Circulating monoclonal B lymphocytes in multiple myeloma

Peripheral blood mononuclear cells from 28 patients with multiple myeloma (MM) and nine patients with monoclonal gammopathy of unknown significance (MGUS) were studied by immunoglobulin gene analysis. Clonal immunoglobulin gene rearrangements in peripheral blood mononuclear cells (PBIGRA) were demonstrated in 10 of the 28 MM patients (36%). Bone marrow and peripheral blood mononuclear cells were studied simultaneously in five of these 10 patients, and identical gene rearrangements were demonstrated in both. The incidence of such gene arrangements was higher in patients with active disease (cases at presentation or relapsed = 10/19 [47%]) compared to remission status (0/9) and higher in untreated (47%) compared to treated patients (11%) (P less than 0.05). Patients with this phenomenon had higher serum calcium levels (P less than 0.001), and higher bone marrow plasma cell counts (P less than 0.05). Serum creatinine and beta 2-microglobulin were also higher but did not reach statistical significance. None of the patients with monoclonal gammopathy of uncertain significance had gene arrangements. Our findings confirm that circulating B lymphocytes are part of the malignant clone in MM and their presence correlates with high tumour volume.     

Circulating clonotypic B cells in multiple myeloma and monoclonal gammopathy of undetermined significance

The B-cell compartment in which multiple myeloma stem cells reside remains unclear. We investigated the potential presence of mature, surface-membrane immunoglobulin-positive B lymphocytes clonally related to the tumor bone marrow plasma cells among different subsets of peripheral blood B cells from ten patients (7 with multiple myeloma and 3 with monoclonal gammopathies of undetermined significance). The presence of clonotypic immunoglobulin heavy chain gene rearrangements was determined in multiple highly-purified fractions of peripheral blood B-lymphocytes including surface-membrane IgM⁺ CD27⁻ naïve B-lymphocytes, plus surface-membrane IgG⁺, IgA⁺ and IgM⁺ memory CD27⁺ B cells, and normal circulating plasma cells, in addition to (mono)clonal plasma cells, by a highly-specific and sensitive allele-specific oligonucleotide polymerase chain reaction directed to the CDR3 sequence of the rearranged IGH gene of tumor plasma cells from individual patients. Our results showed systematic absence of clonotypic rearrangements in all the different B-cell subsets analyzed, including M-component isotype-matched memory B-lymphocytes, at frequencies <0.03 cells/μL (range: 0.0003–0.08 cells/μL); the only exception were the myeloma plasma cells detected and purified from the peripheral blood of four of the seven myeloma patients. These results indicate that circulating B cells from patients with multiple myeloma and monoclonal gammopathies of undetermined significance are usually devoid of clonotypic B cells while the presence of immunophenotypically aberrant myeloma plasma cells in peripheral blood of myeloma patients is a relatively frequent finding.     

Circulating plasma cells in multiple myeloma: characterization and correlation with disease stage

The aim of this study was to develop a flow cytometric test to quantitate low levels of circulating myeloma plasma cells, and to determine the relationship of these cells with disease stage. Cells were characterized using five-parameter flow cytometric analysis with a panel of antibodies, and results were evaluated by comparison with fluorescent consensus-primer IgH-PCR.
Bone marrow myeloma plasma cells, defined by high CD38 and Syndecan-1 expression, did not express CD10, 23, 30, 34 or 45RO, and demonstrated weak expression of CD37 and CD45. 65% of patients had CD19⁻56⁺ plasma cells, 30% CD19⁻56^low, and 5% CD19⁺56⁺, and these two antigens discriminated myeloma from normal plasma cells, which were all CD19⁺56^low.
Peripheral blood myeloma plasma cells had the same composite phenotype, but expressed significantly lower levels of CD56 and Syndecan-1, and were detected in 75% (38/51) of patients at presentation, 92% (11/12) of patients in relapse, and 40% (4/10) of stem cell harvests. Circulating plasma cells were not detectable in patients in CR ( n =9) or normals ( n =10), at a sensitivity of up to 1 in 10 000 cells. There was good correlation between the flow cytometric test and IgH-PCR results: myeloma plasma cells were detectable by flow cytometry in all PCR positive samples, and samples with no detectable myeloma plasma cells were PCR negative. Absolute numbers decreased in patients responding to treatment, remained elevated in patients with refractory disease, and increased in patients undergoing relapse. We conclude that flow cytometry can provide an effective aternative to IgH-PCR that will allow quantitative assessment of low levels of residual disease.     

