Bone Marrow Plasma Cells Research Articles

Identification of transcriptional features and surface markers of plasma cell clones in POEMS syndrome by single-cell RNA sequencing

POEMS syndrome is a rare monoclonal plasma cell disorder with unique symptoms distinct from other plasma cell neoplasms. To identify and find the transcriptional features of clonal plasma cells in POEMS syndrome (POEMS clones), single-cell RNA sequencing was performed on patient-derived bone marrow plasma cells. POEMS clones were identified in 5 out of 10 patients, and the proportions of POEMS clones in the plasma cells were markedly smaller than that of other plasma cell malignancies such as multiple myeloma and MGUS. The transcriptional features of POEMS clones differed from those of other plasma cell diseases, and representative MM-related oncogenes were not upregulated in POEMS clones. Notably, POEMS clones are negative for CD19 and express significantly lower MHC-II levels than normal plasma cells; thus, CD19- HLA-DRlo is confirmed as a useful marker to identify POEMS clones in patients. These findings unveil the unique features of POEMS clones and contribute to the understanding of the pathogenesis of POEMS syndrome.

Priapism and pyrexia of unknown origin presenting as a relapse of multiple myeloma

Pyrexia of unknown origin (PUO) is defined as a body temperature >38.3°C on several occasions for >3 weeks with failure of diagnosis despite one week of inpatient investigations or three outpatient visits. Aetiology for PUO may be infective, inflammatory, autoimmune, malignant, miscellaneous or remains undiagnosed. We describe a patient diagnosed with multiple myeloma (ISS-stage II) who completed induction chemotherapy and presented with PUO and extensive thrombosis as a complication of relapsed myeloma (very rare; 0.2% in myeloma). A 62-year-old man, with diagnosed multiple myeloma, achieved a very good partial remission after 6 cycles of bortezomib-thalidomide-dexamethasone regimen, presented with PUO and right lower limb deep vein thrombosis. His thrombosis was managed successfully with anticoagulation. While on therapeutic anticoagulation with warfarin and being investigated extensively for PUO without a focus, he developed priapism due to bilateral internal pudendal vein thrombosis. His anticoagulation was intensified to a target INR of 2.5-3.5. He recovered without residual damage. Despite broad spectrum antimicrobial agents, trial of antimalarial and anti-tuberculosis treatment, he remained pyrexial with rising inflammatory markers (ESR, CRP). Relapsed multiple myeloma was confirmed with 30% bone marrow plasma cells and raised serum monoclonal para-protein levels of 23.78g/L. He was restarted on chemotherapy with bortezomib-lenalidomide-dexamethasone. His PUO of two months subsided with one week of chemotherapy.
 This case illustrates an atypical presentation of relapsed myeloma and highlights the importance of achieving early diagnosis with a systematic approach and making optimum treatment choice after careful evaluation of previous treatment, drug toxicities, patient’s condition and available treatment options.

SREBP signaling is essential for effective B cell responses.

Our previous study using systems vaccinology identified an association between the sterol regulatory binding protein (SREBP) pathway and humoral immune response to vaccination in humans. To investigate the role of SREBP signaling in modulating immune responses, we generated mice with B cell- or CD11c+ antigen-presenting cell (APC)-specific deletion of SCAP, an essential regulator of SREBP signaling. Ablation of SCAP in CD11c+ APCs had no effect on immune responses. In contrast, SREBP signaling in B cells was critical for antibody responses, as well as the generation of germinal centers,memory B cells and bone marrow plasma cells. SREBP signaling was required for metabolic reprogramming in activated B cells. Upon mitogen stimulation, SCAP-deficient B cells could not proliferate and had decreased lipid rafts. Deletion of SCAP in germinal center B cells using AID-Cre decreased lipid raft content and cell cycle progression. These studies provide mechanistic insights coupling sterol metabolism with the quality and longevity of humoral immunity.

Pathological characteristics of light chain crystalline podocytopathy

Monoclonal immunoglobulin light chain (LC) crystalline inclusions within podocytes are rare, poorly characterized entities. To provide more insight, we now present the first clinicopathologic series of LC crystalline podocytopathy (LCCP) encompassing 25 patients (68% male, median age 56 years). Most (80%) patients presented with proteinuria and chronic kidney disease, with nephrotic syndrome in 28%. Crystalline keratopathy and Fanconi syndrome were present in 22% and 10%, respectively. The hematologic condition was monoclonal gammopathy of renal significance (MGRS) in 55% and multiple myeloma in 45%. The serum monoclonal immunoglobulin was IgG κappa in 86%. Histologically, 60% exhibited focal segmental glomerulosclerosis (FSGS), often collapsing. Ultrastructurally, podocyte LC crystals were numerous with variable effacement of foot processes. Crystals were also present in proximal tubular cells as light chain proximal tubulopathy (LCPT) in 80% and in interstitial histiocytes in 36%. Significantly, frozen-section immunofluorescence failed to reveal the LC composition of crystals in 88%, requiring paraffin-immunofluorescence or immunohistochemistry, with identification of kappa LC in 87%. The LC variable region gene segment, determined by mass spectrometry of glomeruli or bone marrow plasma cell sequencing, was IGKV1-33 in four and IGKV3-20 in one. Among 21 patients who received anti-plasma cell-directed chemotherapy, 50% achieved a kidney response, which depended on a deep hematologic response. After a median follow-up of 36 months, 26% progressed to kidney failure and 17% died. The mean kidney failure-free survival was 57.6 months and was worse in those with FSGS. In sum, LCCP is rare, mostly associates with IgG κappa MGRS, and frequently has concurrent LCPT, although Fanconi syndrome is uncommon. Paraffin-immunofluorescence and electron microscopy are essential to prevent misdiagnosis as primary FSGS since kidney survival depends on early diagnosis and subsequent clone-directed therapy.

