Immunoglobulin Variable Light Chain Restriction, Cytokine Expression and Plasma Cell-Stromal Cell Interactions in POEMS Syndrome Patients

Abstract POEMS syndrome is defined by the presence of peripheral neuropathy (P), organomegaly (O), endocrinopathy (E), monoclonal protein expression (M), and skin changes (S). In addition, patients also have sclerotic bone lesions, papilledema, extravascular volume overload, thrombocytosis, and restrictive lung disease/pulmonary hypertension. A striking but inexplicable feature of the clonal plasma cells in patients with POEMS is that they are virtually always lambda restricted. More surprising is that of the 81 functional immunoglobulin light-chain variable-region genes (IgVL) available in the plasma cell/B cell repertoire, among the 13 cases in which variable gene light chain usage has been reported, all have been either IgVL1-40 or IgVL1-44. The molecular mechanisms triggering the initiation and the progression of POEMS syndrome or the clonal expansion of plasma cells marking this condition remain unclear. We have analyzed the immunoglobulin heavy and light chains sequences in the plasma cells of POEMS patients at the Mayo Clinic Rochester. We found that in 8 out of the 9 patients tested, we could document heavy chain clonality in any given patient; however, no restriction of gene usage among patients was observed in the variable regions of these chains. In the case of light chains, in 14 out of 17 patients we could document not only clonality but also restriction of light chain variable gene usage to IgVL1-40 or IgVL1-44. Our goal is to understand the relevance of this restricted expression of light chain variable region, and its effect on the communication between plasma cells and the neighboring stromal cells that might provide more insight into the disease pathology. To this end, we are generating viral vector constructs that will harbor the germline or mutant versions of IgVλ1-40 and IgVλ1-44 genes and introduced into pre-established malignant plasma cell lines (i.e. myeloma cell lines). We will assay the effects of this over expression in terms of alterations in the expression of cytokines such as VEGF and TNF, and on plasma cell-stromal cell interaction (in a co-culture system). Results from these assays will be discussed.

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Phenotypic analysis of human myeloma cell lines

Blood ◽

10.1182/blood.v73.2.566.bloodjournal732566 ◽

1989 ◽

Vol 73 (2) ◽

pp. 566-572

Author(s):

C Duperray ◽

B Klein ◽

BG Durie ◽

X Zhang ◽

M Jourdan ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Plasma Cell ◽

Plasma Cells ◽

Myeloma Cell ◽

Light Chains ◽

Cell Phenotype ◽

Phenotypic Analysis ◽

Barr Virus ◽

Human Myeloma Cell

Multiple myeloma (MM) is a B-cell malignancy characterized by the accumulation, primarily in bone marrow, of a clone of plasma cells. The nature of the stem cells feeding the tumoral compartment is still unknown. To investigate this special point, we have studied the phenotypes of nine well-known human myeloma cell lines (HMCLs) and compared them with those of normal lymphoblastoid cell lines (LCLs). Twenty-four clusters of differentiation involved in B lymphopoiesis were investigated using a panel of 65 monoclonal antibodies (MoAbs). For each cluster, the percentage of positive cells and the antigen density were determined, giving rise to a “quantitative phenotype”. We thus classified the HMCLs into two different groups: those with cytoplasmic mu chains (c mu+) and those without (c mu-). In the first (c mu+) group, comprising seven cell lines, the HMCLs had a phenotype of pre-B/B cells close to that of Burkitt's lymphoma cell lines. They expressed low densities of surface mu chains, without detectable cytoplasmic or surface light chains. Three of them were infected with the Epstein Barr virus (EBV). These c mu+ HMCLs bore most of the B-cell antigens except CD23. They expressed the CALLA antigen (CD10) and lacked the plasma-cell antigen PCA1. In contrast, LCLs expressed surface light chains, high densities of CD23, low densities of PCA1 antigen, and no CD10 antigen. The c mu- HMCLs had a plasma-cell phenotype, lacking most of the B-cell antigens and expressing high densities of PCA1 antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

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In Vitro and inVivo Activity of Melflufen in Amyloidosis

Blood ◽

10.1182/blood-2019-125952 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3100-3100 ◽

Cited By ~ 2

Author(s):

Ken Flanagan ◽

Muntasir M Majumder ◽

Romika Kumari ◽

Juho Miettinen ◽

Ana Slipicevic ◽

...