Spontaneous monoclonal immunoglobulin-secreting peripheral blood mononuclear cells as a marker of disease severity in multiple myeloma

Peripheral blood from patients with multiple myeloma (MM) contains a small number of plasma cells related to the bone marrow tumour cells by their cytoplasmic immunoglobulin (Ig), their cell membrane antigen expression and/or their gene rearrangements, but hitherto the monoclonal Ig (M-Ig) production by circulating cells has not been reported. Using a two-colour ELISPOT assay, Ig-secreting cells (Ig-SCs) were detected in the blood of 28 MM and five Waldenstrom's macroglobulinaemia (WM) patients. The number of cells that spontaneously produced an Ig isotype similar to that of the M-Ig in serum was greater than that of the other Ig-SCs. MM patients presented an excess of circulating heavy-chain (alpha or gamma) Ig-SCs (0.38% of the PBMC) with kappa or lambda light chains (0.48%) compared with the number of cells secreting the other heavy- (0.02%) and light-chain isotypes (0.03%). WM patients also presented high numbers of cells secreting the mu-heavy-chain isotype (0.66%). The Ig synthesized in vitro was characterized as monoclonal, and the M-Ig secretory capacity of the peripheral blood cells was similar to that observed for Ig-SCs from polyclonal activated B cells in vivo. The number of these monoclonal cells was significantly increased in patients in an advanced stage of MM (I/II vs. III, P < 0.001) and correlated with the serum beta-2 microglobulin concentration (r = 0. 69; P < 0.0003). The number of M-Ig-SCs in MM patients could be a useful marker for evaluating the progression of multiple myeloma.     

Circulating endothelial progenitor cells in multiple myeloma: implications and significance

Angiogenesis governs the progression of multiple myeloma (MM). Circulating endothelial cells (CECs) contribute to angiogenesis and comprise mature ECs and endothelial progenitor cells (EPCs). The present study sought to characterize CECs and their relation to disease activity and therapeutic response in 31 consecutive patients with MM. CECs, identified as CD34(+)/CD146(+)/CD105(+)/CD11b(-) cells, were 6-fold higher in patients compared to controls and correlated positively with serum M protein and beta(2)-microglobulin. Circulating EPCs displayed late colony formation/outgrowth and capillary-like network formation on matrigel; these processes were inhibited after effective thalidomide treatment. Co-expression of vascular endothelial growth factor receptor-2 (KDR) and CD133 characterized EPCs in MM, and KDR mRNA elevations correlated with M protein levels. In vitro exposure of ECs to thalidomide or its derivative CC-5013 inhibited gene expression of the receptors for transforming growth factor-beta and thrombin. Thus, elevated levels of CECs and EPCs covary with disease activity and response to thalidomide, underscoring the angiogenic aspect of MM and suggesting that angioblastlike EPCs are a pathogenic biomarker and a rational treatment target in MM. The results also highlight the anti-angiogenic properties of thalidomide and CC-5013 and further elucidate possible mechanisms of their effectiveness against MM. (Blood. 2005;105:3286-3294).     

Contamination of peripheral blood by monoclonal B cells following treatment of multiple myeloma by high-dose chemotherapy

Summary Peripheral blood samples obtained from five patients with multiple myeloma, after high-dose chemotherapy, were studied for monoclonal B plasma cell contamination. We used the technique of immunoglobulin heavy chain gene 'fingerprinting' at the time of diagnosis and during apheresis. The level of sensitivity of this technique is between 041% and 0.001% in two patients in whom a monoclonal population was detected in peripheral blood.     

Expression of multiple β1 integrins on circulating monoclonal B cells in patients with multiple myeloma