593 PRESENTATION AND OUTCOME OF PATIENTS WITH COEXISTING CARDIAC AL AND ATTR AMYLOIDOSIS

Abstract Background Incidence of ATTRwt amyloidosis increased in the last years, especially thanks to the possibility of a non-bioptic diagnosis. However, if a monoclonal component (MC) is detected, amyloid typing is mandatory to rule out AL amyloidosis. Differential diagnosis is even more important now that we have labelled treatment for both types of amyloidosis. In some cases, typing on endomyocardial biopsy (EMB) revealed the presence of both light chains (LC) and transthyretin (TTR) in the heart of the same patient (Sidiqi, et al, Blood Cancer J. 2019). We present a series of patients with coexisting AL and ATTR in the heart. In these cases, we elected to administer treatment for AL amyloidosis due to the more rapid course of this disease and because in Italy and in Germany tafamidis is not prescribable for patients with coexisting AL amyloidosis. Objective: To evaluate the outcome of patients with coexisting AL and ATTR amyloidosis in the heart after treatment for AL amyloidosis. Material & Methods: We identified 17 patients with coexisting AL and ATTR amyloidosis evaluated in a German (n=5) or Italian (n=12) referral center. Typing was performed by immunohistochemistry with custom made antibodies (IHC; N=5) and immunoelectron microscopy (IEM; N=8). In 4 cases, EBM samples were subjected to protein extraction following a new procedure (patent n EP3417295). SDS-PAGE/Western Blot analysis was performed for the main amyloidogenic proteins and its results were validated by mass spectrometry. Cardiac responses and progression were assessed according to AL amyloidosis criteria. Results 3 patients were excluded because of post-mortem diagnosis and 1 because amyloid deposits were characterized on bone marrow biopsy and it was not possible to unequivocally conclude for the coexistence of LC and TTR in the heart. Thirteen patients were included in the analysis. Four had a positive abdominal fat pad (AFP). Three underwent EMB because typing by IHC was not possible on AFP by IHC. In 1 IEM was positive for TTR only, but given the presence of an abnormal free LC ratio and albuminuria, the patient underwent EBM that was positive both for LC and TTR at IEM. Perugini score 1 was observed in 3 patients, of whom 1 was positive for a TTR mutation (Val40Ile). In 1 case, bone marrow plasma cell infiltrate was ≥60%, in absence of other multiple myeloma defining events. All patients received treatment for AL amyloidosis and 10 had response data. None was treated for ATTR. At 6 months 9 achieved a hematologic response (HR) and 3 a cardiac response. Six patients had a cardiac progression, despite 5 had achieved a HR (complete response [CR] in 2, very good partial response [VGPR] in 2 and partial response in 1 case). After a median follow-up of 33.8 months, 2 patients died of worsening of heart failure after 15 and 48 months from diagnosis, despite the maintenance of CR and VGPR. Both had AL cardiac progression at 6 months. Summary & Conclusion This is the largest series of patients with coexisting AL and ATTR amyloid deposits in the heart and the first reporting outcome to AL treatment. The AFP was commonly negative and when positive typing was not possible by IHC. Moreover, IEM did not find AL deposits in 1 case. This was unexpected and may reflect a selection bias: patients with a MC and AL amyloidosis in the AFP are unlikely to be further tested for ATTR. This finding warrants further studies and a possible revision of diagnostic algorithms. Treatment for AL amyloidosis may not be able to stop progression in these patients, who should be granted access to anti-ATTR therapies.

Progressive differentiation toward the long-lived plasma cell compartment in the bone marrow.

The longevity of plasma cells is dependent on their ability to access and reside in so-called niches that are predominantly located in the bone marrow. Here, by employing a traceable method to label recently generated plasma cells, we showed that homeostatic plasma cells in the bone marrow and spleen were continuously replenished by newly generated B220hiMHC-IIhi populations that progressively differentiated into B220loMHC-IIlo long-lived plasma cell (LLPC) populations. We also found that, in the bone marrow, germinal center (GC)-independent and GC-dependent plasma cells decayed similarly upon NP-CGG engagement, and both entered the B220loMHC-IIlo LLPC pool. Compared with NP+B220hiMHC-IIhi plasma cells, NP+B220loMHC-IIlo cells were more immobilized in the bone marrow niches and showed better survival potential. Thus, our results suggest that the adhesion status of bone marrow plasma cells is dynamically altered during their differentiation and is associated with provision of survival signals.

