scholarly journals Tumor-specific aneuploidy not detected in CD19+ B-lymphoid cells from myeloma patients in a multidimensional flow cytometric analysis

Blood ◽  
1996 ◽  
Vol 88 (2) ◽  
pp. 622-632 ◽  
Author(s):  
PA McSweeney ◽  
DA Wells ◽  
KE Shults ◽  
RA Nash ◽  
WI Bensinger ◽  
...  

Aneuploidy and lg light chain restriction were used as separate, independent tumor specific markers to study 26 patients with multiple myeloma to determine whether bone marrow B cells, as defined by CD19 expression, are clonally related to myeloma plasma cells. Specimens were characterized using multidimensional flow cytometry to identify the presence of clonality in both the B lymphoid and plasma cell populations using both surface and cytoplasmic staining with antibodies specific for kappa or lambda lg light chain In none of the patients with multiple myeloma were CD19+ cells found to be clonally restricted to kappa or lambda. The monoclonal plasma cells (MPC) were found to be uniformly negative for CD10, CD19, and CD34, while the CD19+ B lymphoid cells present within the samples expressed normal intensities and relationships of these antigens, which allowed them to serve as internal positive controls. Combined analysis of call surface antigen expression and DNA content allowed plasma cell populations to be characterized for aneuploidy without interference from normal bone marrow cells. The MPC, detected on the basis of bright CD38 expression (CD38+2), demonstrated DNA aneuploidy in 65% of cases (DNA index range of 0.9 to 1.3). These aneuploid DNA distributions had typical cell cycle profiles (including G1,S and G2+M) expected of a proliferating population. In all cases, DNA aneuploidy was confined almost entirely to the CD38+2, CD19- malignant plasma cells, while cells expressing CD19 were diploid. These results support the concept that myeloma is a disease process mediated by self-replicating, late compartments of B- cell ontogeny.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3396-3396 ◽  
Author(s):  
Robert Kyle ◽  
Ellen Remstein ◽  
Terry Therneau ◽  
Angela Dispenzieri ◽  
Paul Kurtin ◽  
...  

Abstract Smoldering multiple myeloma (SMM) is characterized by a serum M protein ≥ 3g/dL and/or 10% or more of plasma cells in the bone marrow. However, the definition is not standardized, and it is not known whether both serum M protein levels and bone marrow plasma cell counts are necessary for diagnosis or if one parameter is sufficient. We reviewed the medical records and bone marrows of all patients from Mayo Clinic seen within 30 days of recognition of an IgG or IgA M protein ≥ 3g/dL or a bone marrow containing ≥ 10% plasma cells from 1970 to 1995. This allows for a minimum potential follow-up of 10 years. Patients with end-organ damage at baseline from plasma cell proliferation, including active multiple myeloma (MM) and primary amyloidosis (AL) and those who had received chemotherapy were excluded. A differential of the bone marrow aspirate coupled with the bone marrow biopsy morphology and immunohistochemistry using antibodies directed against CD138, MUM-1 and Cyclin D1 were evaluated in every case in order to estimate the plasma cell content. In all, 301 patients fulfilled either of the criteria for SMM. Their median age was 64 years and only 3% were less than 40 years of age; 60% were male. The median hemoglobin value was 12.9 g/dL; 7% were less than 10 g/dL, but the anemia was unrelated to plasma cell proliferation. IgG accounted for 75%, IgA 22%, and biclonal proteins were found in 3%. The serum light-chain was κ in 67% and λ in 33%. The median serum M spike was 2.9 g/dL; 11% were at least 4.0 g/dL. Uninvolved serum immunoglobulins were reduced in 81%; only 1 immunoglobulin was reduced in 31% and both were decreased in 50%. The urine contained a monoclonal κ protein in 36% and λ in 18% and 46% were negative. The median size of the urine M spike was 0.04 g/24h; only 5 (3%) were > 1 g/24h. The median bone marrow plasma cell content was 15 – 19%; 10% had less than 10% plasma cells, while 10% had at least 50% plasma cells in the bone marrow. Cyclin D-1 was expressed in 17%. Patients were categorized into 3 groups: Group 1, serum M protein ≥ 3g/dL and bone marrow containing ≥ 10% plasma cells (n= 113, 38%); Group 2, bone marrow plasma cells ≥ 10% but serum M protein < 3g/dL (n= 158, 52%); Group 3, serum M protein ≥ 3g/dL but bone marrow plasma cells < 10% (n= 30, 10%). During 2,204 cumulative years of follow-up 85% died (median follow-up of those still living 10.8 years), 155 (51%) developed MM, while 7 (2%) developed AL. The overall rate of progression at 10 years was 62%; median time to progression was 5.5 yrs. The median time to progression was 2.4, 9.2, and 19 years in groups 1, 2, and 3 respectively; correspondingly at 10 years, progression occurred in 76%, 59%, and 32% respectively. Significant risk factors for progression with univariate analysis were serum M spike ≥ 4g/dL (p < 0.001), presence of IgA (p = 0.003), presence of urine light chain (p = 0.006), presence of λ urinary light chain (p = 0.002), bone marrow plasma cells ≥ 20% (p < 0.001) and reduction of uninvolved immunoglobulins (p < 0.001). The hemoglobin value, gender, serum albumin, and expression of cyclin D-1 were not of prognostic importance. On multivariate analysis, the percentage of bone marrow plasma cells was the only significant factor predicting progression to MM or AL.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5630-5630 ◽  
Author(s):  
Sudhir Perincheri ◽  
Richard Torres ◽  
Christopher A Tormey ◽  
Brian R Smith ◽  
Henry M Rinder ◽  
...  

Abstract The diagnosis of multiple myeloma (MM) requires the demonstration of clonal plasma cells at ≥10% marrow cellularity or a biopsy-proven bony or extra-medullary plasmacytoma, plus one or more myeloma-defining events. Clinical laboratories use multi-parameter flow cytometry (MFC) evaluation of cytoplasmic light chain expression in CD38-bright, CD45-dim or CD138-positive, CD45dim cells to establish plasma cell clonality with a high-degree of sensitivity and specificity. Daratumumab, a humanized IgG1 kappa monoclonal antibody targeting CD38, has been shown to significantly improve outcomes in refractory MM, and daratumumab was granted breakthrough status in 2013. Daratumumab is currently approved for treatment of MM patients who have failed first-line therapies. It has been noted that daratumumab can interfere in blood bank assays for antibody screening, as well as serum protein electrophoresis (SPEP). We describe for the first time daratumumab interference in the assessment of plasma cell neoplasms by MFC; daratumumab interfered with both CD38- and CD138-based gating strategies in three MM patients. Patient A is a 68 year old man with a 10 year history of MM who had failed multiple therapies. He had then been treated with daratumumab for two months, stopping therapy 25 days prior to bone marrow assessment. Patient B is a 53 year old man with a 3 year history MM who had failed numerous treatments. He had been receiving daratumumab monotherapy for two months at the time of his bone marrow studies. On multiple marrow aspirates at times of relapse prior to receiving daratumumab, both patients had demonstrated CD38-bright positive CD45dim/negative plasma cells expressing aberrant CD56, as well as kappa light chain restriction; mature B cells were polyclonal in both. Patient C is a 65 year old man with a four-year history of MM status post autologous stem cell transplantation, who had been receiving carfilzomib and pomalidomide following relapse and continues to have rising lambda light chains and rib pain. He now has abnormal plasma cells in blood worrisome for plasma cell leukemia. Bone marrow aspirates from patients A and B, and blood from patient C demonstrated near absence of CD38-bright events as detected by MFC (Figure 1). Hypothesizing that these results were due to blocking of the CD38 antigen by daratumumab, gating on CD138-positive events was assessed; surprisingly, virtually no CD138-positive events were detected by MFC. All 3 samples demonstrated a CD56-positive CD45dim population; when light chain studies were employed using specific gating on the CD56-positive population, light chain restriction was demonstrated in all patients (Figure 1). Aspirate morphology confirmed numerous abnormal, nucleolated plasma cells (Figure 2A), thus excluding a sampling error. CD138 and CD38 expression was also tested on the marrow biopsy cores from both patients. In contrast to MFC, immunohistochemistry (IHC) showed positive labeling of plasma cells with both CD138 (Figure 2B) and CD38 (Figure 2C). The reason for the labeling discrepancy between MFC and IHC is unknown. The different antibodies in the assays may target different epitopes; alternatively, tissue fixation/decalcification may dissociate the anti-CD38 therapeutic monoclonal from its target. Detection of clonal plasma cell populations is important for assessing response to therapy. Laboratories relying primarily on MFC to assess marrow aspirates without a concomitant biopsy may falsely diagnose remission or significant disease amelioration in daratumumab-treated patients. MFC is generally highly sensitive for monitoring minimal residual disease (MRD) in MM, but daratumumab-treated patients should have their biopsy evaluated to confirm the MRD assessment by MFC. We were able to detect large numbers of plasma cells and also demonstrate clonality in our patients based on an alternative MFC marker, aberrant CD56 expression, an approach that may not be possible in all cases. Figure 1 Flow cytometry showing near-absence of CD38-bright elements in the marrow of patient A (top panels). Gating on CD56-positive cells in the same sample reveals a kappa light chain-restricted plasma cell population (bottom panels). Figure 1. Flow cytometry showing near-absence of CD38-bright elements in the marrow of patient A (top panels). Gating on CD56-positive cells in the same sample reveals a kappa light chain-restricted plasma cell population (bottom panels). Figure 1 The marrow aspirate from Fig. 1 shows abnormal plasma cells (A). Immunohistochemistry on the concomitant biopsy shows the presence of numerous CD138-positive (B) and CD38-positive (C) plasma cells. Figure 1. The marrow aspirate from Fig. 1 shows abnormal plasma cells (A). Immunohistochemistry on the concomitant biopsy shows the presence of numerous CD138-positive (B) and CD38-positive (C) plasma cells. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4539-4539
Author(s):  
Selina Dobing ◽  
Nikolas Desilet ◽  
Irwindeep Sandhu ◽  
Lauren Bolster

Abstract Objectives: 1. Describe a case of severe DAT-negative intravascular hemolysis in plasma cell dyscrasia. 2. Discuss a potential novel mechanism of light-chain mediated hemolysis. A 34-year old woman was admitted to hospital with fatigue and severe iron deficiency anemia (hemoglobin 47 g/dL, MCV 59 fL, ferritin 2 mcg/L). Her medical history included a presumptive diagnosis of paroxysmal nocturnal hemoglobinuria (PNH) from five years prior. She was transfused 2 units of red cells, started on oral iron and folate, and was discharged symptom-free with a hemoglobin of 71 g/dL. She returned three days later with abdominal pain, dark urine, and evidence of intravascular hemolysis. She was admitted for empiric treatment of PNH with high-dose glucocorticoids and therapeutic enoxaparin for presumed intra-abdominal thrombosis. Her flow cytometry, including granulocytes, was negative for PNH. Her direct antiglobulin test (DAT) was negative for IgG antibodies but positive for C3 complement. A thorough hemolysis workup was negative, including schistocytes and Donath Landsteiner testing. ADAMTS13 testing was uninterpretable due to high plasma free hemoglobin. Despite corticosteroids, brisk hemolysis continued with 10 units of RBCs required over 5 days to maintain a stable hemoglobin. Plasma free hemoglobin reached 1147 mg/L, prompting therapeutic plasmapheresis for renal protection by the end of day 5. She deteriorated clinically after her first plasmapheresis with acute confusion (GCS 10) and lactic acidosis. She was empirically treated for seizure with levetiracetam. CT and MRI scans of her brain and lumbar puncture were normal. Her consciousness improved with daily plasmapheresis. A bone marrow biopsy performed on day twelve of glucocorticoid therapy found monoclonal plasma cell proliferation of 15% with marked lambda light chain predominance (20:1) (Figure 1). Repeat bone marrow biopsy 3 months post-steroid therapy still revealed 10% clonal plasma cells. Hemolysis can be a rare presentation of plasma cell dyscrasia. Case reports of both autoimmune hemolytic anemia and microangiopathic hemolytic anemia associated with multiple myeloma exist. In our case, there was no evidence of a microangiopathic process, making thrombotic thrombocytopenic purpura (TTP) or atypical hemolytic-uremic syndrome (aHUS) unlikely. DAT was negative for IgG but did demonstrate C3 complement molecules bound to red cells. No previous case reports of complement-mediated hemolysis and multiple myeloma were found on literature review. We report the first in vivo association between complement-mediated hemolysis and plasma cell dyscrasia. Complement pathways bridge the innate and acquired immune systems by helping select cells to be targeted by the acquired immune system. The alternative complement pathway does not require an antigen-antibody interaction to become active; rather, it is controlled by direct binding of complement and regulated by cofactor molecules. Jokiranta et al. (J Immunol 1999) identified a monoclonal Ig-lambda dimer that efficiently activated the alternative pathway of complement, triggering complement molecules to enhance hemolysis of serum in vitro. This "miniautoantibody" specifically bound and blocked the function of complement factor H, inhibiting enzymatic inactivation of fluid-phase C3b with uncontrolled activation of the alternative pathway. It is possible that the relative immune dysfunction in this patient's plasma cell dyscrasia led to a disturbance in the alternate complement pathway, perhaps due to dimerization of abnormal lambda light chains, resulting in complement-mediated intravascular hemolysis. Glucocorticoids and plasmapheresis may have helped manage hemolysis in this case. By diagnostic criteria, this patient has smoldering myeloma, with urine monoclonal protein (1.2 g/24 hours), clonal bone marrow plasma cells (10-15%), and absence of myeloma-defining events. We have elected to manage her as such, with close observation. Further work-up performed for her plasma cell dyscrasia included a normal MRI of spine and pelvis. Over a year later, there has been no recurrence of hemolysis. Consideration will be given to treatment if she progresses to overt multiple myeloma. Figure 1. A. Aspirate showing abnormal plasma cells. B. Trephine CD138 stain. C. Trephine kappa light chain stain. D. Trephine lambda light chain stain. Figure 1. A. Aspirate showing abnormal plasma cells. B. Trephine CD138 stain. C. Trephine kappa light chain stain. D. Trephine lambda light chain stain. Disclosures Sandhu: Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria.


2013 ◽  
Vol 31 (34) ◽  
pp. 4319-4324 ◽  
Author(s):  
Taxiarchis V. Kourelis ◽  
Shaji K. Kumar ◽  
Morie A. Gertz ◽  
Martha Q. Lacy ◽  
Francis K. Buadi ◽  
...  

Purpose There is consensus that patients with light chain (AL) amyloidosis with hypercalcemia, renal failure, anemia, and lytic bone lesions attributable to clonal expansion of plasma cells (CRAB criteria) also have multiple myeloma (MM). The aim of this study was to examine the spectrum of immunoglobulin AL amyloidosis with and without MM, with a goal of defining the optimal bone marrow plasma cell (BMPC) number to qualify as AL amyloidosis with MM. Patients and Methods We identified 1,255 patients with AL amyloidosis seen within 90 days of diagnosis between January 1, 2000, and December 31, 2010. We defined a population of patients with coexisting MM on the basis of the existence of CRAB criteria (AL-CRAB). Receiver operating characteristic analysis determined the optimal BMPC cut point to predict for 1-year mortality in patients with AL amyloidosis without CRAB to produce two additional groups: AL only (≤ 10% BMPCs) and AL plasma cell MM (AL-PCMM; > 10% BMPCs). Results Among the 1,255 patients, 100 (8%) had AL-CRAB, 476 (38%) had AL-PCMM, and 679 (54%) had AL only. Their respective median overall survival rates were 10.6, 16.2, and 46 months (P < .001). Because the outcomes of AL-CRAB and AL-PCMM were similar, they were pooled for univariate and multivariate analyses. On multivariate analysis, pooled AL-CRAB and AL-PCMM retained negative prognostic value independent of age, Mayo Clinic AL amyloidosis stage, prior autologous stem-cell transplantation, and difference between the involved and uninvolved free light chain. Conclusion Patients with AL amyloidosis who have more than 10% BMPCs have a poor prognosis, similar to that of patients with AL-CRAB, and should therefore be considered together as AL amyloidosis with MM.


Blood ◽  
1984 ◽  
Vol 64 (2) ◽  
pp. 352-356
Author(s):  
GJ Ruiz-Arguelles ◽  
JA Katzmann ◽  
PR Greipp ◽  
NJ Gonchoroff ◽  
JP Garton ◽  
...  

The bone marrow and peripheral blood of 14 patients with multiple myeloma were studied with murine monoclonal antibodies that identify antigens on plasma cells (R1–3 and OKT10). Peripheral blood lymphocytes expressing plasma cell antigens were found in six cases. Five of these cases expressed the same antigens that were present on the plasma cells in the bone marrow. Patients that showed such peripheral blood involvement were found to have a larger tumor burden and higher bone marrow plasma cell proliferative activity. In some patients, antigens normally found at earlier stages of B cell differentiation (B1, B2, and J5) were expressed by peripheral blood lymphocytes and/or bone marrow plasma cells.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 4-5
Author(s):  
Lijun Yao ◽  
Reyka G Jayasinghe ◽  
Tianjiao Wang ◽  
Julie O'Neal ◽  
Ruiyang Liu ◽  
...  

Multiple myeloma (MM) is a hematological cancer of the antibody-secreting plasma cells. Despite therapeutic advancements, MM remains incurable due to high incidence of drug-resistant relapse. In recent years, targeted immunotherapies, which take advantage of the immune system's cytotoxic defenses to specifically eliminate tumor cells expressing certain cell surface and intracellular proteins have shown promise in combating this and other B cell hematologic malignancies. A major limitation in the development of these therapies lies in the discovery of optimal candidate targets, which require both high expression in tumor cells as well as stringent tissue specificity. In an effort to identify potential myeloma-specific target antigens, we performed an unbiased search for genes with specific expression in plasma and/or B cells using single-cell RNA-sequencing (scRNAseq) of 53 bone marrow samples taken from 42 patients. By comparing &gt;40K plasma cells to &gt;97K immune cells across our cohort, we were able to identify a total of 181 plasma cell-associated genes, including 65 that encode cell-surface proteins and 116 encoding intracellular proteins. Of particular interest is that the plasma cells from each patient were shown to be transcriptionally distinct with unique sets of genes expressed defining each patient's malignant plasma cells. Using pathway enrichment analysis, we found significant overrepresentation of cellular processes related to B-Cell receptor (BCR) signaling, protein transport, and endoplasmic reticulum (ER) stress, involving genes such as DERL3, HERPUD1, PDIA4, PDIA6, RRBP1, SSR3, SSR4, TXNDC5, and UBE2J1. To note, our strategy successfully captured several of the most promising MM therapeutic targets currently under pre-clinical and clinical trials, including TNFRSF17(BCMA), SLAMF7, and SDC1 (CD138). Among these, TNFRSF17 showed very high plasma cell expression, with concomitant sharp exclusion of other immune cell types. To ascertain tissue specificity of candidate genes outside of the bone marrow, we analyzed gene and protein expression data from the Genotype-Tissue Expression (GTEx) portal and Human Protein Atlas (HPA). We found further support for several candidates (incl. TNFRSF17,SLAMF7, TNFRSF13B (TACI), and TNFRSF13C) as being both exclusively and highly expressed in lymphoid tissues. While several surface candidates were not found to be lymphocyte-restricted at the protein level, they remain relevant considerations as secondary targets for bi-specific immunotherapy approaches currently under development. To further investigate potential combinatorial targeting, we examine sample-level patterns of candidate co-expression and mutually-exclusive expression using correlation analysis. As the majority of our detected plasma cell-specific genes encode intracellular proteins, we investigated the potential utility of these epitopes as therapeutic targets via MHC presentation. Highly expressed candidates include MZB1, SEC11C, HLA-DOB, POU2AF1, and EAF2. We analyzed protein sequences using NetMHC and NETMHCII to predict high-affinity peptides for common class-I and class-II HLA alleles. To correlate MHC allelic preference with candidate expression in our cohort, we performed HLA-typing for 29 samples using Optitype. To support our scRNAseq-driven findings, we cross-referenced gene expression data with 907 bulk RNA-sequencing samples, including 15 from internal studies and 892 from the Multiple Myeloma Research Foundation (MMRF), as well as bulk global proteomics data from 4 MM cell lines (TIB.U266, RPMI8226, OPM2, MM1ST) and 4 patients. We see consistent trends across both cohorts, with high positive correlation (Pearson R ranging between 0.60 and 0.99) for a majority of genes when comparing scRNA and bulk RNA expression in the same samples. Our experimental design and analysis strategies enabled the efficient discovery of myeloma-associated therapeutic target candidates. In conclusion, this study identified a set of promising myeloma CAR-T targets, providing novel treatment options for myeloma patients. Disclosures Goldsmith: Wugen Inc.: Consultancy. DiPersio:Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
1948 ◽  
Vol 3 (9) ◽  
pp. 987-1018 ◽  
Author(s):  
EDWIN D. BAYRD

Abstract Generalizing, it can be said that the pathologic cells seen in smears of the bone marrow in multiple myeloma resemble the plasma cell and vary from the very anaplastic and immature cell to the well-differentiated and almost characteristic plasma cell. The feature which the "myeloma" cell shares with the plasma cell is the abundant, granular, basophilic cytoplasm which tends to be fragile and undergo the same degenerative changes in each; namely, the formation of Russell bodies and vacuolization. Fairly frequently a perinuclear clear area or Hof is present and the nucleus tends to be eccentrically placed. Cytoplasmic extensions or pseudopodia may also be seen in either case, but they occur more often and more dramatically in instances of multiple myeloma. Multinucleated cells are commonly seen. In addition, myeloma-plasma cells will often have a large clear nucleolus and a leptochromatic nucleus and will exhibit a tendency to the formation of isolated areas of condensed chromatin. Cytoplasmic extrusions, free cytoplasmic bodies, occasionally complete with Russell bodies and vacuoles are almost universally present. All cases were of the plasma cell type; there was no exception. In these cases, the myeloma-plasma cell constituted from 2.5 to 96 per cent of the leukocytic elements present. The opinion was expressed that all so-called types of multiple myeloma are merely variations in differentiation of this same cell. It was noted that anaplasia, hypernucleation and lack of plasma cell predominance in certain cases were diagnostic pitfalls. Additional evidence was adduced to confirm the reticulo-endothelial origin of the myeloma-plasma cell. It was further observed that certain prognostically valuable information could be gleaned from a careful review of the cytologic characteristics in these cases.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5602-5602
Author(s):  
Divya Akella ◽  
Fnu Aparna ◽  
Marijeta Pekez ◽  
Nirmala S. Nathan ◽  
Hemchand Ramberan ◽  
...  

Abstract Background: Multiple myeloma is a neoplastic proliferation of plasma cells producing a monoclonal immunoglobulin usually restricted to the bone marrow. Recent literature confirms increased extramedullary involvement of skin, liver and lymph nodes but gastrointestinal multiple myelomas remain rare. Case: We report a case of 57-year-old female with a past medical history of progressive multiple myeloma IgA lambda on elotuzumab, lenalidomide and dexamethasone therapy, who presented with generalized weakness and black stools for approximately one week. Initial laboratory work demonstrated a hemoglobin of 6.7 grams per deciliter and heme positive stools consistent with anemia secondary to presumed gastrointestinal blood losses. Esophagogastroduodenoscopy (EGD) was unremarkable. Colonoscopy revealed 6 colonic polyps scattered throughout the distal transverse, cecal and descending colon which were excised and sent for pathology. Pathology of the polyps showed plasma cell myeloma with anaplastic features. Immunohistochemistry demonstrated cells that were positive for CD-138 and negative for keratin staining, confirming plasma cell origin. Furthermore analysis was positive for lambda light chain, but negative for kappa light chain. The patient was managed with packed red cell transfusion with no further evidence of recurrent bleeding. Conclusion: Gastrointestinal multiple myeloma are rare, but as our case demonstrates, they must be considered in the differential diagnosis of patients with gastrointestinal bleeding, particularly those with multiple myeloma. The endoscopic appearance of multiple myeloma polyps may be similar to other more common conditions, making pathological and immunohistochemical analysis of biopsies essential for making a correct diagnosis. Disclosures No relevant conflicts of interest to declare.


1993 ◽  
Vol 178 (3) ◽  
pp. 1023-1031 ◽  
Author(s):  
D Billadeau ◽  
G Ahmann ◽  
P Greipp ◽  
B Van Ness

One of the distinguishing features of multiple myeloma (MM) is the proliferation of a clonal plasma cell population in the bone marrow (BM). It is of particular interest that the tumor plasma cells appear to be restricted to the microenvironment of the BM and are rarely detected in the peripheral system, yet the disease is found widely disseminated throughout the axial skeleton. Furthermore, isolation of MM tumor cell lines has proven to be quite problematic due to their slow growth rate. These observations have instigated the search for earlier cells in the B cell lineage that are clonally related to the plasma cell tumor and that may represent the growth fraction of the tumor. We used allele-specific oligonucleotides (ASO) derived from the third complementarity determining region of the rearranged tumor immunoglobulin heavy chain gene to detect isotypes clonally related to the plasma cell tumor. By reverse transcribing RNA from the BM with a panel of CH primers (mu, delta, alpha, and gamma), followed by ASO-polymerase chain reaction amplification, we demonstrate the existence of preswitch isotype species that are clonally related to the myeloma tumor. Furthermore, we show that separation of the BM cells into CD45+ and CD38+ cell populations results in a lineage-specific expression of the clonally related RNA molecules, with the C mu and C delta in the CD45+, and C gamma in the CD38+ population. Interestingly, clonally related C alpha transcripts are also derived from the CD45+ fraction. These results confirm the presence of B cell populations clonally related to the plasma cell tumor and are consistent with models that propose the existence of myeloma precursors.


Sign in / Sign up

Export Citation Format

Share Document