Cytoplasmic immunoglobulin content in multiple myeloma

Clinical Presentation and Gene Expression Profiling of Immunoglobulin M Multiple Myeloma Compared With Other Myeloma Subtypes and Waldenström Macroglobulinemia

PURPOSE

Multiple myeloma (MM) is a clonal bone marrow disease characterized by the neoplastic transformation of differentiated postgerminal B cells. It is a heterogeneous disease both at the genetic level and in terms of clinical outcome. Immunoglobulin M (IgM) MM is a rare subtype of myeloma. Similar to Waldenström macroglobulinemia (WM), patients with MM experience IgM monoclonal gammopathy; however, both diseases are distinct in terms of treatment and clinical behavior.

MATERIALS AND METHODS

To shed light on the presentation of IgM MM, its prognosis, and its gene expression profiling, we identified and characterized 21 patients with IgM MM from our database.

RESULTS

One of these patients presented with a rare IgM monoclonal gammopathy of undetermined significance that progressed to smoldering myeloma. The median survival of the 21 patients was 4.9 years, which was comparable to a matched group of patients with non-IgM MM with similar myeloma prognostic factors (age, gender, albumin, creatinine, anemia, lactate dehydrogenase, β₂-microglobulin, cytogenetics abnormalities), but much less than the median survival reported for patients with WM (9 years). We identified a cluster of genes that differ in their expression profile between MM and WM and found that the patients with IgM MM displayed a gene expression profile most similar to patients with non-IgM MM, confirming that IgM MM is a subtype of MM that should be differentiated from WM.

CONCLUSION

Because the prognosis of IgM MM and WM differ significantly, an accurate diagnosis is essential. Our gene expression model can assist with the differential diagnosis in controversial cases.

Cytoplasmic Immunoglobulin Vs. DNA Analysis by Flow Cytometry

Cytoplasmic immunoglobulin (CIg) vs DNA by flow cytometric (FCM) method allows us to detect DNA content of the neoplastic plasma cells with monotypic cytoplasmic immunoglobulin and also provide us with clear distinction from normal polytypic plasma cells. Abnormalities in cellular DNA content (DNA aneuploidy) and cell cycle determination (proliferative activity) can be measured rapidly by flow cytometry. FCM can measure gross differences in DNA content and distinguish a cell population with normal DNA content, or diploid from a cell population with an abnormal or aneuploid DNA content. With the dual parameter procedure a monoclonal plasma cell population can be identified down to less than 0.1-0.05% of all cells.

Biphenotypic plasma cell myeloma: two cases of plasma cell neoplasm with a coexpression of kappa and lambda light chains

Plasma cell neoplasm (PCM) is a medullary and extra medullary proliferation of clonal plasma cells that occurs due to accidental translocation of proto-oncogenes into immunoglobulin (Ig) gene loci. While the majority of plasma cell neoplasms are monoclonal, up to 2% of the PCMs [1] considered being biclonal based on electrophoretic analysis, characterized by secretion of paraprotein with two distinct heavy chains or light chains are possible and present unique diagnostic challenges.

METHODS

Traditionally protein electrophoresis has been used to diagnose, characterize, and monitor progression of plasma cell neoplasm. To characterize neoplastic plasma cells, in our institution, other ancillary studies, including in situ hybridization, flow cytometric analyses of plasma cell surface markers and cytoplasmic immunoglobulins with DNA ploidy, are also utilized routinely.

RESULTS

We present two cases of plasma cell myeloma in which the neoplastic plasma cells shows production of cytoplasmic kappa and lambda light chain, with secretion of free lambda light chain only. Co-expression of kappa and lambda light chain by the same neoplastic plasma cells is a rare but reported phenomenon.

CONCLUSIONS

Our study indicates that serum electrophoresis alone could mischaracterize biphenotypic myeloma as monotypic plasma cell myelomas in the absence of additional testing methods.

The flow cytometry-defined light chain cytoplasmic immunoglobulin index and an associated 12-gene expression signature are independent prognostic factors in multiple myeloma

As part of Total Therapy (TT) 3b, baseline marrow aspirates were subjected to two-color flow cytometry of nuclear DNA content and cytoplasmic immunoglobulin (DNA/CIG) as well as plasma cell gene expression profiling (GEP). DNA/CIG-derived parameters, GEP and standard clinical variables were examined for their effects on overall survival (OS) and progression-free survival (PFS). Among DNA/CIG parameters, the percentage of the light chain-restricted (LCR) cells and their cytoplasmic immunoglobulin index (CIg) were linked to poor outcome. In the absence of GEP data, low CIg <2.8, albumin <3.5 g/dl and age ⩾65 years were significantly associated with inferior OS and PFS. When GEP information was included, low CIg survived the model along with GEP70-defined high risk and low albumin. Low CIg was linked to beta-2-microglobulin >5.5 mg/l, a percentage of LCR cells exceeding 50%, C-reactive protein ⩾8 mg/l and GEP-derived high centrosome index. Further analysis revealed an association of low CIg with 12 gene probes implicated in cell cycle regulation, differentiation and drug transportation from which a risk score was developed in TT3b that held prognostic significance also in TT3a, TT2 and HOVON trials, thus validating its general applicability. Low CIg is a powerful new prognostic variable and has identified potentially drug-able targets.

Simplified flow cytometric immunophenotyping panel for multiple myeloma, CD56/CD19/CD138(CD38)/CD45, to differentiate neoplastic myeloma cells from reactive plasma cells

Background

Flow cytometric immunophenotyping has been used to identify neoplastic plasma cell populations in patients with multiple myeloma (MM). Previous reports have described the use of several antigens, including CD38, CD138, CD56, CD117, CD52, CD19 and CD45, to distinguish distinct populations of plasma cells. The aim of this study was to evaluate a simplified immunophenotyping panel for MM analysis.

Methods

A total of 70 patients were enrolled in the study, 62 of which were newly diagnosed with MM (untreated), whereas the remaining 8 were undergoing bone marrow assessment as part of follow-up after treatment (treated). Treated cases included 3 patients with relapse and 5 patients with persistence of MM. Multiparametric flow cytometric immunophenotyping was performed using monoclonal antibodies against CD56, CD19, CD138 (CD38), and CD45.

Results

In differential counts, plasma cells in bone marrow (BM) accounted for 3.6-93.2% of the total nucleated cell count. The positive expression rates of CD56, CD19, CD138, and CD45 in neoplastic myeloma cells were 83.9%, 0%, 98.4%, and 37.1%, respectively, among the 62 untreated cases, and 75.0%, 0%, 87.5%, and 37.5%, respectively, among the 8 treated cases. CD19 expression of neoplastic plasma cells was negative in both untreated and treated cases.

Conclusion

The simplified immunophenotyping panel, CD56/CD19/CD138(CD38)/CD45, is useful for distinguishing neoplastic myeloma cells from reactive plasma cells in clinical practice. In addition, CD19 represents the most valuable antigen for identifying neoplastic myeloma cells in patients with MM.