A case-control study of multiple myeloma patients with central nervous system involvement

Objective: To investigate the treatment options for multiple myeloma patients with central nervous system involvement (CNS-MM) , as well as their clinical characteristics and prognostic factors. Methods: Between January 2011 and January 2022 our center diagnosed 18 people with CNS-MM. A retrospective analysis was done on the clinical information from the initial diagnosis and central nervous system involvement, and it was compared to 1∶3 matched newly diagnosed MM from the same period. Analysis was done on the clinical characteristics and survival rates of the two groups. Results: In patients with CNS-MM, the median time of onset was 14.2 (0.9-79.6) months and the median overall survival (OS) was 30.5 months from initial diagnosis and only 3.8 months in patients after CNS involvement. The CNS-MM patients showed more IgD type (P=0.010) , severer anemia (P=0.014) , a higher proportion of bone marrow plasma cells (P=0.013) , more extramedullary lesions (P=0.001) , and increased lactic dehydrogenase (LDH) (P=0.009) when compared to the control group. Lenalidomide or pomalidomide-based combinations had higher rates of hematology and CNS remission than bortezomib or daratumumab-based regimens (75.0% vs 16.7% , P=0.019) . Patients who received IMiD-based regimens and had 2 high-risk factors at initial diagnosis (high LDH and extramedullary lesions) had a significantly lower incidence of CNS-MM (P=0.026) . At the initial diagnosis, LDH (P=0.008, HR=7.319, 95% CI 1.663-32.219) and extramedullary lesions (P=0.006, HR=8.054, 95% CI 1.828-35.486) were independent risk factors for the occurrence of CNS-MM. Conclusion: Patients with CNS-MM had a poor prognosis. Patients with high LDH or extramedullary lesions at the time of the initial diagnosis are more likely to have CNS-MM. The prognosis of this patient may be improved by immunoregulator-based therapy.

The Combination of Panobinostat and Melphalan for the Treatment of Patients with Multiple Myeloma.

Histone deacetylase inhibitors show synergy with several genotoxic drugs. Herein, we investigated the biological impact of the combined treatment of panobinostat and melphalan in multiple myeloma (MM). DNA damage response (DDR) parameters and the expression of DDR-associated genes were analyzed in bone marrow plasma cells (BMPCs) and peripheral blood mononuclear cells (PBMCs) from 26 newly diagnosed MM patients. PBMCs from 25 healthy controls (HC) were examined in parallel. Compared with the ex vivo melphalan-only treatment, combined treatment with panobinostat and melphalan significantly reduced the efficiency of nucleotide excision repair (NER) and double-strand-break repair (DSB/R), enhanced the accumulation of DNA lesions (monoadducts and DSBs), and increased the apoptosis rate only in patients' BMPCs (all p < 0.001); marginal changes were observed in PBMCs from the same patients or HC. Accordingly, panobinostat pre-treatment decreased the expression levels of critical NER (DDB2, XPC) and DSB/R (MRE11A, PRKDC/DNAPKc, RAD50, XRCC6/Ku70) genes only in patients' BMPCs; no significant changes were observed in PBMCs from patients or HC. Together, our findings demonstrate that panobinostat significantly increased the melphalan sensitivity of malignant BMPCs without increasing the melphalan sensitivity of PBMCs from the same patients, thus paving the way for combination therapies in MM with improved anti-myeloma efficacy and lower side effects.

MinimuMM-seq: Genome Sequencing of Circulating Tumor Cells for Minimally Invasive Molecular Characterization of Multiple Myeloma Pathology.

In this study, we established an approach enabling the enumeration and sequencing of CTCs to replace standard molecular cytogenetics. CTCs harbored the same pathognomonic MM abnormalities as BM plasma cells. Longitudinal sampling of serial CTCs was able to track clonal dynamics over time and detect the emergence of high-risk genetic subclones. This article is highlighted in the In This Issue feature, p. 247.

Molecular Features of the Mesenchymal and Osteoblastic Cells in Multiple Myeloma

Multiple myeloma (MM) is a monoclonal gammopathy characterized by biological heterogeneity and unregulated proliferation of plasma cells (PCs) in bone marrow (BM). MM is a multistep process based on genomic instability, epigenetic dysregulation and a tight cross-talk with the BM microenvironment that plays a pivotal role supporting the proliferation, survival, drug-resistance and homing of PCs. The BM microenvironment consists of a hematopoietic and a non-hematopoietic compartment, which cooperate to create a tumor environment. Among the non-hematopoietic component, mesenchymal stromal cells (MSCs) and osteoblasts (OBs) appear transcriptionally and functionally different in MM patients compared to healthy donors (HDs) and to patients with pre-malignant monoclonal gammopathies. Alterations of both MSCs and OBs underly the osteolytic lesions that characterize myeloma-associated bone disease. In this review, we will discuss the different characteristics of MSCs and OBs in MM patients, analyzing the transcriptome, the deregulated molecular pathways and the role performed by miRNAs and exosome in the pathophysiology of MM.