Keyword(s):

Board Of Directors ◽

Cell Lines ◽

Plasma Cell ◽

Light Chain ◽

Research Funding ◽

Plasma Cells ◽

Al Amyloidosis ◽

Advisory Committees

Background: Immunoglobulin light-chain (AL) amyloidosis is a rare disease caused by plasma cell secretion of misfolded light chains that assemble as amyloid fibrils and deposit on vital organs including the heart and kidneys, causing organ dysfunction. Plasma cell directed therapeutics, aimed at preferentially eliminating the clonal population of amyloidogenic cells in bone marrow are expected to reduce production of toxic light chain and alleviate deposition of amyloid thereby restoring healthy organ function. Melphalan flufenamide ethyl ester, melflufen, is a peptidase potentiated alkylating agent with potent toxicity in myeloma cells. Melflufen is highly lipophilic, permitting rapid cellular uptake, and is subsequently enzymatically cleaved by aminopeptidases within cells resulting in augmented intracellular concentrations of toxic molecules, providing a more targeted and localized treatment. Previous data demonstrating multiple myeloma plasma cell sensitivity for melflufen suggests that the drug might be useful to directly eliminate amyloidogenic plasma cells, thereby reducing the amyloid load in patients. Furthermore, the increased intracellular concentrations of melflufen in myeloma cells indicates a potential reduction in systemic toxicity in patients, an important factor in the fragile amyloidosis patient population. To assess potential efficacy in amyloidosis patients and to explore the mechanism of action, we examined effects of melflufen on amyloidogenic plasma cells invitro and invivo. Methods: Cellular toxicity and apoptosis were measured in response to either melflufen or melphalan in multiple malignant human plasma cell lines, including the amyloidosis patient derived light chain secreting ALMC-1 and ALMC-2 cells, as well as primary bone marrow cells from AL amyloidosis patients, using annexin V and live/dead cell staining by multicolor flow cytometry, and measurement of cleaved caspases. Lambda light chain was measured in supernatant by ELISA, and intracellular levels were detected by flow cytometry. To assess efficacy of melflufen in vivo, the light chain secreting human myeloma cell line, JJN3, was transduced with luciferase and adoptively transferred into NSG mice. Cell death in response to melflufen or melphalan was measured by in vivo bioluminescence, and serum light chain was monitored. Results: Melflufen demonstrated increased potency against multiple myeloma cell lines compared to melphalan, inducing malignant plasma cell death at lower doses on established light chain secreting plasma cell lines. While ALMC-1 cells were sensitive to both melphalan and melflufen, the IC50 for melphalan at 960 nM was approximately 3-fold higher than melflufen (334 nM). However, ALMC-2 cells were relatively insensitive to melphalan (12600 nM), but maintained a 100-fold increase in sensitivity to melflufen (121 nM). Furthermore, while 40% of primary CD138+ plasma cells from patients with diagnosed AL amyloidosis responded to melflufen treatment in vitro, only 20% responded to melphalan with consistently superior IC50 values for melflufen (Figure 1). Light chain secreting cell lines and AL amyloidosis patient samples were further analyzed by single cell sequencing. We further examined differential effects on apoptosis and the unfolded protein response in vitro in response to either melflufen or melphalan. This is of particular interest in amyloidosis, where malignant antibody producing plasma cells possess an increased requirement for mechanisms to cope with the amplified load of unfolded protein and associated ER stress. As AL amyloidosis is ultimately a disease mediated by secretion of toxic immunoglobulin, we assessed the effects of melflufen on the production of light chain invitro, measuring a decrease in production of light chain in response to melflufen treatment. Finally, we took advantage of a recently described adoptive transfer mouse model of amyloidosis to assess the efficacy of melflufen and melphalan in eliminating amyloidogenic clones and reducing the levels of toxic serum light chain in vivo. Conclusions: These findings provide evidence that melflufen mediated toxicity, previously described in myeloma cells, extends to amyloidogenic plasma cells and further affects the ability of these cells to produce and secrete toxic light chain. This data supports the rationale for the evaluation of melflufen in patients with AL amyloidosis. Figure 1 Disclosures Flanagan: Oncopeptides AB: Employment. Slipicevic:Oncopeptides AB: Employment. Holstein:Celgene: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; Genentech: Membership on an entity's Board of Directors or advisory committees; Sorrento: Consultancy. Lehmann:Oncopeptides AB: Employment. Nupponen:Oncopeptides AB: Employment. Heckman:Celgene: Research Funding; Novartis: Research Funding; Oncopeptides: Research Funding; Orion Pharma: Research Funding.

