeloma with Morphological Heterogeneity.

Flower-shaped nuclei in plasma cells are rare in multiple myeloma. We report on an 88-year-old male who presented with a mass lesion in the clavicular region. A biopsy of the mass revealed an increase in mature plasma cells with round nuclei. In contrast, a bone marrow examination showed increased plasma cells with flower-shaped nuclei. The patient tested negative for human T-lymphotropic virus type-1 and was diagnosed with multiple myeloma. While multiple myeloma is known for intra-tumor heterogeneity, reports of morphological heterogeneity based on the site of tumor sampling are limited. In this case, the presence of plasma cells with flower-shaped nuclei enabled the identification of site-dependent morphological tumor heterogeneity.

Daratumumab-Based Therapeutic Approaches and Clinical Outcomes in Multiple Myeloma and other Plasma Cell Dyscrasias: Insights from a Nationwide Real-World Chart Review Study.

Singapore leads Southeast Asia in the routine use of daratumumab for multiple myeloma and other plasma cell dyscrasias. This retrospective review analyzed 112 patients who received daratumumab between 2012 and 2020. Tolerability, and efficacy based on prior lines (PL) of therapy, cytogenetic risk group, and the presence of renal impairment were presented. Infusion-related reactions occurred in 26.8% of patients. Grades 1 and 2 hematological and non-hematological adverse events were observed in 14.3% and 33.9% of patients, respectively. After a median follow-up of 16.9 months, there was no significant difference in overall response rates (ORR) (86% versus 76.3%, p = 0.082) or depth of response (≥ complete response (CR), 35.1% versus 28.9%, p = 0.469) between myeloma patients with and without renal dysfunction. Newly diagnosed and relapsed/refractory patients had an ORR of 92% and 76.3%, and a ≥ VGPR (very good partial response) rate of 80% and 55.3%, respectively. Median progression-free survival (PFS) was better for patients with 0/1 PL compared to ≥ 2 PLs (19.8 versus 6.2 months, p < 0.001), with a deeper response (≥ CR, 38.5% versus 16.7%, p = 0.033). Forty-six and a half percentage of patients had high-risk FISH abnormalities, and those with 0/1 PL had a significantly better ORR than those with ≥ 2 PLs (83.3% vsersus 47.1%, p = 0.022), achieving an ORR similar to that of the general cohort (80.2%, p = 0.905). In conclusion, positioning daratumumab in earlier lines of therapy leads to better outcomes and may mitigate the impact of high-risk FISH abnormalities.

Single-cell sequencing analysis of multiple myeloma heterogeneity and identification of new theranostic targets

Multiple myeloma (MM) is a heterogeneous and incurable tumor characterized by the malignant proliferation of plasma cells. It is necessary to clarify the heterogeneity of MM and identify new theranostic targets. We constructed a single-cell transcriptome profile of 48,293 bone marrow cells from MM patients and health donors (HDs) annotated with 7 continuous B lymphocyte lineages. Through CellChat, we discovered that the communication among B lymphocyte lineages between MM and HDs was disrupted, and unique signaling molecules were observed. Through pseudotime analysis, it was found that the differences between MM and HDs were mainly reflected in plasma cells. These differences are primarily related to various biological processes involving mitochondria. Then, we identified the key subpopulation associated with the malignant proliferation of plasma cells. This group of cells exhibited strong proliferation ability, high CNV scores, high expression of frequently mutated genes, and strong glucose metabolic activity. Furthermore, we demonstrated the therapeutic potential of WNK1 as a target. Our study provides new insights into the development of B cells and the heterogeneity of plasma cells in MM and suggests that WNK1 is a potential therapeutic target for MM.

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.