Retraction Note: A wrapper based feature selection in bone marrow plasma cell gene expression data

Retraction Note: A wrapper based feature selection in bone marrow plasma cell gene expression data

Expression of SIL-2R in Patients with Multiple Myeloma and Its Clinical Significance

To investigate the expression and clinical significance of soluble interleukin-2 receptor(sIL-2R) in patients with multiple myeloma(MM). 54 newly diagnosed MM patients in the Second Affiliated Hospital of Fujian Medical University from February 2020 to December 2021 were selected as the observation group, and 60 healthy people in our hospital in the same period were selected as the control group. The expression levels of sIL-2R in the serum of the two groups were detected by enzyme-linked immunosorbent assay. The differences of sIL-2R expression level among different clinical parameter groups in MM patients were compared. The clinical parameters include:gender, age, ISS stage, hemoglobin, albumin, serum creatinine, lactate dehydrogenase and β2-microglobulin, blood calcium, bone marrow plasma cell ratio and treatment response. The relationship between sIL-2R expression level and progression-free survival(PFS) and overall survival(OS) in MM patients were analyzed. The expression of serum SIL-2R in MM patients was significantly higher than that in healthy control group (P<0.05). The expression of sIL-2R in MM patients who did not achieve complete remission(CR) was significantly higher than those of CR patients (P=0.037). There was no significant difference in the expression of serum sIL-2R between the groups of different sex, age, ISS stage, hemoglobin concentration, albumin content, serum creatinine level, lactate dehydrogenase level, the content of β2-microglobulin, the concentration of blood calcium, and the proportion of bone marrow plasma cells(P>0.05). The PFS of sIL-2R high expression group(15 months) was shorter than that of sIL-2R low expression group (22 months), which was significant difference (P=0.041). But there was no significant difference in OS between sIL-2R high expression group and sIL-2R low expression group (P=0.124). Univariate analysis results showed that the high expression of serum sIL-2R was associated with poor PFS in MM patients. Multivariate analysis results showed that the high expression of serum sIL-2R was still an independent adverse prognostic factor for PFS in MM patients, However, the expression of serum sIL-2R was not statistically significant in evaluating OS in MM patients by univariate and multivariate analysis. The expression of serum sIL-2R in MM patients was significantly higher than that in healthy people. Serum sIL-2R is an independent prognostic factor of PFS in MM patients.

Clinical Significance of CD28 Expression in Newly Diagnosed Multiple Myeloma

To explore the expression of CD28 in multiple myeloma and its correlation with tumor burden and clinical prognosis. Flow cytometry was adopted to analyze bone marrow specimens of 91 newly diagnosed patients with multiple myeloma. According to CD28 expression, the patients were divided into CD28+ group and CD28- group, and the differences between the two groups in clinical features, genetic abnormalities, and treatment response were compared. Staging was carried out in accordance with the International Staging System (ISS). Among 91 newly diagnosed patients, there were 31 cases in CD28+ group and 60 cases in CD28- group. The proportion of ISS-Ⅲ patients in the CD28+ group was 70.97%, which was higher than 50.00% in the CD28- group (P<0.05). The median of bone marrow plasma cells in the CD28+ group was 41.78(2.00-77.00), which was higher than 26.92(2.00-92.00) in the CD28- group (P<0.05). β2-microglobulin level in the CD28+ group was 6.53(2.11-36.50) mg/L, which was higher than 5.76(2.00-31.34) mg/L in the CD28- group (P<0.05). The positive rate of poor karyotype in the CD28+ group was 70.00% (21/30), which was higher than 45.00% (27/60) in the CD28- group (P=0.025). After 4 cycles of chemotherapy, the total effective rate of CD28- group was 86.27%, which was higher than 60.00% of CD28+ group (P<0.05). After a median follow-up of 10 months, the progression-free survival (PFS) time of CD28+ group was 10.7 months, which was lower than 14 months of CD28- group (P<0.05). Univariate analysis showed that age ≥ 65 years old, hemoglobin < 60 g/L, ISS-III, CD28+ expression and ≥ 2 genetic abnormalities were not risk factors for PFS, while further multivariate analysis showed that induction effect < partial response (PR) and CD28+ expression and were independent risk factors for PFS. CD28+ is associated with clinical characteristics and prognosis of newly diagnosed multiple myeloma patients, and can be used as a reference index to evaluate the prognosis.

CD20 expression: A risk stratification factor for newly diagnosed multiple myeloma with t(11;14).