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The JAK1/2 Inhibitor Ruxolitinib Kills Malignant Plasma Cells and Is Synergistic with PI3K and mToR Inhibitors

Blood ◽

10.1182/blood.v120.21.1844.1844 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1844-1844

Author(s):

Renate Burger ◽

Tim Bugdahn ◽

Matthias Staudinger ◽

Anna Lena Michaelis ◽

Matthias Peipp ◽

...

Keyword(s):

Drug Resistance ◽

Cell Growth ◽

Growth Inhibition ◽

Cytotoxic Activity ◽

Signaling Pathways ◽

Cell Lines ◽

Plasma Cell ◽

Stromal Cell ◽

Plasma Cells ◽

Combination Index

Abstract Abstract 1844 Malignant plasma cell growth and survival in multiple myeloma (MM) is regulated by cytokines produced in the tumor environment. Specifically, IL-6 plays a key role by activating important signaling pathways through its gp130 receptor associated Janus kinases (JAK). Ruxolitinib (INC424/INCB018424; Novartis/Incyte) is the first small molecule JAK inhibitor approved for the treatment of patients with myelofibrosis. It is a potent inhibitor of both JAK1 and JAK2 and has an approx. 6-fold selectivity against Tyk2 and marked selectivity against JAK3 (more than 130-fold) and additional kinases. The aim of our study was to evaluate the effects of ruxolitinib on malignant plasma cells as well as its activity in combination with other pathway inhibitors. Ruxolitinib activity was evaluated in MTS-based colorimetric cell growth assays or by [3]H-thymidine uptake. IC50 concentrations and combination index (CI) were calculated with CalcuSyn (Biosoft). Evaluating seven human plasma cell lines, ruxolitinib showed a strong cytotoxic activity on the only IL-6 dependent line INA-6 (IC50 0.23 μM). Complete growth inhibition was achieved at 1 μM, even in the presence of bone marrow stromal cells, whereas stromal cell viability and IL-6 production, as measured by specific ELISA, were maintained. Consistent with the dose-dependent inhibition of IL-6 induced STAT3 phosphorylation, apoptosis was induced, resulting in 39% and 63% annexin V-positive cells in the presence of 1 μM ruxolitinib after 48 or 72 hours, respectively. Likewise, significant growth inhibition was seen in purified tumor cells from a patient with plasma cell leukemia that were stimulated with IL-6 (IC50 0.16 μM), and in a LIF-responsive tumor subline of INA-6 (IC50 0.12 μM). In contrast, autonomously growing MM cell lines were not directly inhibited by ruxolitinib, pointing to the kinase specificity of the drug. However, IL-6 mediated drug resistance can be reversed as shown in dexamethasone-sensitive MM1.S cells. Simultaneous inhibition of JAKs with additional signaling pathways that may be activated in myeloma cells by mutations and/or cytokines such as insulin-like growth factor-1, is hypothesized to result in increased cytotoxicity. In INA-6 cells, p44/p42 MAPK activation due to mutated N-Ras and phosphorylation of S6 protein, a downstream target of the PI3K/AKT/mToR pathway, were not abrogated by ruxolitinib. Using combinations of ruxolitinib with inhibitors of PI3K (Ly294002, NVP-BKM120) and mToR (rapamycin), synergistic effects were achieved with a combination index (CI) <1 at the effective dose levels ED50, ED75 and ED90. Other combinations are currently under evaluation. In conclusion, ruxolitinib has strong direct cytotoxic activity against malignant plasma cells that are dependent on JAK/STAT pathway activation. The rationale exists to combine it with inhibitors of complementary pathways and other drugs to potentiate its activity and overcome cytokine or stromal cell mediated drug resistance. Thus, ruxolitinib, as a generally well tolerated drug, may offer therapeutic options for patients with MM. Clearly, the identification of molecular markers may be helpful to assess its precise use alone or in combination, and to select for patients who will benefit from such a treatment. Disclosures: No relevant conflicts of interest to declare.