Total Therapy 3 for multiple myeloma: prognostic implications of cumulative dosing and premature discontinuation of VTD maintenance components, bortezomib, thalidomide, and dexamethasone, relevant to all phases of therapy

The impact of cumulative dosing and premature drug discontinuation (PMDD) of bortezomib (V), thalidomide (T), and dexamethasone (D) on overall survival (OS), event-free survival (EFS), time to next therapy, and post-relapse survival in Total Therapy 3 were examined, using time-dependent methodology, relevant to induction, peritransplantation, consolidation, and maintenance phases. Univariately, OS and EFS were longer in case higher doses were used of all agents during induction, consolidation (except T), and maintenance (except V and T). The favorable OS and EFS impact of D induction dosing provided the rationale for examining the expression of glucocorticoid receptor NR3C1, top-tertile levels of which significantly prolonged OS and EFS and rendered outcomes independent of D and T dosing, whereas T and D, but not V, dosing was critical to outcome improvement in the bottom-tertile NR3C1 setting. PMDD of V was an independent highly adverse feature for OS (hazard ratio = 6.44; P < .001), whereas PMDD of both T and D independently imparted shorter time to next therapy. The absence of adverse effects on postrelapse survival of dosing of any VTD components and indeed a benefit from V supports the use up-front of all active agents in a dose-dense and dose-intense fashion, as practiced in Total Therapy 3, toward maximizing myeloma survival.

Safety and efficacy assessment of plerixafor in patients with multiple myeloma proven or predicted to be poor mobilizers, including assessment of tumor cell mobilization

This was an open-label, single-center, phase II study of 20 patients with multiple myeloma who were either proven poor mobilizers (n=10; group A) or predicted poor mobilizers (n=10; group B) and were planned for autologous hematopoietic SCT. The aim was to assess the safety and efficacy of plerixafor for stem cell mobilization and tumor cell contamination. The peripheral blood (PB) CD34+ cell count was generally very low pre- plerixafor and increased significantly post-plerixafor administration. Cumulative apheresis yields of > or =2 x 10(6) CD34+ cells/kg were observed in 7 of 10 patients (group A) and 8 of 10 patients (group B). Among the proven poor mobilizers, there was no evidence of tumor cell mobilization in the PB after G-CSF plus plerixafor treatment. Seventeen of 20 (85%) patients underwent transplantation. Neutrophil engraftment occurred at a median of 13 days for all patients. Platelet engraftment occurred at a median of 16 days and 19 days for all proven and predicted poor mobilizers, respectively. At 12 months, 12 of 17 patients had documented durable grafts, 3 of 17 patients died and 2 of 17 patients were lost to follow-up; but they had documented graft durability at the previous 3- and 6-month visit. The safety profile of plerixafor in all patients was consistent with previous reports.

F18-fluorodeoxyglucose positron emission tomography in the context of other imaging techniques and prognostic factors in multiple myeloma

F18-fluorodeoxyglucose positron emission tomography (FDG-PET) is a powerful tool to investigate the role of tumor metabolic activity and its suppression by therapy for cancer survival. As part of Total Therapy 3 for newly diagnosed multiple myeloma, metastatic bone survey, magnetic resonance imaging, and FDG-PET scanning were evaluated in 239 untreated patients. All 3 imaging techniques showed correlations with prognostically relevant baseline parameters: the number of focal lesions (FLs), especially when FDG-avid by PET-computed tomography, was positively linked to high levels of beta-2-microglobulin, C-reactive protein, and lactate dehydrogenase; among gene expression profiling parameters, high-risk and proliferation-related parameters were positively and low-bone-disease molecular subtype inversely correlated with FL. The presence of more than 3 FDG-avid FLs, related to fundamental features of myeloma biology and genomics, was the leading independent parameter associated with inferior overall and event-free survival. Complete FDG suppression in FL before first transplantation conferred significantly better outcomes and was only opposed by gene expression profiling-defined high-risk status, which together accounted for approximately 50% of survival variability (R(2) test). Our results provide a rationale for testing the hypothesis that myeloma survival can be improved by altering treatment in patients in whom FDG suppression cannot be achieved after induction therapy.

VTD combination therapy with bortezomib-thalidomide-dexamethasone is highly effective in advanced and refractory multiple myeloma

Bortezomib (V) was combined with thalidomide (T) and dexamethasone (D) in a phase I/II trial to determine dose-limiting toxicities (DLT's) and clinical activity of the VTD regimen in 85 patients with advanced and refractory myeloma. The starting dose of V was 1.0 mg/m(2) (days 1, 4, 8, 11, every 21 day) with T added from cycle 2 at 50 mg/day, with 50 mg increments per 10 patient cohorts, to a maximum dose of 200 mg. In the absence of DLT's, the same reiteration of T dose increases was applied with a higher dose of V=1.3 mg/m(2). D was added with cycle 4 in the absence of partial response (PR). Ninety-two percent had prior autotransplants, 74% had prior T and 76% abnormal cytogenetics. MTD was reached at V=1.3 mg/m(2) and T=150 mg. Minor response (MR) was recorded in 79%, and 63% achieved PR including 22% who qualified for near-complete remission. At 4 years, 6% remain event-free and 23% alive. Both OS and EFS were significantly longer in the absence of prior T exposure and when at least MR status was attained. The MMSET/FGFR3 molecular subtype was prognostically favorable, a finding since reported for a VTD-incorporating tandem transplant trial (Total Therapy 3) for untreated patients with myeloma (BJH 2008).

Myeloma cells with asurophilic granules--an unusual morphological variant--case presentation

We present the case of an 80-year-old man who was admitted for anemia, back pain and progressive weakness. After a workup of clinical and laboratory data, the final diagnosis was multiple myeloma. The bone marrow aspirate revealed 53% myeloma cells with peculiar and rare morphological features: numerous large asurophilic--bright red granules--mucopolizaccharides and immunoglobulins secreted and accumulated in the endoplasmic reticulum, typically known as Russel bodies.

Suppression of abnormal karyotype predicts superior survival in multiple myeloma

Cytogenetic studies were performed as part of all diagnostic and surveillance bone marrow examinations in 956 newly diagnosed patients with multiple myeloma (MM) receiving total therapy (TT) protocols and in 1085 previously treated patients enrolled in non-TT protocols. In both groups, cytogenetic abnormalities (CA) were present in one-third at baseline and persisted in 14% prior to first and 10% prior to second transplant (TT, 5%; non-TT, 15%); post-transplant detection rates increased progressively with time, from 7% within 6 months to 21% within 24 months to 28% at relapse. According to multivariate analyses, overall survival was adversely affected by the presence of CA at baseline (hazard ratio (HR)=7.20, P<0.001) and the development of CA both prior to (HR=3.28, P<0.001) and after first transplant (HR=6.24, P<0.001), whereas suppression of CA pretransplant was favorable (HR=0.38, P<0.001). The presence of CA at relapse further distinguished patients with a short median post-relapse survival of only 11 versus 47 months in those without CA (P<0.0001). Post-relapse survival was independently adversely affected by the detection of CA both at baseline (HR=1.35, P=0.044) and relapse (HR=2.47, P<0.001). Collectively, these results underscore the importance of monitoring for CA and attest to the favorable prognostic consequences of CA suppression with effective therapy.