Translocation (11;14) is one of the most frequent recurrent cytogenetic abnormalities in multiple myeloma (MM), while its clinical prognostic value remains controversial. CD20 expression is uncommon in MM while strongly associated with t(11;14). This study aimed to investigate whether CD20 could provide further prognostic value in MM patients harboring t(11;14). CD20 expression detected by flow cytometry was retrospectively analyzed in 211 newly diagnosed MM patients with t(11;14). The clinical characteristics and outcomes were analyzed between CD20 positive and negative patients. CD20 expression was found in 34.6% (73/211) newly diagnosed MM (NDMM) patients with t(11;14), associated with lower serum creatine levels and lower incidence of plasmacytoma. Based on similar treatment regimens, CD20 positive patients had a comparable overall response rate to CD20 negative patients, whereas had a lower CR/sCR (complete response/stringent complete response) rate than the latter (31.4% vs. 46.4%, P =0.045). Nevertheless, CD20 positive patients had a longer tendency of progression-free survival (PFS) (59.0 vs. 29.0 months, P =0.163) and significantly longer overall survival (OS) (99.0 vs. 56.0 months, P=0.003) than CD20 negative patients. Further investigation among CD20 expression proportion showed that strong expression of CD20 (>80% of bone marrow plasma cells) exhibited the longest OS (median not reached, P =0.011). However, the favorable impact of CD20 expression on survival was eliminated with the contaminant presence of cytogenetic abnormalities besides t(11;14). Autologous stem cell transplantation (ASCT) could improve the prognosis of CD20 negative t(11;14) patients. Multivariate analysis confirmed that CD20 expression was an independent favorable indicator for longer OS in t(11;14) MM patients. CD20 expression is a favorable prognostic factor in NDMM with t(11;14) and could provide further risk-stratification value in this heterogeneous disease subgroup.

Human lymphoid tissue sampling for vaccinology.

Long-lived plasma cells (LLPCs) - largely resident in the bone marrow - secrete antibody over months and years, thus maintaining serum antibody concentrations relevant for vaccine-mediated immunity. Little is known regarding factors that can modulate the induction of human LLPC responses in draining lymph node germinal centres, or those that maintain LLPCs in bone marrow niches following vaccination. Here, we review human and non-human primate vaccination studies which incorporate draining lymph node and/or bone marrow aspirate sampling. We emphasise the key contributions these samples can make to improve our understanding of LLPC immunology and guide rational vaccine development. Specifically, we highlight findings related to the impact of vaccine dosing regimens, adjuvant/vaccine platform selection, duration of germinal centre reactions in draining lymph nodes and relevance for timing of tissue sampling, and heterogeneity in bone marrow plasma cell populations. Much of this work has come from recent studies with SARS-CoV-2 vaccine candidates or, with respect to the non-human primate work, HIV vaccine development.

Evidence Supporting Light Chain Cast Nephropathy As a Myeloma Defining Event

BACKGROUND In 2014, the International Myeloma Working Group (IMWG) revised the Renal involvement of the CRAB (hyperCalcemia, Renal, Anemia, Bone lesions) criteria for the diagnosis of multiple myeloma (MM) as an acute decline in kidney function represented by either a serum creatinine (Scr) > 2 mg/dl or an estimated glomerular filtration rate of < 40 ml/min/1.73 m2 secondary to light chain cast nephropathy (LCCN) biopsy proven or suspected. Since LCCN occurs only in patients with high serum free light chain (FLC) levels, a high tumor burden is presumed but how often it occurs with other myeloma defining events (MDE) is unknown. METHODS Patients were selected from 2 cohorts. The first cohort came from a multicenter study on LCCN who were all diagnosed with MM between 2000 and 2018. Only newly diagnosed patients were included in this study. A second cohort was identified from the Mayo Clinic Kidney Biopsy database from 2003 to 2013. Inclusion criteria of this cohort were: the LCCN must be the dominate pathology on the kidney biopsy and it is secondary to a plasma cell proliferative disorder. Laboratory and radiologic data were collected to assess for CRAB criteria. Bone lesions were assessed by standard skeletal X-ray, MRI or CT/PET. Most had skeletal X-ray. The new SLiM CRAB criteria which have the addition 3 biomarkers: (S) >60% bone marrow plasma cells, (Li) an involved to uninvolved free light chain (FLC) ratio > 100 and (M) >1 bone lesion on MRI were also assessed. RESULTS From the multicenter study, 28 patients were excluded for having relapsed MM and 27 were from Mayo who were included in the second cohort leaving 123 patients. In the Mayo cohort, 52 patients were identified who met criteria. Both cohorts were comparable in age, sex, bone marrow plasma cells and hemoglobin at diagnosis (Table 1). Interestingly, 3.3% of the multicenter cohort and 3.9% of the Mayo cohort did not meet the R criterion due to a presenting creatinine of ≤ 2.0 mg/dl. In the multicenter cohort 2/99 (2.0%) and 4/52 (7.7%) of the Mayo cohort had < 10% bone marrow plasma cells. The presenting involved FLC was higher in the multicenter group (p = 0.001). In the multicenter cohort, 99.1% met at least one of the SLiM criteria and 84.7% met one the C,A,B criteria. In the Mayo cohort, fewer patients met at least one of the SLiM criteria (86.5%, p < 0.001) but more patients met one or more of the C,A,B criteria (98.1%, p = 0.01). All but 1 patient from the multicenter cohort met one or more of the SliM C,A,B criteria. The most common SLiM criteria met in the multicenter cohort was Li while it was M in the Mayo cohort. The most common C,A,B criteria in the multicenter cohort was A while it was B in the Mayo cohort. DISCUSSION This study provides the first evidence that nearly all patients who present with biopsy proven LCCN have at least one other MDE. Bone marrow burden was met in 98.0% of the multicenter cohort where all patients were diagnosed with MM, 92.3% of the Mayo cohort where the diagnosis of MM was not a prerequisite. More importantly, 84.7% and 98.1% of patients from the 2 cohorts respectively had another MDE besides LCCN confirming that LCCN is associated with high tumor burden. All but 1 patient would have been diagnosed with MM based on the SLiM CRAB criteria. In comparison to patients with other kidney lesions associated with monoclonal immunoglobulin, generally only 20-30% met the CRAB criteria for MM. This is why it is more appropriate to classify those patients as having monoclonal gammopathy of renal significance while patients with LCCN should be diagnosed with MM. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Validation of the CIBMTR Scoring System in Predicting Early Relapse of Multiple Myeloma Post Autologous Hematopoietic Cell Transplant