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AL Amyloidosis — Pathogenesis and Prognosis Are Determined By the Amyloidogenic Potential of the Light Chain and the Molecular Characteristics of Malignant Plasma Cells

Blood ◽

10.1182/blood-2018-187 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 187-187

Author(s):

Anja Seckinger ◽

Ute Hegenbart ◽

Susanne Beck ◽

Martina Emde ◽

Tilmann Bochtler ◽

...

Keyword(s):

Gene Expression ◽

Plasma Cell ◽

Light Chain ◽

Research Funding ◽

Plasma Cells ◽

Memory B Cells ◽

Light Chains ◽

Molecular Characteristics ◽

Al Amyloidosis ◽

Malignant Plasma Cell

Abstract INTRODUCTION. Systemic light chain amyloidosis (AL) is caused by accumulation of plasma cells producing misfolded monoclonal light chains depositing as amyloid fibrils in different organs, most frequently heart and kidney. AIM of our study is first assessing the molecular characteristics of malignant plasma cells from AL-patients in relation to those from MGUS, asymptomatic, and symptomatic myeloma: Are these plasma cells different, does this difference explain amyloidogenicity? Does AL correspond to a certain developmental stage during evolution of symptomatic myeloma? Secondly, to what extent is prognosis determined by amyloid-deposition (organotropism, amount, amyloidogenicity) vs. number and molecular characteristics of malignant plasma cells? PATIENTS & METHODS . Consecutive patients (n=3023) with AL (n=582), MGUS (n=306), asymptomatic (n=444, AMM), or previously untreated, therapy-requiring multiple myeloma (n=1691, MM) were included. CD138-purified plasma cell samples were subjected to iFISH (n=582/306/444/1691), 1297 to gene expression profiling using Affymetrix U133 2.0 plus arrays (n=196/64/272/765), 712 to RNA- (n=124/52/38/489), and 258 to whole exome sequencing (n=115/53/39/51). Samples of normal bone marrow plasma cells, memory B-cells, and polyclonal plasmablasts were used as comparators. The CoMMpass-cohort (n=647) was used as comparator for the mutational spectrum of myeloma. RESULTS . Prognosis. By AL-factors. Expectedly, organ involvement, i.e. heart only vs. kidney only vs. heart+kidney vs. other (overall survival (OS), P=.001), the amount of free light chains (dFLC ≥18 mg/dL, HR=2.56, P=.01), and the cardiac European Mayo IIIB score (I/II/IIIA/IIIB, median OS 110/55/16/3 months, HR=1/1.94/3.73/7.90, P<.001) strongly determine prognosis (Fig. 1A). By malignant plasma cell factors. High proliferation rate (HR=3.58, P=.001) and expression-based risk factors for MM (GEP70 high, HR=2.38, P=.005; Rs-score high HR=4.63, P<.001) identify patients with very adverse prognosis (Fig. 1A). Tumor load, e.g. plasma cell infiltration >10%/>30% (HR=1.31/1.81, P=.01, P=.002) and M-protein ≥ 30g/l (HR=3.01, P=.005), are likewise prognostic (Fig. 1A). In multivariate analysis, all tested AL-specific (European Mayo IIIB score) and malignant plasma cell factors (proliferation or GEP70 and plasma cell infiltration) are independent. Molecular characteristics.iFISH. As MM (96.2%) and AMM (92.8%) AL-patients (93.1%) carry at least one recurrent myeloma typical aberration. The mean number of progression-associated aberrations in AL (n=0.98) fits between MGUS (n=0.85) and AMM (n=1.45) with significant difference compared to AMM (P<.001) unlike to MGUS. Main differences in frequency are found for t(11;14) and hyperdiploidy with a comparable pattern of non-etiologic aberrations. Gene expression (GEP and RNA-seq). Aberrant plasma cells in AL amyloidosis show the least difference with AMM, followed by MGUS and MM. In principal component analysis, AL overlaps with AMM and MGUS, independent of presence or absence of heart involvement (Fig. 1B). Pairwise assessment of similarity using a multivariate generalization of the squared Pearson correlation coefficient shows closest similarity to AMM and MM followed by MGUS, with comparable differences to normal plasma cells, polyclonal plasmablasts, and memory B-cells. Significantly more AL-patients present with higher proliferation rate vs MGUS (P<.001) and AMM (P<.02). AL and MM differ significantly regarding distinct molecular entities as determined by GEP (e.g. TC-classification; Fig. 1C). Mutation spectrum in AL amyloidosis vs. MM. From the 20 most frequently synonymously mutated non-Ig transcripts (CoMMpass-cohort), 16 could likewise be detected in AL amyloidosis, i.e. KRAS, NRAS, IGLL5, DIS3, FAM46C, MUC16, BRAF, TRAF3, PCLO, RYR2, FATA4, CSMD3, TP53, DNAH5, RYR2A, and FLG. CCND1 mutations were significantly more frequent in AL and AMM compared to MM (P=.02). DISCUSSION & CONCLUSION. Pathogenesis and prognosis of AL amyloidosis are explained both by AL-specific and malignant plasma cell characteristics. Aberrant plasma cells in AL amyloidosis show the same aberration- and expression pattern and a "molecular age" between MGUS and AMM, most closely resembling the latter. AL amyloidosis is thus mostly a rather early plasma cell dyscrasia with an unstable and toxic immunoglobulin light chain. Disclosures Seckinger: Celgene: Research Funding; EngMab: Research Funding; Sanofi: Research Funding. Hose:Celgene: Honoraria, Research Funding; Sanofi: Research Funding; EngMab: Research Funding.

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Phenotypic analysis of human myeloma cell lines

Blood ◽

10.1182/blood.v73.2.566.566 ◽

1989 ◽

Vol 73 (2) ◽

pp. 566-572 ◽

Cited By ~ 49

Author(s):

C Duperray ◽

B Klein ◽

BG Durie ◽

X Zhang ◽

M Jourdan ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Plasma Cell ◽

Plasma Cells ◽

Myeloma Cell ◽

Light Chains ◽

Cell Phenotype ◽

Phenotypic Analysis ◽

Barr Virus ◽

Human Myeloma Cell

Abstract Multiple myeloma (MM) is a B-cell malignancy characterized by the accumulation, primarily in bone marrow, of a clone of plasma cells. The nature of the stem cells feeding the tumoral compartment is still unknown. To investigate this special point, we have studied the phenotypes of nine well-known human myeloma cell lines (HMCLs) and compared them with those of normal lymphoblastoid cell lines (LCLs). Twenty-four clusters of differentiation involved in B lymphopoiesis were investigated using a panel of 65 monoclonal antibodies (MoAbs). For each cluster, the percentage of positive cells and the antigen density were determined, giving rise to a “quantitative phenotype”. We thus classified the HMCLs into two different groups: those with cytoplasmic mu chains (c mu+) and those without (c mu-). In the first (c mu+) group, comprising seven cell lines, the HMCLs had a phenotype of pre-B/B cells close to that of Burkitt's lymphoma cell lines. They expressed low densities of surface mu chains, without detectable cytoplasmic or surface light chains. Three of them were infected with the Epstein Barr virus (EBV). These c mu+ HMCLs bore most of the B-cell antigens except CD23. They expressed the CALLA antigen (CD10) and lacked the plasma-cell antigen PCA1. In contrast, LCLs expressed surface light chains, high densities of CD23, low densities of PCA1 antigen, and no CD10 antigen. The c mu- HMCLs had a plasma-cell phenotype, lacking most of the B-cell antigens and expressing high densities of PCA1 antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

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Identification of Clonal Immunoglobulin λ Light-Chain Gene Rearrangements in AL Amyloidosis Using Next Generation Sequencing

Blood ◽

10.1182/blood-2019-125028 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1748-1748

Author(s):

Kenji Kimura ◽

Shokichi Tsukamoto ◽

Kanji Miyazaki ◽

Chika Kawajiri-Manako ◽

Bahityar Rahmutulla ◽

...

Keyword(s):

Next Generation Sequencing ◽

Plasma Cell ◽

Light Chain ◽

Research Funding ◽

Plasma Cells ◽

Light Chains ◽

Al Amyloidosis ◽

Next Generation ◽

Clonal Composition ◽

Generation Sequencing

[Introduction] AL amyloidosis is caused by the deposition of abnormally folded clonal immunoglobulin (IG) light chains (LCs, λ:κ = 3:1) made by malignant plasma cells in the bone marrow (BM), which leads to multi-organ dysfunction, often involving the heart, kidney, liver, skin, and nerves. However, little is known about what regulates organ tropism of amyloid deposition in this disease. In addition, no study has analyzed the repertoire of IG germlines of plasma cells in the BM in AL amyloidosis using next generation sequencing (NGS). In this study, we aimed to identify the clonal composition of IG λ light-chain variable region (IGLV) genes in BM cells in patients with AL amyloidosis using NGS. [Material and method] BM cells were obtained at diagnosis from 38 patients with AL amyloidosis and those with other plasma cell disorders: multiple myeloma (MM, n = 7), and monoclonal gammopathy of undetermined significance (MGUS, n = 11) with λ-type monoclonal paraprotein. Seven normal control (NC) patients had either immune thrombocytopenia or malignant lymphoma without BM invasion. Genomic DNA was extracted from the BM mononuclear cells preserved in LABO Banker1 or BM clots in O.C.T compound using QIAamp DNA Blood Mini kit. The IGLV1 and IGLV2 genes were amplified by polymerase chain reaction using a 5′ primer for the IGLV1/2 framework 3 (FR3) region and 3′ consensus primers for the IGLJ1/2/3 joining regions. Multiple samples were pooled, and paired-end 2 × 250 base pair sequencing reactions were performed using an Illumina MiSeq sequencer and then analyzed by an open-source program called Vidjil. All subjects provided written informed consent to participate in the study, in accordance with the Declaration of Helsinki. This study was approved by the ethics committee of the Chiba University Graduate School of Medicine and Japanese Red Cross Medical Center. [Results] Clinical and laboratory features of 38 patients with AL amyloidosis were as follows: primary AL amyloidosis (n = 31); 15 and 20 patients had cardiac and renal dysfunctions, respectively, and secondary AL amyloidosis with MM (n = 7); 4 and 1 patient had cardiac and renal dysfunctions, respectively. In patients with AL amyloidosis, the median plasma cell count in BM aspirate smears was 3.3% (0.1%-50.4%), and the median difference in involved and uninvolved light chains (dFLC) was 104.5 mg/L (28.5mg/L -2673.3mg/L). Representative results of the Vidjil analysis in NC, MGUS, AL amyloidosis, and MM are shown in Figure 1. The most abundant IGLV gene accounted for not >1% of the reads, and there was no dominant germline in NC samples. Therefore, we defined the dominant clone as >1% of IG germlines in plasma cells. According to this definition, clonal IG germlines were found in 27 of 31 patients with primary AL amyloidosis (87%), 5 of 7 with secondary AL amyloidosis (71%), 7 of 7 with MM (100%), and 8 of 11 with MGUS (73%). However, the size of clones in AL amyloidosis (median 3.1%, 0.38%-14.3%) was significantly smaller than that in MM (median 17.8%, 2.2%-17.9%) (P<0.001), and similar to that in MGUS (median 3.8%, 0.4%-32.0%). Importantly, in patients with AL amyloidosis, the dFLC and involved/uninvolved FLC ratio was not correlated with the clonal size of plasma cells in our repertoire analysis using NGS, suggesting that small malignant clones of plasma cells may secret FLC and cause LC depositions in AL amyloidosis. Regarding IGLV germline usage, IGLV1-51 was the most frequent repertoire in AL amyloidosis with heart dysfunction (7 of 16 cases) and renal dysfunction (7 of 21 cases). No relationship between the IGLV germlines and organ tropisms was observed. [Conclusion] We successfully identified the clonal composition of IGLV genes in the BM of most patients with AL amyloidosis using NGS, according to the differences in the V and J region recombination and CDR3 sequences using the Vidjil program. In AL amyloidosis, the clonal size of plasma cells in the BM is small and small malignant clones of plasma cells may secret FLC and cause LC depositions in AL amyloidosis. Figure 1 Disclosures Suzuki: Ono: Research Funding; BMS: Honoraria, Research Funding; Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria.

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Immunological phenotype of lymphomas induced by avian leukosis viruses

Molecular and Cellular Biology ◽

10.1128/mcb.3.6.1077-1085.1983 ◽

1983 ◽

Vol 3 (6) ◽

pp. 1077-1085

Author(s):

L C Chen ◽

S A Courtneidge ◽

J M Bishop

Keyword(s):

B Lymphocytes ◽

Cell Lines ◽

Light Chain ◽

Avian Leukosis Virus ◽

Immunoglobulin M ◽

Light Chains ◽

Free Light Chains ◽

Viral Antigens ◽

Immunological Phenotype ◽

Avian Leukosis Viruses

The production of immunoglobulin by six cell lines derived from bursal tumors induced by avian leukosis virus follows two general patterns: (i) three cell lines that have been extensively passaged in culture synthesize and secrete light chains only; (ii) three cell lines that are recently isolated produce and secrete monomeric immunoglobulin M in addition to free light chains. All six cell lines synthesize and secrete both glycosylated and unglycosylated forms of light chain. We conclude that the cell lines established from lymphomas induced by avian leukosis virus represent relatively mature, but possibly abnormal, stages in the development of chicken B-lymphocytes. The immunoglobulin M produced by the cell lines failed to form detectable immune complexes with avian leukosis virus. It therefore appears that the immunoglobulin M is not directed against viral antigens and that autogenous antigenic stimulus cannot account for the sustained growth of the neoplastic B-lymphocytes.

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THUR 215 Lessons in the diagnosis and management of poems syndrome

Journal of Neurology Neurosurgery & Psychiatry ◽

10.1136/jnnp-2018-abn.106 ◽

2018 ◽

Vol 89 (10) ◽

pp. A30.4-A31

Author(s):

Adams-Carr Kerala ◽

Keddie Stephen ◽

Lunn Michael

Keyword(s):

Light Chain ◽

Plasma Cells ◽

Selection Process ◽

Position Sense ◽

Joint Position Sense ◽

Poems Syndrome ◽

Ivig Treatment ◽

Bone Lesions ◽

Limb Weakness ◽

Pet Ct

We present the case of a 46 year old man who developed a rapidly progressive sensorimotor neuropathy and skin changes. He was diagnosed with Guillain-Barré Syndrome, and subsequently CIDP, but his condition continued to progress despite IVIG treatment and plasma exchange. On transfer to the National Hospital of Neurology and Neurosurgery, six months after the onset of illness, he had profound lower limb weakness with power 0 distal to his knees, and upper limb involvement to the elbows. Deep tendon reflexes were absent, and vibration and joint position sense were reduced peripherally. Nerve conduction studies identified a length-dependent demyelinating polyneuropathy with secondary axonal loss, and blood tests demonstrated thrombocytosis, endocrine dysfunction, and a raised VEGF. Two FGD-avid mixed sclerotic and lytic bone lesions were identified on PET-CT. Biopsy of these lesions demonstrated plasmacytomas with lambda light-chain restriction, and bone marrow biopsy revealed 4% plasma cells, with polytypic light chain staining. A diagnosis of POEMS syndrome was made, and he was initiated on lenalidomide and dexamethasone treatment. With reference to this case we will discuss the challenges in the diagnosis of POEMS syndrome. Additionally, we will outline the therapeutic options available; providing an algorithm to simplify the treatment selection process.

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Light Chain Shifting: Identification of a Human Plasma Cell Line Actively Undergoing Light Chain Replacement

Blood ◽

10.1182/blood.v93.1.198 ◽

1999 ◽

Vol 93 (1) ◽

pp. 198-207 ◽

Cited By ~ 5

Author(s):

Hirofumi Tachibana ◽

Hirotaka Haruta ◽

Koji Yamada

Keyword(s):

Cell Line ◽

Human Plasma ◽

Plasma Cell ◽

Light Chain ◽

Plasma Cells ◽

High Rate ◽

Cell Phenotype ◽

Recombination Activating Genes ◽

Λ Light Chain ◽

Rag 1

Abstract We identified an antibody-secreting human B-cell line (HTD8), which actively replaces the production of the original λ light chain with a new λ chain (light chain shifting) at a high rate. Loss of the original rearranged λ light chain occurs by significantly reducing the amount of transcript expressed. Expression of the new λ chain, which replaces the original λ chain, occurs by rearranging new VJ segments on a previously excluded allele. V λ gene usage of these new rearrangements are biased toward Vλ4, Vλ6, and Vλ10 families, which are known to be the least frequently used. In striking contrast to the plasma cell phenotype, recombination activating genes, RAG-1 and RAG-2, were expressed in the HTD8 cells and were shown to be necessary, but insufficient for inducing expression of the new λ chain. These results suggest that human plasma cells have the potential to actively undergo light chain replacement.

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Stabilization of amyloidogenic immunoglobulin light chains by small molecules

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1817567116 ◽

2019 ◽

Vol 116 (17) ◽

pp. 8360-8369 ◽

Cited By ~ 15

Author(s):

Gareth J. Morgan ◽

Nicholas L. Yan ◽

David E. Mortenson ◽

Enrico Rennella ◽

Joshua M. Blundon ◽

...

Keyword(s):

Small Molecules ◽

Light Chain ◽

Cardiac Involvement ◽

Plasma Cells ◽

Full Length ◽

Light Chains ◽

Immunoglobulin Light Chains ◽

X Ray ◽

Tissue Degeneration ◽

Dimerization Interface

In Ig light-chain (LC) amyloidosis (AL), the unique antibody LC protein that is secreted by monoclonal plasma cells in each patient misfolds and/or aggregates, a process leading to organ degeneration. As a step toward developing treatments for AL patients with substantial cardiac involvement who have difficulty tolerating existing chemotherapy regimens, we introduce small-molecule kinetic stabilizers of the native dimeric structure of full-length LCs, which can slow or stop the amyloidogenicity cascade at its origin. A protease-coupled fluorescence polarization-based high-throughput screen was employed to identify small molecules that kinetically stabilize LCs. NMR and X-ray crystallographic data demonstrate that at least one structural family of hits bind at the LC–LC dimerization interface within full-length LCs, utilizing variable-domain residues that are highly conserved in most AL patients. Stopping the amyloidogenesis cascade at the beginning is a proven strategy to ameliorate postmitotic tissue degeneration.

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