We have previously reported the presence of monoclonal, tumor-related B lineage cells in the blood of myeloma patients. The cells are continuously differentiating, and the majority are at a very late stage of B cell differentiation into plasma cells, consistent with the hypothesis that they comprise a precursor cell subset responsible for disseminating and possibly for relapse of the disease. The pattern of β1 integrin expression on monoclonal B lineage cells from blood and bone marrow of myeloma patients was evaluated using multiparameter flow cytometry in comparison to normal blood or tissue B cells and malignant B cells from B-CLL, B lymphoma, or plasma cell leukemia. The α4 and β1 chains were found on the majority of normal B cells, usually with a higher expression of α4 compared to β1. α5 was detectable at low density on B cells from lymph node, bone marrow, and lamina propria. The α2 and α6 chains are absent on B cells localized in normal lymphoid tissues as well as on normal blood B cells and in vitro activated B cells. In myeloma, the blood B cells express α2, α5 and α6, suggesting important functional differences between these tumor-related B cells and their normal counterparts. The plasma cells located in myeloma bone marrow express no α2, and almost no α6, although they have variable expression of α4, α5, and β1. Thus the end-stage plasma cells appear to lack receptors that would support a propensity for invasion of basement membranes and exit to extravascular spaces. In contrast, the circulating plasmablasts in a patient with plasma cell leukemia make up a large subset of early plasma cells expressing all integrin receptors analyzed, including α2 and α6. Malignant cells from B-CLL and B lymphoma express only the α4 and β integrins, and some B-CLL have very low levels of α3, but no α2, α5, or α6, suggesting that they may be limited to the vascular spaces and do not extravasate, at least for the stages of disease analyzed here. Our results are therefore consistent with a working hypothesis that invasive capacity in myeloma is to be found within the abnormal monoclonal B cells in peripheral blood, which alone among B cells or plasma cells, and like plasma cell leukemia, express multiple β1 integrins, including the α2 and α6 integrin receptors, necessary for cellular translocation across the endothelial basement membranes and into extravascular spaces. This study raises the possibility that expression of, in particular, the α2 and α6 integrins may underlie the invasiveness of these diseases and offers a new perspective for future avenues of clinical intervention.     

Incidence of monoclonal B-cell disease in siblings of patients with multiple myeloma

We observed clustering of monoclonal B-cell disease in siblings being screened as allogeneic donors for patients with multiple myeloma (MM) scheduled for stem cell transplantation (SCT). Of 134 asymptomatic donors, the incidence of monoclonal B-cell disease was 8/84 in siblings and 1/50 in matched unrelated donors. From an analysis of five MM families scheduled for allogeneic SCT, monoclonal B-cell disease was detected in 8/27 siblings.     

The relationship between monoclonal myeloma precursor B cells in the peripheral blood stem cell harvests and the clinical response of multiple myeloma patients

The aim of this study was to determine the presence of monoclonal myeloma precursor B cells in peripheral blood stem cell harvests and to investigate their role in the clinical outcome of multiple myeloma patients. A total of 39 multiple myeloma patients were treated with a sequential therapy including double high-dose melphalan therapy followed by a double transplant procedure. The apheresis products for the second transplant were purged using a panel of four or five different mouse monoclonal antibodies against B-cell antigens (CD10, CD19, CD20, CD22 and CD37). In 19/39 patients a tumour-specific CDR III signal was identified in the diagnostic bone marrow. Gene scan analysis after CDR III PCR of the magnetic bead isolated B-cell fraction from the apheresis products in these 19 patients revealed three different patterns: 32% of patients had a predominantly monoclonal B-cell population; 63% of patients had an identifiable monoclonal signal within an oligoclonal B-cell population. In only 1/19 patients were no monoclonal B cells identified in the B-cell population of the apheresis product. A correlation between the clonal pattern and the clinical response after sequential chemotherapy was found. Patients with a predominance of monoclonal myeloma or myeloma precursor B cells had an early relapse or achieved a minimal response or a partial remission. Patients with an oligo- and/or polyclonal pattern achieved a high percentage of partial as well as complete remissions.     

P53 deletion may drive the clinical evolution and treatment response in multiple myeloma

We report a patient with multiple myeloma presenting with a paraspinal plasmacytoma with a marked dissociation between the response obtained in bone marrow (BM) infiltration and that achieved in soft tissue masses. While a complete remission was reached and maintained in BM, extramedullary plasmacytomas were refractory to every line of treatment. Genetic analysis identified the presence of t(4;14) and RB deletion in myeloma cells of both origins. However, a P53 deletion was only detected in plasma cells from extramedullary plasmacytomas. This finding suggests that P53 deletion has a role in the lack of treatment response of extramedullary plasmacytomas.     