Introduction: Despite good initial responses, many multiple myeloma (MM) patients eventually relapse post autologous hematopoietic cell transplant (AHCT). Risk stratification to Identify patients that are at an increased risk of early relapse may influence post-AHCT monitoring and selection of maintenance therapy. Recently, the Center for International Blood and Marrow Transplant Research (CIBMTR) scoring system was introduced as a tool to identify patients at risk of early relapse post-AHCT. The scoring system relies on each patient's albumin level at time of MM diagnosis, bone marrow plasma cell (BMPC) percentage at time of AHCT, and cytogenetic risk profile to classify them into three risk categories. Here, we aimed to test the validity of the CIBMTR scoring system by applying it to our cohort. Methods: We reviewed all patients who underwent AHCT for MM at Cleveland Clinic between 2011-2021, and then identified the patients with available data to be incorporated into the CIBMTR system. As per the scoring system's requirements, points were assigned for the following patient characteristics: 4 points for high risk (HR) cytogenetics, 4 points for BMPC ≥10% at AHCT, 2 points for albumin <3.5 g/dL at diagnosis, 1 point for standard risk (SR) cytogenetics, 0 points for normal cytogenetics, BMPC <10% at AHCT, and albumin ≥3.5 g/dL at diagnosis. Baseline demographic, clinical, and cytogenetic data of the included patients were retrospectively collected by reviewing electronic medical records to compare the three risk groups. Analysis was conducted through multivariate analysis using the Statistical Package for Social Sciences (SPSS), while median overall survival (mOS) and median progression free survival (mPFS) of the three groups were analyzed using GraphPad Prism. Results: A total of 313 patients met inclusion criteria and were included in our study. Our cohort had a median age of 61.7 years at AHCT, a 57.2% male preponderance and a median follow up of 31.9 months. With regards to the CIBMTR scoring system constituents, 106 (33.9%) had HR cytogenetics as compared to 146 (46.6%) with SR and 61 (19.5%) with normal cytogenetics. Albumin ≥3.5 g/dL occurred in 85 (27.2%) while BMPC ≥10% were present in 31 (9.9%). CIMBTR risk score application yielded 191 (61%) patients classified as low risk (score 0-3), 110 (35.2%) patients as intermediate risk (score 4-8), and 12 (3.8%) patients as high risk (score 9-10) of early relapse after AHCT. There were no significant differences between the low-, intermediate and high-risk groups with respect to median age at transplant (61 vs 63.1 vs 62.3%, P=0.1), Gender representation (Males 56.5 vs 60 vs 50%, P=0.7), Ethnicity (White 82.2 vs 86.4 vs 91.7%, P=0.5), median lines of therapy pre-AHCT (P=0.3), or remission status (partial/very good partial/complete) pre-AHCT (P=0.17). Compared to low- and intermediate-risk patients, respectively, patients belonging to the high-risk group had higher 1-year relapse (41.7 vs 10.5 vs 18.2%, P=0.0043), 2-year relapse (58.3 vs 17.8 vs 38.2%, P=0.0001) and 3-year relapse (66.7 vs 25.7 vs 50.9%, P<0.0001) rates. Kaplan-Meier based survival analysis confirmed a lower mPFS in the high-risk group compared to the low- and intermediate-risk groups, respectively (14.7 vs 67.7 vs 29 months, P<0.0001) (Fig 1A). Interestingly, the CIBMTR score also distinguished the three risk groups with respect to overall survival. High-risk patients had higher mortality at the 5-year (50 vs 15.7 vs 22.7%, P=0.0082) and 7-year (58.3 vs 17.3 vs 29%, P=0.0008) follow up intervals as compared to low- and intermediate-risk patients, respectively. Kaplan-Meier analysis further corroborated the mortality rates since high-risk patients had lower mOS relative to intermediate- and low-risk patients, respectively (56.6 vs 68 vs unreached, P=0.0046) (Fig 1B). Conclusion: We validated the CIBTMR scoring system criteria within an internal cohort, demonstrating that this system is a reliable tool for identification of patients with a higher risk of early relapse post-AHCT. We further identified differences between risk groups in mortality at 5- and 7-years following AHCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Characteristics of 6 Cases of Overlapping Plasma Cell Disorders