Investigative Tools for Diagnosis and Management

Recent advances in genomics and proteomics have advanced our understanding of myeloma pathogenesis, recognized novel mediators of disease process, and identified new therapeutic targets. These developments have provided newer diagnostic tools for myeloma, improved monitoring of the disease status and allowed for molecular classification of the disease. The recent advances in investigative techniques that have helped refine the diagnostic work up in myeloma includes use of serum free light chains, especially in oligosecretory myeloma, patients with renal disease and with amyloidosis; use of MRI and PET scan in diagnosis and managing bone disease; and use of cytogenetics and fluorescent in situ hybridization (FISH) technique to determine prognosis. Newer risk stratification protocols have included international staging systems as well as FISH-detected chromosomal changes, specifically t(4;14), t(14;16), and del 17p. These improved predictive risk stratification models are guiding treatment algorithms. As the novel therapies are able to attain complete responses in a significant number of patients, the response categories are also being redefined. Immunophenotypic identification of clonal plasma cells, inclusion of free light chain response and molecular markers of disease now allow us to define stringent complete responses. Recent studies show the increasing importance of attaining complete remission to extended overall survival. The ongoing oncogenomic studies including high-throughput expression profiling, high-density single nucleotide polymorphism (SNP)–arrays and array based comparative hybridization (aCGH) have been utilized to not only understand myeloma pathobiology, but for gene discovery, identification of biomarkers, and delineation of patient subgroups to incorporate them into therapeutic strategies and to eventually provide optimal individualized therapy.

Incorporating bortezomib into upfront treatment for multiple myeloma: early results of total therapy 3

Total therapy 3 incorporated bortezomib into a melphalan-based tandem transplant regimen for 303 newly diagnosed patients with myeloma. Induction chemotherapy prior to and consolidation chemotherapy after transplants each consisted of two cycles of VTD-PACE (bortezomib, thalidomide, dexamethasone and 4-d continuous infusions of cis-platin, doxorubicin, cyclophosphamide, etoposide); 3-year maintenance comprised monthly cycles of VTD in the first and TD in the remaining years. The median age was 59 years (age >64 years, 28%). A minimum of 20 x 10(6) CD34 cells/kg was collected in 87% of patients; 83% completed both transplants, and only 5% suffered a treatment-related death. At 24 months, 83% had achieved near-complete remission, which was sustained in 88% at 2 years from its onset. With a median follow-up of 20 months, 2-year estimates of event-free and overall survival were 84% and 86% respectively. The 44 patients who experienced an event more often had a high-risk gene array profile, cytogenetic abnormalities and indicators of high lactate dehydrogenase, beta-2-microglobulin, creatinine and International Staging System stage. Toxicities of grade > 2 included thrombo-embolic events in 27% and peripheral neuropathy in 12%. Results of this phase-2 study demonstrated that bortezomib could be safely combined with multi-agent chemotherapy, effecting near-complete remission status and 2-year survival rates in more than 80% of patients.

High serum-free light chain levels and their rapid reduction in response to therapy define an aggressive multiple myeloma subtype with poor prognosis

Serum-free light chain (SFLC) levels are useful for diagnosing nonsecretory myeloma and monitoring response in light-chain-only disease, especially in the presence of renal failure. As part of a tandem autotransplantation trial for newly diagnosed multiple myeloma, SFLC levels were measured at baseline, within 7 days of starting the first cycle, and before both the second induction cycle and the first transplantation. SFLC baseline levels higher than 75 mg/dL (top tertile) identified 33% of 301 patients with higher near-complete response rate (n-CR) to induction therapy (37% vs 20%, P = .002) yet inferior 24-month overall survival (OS: 76% vs 91%, P < .001) and event-free survival (EFS: 73% vs 90%, P < .001), retaining independent prognostic significance for both EFS (HR = 2.40, P = .008) and OS (HR = 2.43, P = .016). Baseline SFLC higher than 75 mg/dL was associated with light-chain-only secretion (P < .001), creatinine level 176.8 microM (2 mg/dL) or higher (P < .001), beta-2-microglobulin 297.5 nM/L (3.5 mg/L) or higher (P < .001), lactate dehydrogenase 190 U/L or higher (P < .001), and bone marrow plasmacytosis higher than 30% (P = .003). Additional independent adverse implications were conferred by top-tertile SFLC reductions before cycle 2 (OS: HR = 2.97, P = .003; EFS: HR = 2.56, P = .003) and before transplantation (OS: HR = 3.31, P = .001; EFS: HR = 2.65, P = .003). Unlike baseline and follow-up analyses of serum and urine M-proteins, high SFLC levels at baseline-reflecting more aggressive disease-and steeper reductions after therapy identified patients with inferior survival.

Diffuse pulmonary parenchymal involvement in multiple myeloma: antemortem diagnosis

Antemortem diagnosis of diffuse myelomatous pulmonary infiltrate is rare. We present one such case in which diagnosis was established from bronchoalveolar lavage (BAL) fluid demonstrating the presence of monoclonal plasma cells. The diffuse involvement of the lungs by myeloma was confirmed at autopsy. The possibility of myelomatous pulmonary infiltrates was suggested by the absence of fever or failure to respond to antibiotics but regression with myeloma treatment. Analysis of BAL fluid for the presence of plasma cells and for cytoplasmic immunoglobulin DNA provides a noninvasive means of establishing the diagnosis. Diffuse parenchymal lesions in the lung due to myeloma should be entertained as a differential of pulmonary infiltrates.

Malignant pleural effusion of multiple myeloma: prognostic factors and outcome

Malignant pleural effusion (MPE) in multiple myeloma (MM) is rare. Approximately 80 cases have been reported. To delineate optimal treatment and prognostic variables in these patients, we reviewed 11 MM patients with MPE. MPE developed at median of 12 months from diagnosis of MM. All the patients had high-risk disease based on complex karyotypic abnormalities including deletions of chromosome-13 (n=9), elevated beta-2 microglobulin (B2M) (n=9), high C-reactive protein (CRP) (n=8), high plasma cell labeling index (n=5) or high LDH (n=5). A significant increase in B2M, LDH, and CRP was observed at the onset of MPE. The initial diagnosis of MPE was based on positive cytology (n=9), pleural fluid cIg/DNA (n=9) or pleural fluid cytogenetics (n=4). Pleural tissue infiltration was found on pleural biopsy and autopsy in one patient each. Systemic chemotherapy comprising dexamethasone, cyclophosphamide, etoposide and cisplatin (DCEP) (n=7) and pleurodesis (n=7) were effective in resolving MPE but survival was short. High dose chemotherapy with peripheral blood stem cell support for MPE in six patients conferred no clear survival advantage. These patients died at median of four months from onset of MPE. Patients with bone marrow complex karyotypic abnormalities including deletion-13 (n=9) had a shorter (median--18 months) overall survival compared to patients with normal cytogenetics (median--38 months). MPE in patients with MM is often associated with high-risk disease including deletion 13 chromosomal abnormality and heralds a poor prognosis despite aggressive local and systemic treatment.

Thalidomide and hematopoietic-cell transplantation for multiple myeloma

BACKGROUND

High-dose therapy with melphalan can prolong survival among patients with multiple myeloma. We assessed whether the addition of thalidomide, which has activity against advanced and refractory myeloma, would further improve survival.

METHODS

Between October 1998 and February 2004, 668 patients with newly diagnosed multiple myeloma received two cycles of intensive melphalan-based chemotherapy, each supported by autologous hematopoietic stem-cell transplantation. A total of 323 were randomly assigned to receive thalidomide from the outset until disease progression or undue adverse effects, and 345 did not receive thalidomide. The primary end point was the five-year event-free survival rate. Secondary end points were complete response and overall survival.

RESULTS

After a median follow-up of 42 months among survivors, the thalidomide and control groups had rates of complete response of 62 percent and 43 percent, respectively (P<0.001), and five-year event-free survival rates of 56 percent and 44 percent (P=0.01). The five-year rate of overall survival was approximately 65 percent in both groups (P=0.90). Median survival after relapse was 1.1 years in the thalidomide group and 2.7 years in the control group (P=0.001). Severe peripheral neuropathy and deep-vein thrombosis occurred more frequently in the thalidomide group than in the control group.

CONCLUSIONS

When incorporated into high-dose therapy for myeloma, thalidomide increased the frequency of complete responses and extended event-free survival at the expense of added adverse effects without improving overall survival. (ClinicalTrials.gov number, NCT00083551.).

MDS-type abnormalities within myeloma signature karyotype (MM-MDS): only 13% 1-year survival despite tandem transplants

Cytogenetic abnormalities (CA), especially of chromosome 13, have been used to identify a subgroup of previously untreated multiple myeloma (MM) patients with very poor prognosis despite high-dose therapy (HDT). We examined the prognostic implications of CA in 1000 MM patients receiving melphalan-based tandem autotransplants (median follow-up, 5 years). Negative consequences for both overall survival (OS) and event-free survival (EFS) in the presence of any CA were confirmed, especially when detected within 3 months of HDT. In the context of standard prognostic factors (SPF), 'MM-MDS' (MM karyotype that contains, in addition, CA typical of MDS) imparted a poor OS and EFS, after adjusting for any CA and all individual CA. One-year mortality was also high, especially for the MM-MDS subgroup with trisomy 8 within a MM signature karyotype (87%vs 34% in its absence, P < 0.001). No patient remained event free 5 years post transplant in the presence of these baseline high-risk CA. However, certain trisomies (e.g. chromosomes 7 and 9) and del 20 had favourable clinical consequences. The higher risk that is associated with CA compared with SPF justifies routine cytogenetic studies in all patients with MM at diagnosis and whenever additional treatment decisions are considered, such as in planning HDT either for initial response consolidation, at the time of primary unresponsiveness to induction therapy, or at relapse.

Prognostic impact of cytogenetic and interphase fluorescence in situ hybridization-defined chromosome 13 deletion in multiple myeloma: early results of total therapy II

Cytogenetic abnormalities of chromosome 13 (CA 13) and those detected by fluorescence in situ hybridization (FISH 13) have both been associated with poor prognosis in multiple myeloma (MM) patients. The prognostic implications of CA, FISH 13 and other standard laboratory parameters were examined in the first 231 patients enrolled in Total Therapy II, an intensive cytotoxic chemotherapy programme with tandem autotransplants. Three-year projections of event-free survival (EFS) and overall survival (OS) were 71% and 77% respectively. CA 13 was detected in 14% and significantly correlated with FISH 13 (present in 51%), tumour burden, proliferative activity and lactic dehydrogenase (LDH). Both EFS and OS were significantly shorter in patients with CA 13, FISH 13, LDH >or= 190 U/l, beta2 microglobulin >or= 4 mg/l and C reactive protein >or= 4.0 mg/l; other CA was an additional risk factor for OS. Two-thirds of CA 13 patients were identified by FISH 13 and plasma-cell-labelling index (PCLI) >or= 0.4%; however, PCLI failed to identify additional risk groups in FISH subsets. Although present in considerably fewer patients, CA 13 imparted more rapid relapse (61% at 3 years) and death (43% at 3 years) than FISH 13 (38% and 35%; P = 0.02 and 0.1 respectively) and should be part of the initial work-up of patients with MM.

Syndecan-1 (CD138) immunoreactivity in bone marrow biopsies of multiple myeloma: shed syndecan-1 accumulates in fibrotic regions

Syndecan-1 (CD138) mediates myeloma cell adhesion, and loss of syndecan-1 from the cell surface may contribute to myeloma proliferation and dissemination. Flow cytometry analysis of myeloma cells in bone marrow specimens shows heterogeneity in cell surface syndecan-1 expression. It is not known whether weaker expression correlates with more aggressive disease. However, recent reports suggest that variations in syndecan-1 staining intensity on myeloma cells may be an artifact of specimen handling. In this study, we evaluate syndecan-1 expression in bone marrow biopsy sections from 28 multiple myeloma patients, to elucidate the heterogeneity of syndecan-1 expression in situ. Immunoreactivity for syndecan-1, using the antibody B-B4 (CD138), was found in more than 95% of multiple myeloma cells in 27 of 28 biopsies. However, one biopsy had more than 50% CD138-negative cells and cells with weak CD138 expression were identified in the majority of cases. Loss of syndecan-1 did not appear to relate to myeloma cell differentiation. In addition, syndecan-1 was detected on intravascular and intrasinusoidal myeloma cells suggesting that loss of syndecan-1 may not be required for extramedullary dissemination. Bone marrow biopsies from nine additional patients, with variable CD138 staining intensity on myeloma cells as determined by flow cytometry, were studied by immunohistochemistry. The heterogeneous CD138 expression was confirmed in situ, with weakly positive cells concentrated in areas of reticulin fibrosis. These cells had a disrupted pattern of membrane staining in contrast to the strong linear membrane staining seen in the other multiple myeloma cells. In addition, the fibrotic stroma stained intensely for syndecan-1. Accumulation of syndecan-1 within the extracellular matrix of the marrow likely is derived by shedding of the molecule from the surface of myeloma cells. Because syndecan-1 can act to regulate the activity of heparan-binding growth factors, these reservoirs of syndecan-1 may play a critical role in promoting myeloma pathogenesis, or in regeneration of the tumor after chemotherapy.

A novel multiparametric approach for analysis of cytoplasmic immunoglobulin light chains by flow cytometry

We describe a novel flow cytometric approach using a two-step acquisition technique to determine the cytoplasmic immunoglobulin light chains (LC) expression. Samples were prepared by a lysed-whole-blood technique and incubated with CD38-PE (phycoerythrin) and CD45-FITC (fluorescein isothiocyanate). The cells were fixed and acquired on an FACSCalibur flow cytometer (first acquisition). The cells were then permeabilized, incubated with either kappa-FITC or lambda-FITC and reacquired (second acquisition). Analysis of the data was performed by gating on the differing intensities of CD38 and evaluating them for the presence of a shifting FITC-positive population from the first acquisition to the second acquisition. The FITC fluorescence intensity of the second acquisition was equal to the sum of surface CD45 expression obtained during the first acquisition and the cytoplasmic LC expression obtained during the second acquisition. Thus, the shifting (increase) of FITC fluorescence intensity during the second acquisition is specifically due to the cytoplasmic expression of either the kappa or lambda LC. We studied 15 multiple myeloma (MM) patients and 10 controls (samples from patients without plasma cell dyscrasias). None of the controls showed evidence of any clonal populations. Thirteen of 15 MM patients exhibited clonal plasma cells (CD38 bright), ranging from 0.01% to 34% of total events collected. In addition, we identified another minute clonal population of lymphocytes (CD38 dim, CD45 bright, low forward and side scatter) in 12 of 13 MM patients with clonal plasma cells. This population, ranging from 0.01% to 0.6% of total events collected, had the same LC restriction as the clonal plasma cells. Patients with a ratio of minor clonal population to clonal plasma cells less than 0.07 tended to remain in partial or complete remission than those with a ratio > or =0.07 (4/5 versus 1/4, P <.1, chi(2)). We conclude that this method is highly sensitive and permits us to identify the minute clonal population of lymphocytes in MM patients. Our preliminary observations with a small cohort of patients imply that this minute clonal population may have important prognostic significance. The prognostic significance should be confirmed by further studies.

Cyclin D1 and E2F-1 immunoreactivity in bone marrow biopsy specimens of multiple myeloma: relationship to proliferative activity, cytogenetic abnormalities and DNA ploidy

Cyclin D1, encoded by the CCND1 gene, is immunohistochemically detectable in up to one-third of cases of multiple myeloma (MM). To examine the mechanism of cyclin D1 overexpression, we compared cyclin D1 immunoreactivity with the results of conventional cytogenetics to determine if the t(11;14)(q13;q32) or other abnormalities of 11q11-14 explained cyclin D1 overexpression. Karyotypic abnormalities were found in 45 out of 67 (67%) MM cases; the t(11;14) was present in seven cases (10%). Additional 11q11-14 abnormalities were not identified. The t(11;14) correlated with cyclin D1 upregulation in low to intermediately proliferative MM, but was not present in highly proliferative tumours (assessed using bromodeoxyuridine labelling index). Cyclin D1 indirectly activates the transcription factor E2F-1. In the bone marrow biopsy specimens of MM cases, E2F-1 was concurrently expressed with cyclin D1 (P = 0.001), indicating that cyclin D1 is functional. However, as neither E2F-1 nor cyclin D1 expression correlated with proliferative activity, the speculation that t(11;14) upregulates the CCND1 gene to induce higher proliferation and possibly more aggressive disease is not supported. We conclude that in low to intermediately proliferative MM cases, cyclin D1 is probably upregulated by t(11;14), but an alternative mechanism is more probable in highly proliferative MM.

Cytology and flow cytometry of malignant effusions of multiple myeloma

Identifying malignant plasma cells in body fluids from multiple myeloma patients is important for therapeutic and prognostic considerations. This can be difficult when plasma cells are mature in appearance or low in number. We examined the cytological and flow cytometric findings of myelomatous pleural and pericardial effusions from 8 patients with advanced multiple myeloma. Cytoplasmic immunoglobulin light chain excess vs. DNA ploidy in the plasma-cell population was evaluated by flow cytometry (FCM). The cytology smears of one pericardial and 14 pleural effusions from the 8 patients were reviewed. Screening Papanicolaou-stained smears facilitated the detection of malignant nuclear features; however, morphology of plasma cells was best seen in Diff-Quik-stained smears. Low cellularity and inadequate air-drying of smears accounted for the false-negative cytology seen in two fluids from a single patient. A malignant plasma cell population was identified in 9 of 10 fluids submitted for FCM, including the two fluids with negative cytology. The false-negative FCM was from a suboptimal specimen with high background staining. Six fluids had an aneuploid DNA content, and four were diploid. A combination of Papanicolaou- and Diff-Quik-stained smears is recommended for the evaluation of plasma cells in effusions from patients with multiple myeloma. Cytology and flow cytometry confirmed malignancy in 87% and 90% of fluids evaluated, respectively; all cases were diagnosed by either one or both methods. Our results suggest that FCM and cytology of serous effusions in multiple myeloma patients are complementary and should be used in difficult cases. Diagn. Cytopathol. 2000;22:147-151.

Age Is Not a Prognostic Variable With Autotransplants for Multiple Myeloma

Multiple myeloma (MM) typically afflicts elderly patients with a median age of 65 years. However, while recently shown to provide superior outcome to standard treatment, high-dose therapy (HDT) has usually been limited to patients up to 65 years. Among 550 patients with MM and a minimum follow-up of 18 months, 49 aged ≥65 years were identified (median age, 67; range, 65 to 76 years). Their outcome was compared with 49 younger pair mates (median, 52; range, 37 to 64 years) selected among the remaining 501 younger patients (<65 years) matched for five previously recognized critical prognostic factors (cytogenetics, β2-microglobulin, C-reactive protein, albumin, creatinine). Nearly one half had been treated for more than 1 year with standard therapy and about one third had refractory MM. All patients received high-dose melphalan-based therapy; 76% of the younger and 65% of the older group completed a second transplant (P = .3). Sufficient peripheral blood stem cells to support two HDT cycles (CD34 > 5 × 106/kg) were available in 83% of younger and 73% of older patients (P = .2). After HDT, hematopoietic recovery to critical levels of granulocytes (>500/μL) and of platelets (>50,000/μL) proceeded at comparable rates among younger and older subjects with both first and second HDT. The frequency of extramedullary toxicities was comparable. Treatment-related mortality with the first HDT cycle was 2% in younger and 8% among older subjects, whereas no mortality was encountered with the second transplant procedure. Comparing younger/older subjects, median durations of event-free and overall survival were 2.8/1.5 years (P = .2) and 4.8/3.3 years (P = .4). Multivariate analysis showed pretransplant cytogenetics and β2-microglobulin levels as critical prognostic features for both event-free and overall survival, whereas age was insignificant for both endpoints (P = .2/.8). Thus, age is not a biologically adverse parameter for patients with MM receiving high-dose melphalan-based therapy with peripheral blood stem cell support and, hence, should not constitute an exclusion criterion for participation in what appears to be superior therapy for symptomatic MM.

Age Is Not a Prognostic Variable With Autotransplants for Multiple Myeloma

Multiple myeloma (MM) typically afflicts elderly patients with a median age of 65 years. However, while recently shown to provide superior outcome to standard treatment, high-dose therapy (HDT) has usually been limited to patients up to 65 years. Among 550 patients with MM and a minimum follow-up of 18 months, 49 aged ≥65 years were identified (median age, 67; range, 65 to 76 years). Their outcome was compared with 49 younger pair mates (median, 52; range, 37 to 64 years) selected among the remaining 501 younger patients (&lt;65 years) matched for five previously recognized critical prognostic factors (cytogenetics, β2-microglobulin, C-reactive protein, albumin, creatinine). Nearly one half had been treated for more than 1 year with standard therapy and about one third had refractory MM. All patients received high-dose melphalan-based therapy; 76% of the younger and 65% of the older group completed a second transplant (P = .3). Sufficient peripheral blood stem cells to support two HDT cycles (CD34 &gt; 5 × 106/kg) were available in 83% of younger and 73% of older patients (P = .2). After HDT, hematopoietic recovery to critical levels of granulocytes (&gt;500/μL) and of platelets (&gt;50,000/μL) proceeded at comparable rates among younger and older subjects with both first and second HDT. The frequency of extramedullary toxicities was comparable. Treatment-related mortality with the first HDT cycle was 2% in younger and 8% among older subjects, whereas no mortality was encountered with the second transplant procedure. Comparing younger/older subjects, median durations of event-free and overall survival were 2.8/1.5 years (P = .2) and 4.8/3.3 years (P = .4). Multivariate analysis showed pretransplant cytogenetics and β2-microglobulin levels as critical prognostic features for both event-free and overall survival, whereas age was insignificant for both endpoints (P = .2/.8). Thus, age is not a biologically adverse parameter for patients with MM receiving high-dose melphalan-based therapy with peripheral blood stem cell support and, hence, should not constitute an exclusion criterion for participation in what appears to be superior therapy for symptomatic MM.

Oligoclonal Protein Bands and Ig Isotype Switching in Multiple Myeloma Treated With High-Dose Therapy and Hematopoietic Cell Transplantation

Multiple myeloma (MM) is usually characterized by production of a single serum monoclonal protein of constant isotype and light-chain restriction. Multiple Ig isotypes and isotype switches, which are rare in untreated patients, are reported to be more common in patients undergoing myeloablative therapy. These additional protein bands, detected by immunofixation electrophoresis (IFE), could be due to altered paraprotein production by the malignant plasma cell clone or oligoclonal Ig production during recovery of B-cell function after myeloablative therapy. We analyzed abnormal protein bands (APB), distinct from the presenting paraprotein, in 550 patients receiving high-dose therapy with autologous hematopoietic cell transplantation at a single institution. Fifty-five patients (10%) had APB, 48 had oligoclonal bands (OB), and 23 had an apparent isotype switch (IS) on IFE (16 had both OB and IS). Morphologic and flow cytometric examination of bone marrow in 17 patients with IS showed no evidence of a clonal plasma cell isotype switch. Patients with APB had significantly higher complete response to therapy (67% v 37%,P = .001). To assess the independent prognostic relevance of APB, a multivariate analysis was performed among 471 patients surviving at least 12 months from first transplant (all patients developing APB had done so by 12 months from first transplant). APB (in 50 patients) was a favorable feature for both event-free (rank 3, P = .004) and overall survival (rank 3, P = .0005). We propose that OB and IS are likely to be due to recovery of Ig production rather than alterations in the biology of the malignant plasma cell clone.

Oligoclonal Protein Bands and Ig Isotype Switching in Multiple Myeloma Treated With High-Dose Therapy and Hematopoietic Cell Transplantation

Multiple myeloma (MM) is usually characterized by production of a single serum monoclonal protein of constant isotype and light-chain restriction. Multiple Ig isotypes and isotype switches, which are rare in untreated patients, are reported to be more common in patients undergoing myeloablative therapy. These additional protein bands, detected by immunofixation electrophoresis (IFE), could be due to altered paraprotein production by the malignant plasma cell clone or oligoclonal Ig production during recovery of B-cell function after myeloablative therapy. We analyzed abnormal protein bands (APB), distinct from the presenting paraprotein, in 550 patients receiving high-dose therapy with autologous hematopoietic cell transplantation at a single institution. Fifty-five patients (10%) had APB, 48 had oligoclonal bands (OB), and 23 had an apparent isotype switch (IS) on IFE (16 had both OB and IS). Morphologic and flow cytometric examination of bone marrow in 17 patients with IS showed no evidence of a clonal plasma cell isotype switch. Patients with APB had significantly higher complete response to therapy (67% v 37%,P = .001). To assess the independent prognostic relevance of APB, a multivariate analysis was performed among 471 patients surviving at least 12 months from first transplant (all patients developing APB had done so by 12 months from first transplant). APB (in 50 patients) was a favorable feature for both event-free (rank 3, P = .004) and overall survival (rank 3, P = .0005). We propose that OB and IS are likely to be due to recovery of Ig production rather than alterations in the biology of the malignant plasma cell clone.

Tumor necrosis factor-alpha and interleukin 4 in myeloma cell precursor differentiation

Multiple myeloma is a B-cell malignancy characterized by the accumulation of a clonal population of plasma cells in the bone marrow that secrete a monoclonal immunoglobulin protein. It has been regarded as a tumor arising at the B, pre-B lymphocyte, or even stem cell level. Precursor cells are presumed to proliferate and differentiate, giving rise to clonal expansion in plasma cells. Peripheral blood mononuclear cells (PBMC) from 36 patients with multiple myeloma, 12 with monoclonal gammopathy of undetermined significance (MGUS), and 21 healthy controls were cultured in vitro in the presence of tumor necrosis factor-alpha (TNF-alpha) and interleukin 4 (IL-4). We have demonstrated that monoclonal plasma cells can be induced in different proportions from PBMC obtained from myeloma patients when exposed in vitro to TNF-alpha and IL-4. Although myeloma cell precursors cannot be distinguished from other cells by morphology, a high number of monoclonal plasma cells was detected in our culture system on day 4 even when plasma cells accounted for less than 0.2% of the cells seeded on day 0. In 16 of the 36 patients with myeloma, monoclonal plasma cells appeared after 4 days. These changes were not observed in PBMC from patients with MGUS or from controls. These findings thus suggest that circulating myeloma cell precursors differentiate into plasma cells in the presence of TNF-alpha and IL-4, and the variation in the number of myeloma cell precursors in peripheral blood could therefore be used as a prognostic parameter in response to chemotherapy in myeloma patients.

Primary extranodal non-Hodgkin's lymphoma in adults: clinicopathological and survival characteristics

Among 318 cases of non-Hodgkin's lymphoma (NHL) treated in our unit, 145 (45.6%) had primary extranodal NHL (PE-NHL). The stomach was the most common site (42.1%), followed by the PE-NHL of the head and neck region. Histologically aggressive histologies (65.5% intermediate and 20.7% high grade) predominated. 89.6% of the cases were localized (stage IE, 51% and stage II, 38.6%) but 28% had B symptoms. CR was achieved in 82.1% of the cases. 5-years disease free survival and overall survival were both 65%. Factors that influence prognosis were stage and high grade histology. Among various primary sites the Waldeyer's ring, small intestine and testes had the worse prognosis. Compared to nodal NHL, the PE-NHL were more frequently localized, belonged more often to aggressive histologies and had more often distal extranodal relapses. CR rates and disease free and overall survival were significantly better for PE-NHL. The survival rates, however, listed according to stage and histology for nodal and PE-NHL were not different. We conclude that although PE-NHL differed from nodal NHL in several respects, prognosis is mainly a factor of stage and histology rather than of the primary localization per se.

Simultaneous expression of kappa and lambda light chains in a murine IgG3 anti-Cryptococcus neoformans hybridoma cell line

Allelic exclusion normally results in the expression of only one light and one heavy chain gene. However, some hybridomas have been reported to express two different heavy chain genes. Here we report that the IgG3 hybridoma 4H3.C8B expresses both kappa and lambda light chains. 4H3.C8B was originally recovered by screening for antibody binding to Cryptococcus neoformans polysaccharide antigen and characterized as gamma 3 lambda. The gamma 3 lambda but not the gamma 3 kappa binds to polysaccharide antigen. Some of the antibody molecules were heterodimers composed of both lambda and kappa. IgG1 and IgG2b isotype switch variants were identified and isolated by the technique of sib selection, using the ELISA spot assay. Like the parent IgG3 line, the switch variants continued to express both kappa and lambda light chains but only the lambda-containing antibodies bound to the antigen. Our experience suggests that hybridomas recovered by assays that are antigen dependent should also be tested for the expression of other isotypes and light chains in a non-antigen-binding immunoassay.

Unusual patterns of immunoglobulin gene rearrangement and expression during human B cell ontogeny: human B cells can simultaneously express cell surface kappa and lambda light chains

Immunoglobulin gene rearrangement during mammalian B cell development generally follows an ordered progression, beginning with heavy (H) chain genes and proceeding through kappa and lambda light (L) chain genes. To determine whether the predicted kappa-->lambda hierarchy was occurring in vitro, we generated Epstein-Barr virus-transformed cell lines from cultures undergoing human pre-B cell differentiation. A total of 143 cell lines were established. 24 expressed cell surface mu/lambda by flow cytometry and were clonal by Southern blotting. Surprisingly, two of the mu/lambda-expressing cell lines contained both kappa alleles in germline configuration, and synthesis/expression of conventional lambda L chains was directly proven by immunoprecipitation/sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in one of them. Thus, human fetal bone marrow B lineage cells harbor the capacity to make functional lambda L chain gene rearrangements without rearranging or deleting either kappa allele. A third unusual cell line, designated 30.30, was observed to coexpress cell surface kappa and lambda L chains associated with mu H chains. The 30.30 cell line had a diploid karyotype, a single H chain rearrangement, both kappa alleles rearranged, and a single lambda rearrangement. Immunoprecipitation/SDS-PAGE confirmed that 30.30 cells synthesized and expressed kappa and lambda L chains. Multiparameter flow cytometry was used to demonstrate the existence of kappa+/lambda+ cells in fetal bone marrow and fetal spleen at frequencies of 2-3% of the total surface Ig+ B cell population. The flow cytometry data was confirmed by two-color immunofluorescence microscopy. The existence of normal human B cells expressing cell surface kappa and lambda refutes the widely accepted concept that expression of a single L chain isotype is immutable. The kappa+/lambda+ cells may represent transients undergoing L chain isotype switching.

Flow cytometric detection of cytoplasmic antigens in acute leukemias: implications for lineage assignment

This study aimed at optimizing the conditions for flow cytometric detection of myeloperoxidase (MPO), cytoplasmic CD3 (cCD3), and cytoplasmic CD22 (cCD22), which seem to be more reliable lineage-associated markers in acute leukemia than surface antigens. Fixation methods employing saponin as detergent resulted in accurate detection of MPO and cCD3, whereas cCD22 was detectable only after buffered-formaldehyde-acetone fixation. MPO was detected in 16/17 AML, but only in 1/6 ALL, the MPO positive ALL being also CD13 positive. MPO was detectable in 3/4 AML with T-lymphoid features; a case of myeloid antigen-positive T-ALL, however, was MPO-negative. cCD3 was expressed only in T-ALL, and five cases of lymphoid antigen-positive AML were cCD3-negative. We suggest that these flow cytometric assays are useful for the lineage assignment of poorly differentiated leukemias and contribute to the identification of truly biphenotypic acute leukemias.

Multiple myeloma and chronic lymphocytic leukemia: parallels and contrasts

Multiple myeloma (MM) and chronic lymphocytic leukemia (CLL) are closely related B-cell cancers. Parallel and divergent features of these diseases are reviewed. In MM, expression of multiple hemopoietic lineage-associated antigens on the malignant cells and the substantial likelihood of progression to acute myelogenous leukemia suggest transformation of a pluripotent stem cell. In CLL, transformation more likely involves a committed B-cell progenitor. Another difference is that clonal evolution with associated cytogenetic progression is common in MM but not CLL. Other data, including studies of proto-oncogenes and tumor suppressor genes, suggest that MM results both from increased proliferation and accumulation of tumor cells, whereas tumor cell accumulation is the predominant feature of CLL. These differences may be reflected in the seemingly greater role of cytokine abnormalities in MM progression. For example, osteoclast-activating properties of some cytokines account for bone involvement in MM but not in CLL. MM and CLL share common features such as stage-dependent anemia and immune deficiency. Both diseases respond to alkylating agents but vary markedly in their sensitivity to fludarabine (CLL greater than MM) and glucocorticoids (MM greater than CLL). Differences between these diseases in progression-free interval and survival may reflect different definitions of premalignant and malignant phases rather than biologic differences. Detailed comparisons between MM and CLL may provide additional insights into these and related B-cell cancers.

Multiparameter analyses of normal and malignant human plasma cells: CD38++, CD56+, CD54+, cIg+ is the common phenotype of myeloma cells

Plasma cells obtained from bone marrow samples of 45 patients with MM, eight patients with MGUS, eight patients with Waldenström's macroglobulinaemia (WM), one patient with immunocytoma, and 12 controls were characterized by immunophenotyping, estimation of DNA content, and labeling index, as well as by morphological analysis. Plasma cells from 37/45 myeloma and 5/8 MGUS patients expressed CD38 and CD56 (N-CAM) on their surface but were negative for other NK cell-associated antigens such as CD16 (Fc gamma RIII) or CD2. All tumor cells of less-differentiated cell type (WM, immunocytoma) and normal polyclonal plasma cells were negative for CD56. CD56-specific mRNA was demonstrated in myeloma cells by northern blot analysis. Another adhesion molecule, ICAM-1 (CD54), was found on plasma cells from all patients and controls examined. Coexpression of CD19 (1/45), CD20 (9/45), or CD33 (3/45) was rare and CD10 with CD14 was expressed by a small tumor cell subpopulation of only one myeloma patient. The individual pattern of surface marker expression was not associated with a special-type myeloma protein isotype, stage or status of disease, LI or histological classification; however, a correlation between CD56 expression or histological classification and DNA content of the tumor cells was found.

Sequential paraformaldehyde and methanol fixation for simultaneous flow cytometric analysis of DNA, cell surface proteins, and intracellular proteins

A cell fixation and permeabilization procedure consisting of sequential paraformaldehyde and methanol was evaluated and found suitable for concomitant flow cytometric quantification of total cellular DNA, immunofluorescence measurements of cell surface proteins, and immunofluorescence measurements of intracellular proteins. Paraformaldehyde/methanol-fixed cells exhibited significantly greater intracellular antitubulin immunofluorescence than cells fixed with paraformaldehyde or methanol alone (p less than 0.002) and significantly greater intracellular antitubulin immunofluorescence than cells fixed with methanol followed by paraformaldehyde (p less than 0.006). With paraformaldehyde/methanol fixation, cell morphology was well preserved and forward and right angle light scatter properties were sufficiently well maintained to permit gating on these parameters. Cell surface marker staining with fluorescent anti-leukocyte antibodies was unaffected by fixation with paraformaldehyde/methanol. Paraformaldehyde effects on the intensity of DNA staining with propidium iodide were dependent on paraformaldehyde concentration and fixation temperature; these effects were least pronounced at low paraformaldehyde concentrations (0.25% or less), and at temperatures lower than 37 degrees C. Paraformaldehyde fixation may result in differences in propidium iodide staining of DNA in some diploid cells, which may produce small spurious aneuploid peaks in normal peripheral blood leukocytes. Paraformaldehyde fixation also produces an apparent increase in the DNA index of aneuploid cell populations in comparison with methanol fixation, particularly when the DNA index exceeds 1.5. Occasionally, this paraformaldehyde fixation-induced effect is useful in identifying biologically distinct near-diploid subpopulations in tumors.

Expression of the neural cell adhesion molecule (CD56) by human myeloma cells

Recent studies in multiple myeloma indicate that molecules associated with different haematopoietic lineages may be expressed aberrantly by myeloma cells. In order to investigate this phenomenon further, we studied the immunophenotype of bone marrow cells from 21 patients with multiple myeloma using a panel of monoclonal antibodies against T,B, myelomonocytic, and natural killer (NK)-cell antigens. Leu-19/NKH1 (CD56), a molecule identical to N-CAM, which is normally expressed by neuroectodermal and NK cells, was found in 13 patients (62%). Dual-parameter flow cytometry was used to correlate N-CAM positivity with DNA aneuploidy or cytoplasmic immunoglobulin expression as markers of myeloma cells. When N-CAM was found positive, other haematopoietic antigens were expressed only in three out of 13 cases (23%). In contrast, myeloma cells not expressing N-CAM frequently exhibited pre-B cell markers, myeloid antigen, and HLA-DR, respectively (seven out of eight cases, 88%). Six out of eight N-CAM-negative myelomas were of the IgG lambda isotype, otherwise no clearcut association with basic clinical and laboratory parameters was noted. We conclude that N-CAM expression is a common finding in multiple myeloma. Whether its expression and the observed antigenic heterogeneity is just a manifestation of malignancy or N-CAM may play a role in the biology of multiple myeloma regarding tumour cell spread, remains to be explained.

Myeloma

Myeloma is a malignancy of plasma cells that are terminally differentiated B-lymphocytes. The clinical spectrum varies from the incidental discovery of a pathologically raised monoclonal immunoglobulin on routine electrophoresis in asymptomatic patients to widespread skeletal involvement with incapacitating bone pain. Symptoms may result from a solitary tumor mass, described as an extramedullary plasmacytoma, in virtually any part of the body. Metabolic abnormalities commonly include hypercalcemia, elevated plasma urate levels, or the development of amyloidosis, all of which may disturb renal function. High paraprotein levels cause hyperviscosity, resulting in generalized debility and varying degrees of disturbed mental function. The natural history is determined by the mass of the tumor coupled with its unique biologic features. Median survival of unselected patients, without effective treatment but once symptoms are evident, is approximately 7 months; this period can be significantly prolonged with appropriate therapy. As a first step, urgent medical management is often necessary, centering on rehydration, correction of hyperviscosity, and reversal of metabolic defects, each of which may improve renal function. Over the longer term, specific antitumor drugs have extended median survival to approximately 30 months, and most regimens include a combination of melphalan and prednisone, with or without other cytotoxic drugs. Alternative forms of treatment include sequential hemibody irradiation, recombinant alpha interferon, and in suitably selected patients, high-dose chemoradiotherapy followed by bone marrow transplantation. The latter approaches offer promising management options and are currently the subject of evaluation in controlled clinical trials.

Markers of multiple hematopoietic-cell lineages in multiple myeloma

Multiple myeloma is considered a cancer of mature plasma cells. Recent studies, however, suggest the possible involvement of early B cells and the expression of myelomonocytic antigens by myeloma cells. Using flow cytometry, we searched for evidence of the expression of genes specific for different hematopoietic lineages by tumor cells in bone marrow aspirates from 27 patients with aneuploid multiple myeloma. In addition to features characteristic of myeloma cells, we found evidence of the frequent expression by myeloma tumor cells of the pre-B-cell antigen CALLA (common acute lymphocytic leukemia antigen) (in specimens from 58 percent of patients) and of megakaryocytic (88 percent), myelomonocytic (65 percent), and erythroid (39 percent) surface markers. The proportion of tumor cells expressing the different markers varied among patients, from 2 to 100 percent of recognizable tumor cells. We conclude that cells of multiple lineages are involved in myeloma--a finding that is consistent with the hypothesis that there is a common primary neoplastic lesion for all hematologic cancers.

In situ hybridization detection of light chain mRNA in routine bone marrow trephines from patients with suspected myeloma

A method for the detection of immunoglobulin light chain mRNA by situ hybridization has been applied to routine bone marrow trephines, from patients suspected of having multiple myeloma. The principle aim was to define monoclonal populations even in cases lacking a paraprotein or an obvious atypical plasma cell proliferation. The expression of light chain mRNA in plasma cells in routine bone marrow trephines from 14 patients with suspected myeloma was studied. Plasma cells in the marrow ranged from 4% to 99%. Clonal populations based on light chain restriction were delineated in 12 patients, using biotinylated probes to kappa and lambda mRNA and visualized using an alkaline phosphatase/fast red naphthol capture method. Normal tonsil and bone marrow trephines were used as controls. In situ hybridization was found to be a specific, safe and rapid technique. It could be applied to both fixed and fresh tissue. It was found to lack the background staining of interstitial immunoglobulin, particularly in sclerotic cases, which is so often encountered with immunocytochemistry. Additionally, this technique will type plasma cell neoplasms (undetected by routine immunocytochemistry) in post-transcriptional block or non-secretory myeloma.