Idiotype‐pulsed antigen presenting cells following autologous transplantation for multiple myeloma may be associated with prolonged survival

Vaccines are attractive as consolidation therapy after autologous stem cell transplantation (ASCT) for multiple myeloma (MM). We report the results of a phase II trial of the immunotherapeutic, APC8020 (Mylovenge?), given after ASCT for MM. We compared the results with that of other patients with MM who underwent ASCT at Mayo Clinic during the same time period. Twenty‐seven patients were enrolled on the trial between July, 1998 and June, 2001, and the outcomes were compared to that of 124 consecutive patients transplanted during the same period, but not enrolled on the trial. The median (range) follow‐up for patients still alive from the vaccine trial is 6.5 (2.9–8 years), and 7.1 (6–8 years) in the control group. The median age was 57.4 range (36.1–71.3) in the DB group and 56.4 (range, 30–69) in the trial group. Known prognostic factors including PCLI, B2M, and CRP were comparable between the groups. The median overall survival for the trial patients was 5.3 years (95% CI: 4.0 years—N/A) compared to 3.4 years (95% CI: 2.7–4.6 years) for the DB group (P = 0.02). The median time to progression and progression‐free survival for the trial group was similar to the DB group. Although not a controlled trial, the vaccines given after ASCT appear to be associated with improved overall survival compared to historical controls. This approach warrants further investigation to confirm this and define the role of vaccine therapy in myeloma. Am. J. Hematol. 2009. © 2009 Wiley‐Liss, Inc.     

Severe acute cholestatic hepatitis by infiltration of monoclonal plasma cells in multiple myeloma

BACKGROUND: Plasma cell infiltration of the liver can be detected in 25 to 40% of patients with multiple myeloma. However, there are only rare cases of multiple myeloma clinically presenting as acute liver disease. CASE REPORT: We report an 88-year-old woman with painless jaundice and abnormal liver function tests, resembling acute cholestatic hepatitis. Viral hepatitis as well as autoimmune hepatitis could be excluded. Liver biopsy revealed a diffuse portal and sinusoidal infiltration of plasma cells with lambda light chain restriction. Serological immune fixation disclosed monoclonal gammopathy of IgG lambda with bone marrow infiltration of 25% plasma cells. After administration of 60 mg prednisolone per day, the elevated liver enzymes declined considerably. CONCLUSION: Hepatic plasma cell infiltration of multiple myeloma can, in rare cases, manifest as acute cholestatic hepatitis, which may respond to treatment with corticosteroids.     

Mass spectrometry methods for detecting monoclonal immunoglobulins in multiple myeloma minimal residual disease

Mass spectrometry methods that can detect low levels of monoclonal immunoglobulin in serum have recently been developed. These assays are based on the principle that each immunoglobulin has a unique amino acid sequence and therefore, has a unique mass. This mass can be used as a surrogate marker in order to monitor a patient’s disease over time and at low levels. Here, we explain these methods, discuss their advantages and disadvantages and how they may be used to monitor monoclonal immunoglobulins for minimal residual disease detection in multiple myeloma.     

Circulating clonal lymphocytes in myeloma constitute a minor subpopulation of B cells [see comments]

The mononuclear cells in the blood of myeloma patients have been reported to contain a high proportion of phenotypically abnormal myeloma B lymphocytes. These cells have been proposed to constitute the drug-resistant proliferative myeloma cell compartment. To determine the extent of B lymphocyte involvement, the proportion of clonotypic cells among the CD19-expressing cells from myeloma patients was estimated by quantitative polymerase chain reaction analysis of the third complementarity determining region (CDR3). The results indicate that the B lymphocytes constitute, on average, 6% of blood mononuclear cells, and that only a minor fraction of these are clonally related to the myeloma cells. While the small number of circulating clonal cells is not incompatible with their proposed role as a reservoir of proliferating myeloma progenitors, the majority of the B cells appear not to be clonally related to the myeloma cells.     

Idiotype vaccination in multiple myeloma induced a reduction of circulating clonal tumor B cells

Myeloma cells express the idiotype (Id)-specific antigen that may be targeted by Id vaccination. Six patients with stage I IgG myeloma were immunized with the autologous purified M component together with the adjuvant cytokines interleukin 12 (IL-12) alone or in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF). The effect of Id vaccination on circulating clonal tumor B cells was monitored by a real-time allele-specific oligonucleotide polymerase chain reaction method. No other treatment was given. Reduction of blood tumor mass was observed in 4 of 6 patients, with one patient achieving a complete molecular remission in blood. In 3 of these 4 patients an Id-specific T-cell response was induced. In the remaining 2 patients with an unchanged level of blood tumor cells, one patient mounted a T-cell response, whereas the other did not. No significant change in the serum M protein level was noted. Id vaccination may target clonal B cells, suggesting that this strategy might be conducive to achieving tumor control. The clinical significance of these findings remains to be established.     

Intranuclear inclusions in myeloma cells in a case of nonsecretory multiple myeloma

Inclusions in the nucleus, compared with those in the cytoplasm, are rare in myeloma cells but have been reported in all electrophoretic varieties of multiple myeloma except the nonsecretory type. In this unusual case, a 54 year old Chinese woman had a pathological fracture of the left femur, and biopsy of the fracture site revealed a round cell tumor compatible with plasmacytoma. A bone marrow aspirate revealed 50% plasma cells, many of which contained intranuclear inclusions. Protein electrophoresis was normal with no paraprotein, and urine was free from Bence-Jones protein. Under electron microscopy, the plasma cells showed electron-dense spherules not circumscribed by a membrane. The absence of a membrane was unusual, because according to all reported cases, these intranuclear inclusions were invariably membrane-bound. The association of nonsecretion of paraprotein in myeloma, which is rare, and the absence of a membrane enclosing the intranuclear inclusions, which is heretofore unreported, is probably not coincidental but causally related in that paraprotein produced in the nucleus of myeloma cells (stored in the form of intranuclear inclusions) fails to be detected in serum and urine because of noninteraction between these inclusions and the membranes of the nucleus and endoplasmic reticulum.     

Myelodysplasia in childhood may be a polyclonal disease

Myelodysplasia in childhood can be associated with constitutional abnormalities. Two main situations can be observed: constitutional diseases such as Down’s Syndrome may be the first step of a malignant stem cell transformation leading to monoclonal hematopoiesis. However, in other situations such as mitochondrial cytopathies or other polymalformative syndromes, myelodysplasia may simply be the hematological expression of a multi-tissue constitutional disease. In such cases, the bone marrow karyotype is usually found to be normal and, in affected females, clonality studies show a polyclonal pattern. Clonality assessment should be, when possible, a mandatory step before any major therapeutic decision during the course of childhood myelodysplasia.     

Detection of monoclonal B lymphocytes in multiple myeloma by immunofluorescence tests of surface immunoglobulins.

Peripheral blood lymphocytes of 16 patients with secretory type of multiple myeloma and 5 with nonmyelomatous monoclonal gammopathy were investigated for the surface immunoglobulins on the cell by immunofluorescence. A low pH shock of cells before staining was applied to dissociate the passively absorbed immunoglobulins present on the cell surface. Increases of B lymphocytes bearing surface immunoglobulins which have the same light chains as those of monoclonal immunoglobulins produced by the plasma cells were found in 5 of 11 common secretory myeloma patients and in all of 6 Bence-Jones myeloma patients. Ratios of cells bearing light chains of kappa- and lambda-types (kappa/lambda) appeared abnormal in almost all with an exception of only 3 cases of myeloma patients, even in the cases where the number of Ig bearing cells did not increase. Increases of possible monoclonal B cells bearing IgG, in addition to IgA cells, were observed in some patients with IgA myeloma. Increases of B cells bearing certain heavy chains were also observed in all 5 patients with Bence-Jones myeloma during the course of disease. No abnormalities of B cells bearing surface immunoglobulin were found in nonmyelomatous monoclonal gammopathy. These results suggest that proliferation of monoclonal B lymphocytes, which may be progenitors to the malignant plasma cells, occurs in a majority of myeloma patients, but not in nonmyelomatous monoclonal gammopathy.     

Myelodysplasia in childhood may be a polyclonal disease

Myelodysplasia in childhood can be associated with constitutional abnormalities. Two main situations can be observed: constitutional diseases such as Downs Syndrome may be the first step of a malignant stem cell transformation leading to monoclonal hematopoiesis. However, in other situations such as mitochondrial cytopathies or other polymalformative syndromes, myelodysplasia may simply be the hematological expression of a multi-tissue constitutional disease. In such cases, the bone marrow karyotype is usually found to be normal and, in affected females, clonality studies show a polyclonal pattern. Clonality assessment should be, when possible, a mandatory step before any major therapeutic decision during the course of childhood myelodysplasia.