BACKGROUND: Plasma cell disorders (PCD) are a group of diseases in which monoclonal plasma cells overproliferate and produce monoclonal immunoglobulins, including monoclonal gammopathy of undetermined significance, multiple myeloma, primary systemic light chain amyloidosis, extramedullary plasmacytoma, POEMS syndrome and so on. These groups of diseases are diagnosed according to signs, symptoms, laboratory examination and pathological manifestations, based on corresponding diagnostic criteria. It is generally believed that all kinds of plasma cell disorders exist independently and will not occur together. However, in clinic, we found that few patients can meet the diagnostic criteria of more than one kind of plasma cell diseases at the same time, and we named the diagnosis of such patients overlapping plasma cell disease. Methods: This study retrospectively analyzed the characteristics of 6 cases of overlapping plasma cell disorders which were diagnosed in First Affiliated Hospital, Sun Yat-sen University. Results: All 6 cases of overlapping plasma cell disorders were diagnosed with two plasma cell disorders at the same time at the onset. Among them, 5 cases were POEMS syndrome overlapping other plasma cell diseases, including 4 cases of POEMS syndrome overlapping solitary plasmacytoma and 1 case of POEMS syndrome overlapping active multiple myeloma (AMM). Another case was smoldering multiple myeloma (SMM) overlapping primary systemic light chain amyloidosis (pAL). All 6 patients were diagnosed strictly according to the diagnostic criteria, and they all met the diagnostic criteria of two plasma cell diseases. There are 3 males and 3 females, and the median age is 57 years old. Among them, the median plasma cells in bone marrow of 4 cases of POEMS syndrome overlapping solitary plasmacytoma were 2%, and no clonal plasma cells were found by flow cytometry. Plasma cells in bone marrow of patients with POEMS syndrome overlapping AMM and SMM overlapping pAL were 22% and 12%. The median level of VEGF of 5 cases of POEMS overlapping other plasma cell diseases was 441.38pg/ml. Of the 5 patients with POMES overlapping other PCDs, 3 received lenalidomide-based treatment, 2 received bortezomib-based treatment, and the patient with SMM overlapping pAL received Dara+Rd. The median follow-up time of these patients was 24 months. The median progression-free survival and median overall survival were not achieved. Conclusion: Overlapping plasma cell disorders are a group of rare plasma cell diseases, which requires careful screening of various clinical manifestations, laboratory tests and pathological features for diagnosis. At present, it is difficult to diagnose this kind of disease, and we need to accumulate cases and experience.

Novel Antigens LMA and Kma Are Expressed on Malignant Bone Marrow Plasma Cells from Patients with Relapsed Refractory Multiple Myeloma and Plasma Cell Dyscrasias