The potential role of CAR-T in Multiple Myeloma Treatment. A review

Background: Multiple myeloma (MM) is a hematologic malignancy, which causes accumulation of plasma cells in the bone marrow. The symptoms of MM are associated with organ dysfunction and include hypercalcemia, renal failure, anaemia and bone destruction. A relatively new and promising therapeutic option for MM is CAR-T therapy. Aim of the study: The study aimed to outline the role of CAR-T therapy in MM treatment.Material and methods: We conducted a literature review containing 24 articles. We described the role of CAR-T in MM therapy, its therapeutic points, the effectiveness of therapy, and its side effects.Results: CAR-T cells transduced with CAR can recognize specific antigens and kill the cancer cells. For MM these specific antigens are integrin β7, SLAMF7, CD138, BCMA, GPRC5D and FCRL5. Integrin β7 in its active form, can be found in MM cells, whereas in other blood cells, integrin β7 is in the inactive form. The expression of SLAMF7 on MM cells is high and uniform, but its function is not clear: expression of SLAMF7 in MM is suspected to increase the survival and adhesion of MM cells to bone marrow stromal cells. CD138's strong expression on MM cells is contributing to their development and proliferation. BCMA expression was not detected in other human tissues, only in MM cells. GPRC5D is highly expressed in bone marrow samples from MM patients, and minimally expressed in other hematologic malignancies. FCRL5 is a protein marker found specifically on plasma cells in MM, its increased expression promotes B cell proliferation. The AlloCAR-T therapy also seems to be an effective method.CAR-T therapy has also adverse effects including cytokine release syndrome, neurological toxicity, haematological disorders and infusion fever. Conclusions: The effects of CAR-T therapy in MM are really promising and give real benefits to patients. For this reason, it should be further developed and subjected to further research.

CiRS-7 circular RNA overexpression in plasma cells is a promising molecular biomarker of unfavorable prognosis in multiple myeloma.

Several non-coding RNAs are known to be associated with the pathobiology and progression of multiple myeloma (MM). ciRS-7 (also known as CDR1-AS), a key oncogenic circular RNA (circRNA) that sponges miR-7-5p and other cancer-related microRNAs, was recently found to be downregulated in malignant plasma cells resistant to immunomodulatory drugs. Considering that various circRNAs have a strong potential as molecular biomarkers, we aimed to investigate the expression of ciRS-7 in plasma cell disorders, assess its prognostic importance in MM, and compare these findings with those of individuals with smoldering MM (SMM) and monoclonal gammopathy of unknown significance (MGUS). This study included 171 patients (110 newly diagnosed MM, 34 SMM, and 27 MGUS cases), from which bone marrow aspirate samples were collected for CD138+ plasma cell selection. Total RNA was reversely transcribed using random hexamer primers, and the expression levels of ciRS-7 were quantified using an in-house-developed protocol that includes pre-amplification and real-time quantitative polymerase chain reaction. ciRS-7 levels were found to significantly differ among CD138+ plasma cells of MM, SMM, and MGUS patients. ROC analysis indicated that ciRS-7 expression effectively distinguishes between MM and SMM patients. Moreover, high levels of ciRS-7 were associated with unfavorable prognosis in MM, independently of MM patients' age and Revised International Staging System stage. Additionally, in silico analysis predicted the binding of 85 microRNAs to ciRS-7. In conclusion, this study provides novel insights into the role of ciRS-7 as a promising molecular marker able to distinguish MM from SMM and predict prognosis in MM.

The early and rapid response to daratumumab in children with chronic refractory immune thrombocytopenia from a referral single centre of China.

Chronic refractory primary immune thrombocytopenia (CRITP) is currently defined as refractory to multiple therapeutic of second-line agents with or without splenectomy, faced with the threat of severe bleeding and challenging to obtain effective treatment. Although stable and effective drug therapy is needed, it is tough to find one. Daratumumab (Dara), an anti-CD38 monoclonal antibody presented the target cloned plasma cells in multiple myeloma, has also been reported to be effective in refractory autoimmune cytopenia in some case or series reports and ongoing clinical trials for adult patients with CRITP. Here, we report the early and durable response of Dara combination with avatrombopag in three CRITP patients (2 male and 1 female aged 12, 5 and 7 years, respectively) in our centre, with a follow-up period of more than 25 weeks. Before Dara, the duration of immune thrombocytopenia was 9, 1.4 and 4 years, respectively, a baseline platelet count of 4, 6, 9 × 109/L, the bleeding score was all above level 2 and the number of previous drugs was >3. The time to response (R: Plt ≥30 × 109/L with at least a twofold increase in the baseline count) of Dara was on Day 45, 6 and 4 and achieved complete response (CR: Plt ≥100 × 109/L) on Day 51, 6 and 8, the sustained response (SR: Plt >30 × 109/L following Dara at ≥75% of the platelet count assessment at follow-up end-point since the patient achieved response) was 48, 175 and 204 days with the follow-up time of 39.1, 25.9 and 29.7 weeks. The bleeding score decreased from grade 3 to grade 0 during follow-up. No significant treatment-related adverse events were found during follow-up. Dara combination with avatrombopag may be a safe and efficacious therapy for children with CRITP, but it needs to be further explored.

Novel method for the detection of circulating tumor plasma cells in multiple myeloma.

e19520 Background: Multiple Myeloma (MM) is characterized by the proliferation of abnormal plasma cells within the bone marrow. A bone marrow examination is essential for the diagnosis of multiple myeloma. This is a test that causes great pain to patients because it requires collecting and analyzing the bone marrow fluid inside the bone. In addition, there is a disadvantage that it cannot be carried out frequently due to cost issues. Therefore, the development of new diagnostic methods is absolutely necessary. The aim of this study is to access the potential of circulating tumor plasma cells (CTPC) for the diagnosis of MM using CytoGen's Smart Biopsy platform. Methods: Spiking tests using MM cell line (RPMI8226) was conducted with the purpose of making an environment similar to the MM patient's blood. RPMI8226 cells (200 cells) stained with CellTracker were spiked into human blood sample (5mL, healthy donor). Then, spiked cells were isolated by CytoGen’s Smart Biopsy isolator, subsequently recovery rate was accessed by counting of isolated RPMI8226 or immunofluorescence (IF) staining with multiple myeloma-specific marker, CD138. Then, clinical evaluation was performed with bone marrow (3mL) and peripheral blood (5mL) samples of MM patients (n=20). The presence of CTPC in patient samples was tested by IF staining with anti-CD138 antibody. Results: In in vitro experiments to test recovery rate of CTPC using CytoGen's Smart Biopsy isolator, MM cell line’s recovery rate was validated to over 80%. CD138 expression was clearly detected by IF staining of spiking samples of multiple myeloma cell line and was not detected at all in the negative controls. In clinical evaluation study, CTPC was successfully observed after the isolation from bone marrow and peripheral blood using CytoGen's Smart Biopsy isolator by IF staining with CD138. Conclusions: This study shows a novel method for the detection of MM with liquid biopsy. CTPC from liquid biopsy of MM could be isolated using CytoGen's Smart Biopsy isolator with high recovery rate and can clearly be detected with specific marker of MM, CD138 by IF staining. These results suggested that CytoGen's Smart Biopsy platform might be an effective diagnostic tool for the detection of MM. Expanded clinical study will be performed with more MM samples for clinical validation. Clinical trial information: 2013-09-009 .

Real world outcomes of high dose melphalan conditioning prior to autologous stem cell transplant in extramedullary multiple myeloma vs. multiple myeloma without extramedullary involvement: A single center experience.

7550 Background: Extramedullary multiple myeloma (EMM) is defined as the presence of multiple myeloma plasma cells, which develop outside of the bone marrow. It is an aggressive form of multiple myeloma that is associated with a poor prognosis. The current standard of care for multiple myeloma consists of induction, high dose melphalan autologous stem cell transplant (ASCT), followed by maintenance. However, there is limited data on the outcome of patients with extramedullary multiple myeloma who undergo ASCT. Therefore, we examined the outcomes of high dose melphalan conditioning prior to ASCT in EMM patients compared to multiple myeloma patients without extramedullary involvement (non-EMM) at an academic institution in Los Angeles. Methods: We retrospectively reviewed 246 multiple myeloma patients who underwent ASCT after receiving high dose melphalan conditioning at USC Norris Comprehensive Cancer Center from Jan 2017 to Dec 2022. The cohort was subdivided into 70 EMM patients and 176 non-EMM patients. Outcomes were measured as the status of disease response, which was evaluated at 100 days (D+100) and 365 days (D+365) after the date of transplant. Results: In the EMM group, 1.43% (n=1) was found to have progression at D+100 and 12.86% (n=9) at D+365. In the non-EMM group, 0.57% (n=1) was found to have progression at D+100 and 11.93% (n=21) at D+365. There was no statistical significance between the EMM and non-EMM groups for progression free survival at D+100 (p-0.50) and D+365 (p-0.75). Regarding overall survival, there were 0 deaths observed at D+100 in both the EMM and non-EMM groups. For D+365, the overall survival was 98.57% (n=69) for the EMM group and 99.43% (n=175) for the non-EMM group. There was no statistical significance between the overall survival at D+365 (p-0.14). Conclusions: The EMM cohort exhibited similar rates of progression free survival (87.14% vs. 88.07%) and overall survival (98.57% vs. 99.43%) compared to the non-EMM cohort at one year post ASCT after receiving high dose melphalan conditioning. We observed that there was no significant statistical difference between the EMM and non-EMM cohorts regarding progression-free survival (p-0.75) and overall survival (p-0.14) on day 365. According to our data, high dose melphalan conditioning prior to autologous stem cell transplant is equally as effective for patients with multiple myeloma with or without extramedullary involvement. Future studies with long-term follow-up are recommended to further explore these findings. [Table: see text]

Human IL-6 fosters long-term engraftment of patient-derived disease-driving myeloma cells in immunodeficient mice.

Multiple myeloma is a largely incurable and life-threatening malignancy of antibody-secreting plasma cells. An effective and widely available animal model that recapitulates human myeloma and related plasma cell disorders is lacking. We show that busulfan-conditioned human IL-6-transgenic (hIL-6-transgenic) NSG (NSG+hIL6) mice reliably support the engraftment of malignant and premalignant human plasma cells, including from patients diagnosed with monoclonal gammopathy of undetermined significance, pre- and postrelapse myeloma, plasma cell leukemia, and amyloid light chain amyloidosis. Consistent with human disease, NSG+hIL6 mice engrafted with patient-derived myeloma cells developed serum M spikes, and a majority developed anemia, hypercalcemia, and/or bone lesions. Single-cell RNA sequencing showed nonmalignant and malignant cell engraftment, the latter expressing a wide array of mRNAs associated with myeloma cell survival and proliferation. Myeloma-engrafted mice given CAR T cells targeting plasma cells or bortezomib experienced reduced tumor burden. Our results establish NSG+hIL6 mice as an effective patient-derived xenograft model for study and preclinical drug development of multiple myeloma and related plasma cell disorders.

Immune escape of multiple myeloma cells results from low miR29b and the ensuing epigenetic silencing of proteasome genes

BackgroundActivation of CD28 on multiple myeloma (MM) plasma cells, by binding to CD80 and CD86 on dendritic cells, decreases proteasome subunit expression in the tumor cells and thereby helps them evade being killed by CD8+ T cells. Understanding how CD28 activation leads to proteasome subunit downregulation is needed to design new MM therapies.MethodsThis study investigates the molecular pathway downstream of CD28 activation, using an in vitro model consisting of myeloma cell lines stimulated with anti-CD28-coated beads.ResultsWe show that CD28 engagement on U266 and RPMI 8226 cells activates the PI3K/AKT pathway, reduces miR29b expression, increases the expression of DNA methyltransferase 3B (DNMT3B, a target of miR29b), and decreases immunoproteasome subunit expression. In vitro transfection of U266 and RPMI 8226 cells with a miR29b mimic downregulates the PI3K/AKT pathway and DNMT3B expression, restores proteasome subunit levels, and promotes myeloma cell killing by bone marrow CD8+ T cells from MM patients. Freshly purified bone marrow plasma cells (CD138+) from MM patients have lower miR29b and higher DNMT3B (mRNA and protein) than do cells from patients with monoclonal gammopathy of undetermined significance. Finally, in MM patients, high DNMT3B levels associate with shorter overall survival.ConclusionsAltogether, this study describes a novel molecular pathway in MM. This pathway starts from CD28 expressed on tumor plasma cells and, through the PI3K-miR29b-DNMT3B axis, leads to epigenetic silencing of immunoproteasome subunits, allowing MM plasma cells to elude immunosurveillance. This discovery has implications for the design of innovative miR29b-based therapies for MM.

Prognostic Implications of Circulating Plasma Cell Percentage in Multiple Myeloma and Primary Plasma Cell Leukemia Defined by New Criteria

Introduction: The definition of primary plasma cell leukemia (pPCL) has been revised from ≥20% to ≥5% circulating plasma cells (CPC). However, the precise prognosis associated with CPC remains controversial. This study aimed to investigate prognostic biomarkers for myeloma patients based on CPC presence. Methods: A comprehensive analysis was conducted on 309 consecutive patients diagnosed with either multiple myeloma or pPCL, utilizing peripheral blood smears stained with Wright-Giemsa. Results: Patients were grouped by CPC percentage: 0% (221, 71.5%), 1–4% (49, 15.9%), 5–19% (16, 5.2%), ≥20% (23, 7.4%). CPC >5% correlated with unfavorable characteristics, including anemia, renal dysfunction, and advanced International Staging System. Common cytogenetic abnormalities such as 1q21 amplification, 17p deletion, and Myc rearrangement were prevalent among CPC-positive patients. Median progression-free survival (PFS) and overall survival (OS) were shorter in patients with CPC ≥5% (29.47 vs. 10.03 months; 64.10 vs. 12.30 months). Additionally, PFS and OS were shorter in CPC-positive patients without autologous hematopoietic stem cell transplantation (ASCT) and those with response < partial remission to the first-line regimen. Furthermore, an association emerged between soft tissue-related extramedullary disease and inferior PFS, while Myc rearrangement correlated with abbreviated OS. Conclusion: Biological characteristics displayed greater aggressiveness in patients with positive CPC, leading to significantly shorter PFS and OS. The presence of CPC, ASCT, and overall response rate were independent prognostic factors. While no new threshold for pPCL with CPCs is proposed, Myc rearrangements and CPC positivity could serve as ultra-high-risk factors for multiple myeloma.

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.

Expression of the chemokine receptor CCR1 decreases sensitivity to bortezomib in multiple myeloma cell lines

BackgroundThe proteasome inhibitor bortezomib is one of the primary therapies used for the haematological malignancy multiple myeloma (MM). However, intrinsic or acquired resistance to bortezomib, via mechanisms that are not fully elucidated, is a barrier to successful treatment in many patients. Our previous studies have shown that elevated expression of the chemokine receptor CCR1 in MM plasma cells in newly diagnosed MM patients is associated with poor prognosis. Here, we hypothesised that the poor prognosis conferred by CCR1 expression is, in part, due to a CCR1-mediated decrease in MM plasma cell sensitivity to bortezomib. MethodsIn order to investigate the role of CCR1 in MM cells, CCR1 was knocked out in human myeloma cell lines OPM2 and U266 using CRISPR-Cas9. Additionally, CCR1 was overexpressed in the mouse MM cell line 5TGM1. The effect of bortezomib on CCR1 knockout or CCR1-overexpressing cells was then assessed by WST-1 assay, with or without CCL3 siRNA knockdown or addition of recombinant human CCL3. NSG mice were inoculated intratibially with OPM2-CCR1KO cells and were treated with 0.7 mg/kg bortezomib or vehicle twice per week for 3 weeks and GFP+ tumour cells in the bone marrow were quantitated by flow cytometry. The effect of CCR1 overexpression or knockout on unfolded protein response pathways was assessed using qPCR for ATF4, HSPA5, XBP1, ERN1 and CHOP and Western blot for IRE1α and p-Jnk. ResultsUsing CCR1 overexpression or CRIPSR-Cas9-mediated CCR1 knockout in MM cell lines, we found that CCR1 expression significantly decreases sensitivity to bortezomib in vitro, independent of the CCR1 ligand CCL3. In addition, CCR1 knockout rendered the human MM cell line OPM2 more sensitive to bortezomib in an intratibial MM model in NSG mice in vivo. Moreover, CCR1 expression negatively regulated the expression of the unfolded protein response receptor IRE1 and downstream target gene XBP1, suggesting this pathway may be responsible for the decreased bortezomib sensitivity of CCR1-expressing cells. ConclusionsTaken together, these studies suggest that CCR1 expression may be associated with decreased response to bortezomib in MM cell lines.

Imaging flow cytometric detection of del(17p) in bone marrow and circulating plasma cells in multiple myeloma.

Detection of del(17p) in myeloma is generally performed by fluorescence in situ hybridization (FISH) on a slide with analysis of up to 200 nuclei. The small cell sample analyzed makes this a low precision test. We report the utility of an automated FISH method, called "immuno-flowFISH", to detect plasma cells with adverse prognostic risk del(17p) in bone marrow and blood samples of patients with myeloma. Bone marrow (n = 31) and blood (n = 19) samples from 35 patients with myeloma were analyzed using immuno-flowFISH. Plasma cells were identified by CD38/CD138-immunophenotypic gating and assessed for the 17p locus and centromere of chromosome 17. Cells were acquired on an AMNIS ImageStreamX MkII imaging flow cytometer using INSPIRE software. Chromosome 17 abnormalities were identified in CD38/CD138-positive cells in bone marrow (6/31) and blood (4/19) samples when the percent plasma cell burden ranged from 0.03% to 100% of cells. Abnormalities could be identified in 14.5%-100% of plasma cells. The "immuno-flowFISH" imaging flow cytometric method could detect del(17p) in plasma cells in both bone marrow and blood samples of myeloma patients. This method was also able to detect gains and losses of chromosome 17, which are also of prognostic significance. The lowest levels of 0.009% (bone marrow) and 0.001% (blood) for chromosome 17 abnormalities was below the detection limit of current FISH method. This method offers potential as a new means of identifying these prognostically important chromosomal defects, even when only rare cells are present and for serial disease monitoring.

Serum free light chains among twin siblings: is the kappa/lambda ratio genetically determined?

Background Serum kappa, lambda, the K/λ light chain concentrations are used for screening, diagnosis, and monitoring of patients with multiple myeloma and other plasma cell disorders. Biological variation studies conducted on healthy subjects showed that free light chains have a low within and high between-individual variation. We determined if this variation were genetically linked. Methods We obtained a single serum sample from 16 pairs of identical twins, 8 neonate twins, and 19 presumed directly-related siblings children, measured Κ and λ light chains and computed the Κ/λ ratio. Results As expected, Κ/λ results from each twin neonate were near identical (reflecting maternal/placental transfer). For older children and adult twins, the Κ/λ ratio form a cluster of results that were a subset of the reference range. There was one outlier, a female with a high, different from her twin sister. She likely had a monoclonal gammopathy (no followup was possible). Excluding this pair, results from neonate twins (14.4% ±10.3%) and non-neonate twins (18.0 ± 15.3%) were not significantly different. Results between non-twin siblings were more scattered (53.2%±53.4%) and different from neonate and non-neonate twin adult and children. Conclusion We suggest that the Κ/λ free light chains may be genetically linked.

Circulating Plasma Cells in Multiple Myeloma: Clinical Implications and Prognostic Significance

Circulating Plasma Cells in Multiple Myeloma: Clinical Implications and Prognostic Significance

The Involvement of LAG-3positive Plasma Cells in the Development of Multiple Myeloma.

The Lymphocyte-Activation Protein 3 (LAG-3) inhibitory receptor is expressed on regulatory plasma cells (PCs). Micro-environmental cells that express LAG-3 were found to be increased during the progression of smoldering multiple myeloma (SMM). To assess the possible role of LAG-3 expression on regulatory PCs in patients with plasma cell dyscrasia. Purified Cluster of Differentiation 138 (CD138+) PCs from patients with premalignant conditions, active multiple myeloma (MM), and controls were analyzed for the expression of LAG-3 by flow cytometry. Autologous CD8+T cells were incubated with sorted LAG-3pos or LAG-3neg PCs for 24 h. The expression of granzyme (Grz) in CD8+T cells was assessed by flow cytometry. LAG-3 expression on PCs in active MM (newly diagnosed and relapse refractory MM) was significantly increased compared to monoclonal gammopathy of undetermined significance (MGUS)/ SMM. Grz expression was significantly decreased in CD8+T cells incubated with CD138+LAG-3pos PCs, compared to CD138+LAG-3neg PCs in patients with plasma cell dyscrasia, n = 31, p = 0.0041. LAG-3 expression on malignant PCs can be involved in the development of MM from MGUS by decreasing the expression of Grz in CD8+T cells.

Nicotinamide-Expanded Allogeneic Natural Killer Cells with CD38 Deletion, Expressing an Enhanced CD38 Chimeric Antigen Receptor, Target Multiple Myeloma Cells.

Natural killer (NK) cells are a vital component of cancer immune surveillance. They provide a rapid and potent immune response, including direct cytotoxicity and mobilization of the immune system, without the need for antigen processing and presentation. NK cells may also be better tolerated than T cell therapy approaches and are susceptible to various gene manipulations. Therefore, NK cells have become the focus of extensive translational research. Gamida Cell's nicotinamide (NAM) platform for cultured NK cells provides an opportunity to enhance the therapeutic potential of NK cells. CD38 is an ectoenzyme ubiquitously expressed on the surface of various hematologic cells, including multiple myeloma (MM). It has been selected as a lead target for numerous monoclonal therapeutic antibodies against MM. Monoclonal antibodies target CD38, resulting in the lysis of MM plasma cells through various antibody-mediated mechanisms such as antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity, and antibody-dependent cellular phagocytosis, significantly improving the outcomes of patients with relapsed or refractory MM. However, this therapeutic strategy has inherent limitations, such as the anti-CD38-induced depletion of CD38-expressing NK cells, thus hindering ADCC. We have developed genetically engineered NK cells tailored to treat MM, in which CD38 was knocked-out using CRISPR-Cas9 technology and an enhanced chimeric antigen receptor (CAR) targeting CD38 was introduced using mRNA electroporation. This combined genetic approach allows for an improved cytotoxic activity directed against CD38-expressing MM cells without self-inflicted NK-cell-mediated fratricide. Preliminary results show near-complete abolition of fratricide with a 24-fold reduction in self-lysis from 19% in mock-transfected and untreated NK cells to 0.8% of self-lysis in CD38 knock-out CAR NK cells. Furthermore, we have observed significant enhancements in CD38-mediated activity in vitro, resulting in increased lysis of MM target cell lines. CD38 knock-out CAR NK cells also demonstrated significantly higher levels of NK activation markers in co-cultures with both untreated and αCD38-treated MM cell lines. These NAM-cultured NK cells with the combined genetic approach of CD38 knockout and addition of CD38 CAR represent a promising immunotherapeutic tool to target MM.