Introduction Previous studies have identified the lambda myeloma antigen (LMA) and kappa myeloma antigen (KMA) on the surface of malignant plasma cells in myeloma patient bone marrow samples, human myeloma cell lines and other plasma cell dyscrasias1-3. LMA and KMA are not present on normal B cells and are found on occasional mononuclear cells in tonsillar tissue and secondary mucosal lymphoid tissue. Targeting KMA and LMA through cellular and other immunological therapies has the potential advantage of leaving a population of normal plasma cells untouched and minimising the risk of serious post-treatment infection. Characteristics of the antibodies called KappaMab and LambdaMabs (10B3 and 7F11) that bind to specific conformational epitopes in the constant regions of these surface-bound light chains have been described in clinical trials and in vitro experiments1, 2, 4-6. Here, we present data on a larger series of patients with plasma cell dyscrasias, demonstrating the expression of LMA on plasma cells from patients in whom myeloma evolves from monoclonal gammopathy of unknown significance (MGUS). We also describe the difference in phenotype between LMA and KMA expressing malignant plasma cells and the frequent expression of KMA in relapsed refractory myeloma patient (RRMM) samples. Methods Patient BM samples (κ=49 and λ=31) were analysed using multiparametric FCM immunophenotyping with APC labelled LambdaMab (10B3) and KappaMab Fab'2 fragments, CD38, CD138, CD269 (BCMA), CD319 (SLAM F7), CD56 and CD45 monoclonal antibodies. Plasma cells were identified as previously described by initial gating using CD38 and CD138. LMA and KMA expression was determined and compared with the other cell markers. Results Nine of 12 (75%) newly diagnosed λ-type patients with MGUS or SMM expressed LMA on the surface of BM plasma cells. Longitudinal data from two patients was available. One patient showed LMA expression and antigen density increasing on the surface of bone marrow plasma cells during progression from MGUS (2020) to smoldering myeloma (SMM) (2022) (% of plasma cells positive for LMA rose from 61% to 92%, antigen density increased from 532 to 5164 molecules of PE/cell). In a second individual, LMA expression and antigen density increased on bone marrow plasma cells during progression from SMM (2020) to myeloma (2022) (% of plasma cells positive for LMA rose from 94% to 100%, antigen density increased from 3981 to 8941 molecules of PE/cell). KMA expression continued to be observed on plasma cells in 4 of 6 patients after autologous stem cell transplant. KMA was expressed in 86% of patients with ĸRRMM (n=14). LMA expression was observed in 2 of 4 patients with λRRMM. Both KMA and LMA antigen densities were higher than BCMA in the RRMM population (KMA mean 1802, range 468-7943 vs BCMA mean 1306, range 350-2630 molecules of PE/cell), (LMA mean 2439, range 263-6664 vs BCMA mean 817, range 537-1065 molecules of PE/cell). Conclusions In an enlarged cohort of patients with myeloma, we have confirmed that KMA and LMA are expressed at all stages of disease. Our data examining longitudinal expression in individual patients suggests that expression of LMA on BM plasma cells increases from MGUS to MM. The majority of patients with relapsed refractory kappa myeloma expressed KMA. Further data is required to confirm LMA expression in this population. The antigen density of both LMA and KMA is higher than BCMA on RRMM BM plasma cells. KMA and LMA expression is independent of serum Ig and FLC levels and % marrow plasma cells. These data show that KappaMab and LambdaMab have therapeutic potential in the treatment of myeloma patients, especially in the setting of relapsed refractory disease where the combination of high antigen density and restriction of the target antigen to the malignant subpopulation of plasma cells will confer valuable clinical benefit.

Retrospective Analysis of Prognostic Factors and Survival in Multiple Myeloma Patients Aged 65 Years or Older at Diagnosis in a Real-Life Setting and a Proposed New Staging System

Introduction: The incidence of multiple myeloma (MM) increases with age. Novel agents provide better treatment results. However, adults >65 years of age are often underrepresented in clinical trials making it difficult to assess treatment outcomes in older patients. Appropriate strategies are necessary and treatment must be individualized in this heterogeneous population. Methods: We retrospectively reviewed the charts of 534 patients diagnosed with MM between January 2010 and January 2020 who presented to our department. One hundred twenty-three of them were aged 65 years or older at diagnosis and were included in the study. Clinical and laboratory data were collected and potential prognostic factors of overall survival (OS) were evaluated by univariate and multivariate analyses. Results: Of 123 patients analyzed 54.5% (67) were male and 45.5% (56) were female. The median age was 71 years and 32.5% of patients were equal or older than 75 years. Median follow-up time was 28 months (1-117). Median OS and progression free survival (PFS) were 46 and 17 months, respectively. Of the patients 63.4% (78) died during the study period. The patients were divided into 3 groups according to age: 65-69 (47 patients, median OS 68 months), 70-74 (36 patients, median OS 45 months) and ≥75 (40 patients, median OS 36 months) years old (p: 0.022). International Staging System (ISS) stage could be defined in 117 patients (19 had ISS I, 40 ISS II and 58 had ISS III disease). Revised ISS (R-ISS) could also be defined in 117 patients (17 R-ISS I, 82 R-ISS II and 18 R-ISS III). Both ISS and R-ISS could not identify statistically significant differences regarding OS and PFS. Chromosomal abnormalities were detected by fluorescence in situ hybridization (FISH) and conventional cytogenetics in 56 and 39 patients respectively. Eleven of 56 patients and 4 of 39 patients had unfavorable genetic features and due to the small number these patients are not included in the survival analyses. Bortezomib based doublet and triplet induction regimens were given in 86% of patients. Univariate analysis revealed that age, hemoglobin, creatinine, calcium, albumin, extramedullary disease and bone marrow plasma cell (BMPC) percentage were strongly associated with OS. Receiver operating curve (ROC) analysis determined the optimal cut-off value of BMPC 26.5%. On multivariate analysis albumin, extramedullary disease and BMPC ratio retained prognostic value. Presence of none, one, two or all three of these factors could identify 4 patient subgroups showing median OS rates of 108, 55, 25 and 12 months, respectively (p: <0.001) (Figure). Conclusions: MM primarily affects older adults. Hence, there is a need for simple and reliable staging systems for elderly MM patients. We propose a prognostic scoring method for outcome incorporating easy to use variables such as albumin, extramedullary disease and BMPC ratio. Hypoalbuminemia (≤ 3.5 g/dl), presence of extramedullary disease and BMPC ratio ≥ 26.5% predicted different OS ratios in the study population. A validation of the score in an independent series of patients is planned. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal