A phase I study of anti-BCMA CAR T cell therapy in relapsed/refractory multiple myeloma and plasma cell leukemia

BACKGROUND

Relapsed/refractory (R/R) multiple myeloma (MM) patients and primary plasma cell leukemia (PCL) have an unfavorable prognosis and no effective treatment. This study was designed to assess the safety and preliminary efficacy of a novel anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T cell in R/R MM and PCL.

METHODS

Between February 22, 2017, and June 25, 2018, 28 R/R and two R/R primary PCL patients received a median dose of 11.2 × 106 CAR+ cells/kg. The subjects were refractory to a proteasome inhibitor and/or an immunomodulatory agent. Fludarabine and cyclophosphamide were given as lymphodepletion chemotherapy.

RESULTS

Results for these 30 consecutive patients who received an anti-BCMA CAR T cell infusion are reported. The patients had received a median of four prior lines of therapy. A total of 44 different types of adverse events were recorded, and hematologic toxic effects were the most common events of any grade during treatment. Hematologic toxic effects were also the most common events of grade 3 or higher. A total of 29 patients (96.7%) had cytokine release syndrome, which was of grade 1 or 2 in 24 patients (80%) and grade 3 in five patients (16.7%). Neurologic toxic effects only occurred in one patient (3.3%) and were of grade 1. The objective response rate was 90%, and the complete response rate was 43.3%. With a median follow-up of 12.6 months, the median progression-free survival (PFS) and overall survival were 5.2 months and 14.0 months. One of the two primary PCL achieved a complete response with a PFS of 307 days. The other patients achieved a very good partial response with a PFS of 117 days.

CONCLUSIONS

Anti-BCMA CAR T cell treatment is safe and highly active in R/R multiple myeloma.

Single-Cell Transcriptomic Analysis Reveals BCMA CAR-T Cell Dynamics in a Patient with Refractory Primary Plasma Cell Leukemia

Chimeric antigen receptor T cell (CAR-T) therapy has revolutionized the clinical treatment of hematological malignancies due to the prominent anti-tumor effects. B cell maturation antigen (BCMA) CAR-T cells have demonstrated promising effects in patients with relapsed/refractory multiple myeloma. However, the dynamics of CAR-T cell proliferation and cytotoxicity in clinical patients remains unexplored. Here, we longitudinally profiled the transcriptomes of 55,488 T cells including CAR-T products, CAR-T cells, and endogenous T cells at the peak and remission phases in a plasma cell leukemia (PCL) patient treated with BCMA CAR-T cells by single-cell transcriptomic analysis. Our results showed distinct CAR-T and endogenous T cell subsets indicating stage-specific expression in proliferation, cytotoxicity, and intercellular signaling pathways. Furthermore, we found that CAR-T cells at peak phase gradually convert to a highly cytotoxic state from a highly proliferative state along a development trajectory. Moreover, re-analysis of a single cell study from CD8+ CD19 CAR-T confirmed our findings. These commonalities suggest conserved mechanisms for CAR-T treatment across hematological malignancies. Taken together, our current study provides insight into CAR-T cell dynamics during CAR-T therapy and proves that both BCMA CAR-T and CD19 CAR-T have similar transcriptional characteristics, especially at the CAR-T peak phase.

Bispecific Antibodies for Multiple Myeloma: A Review of Targets, Drugs, Clinical Trials, and Future Directions

Multiple myeloma (MM) is a plasma cell malignancy and the second most common hematological neoplasm in adults, comprising 1.8% of all cancers. With an annual incidence of ~30,770 cases in the United States, MM has a high mortality rate, leading to 12,770 deaths per year. MM is a genetically complex, highly heterogeneous malignancy, with significant inter- and intra-patient clonal variability. Recent years have witnessed dramatic improvements in the diagnostics, classification, and treatment of MM. However, patients with high-risk disease have not yet benefited from therapeutic advances. High-risk patients are often primary refractory to treatment or relapse early, ultimately resulting in progression toward aggressive end-stage MM, with associated extramedullary disease or plasma cell leukemia. Therefore, novel treatment modalities are needed to improve the outcomes of these patients. Bispecific antibodies (BsAbs) are immunotherapeutics that simultaneously target and thereby redirect effector immune cells to tumor cells. BsAbs have shown high efficacy in B cell malignancies, including refractory/relapsed acute lymphoblastic leukemia. Various BsAbs targeting MM-specific antigens such as B cell maturation antigen (BCMA), CD38, and CD138 are currently in pre-clinical and clinical development, with promising results. In this review, we outline these advances, focusing on BsAb drugs, their targets, and their potential to improve survival, especially for high-risk MM patients. In combination with current treatment strategies, BsAbs may pave the way toward a cure for MM.

A case of secondary plasma cell leukemia resistant to novel agents, in which stringent complete remission was achieved and maintained for a long period of time after VAD therapy and tandem autologous transplantation

A 61-year-old woman was diagnosed in June 2011 as having immunoglobulin G (IgG) ĸ-type multiple myeloma (MM), stage II, according to the International Staging System (ISS). Chromosome analysis showed a complex karyotype, including t(11;14) and del 13q. Analysis of the cell surface markers revealed that the cells were positive for mature plasma cell-1 (MPC-1), and negative for cluster of differentiation (CD) 45 and CD49e, suggestive of an intermediate level of maturity of the cells. The disease was refractory to bortezomib-dexamethasone (BD) therapy and progressed to plasma cell leukemia despite the treatment. Treatment was therefore switched to lenalidomide-dexamethasone (RD) therapy, however, the condition again proved to be refractory to this therapy. A partial response (PR) was achieved with vincristine-doxorubicin-dexamethasone (VAD) therapy. The residual plasma cells became CD45-positive, suggesting a change of the cells from an intermediate level of maturity to mature cells. In December, autologous peripheral blood stem cell transplantation (Auto-PBSCT) was performed after high-dose melphalan therapy (melphalan 200 mg/m(2)) as pretreatment. PR was observed and a second Auto-PBSCT was performed in July 2012. Stringent complete remission (sCR) has been maintained for 2 years since, without any further treatment. This is the first reported case of secondary plasma cell leukemia (sPCL) resistant to new drugs that was successfully treated by high-dose melphalan in combination with VAD therapy and Auto-PBSCT.

Peripheral blood polyclonal plasmacytosis mimicking plasma cell leukemia in patients with angioimmunoblastic T-cell lymphoma: report of 3 cases and review of the literature

Angioimmunoblastic T-cell lymphoma (AITL) is a unique type of peripheral T-cell lymphoma. Patients with AITL may have occasional reactive plasma cells present in the peripheral circulation. Prominent peripheral blood polyclonal plasmacytosis mimicking plasma cell leukemia, however, is distinctly uncommon. Here we describe 3 such cases from two large tertiary medical centers and discuss the role of ancillary studies in the differential diagnosis of peripheral blood plasmacytosis.

Flow cytometric immunophenotypic characteristics of 36 cases of plasma cell leukemia

Prospective flow cytometric analysis of antigens expression on bone marrow and peripheral blood plasma cells of 36 plasma cell leukemia (PCL) patients enabled to establish the following immunophenotype of leukemic plasma cell: CD38(++), CD138(+), CD54(+), CD49d(+), CD29(+), CD44(+), CD126(+), CD19(-), CD45(-). In one-third of patients PCL cells express CD56, CD71 and CD117. Expression of CD54 on plasma cells was higher as compared to expression of adhesion molecules CD11a, CD18 and CD11b (p<0.01). Expression of CD18, CD11a, CD11b was lower on bone marrow and higher on peripheral blood cells. In conclusion, impaired expression of adhesion molecules such as CD11a/CD18 or CD56 may explain hematogenic dissemination characterizing PCL.

Primary plasma cell leukemia mimicking an adult T-cell leukemia-lymphoma: a case report

BACKGROUND

Malignant plasma cells ofmultiple myeloma (MM), or plasma cell leukemia (PCL), may present highly variable morphologic aspects. Adult T-cell leukemia-lymphoma (ATLL) is a peripheral T-cell neoplasm composed of highly pleomorphic lymphoid cells. We report an unusual case ofprimary PCL with misleading cellular morphology and some clinical and biologic similarities simulating ATLL.

CASE

A 40-year-old Caribbean man presented with asthenia, epistaxis and diffuse bone pain. Blood cell count showed anemia and thrombocytopenia and a hyperleukocytosis composed of deeply basophilic cells with a polylobulated nucleus resembling flower cells. An ATLL diagnosis was given at first, without ruling out the possibility of a PCL diagnosis. Hypercalcemia and lytic bone lesions were compatible with both diagnoses. Immunophenotyping was key to the diagnosis of primary PCL.

CONCLUSION

Some clinical and biological overlap may exist between PCL and ATLL, leading to a false diagnosis or delaying a correct one. An accurate cytologic analysis leading to a rapid detection of plasma cell markers is essential for an early diagnosis.

Phenotypic and functional characterization of normal and malignant terminal B (plasma) cells

A number of antigens (Ags) are expressed on normal and malignant terminal B (plasma) cells, including plasma-cell, earlier B-cell, and non-B cell-Ags. These Ags, coupled with indirect and dual fluorochrome labelling techniques, permit characterization of normal and malignant in vitro and in vivo terminal B-cell differentiation. The majority (90%) of B cells within spleen bear Bl and lack PCA-1 Ags. As B cells differentiate to pokeweed mitogen in vitro, immunoglobulin (Ig) secretion precedes the appearance of cell surface PCA-1 and plasmacytoid morphology. Dual fluorescence cell sorting permits characterization of in vivo B-cell differentiation: Bl + PCA-1 + cells are more "differentiated" since they are more prevalent in lymph node than spleen, exhibit plasmacytoid morphology and maximal Ig secretion, and no longer respond to triggers of B-cell proliferation; in contrast, Bl + PCA-1-cells are lymphoid in morphology and may respond to triggers of B-cell proliferation as "resting" B cells. Similar studies of myeloma cells demonstrated that they may also include cells expressing plasma-cell, earlier B, and non-B cell Ags. Although they neither proliferated nor secreted Ig in vitro to G/M-CSF, G-CSF, M-CSF, IL-1, IL-1B, IL-2, or IL-4, proliferation without Ig secretion (Stimulation Index greater than or equal to 3.0) was induced to IL-6 in 6 of 10 patients (pts); to IL-3 (2 pts) and to IL-5 (2 pts).(ABSTRACT TRUNCATED AT 250 WORDS)

[Long-term complete remission in primary plasma cell leukemia after treatment with VAD chemotherapy and tandem autologous peripheral blood stem cell transplantation]

A 54-year-old woman visited our hospital with the chief complaints of generalized pain and thirst. Through hematologic and bone marrow examination, we diagnosed her illness as primary plasma cell leukemia. Three courses of VAD (vincristine, adriamycin and dexamethasone)therapy induced complete remission. Afterward, the patient received high-dose cyclophosphamide (4 g/m(2))for hematopoietic stem cell mobilization, and peripheral blood hematopoietic stem cells were collected 14 days later from the start of chemotherapy. Thereafter, the patient received 2 courses of high-dose melphalan (200 mg/m(2)), followed by tandem autologous peripheral blood stem cell transplantation. The patient developed no adverse events other than fever and stomatitis during the 2 transplantation courses. Fifty-six months after the transplantations, she remains in complete remission with continuous oral administration of bisphosphonate alone. Taken together, although primary plasma cell leukemia is a rare hematologic malignancy with poor prognosis, the intensive chemotherapy followed by tandem autologous peripheral blood stem cell transplantation may well improve the clinical outcome.

Plasmacytoid dendritic cell leukaemia/lymphoma: towards a well defined entity?

CD4(+)/CD56(+) haematodermic neoplasm or 'early' plasmacytoid dendritic cell leukaemia/lymphoma (pDCL) was described as a disease entity in the last World Health Organisation/European Organisation for Research and Treatment of Cancer classification for cutaneous lymphomas. These leukaemia/lymphomas co-express CD4 and CD56 without any other lineage-specific markers and have been identified as arising from plasmacytoid dendritic cells. Despite a fairly homogeneous pattern of markers expressed by most pDCL, numerous distinctive features (e.g. cytological aspects and aberrant marker expression) have been reported. This may be related to the 'lineage-independent developmental' programme of dendritic cells, which may be able to develop from either immature or already committed haematopoietic progenitors. This highlights the need for specific validated markers to diagnose such aggressive leukaemia. Here, we propose--among others (e.g. T-cell leukaemia 1)--blood dendritic cell antigen-2 and high levels of CD123 expression as potential markers. In addition, we propose a multidisciplinary approach including several fields of haematology to improve pDCL diagnosis.

[Plasma cell leukemia presenting with cleaved nuclei and a monocytoid appearance]

A 74-year-old man presented with anemia, thrombocytopenia and leukocytosis with 41% abnormal cells having cleaved and monocytoid nuclei. The bone marrow was infiltrated with 43.6% abnormal cells that were negative for peroxidase staining and positive for PAS staining. Surface antigen analysis revealed no expression of CDs 2, 3, 4, 8, 10, 19, 20, 13 or 33. Serum immunoelectrophoresis detected a monoclonal band, which was identifiable as kappa-type IgA protein. Immunostaining also revealed expression of IgA and kappa-type in the abnormal cells. The patient was diagnosed as having plasma cell leukemia but the morphological findings were unusual. Surface antigen analysis revealed expression of CD38 later. This case suggests that immunostaining of abnormal cells is required for the differential diagnosis of plasma cell leukemia in leukocytosis.

Mechanisms of TRAIL-induced apoptosis in leukemic plasmacytoid dendritic cells

OBJECTIVE

Dendritic cells play a central role in regulating the innate and adaptive immune responses. Plasmacytoid dendritic cells (PDC) represent a newly identified kind of DC with specialized functions aimed at fighting against viral infections. Recently, we have shown that CD4+CD56+ malignancies were leukemia arising from PDC, with a particularly aggressive clinical course. Hence, we asked whether these malignant PDC could be killed via TRAIL, a death-inducing ligand that belongs to a new class of anticancer drugs currently under development.

MATERIALS AND METHODS

In this study we used a PDC line (GEN2.2) we recently developed from leukemic PDC as a model.

RESULTS

We show that GEN2.2 PDC are sensitive to TRAIL-induced apoptosis and can be killed in vitro by TRAIL-expressing NK cells. Our results suggest that TRAIL binds to Death Receptor 5 (DR5) expressed by GEN2.2 and induces apoptosis mainly via caspases 10, 8, and 3. Interestingly, during infection with influenza, DR5 decreases on GEN2.2 cell surface, which consequently become resistant to TRAIL-induced apoptosis. Moreover, we confirmed the expression of DR5 or DR4 on half of LPDC tested, suggesting the possibility to kill these cells via TRAIL. Hopefully, normal PDC expressed neither DR4 nor DR5.

CONCLUSION

These results suggest that TRAIL agonists represent a therapeutic alternative for the treatment of LPDC.

Primary plasma cell leukemia: morphologic, immunophenotypic, and cytogenetic features of 4 cases treated with chemotherapy and stem cell transplantation

Plasma cell leukemia (PCL) is a neoplastic disorder of plasma cells of which there are 2 forms, primary PCL and secondary PCL, the latter occurring in patients with a history of plasma cell myeloma. We describe 4 patients with primary PCL. In all cases, the bone marrow aspirate smears and biopsy specimens demonstrated a diffuse infiltrate of atypical plasma cells that were difficult to classify using morphologic criteria alone. Immunophenotypic studies showed that each case was positive for plasma cell-associated antigens (cytoplasmic immunoglobin, CD38, or CD138) and negative for CD20. Of 4 cases, 3 had complex karyotypes, including the t(11;14)(q13;q32) or del(11)(q13). Despite chemotherapy and the use of novel therapeutic agents and stem cell transplantation, all 4 patients had short survival.

Characterization of bone marrow T cells in monoclonal gammopathy of undetermined significance, multiple myeloma, and plasma cell leukemia demonstrates increased infiltration by cytotoxic/Th1 T cells demonstrating a squed TCR-Vβ repertoire

BACKGROUND

The majority of studies published to date regarding the role of the bone marrow (BM) microenvironment in the pathogenesis of monoclonal gammopathies (MG) have focused on the interaction between stroma cells and plasma cells, whereas information concerning the lymphocytes infiltrating the tumor microenvironment is scanty.

METHODS

The authors measured the distribution, TCR-Vbeta repertoire, immunophenotype, and functional characteristics of different subsets of BM T lymphocytes from 61 nontreated patients with MG (30 patients with MG of undetermined significance [MGUS], 27 patients with multiple myeloma [MM], and 4 patients with plasma cell leukemia [PCL]).

RESULTS

The authors found a significantly increased rate of BM infiltration by T cells in all patient groups, at the expense of CD4+CD8- and CD4-CD8- T lymphocytes and both CD4+CD28- and CD8+CD28- cytotoxic/effector T cell subsets, and associated with TCR-Vbeta expansions in both CD4+ and CD8+ BM T cells in the majority of patients with MGUS, MM, and PCL. Moreover, the percentage of T cells secreting interferon (IFN)-gamma was found to be increased (P < or = 0.05) both in CD4+ and CD8+ T cells in MGUS and MM patients, and a higher plasma concentration of IFN-gamma was found in patients with MM. It is interesting to note that a positive correlation was noted between the proportion of CD28- and both the percentage of IFN-gamma-secreting cells and the proportion of expanded TCR-Vbeta lymphocytes within the total BM CD4+ T cells.

CONCLUSIONS

The results of the current study demonstrated an increased infiltration of BM by T cells associated with frequent TCR-Vbeta expansions and a more prominent cytotoxic/Th1 phenotype in all the patient groups studied.

[Plasma cell leukaemia: a rare variant of multiple myeloma. A case report]

Plasma cell leukaemia is a rare variant of multiple myeloma (2-3%), with an aggressive disease with short survival. It is defined as circulating peripheral blood plasma cells exceeding 2.000/ul and 20% of peripheral blood white cells. We present the case of 32-years-old man with left chest-wall pain, hepatomegaly, righ cervical adenopathy, 8800 leukocytes/ul with 33% of lymphocytes and 40% of plasma cell, 10.8 g/dl of proteins and a monoclonal hypergammaglobulinemia. Bone marrow biopsy showed 40-50 % of intramedullary plasma cell. There was a Ig G-kappa paraproteinemia.

CD44v6, a target for novel antibody treatment approaches, is frequently expressed in multiple myeloma and associated with deletion of chromosome arm 13q

BACKGROUND AND OBJECTIVES

Despite recent advances in the treatment of multiple myeloma (MM), this disease remains incurable in the majority of patients. Therefore, innovative treatment strategies are mandatory. Bivatuzumab mertansine is a novel cytotoxic immunoconjugate specifically targeting the CD44 splice variant CD44v6. To investigate the applicability of this compound to clonal plasma cell disorders, we analyzed CD44v6 expression on malignant plasma cells from patients with multiple myeloma.

DESIGN AND METHODS

Bone marrow samples from 57 patients with monoclonal gammopathy of undetermined significance (MGUS), MM, and plasma cell leukemia (PCL) were examined for CD44v6 expression by using flow cytometry (FACS) analysis. In addition, all samples were investigated by fluorescence in situ hybridization (FISH) with a specific probe for the chromosomal band 13q14.

RESULTS

In only 1 of 16 cases (6%) with MGUS and 1 out of 6 cases (17%) with stage I MM were plasma cells CD44v6 positive. In contrast, 43% of the cases with stage II/III MM or PCL expressed CD44v6. In these cases, CD44v6 expression was significantly correlated with chromosome 13q14 deletion as determined by FISH (p=0.02).

INTERPRETATION AND CONCLUSIONS

CD44v6 is frequently expressed in advanced, high-risk MM. CD44v6 expression correlates with chromosomal band 13q14 deletions, a well-known risk factor in MM. These results suggest that this epitope is a potential new target for monoclonal antibodies such as bivatuzumab mertansine.

Expression of the myeloid-associated marker CD33 is not an exclusive factor for leukemic plasmacytoid dendritic cells

A new entity of acute leukemia coexpressing CD4(+)CD56(+) markers without any other lineage-specific markers has been identified recently as arising from lymphoid-related plasmacytoid dendritic cells (pDCs). In our laboratory, cells from a patient with such CD4(+)CD56(+) lineage-negative leukemia were unexpectedly found to also express the myeloid marker CD33. To confirm the diagnosis of pDC leukemia despite the CD33 expression, we demonstrated that the leukemic cells indeed exhibited pDC phenotypic and functional properties. In 7 of 8 other patients with CD4(+)CD56(+) pDC malignancies, we were able to confirm that the tumor cells expressed CD33 although with variable expression levels. CD33 expression was shown by flow cytometry, reverse transcriptase-polymerase chain reaction, and immunoblot analysis. Furthermore, CD33 monoclonal antibody stimulation of purified CD4(+)CD56(+) leukemic cells led to cytokine secretion, thus confirming the presence of a functional CD33 on these leukemic cells. Moreover, we found that circulating pDCs in healthy individuals also weakly express CD33. Overall, our results demonstrate that the expression of CD33 on CD4(+)CD56(+) lineage-negative cells should not exclude the diagnosis of pDC leukemia and underline that pDC-specific markers should be used at diagnosis for CD4(+)CD56(+) malignancies.

CD27-triggering on primary plasma cell leukaemia cells has anti-apoptotic effects involving mitogen activated protein kinases

Primary plasma cell leukaemia (PCL) is a rare plasma cell malignancy, which is related to multiple myeloma (MM) and is characterized by a poor prognosis. In a previous study we demonstrated that PCL plasma cells display a high expression of CD27, in contrast to MM plasma cells. The present study was set out to assess the functional properties of CD27 expressed on PCL plasma cells by triggering with its ligand CD70. Using CD27-expressing purified plasma cells from a PCL patient we demonstrated that CD27-triggering modestly inhibited spontaneous and dexamethasone-induced apoptosis. In vitro stimulation and Western blotting showed that activation of p38 and extracellular-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinases (MAPK) was associated with CD27-mediated signal transduction. Specific inhibition of p38 and ERK1/2 MAPK abolished the anti-apoptotic effects of CD27-triggering. Interestingly, simultaneous inhibition of p38 and ERK1/2 strongly sensitized PCL cells for dexamethasone-induced apoptosis. Finally, in dexamethasone-treated PCL cells, CD27-triggering was associated with persistent DNA-binding activity of activator protein 1 (AP-1) but not of nuclear factor-kappaB. These findings suggest that, in primary PCL, specific anti-apoptotic pathways exist that might provide novel therapeutic targets.

Interaction between clonal plasma cells and the immune system in plasma cell dyscrasias

The term "monoclonal gammopathy" (MG) includes a group of clonal plasma cell disorders, which show heterogeneous clinical behavior. While multiple myeloma (MM) and plasma cell leukemia (PCL) are incurable malignant diseases, most patients with MG of undetermined significance (MGUS) show an indolent/benign clinical course. Evidence has accumulated which supports the role of the bone marrow microenvironment in MG. Accordingly, the survival, drug-resistance and proliferation of MM cells have been shown to be largely dependent on a supportive microenvironment. Among the different environment-associated parameters, those related to the status/activity of the immune system are particularly relevant. This review focuses on the different ways clonal plasma cells (PC) interact with the immune system in different models of MG, to characterize crucial events in the development and progression of MG. These advances may support the design of novel therapeutic approaches in patients with MG.

Diagnosis of plasma cell leukaemia: findings of the UK NEQAS for Leucocyte Immunophenotyping scheme

The diagnosis of plasma cell leukaemia, a rare disorder with an aggressive clinical course and poor prognosis, is not always straightforward and may be dependent on the results of immunophenotyping. Samples from two cases of plasma cell leukaemia have been issued by the UK NEQAS for Leucocyte Immunophenotyping Scheme during the last 5 years and on each occasion a significant number of laboratories failed to make the correct diagnosis. The details of the two samples issued and the results of both surveys are presented. The data highlights the need to adhere to guidelines for immunophenotyping, with respect to using the correct antibody panels, the importance of data interpretation in conjunction with morphological appearance as well as the need to participate in external quality assurance schemes.

Multiple myeloma presenting as primary non-secretory plasma cell leukemia

Primary plasma cell leukemia is a rare manifestation of multiple myeloma, whose neoplastic hierarchy in the classification of malignant hematological disorders is not yet very clearly defined. Morphological and immunological criteria indicate that the cells are at end stage of B cell maturation pathway. This unusual disorder is diagnosed by the presence of more than 2 x 10(9) plasma cells per liter of peripheral blood or more than 20% of the leucocytes being plasma cells on differential count. This occurs either denovo or as a terminal event in patients with long standing multiple myeloma. A case report of a young male patient with primary plasma cell leukemia is presented.

Generation of potent T(h)1 responses from patients with lymphoid malignancies after differentiation of B lymphocytes into dendritic-like cells

Dendritic cells (DC) are a group of potent antigen-presenting cells (APC) specialized for initiating T cell immune responses. They originate from the bone marrow and upon stimulation with bacterial products, cytokines or CD40 ligation they acquire the ability to migrate to the secondary lymphoid organs. In vitro DC can be generated from human CD34(+) bone marrow cells and CD14(+) peripheral blood monocytes after culture with different cytokine combinations. Since most leukemic cells and tumors in general are devoid of APC capacities, various strategies have been used to increase their recognition and confer the capacity of antigen presentation on them. Because of our interest in the design of vaccine immunotherapy protocols for the adjuvant treatment of patients with lymphoid malignancies (LM), we chose to explore the capacity of human acute lymphoblastic leukemia, chronic lymphocytic leukemia and plasma cell leukemia to differentiate into cells with APC and DC features. Our results among a sample of 10 patients demonstrate that such approach is feasible. Leukemic cells could be induced in the presence of IL-4 and CD40L to exhibit a DC morphology with a phenotype of mature DC-like cells. They could also induce a potent proliferative response in naive CD4(+) T cells. In addition, they expressed chemokine receptor CCR7 and CD62L, and could drive T cells towards a T(h)1 response with secretion of IFN-gamma. Our strategy leading to increased LM cell immunogenicity may have potential clinical applications and LM appear to be attracting candidates for adjuvant vaccination and adoptive immunotherapy.

Aggressive primary plasma cell leukemia with skin manifestations, trisomy 8 and molecular oligoclonal features

Plasma cell leukemia (PCL) is a very rare variant of multiple myeloma (MM) occurring in about 2% of newly diagnosed patients. Plasma cell leukemia may develop during the course of MM (secondary PCL) or it can occur without any prior sign of MM (primary PCL). We report a case of aggressive primary PCL with unusual clinical, cytogenetic and molecular features. A 36-year-old male patient was first seen because of fever and bone pain. On the skin of his chest, back, abdomen, and palpebras, there were nodular infiltrations resembling urticaria. White blood cell count was 10.8 x 10(9)/l with 41% plasmacytes. Bone marrow aspiration was hypercellular, 93.5% of cells were atypical plasmacytes and plasmablasts. The cytogenetic analysis of G-banded chromosomes in bone marrow cells yielded the trisomy 8. The skin biopsy specimen showed intensive infiltrates of uninucleated blastic cells similar to those found in the bone marrow. Immunophenotyping of bone marrow and skin neoplastic cells showed CD45+, CD45Ro+, CD68+, CD38+ and cytoplasmic kappa light chain +. The neoplastic cells stained negatively for lambda light chain, CD3, CD20, CD30, EMA, CD15, CD34, CD56 and factor VIII. The pattern of IgL genes rearrangement in the bone marrow aspirate, peripheral blood mononuclear cells, and skin specimens was examined by PCR analysis. All studied specimens showed three different IgK gene configurations suggesting that the neoplastic cells originated as a result of oligoclonal lymphoproliferation process. The patient received two courses of VAD (vincristine, doxorubicin, dexamethasone) without improvement and three courses of CHOP with only temporary stabilization of the disease. He died 5 months after the diagnosis of PCL because of disease progression and pneumonia.

IgG-secreting lymphoplasmacytoid leukaemia: a B-cell disorder with extensively mutated VH genes undergoing Ig isotype-switching frequently associated with trisomy 12

We investigated 16 patients with elevated serum monoclonal IgG and a leukaemic B-cell lymphocytic disorder different from multiple myeloma. Their clinical history was that of a non-aggressive disease with dominant splenomegaly and long survival. Whereas abnormal blood and bone marrow cells were predominantly small lymphocytes with a few lymphoplasmacytoid cells, histopathological features included a lymphoplasmacytic infiltrate in eight cases. Most frequently, abnormal blood cells displayed a CD19+CD5-CD23+/- immunophenotype different from that of chronic lymphocytic leukaemia, except in two cases with a CD19+CD5+CD23+ phenotype. Interestingly, a coexistent serum monoclonal IgM and/or surface IgMG+ with identical light chain was identified in 10 patients, whereas in the remaining six patients only IgG expression was determined. VH gene analysis was performed in eight patients to investigate the clonal origins of tumour cells. All cases utilized the VH3 family, with evidence of extensive somatic mutations and intraclonal homogeneity in all cases. VH gene analysis indicated a clonal relationship between cells expressing IgM and IgG, with one case being biclonal. Cytogenetic evaluation showed a high incidence of trisomy 12 (60%) and 13q14 deletion (40%). In conclusion, we have described an unusual subset of low-grade lymphoma with high-serum IgG and frequent lymphoplasmacytoid features in which tumour cells derive from post-follicular memory B cells undergoing isotype switching with some cases arrested at both the IgM and IgG stage and others as IgG-positive cells only.

A plasma cell leukemia patient showing bialleic 14q translocations: t(2;14) and t(11;14)

We report here an IgG/lambda-type plasma cell leukemia patient showing bialleic 14q32 translocations. All immunoglobulins were suppressed in this patient, but a small amount of monoclonal IgG was detected by immunoelectrophoresis. Two cells of six peripheral blood mononuclear cells showed 46,XY,t(2;14)(q11;q32), i(8)(q10), t(11;14)(q13;q32), del(12)(q13.1) by karyotypic analysis. We confirmed the juxtaposition of IgH and PRAD1/Cyclin D1 genes by fluorescent in situ hybridization and overexpression of the PRAD1/Cyclin D1 gene, but Southern analysis showed no bcl-1 rearrangement. We analyzed the t(2;14)(q11;q32) using DNA fragments derived from childhood B-chronic lymphocytic leukemia cases bearing t(2;14)(p13;q32). Southern and Northern analyses demonstrated no alteration of these genes, indicating that this t(2;14) was different from that of childhood B-chronic lymphocytic leukemia. At the IgH loci, Southern analysis showed two rearranged bands and one germ-line band of JH. Cmicro was deleted on one rearranged allele but remained on the other, suggesting that the chromosome translocation occurred after productive class switch recombination on the Cmicro deleted allele.

cCD79a expression in a case of plasma cell leukemia

In the present report we analyzed the immunophenotype of the neoplastic cells in a case of primary plasma cell leukemia (PCL). We performed simultaneous analysis of bone marrow and peripheral blood samples to investigate minor phenotypic variations that could explain the tendency of a population to leave medullary compartments. No major differences were observed between the two populations. The phenotype of the malignant clone was: CD38+, CD138+, CD19-, CD56+, CD117-, CD33+, CD44 , CD49e , cCD79a+ with positive cytoplasmic stain for kappa and IgG. Our findings expands the potential uses of cCD79a to cases of PCL with atypical morphology.

Cyclin D1 protein in multiple myeloma and plasmacytoma: an immunohistochemical study using fixed, paraffin-embedded tissue sections

In this study, we analyzed 69 plasma cell neoplasms, including 54 multiple myelomas (MMs), 3 cases of plasma cell leukemia, and 12 plasmacytomas, for expression of cyclin D1 protein using an immuno-histochemical method applied to routinely fixed, paraffin-embedded tissue sections. Cyclin D1 was expressed in 18 (26%) of 69 plasma cell neoplasms, including 16 (30%) of 54 MMs and 2 (17%) of 12 plasmacytomas. Three cases of plasma cell leukemia were negative. Cyclin D1 expression correlated with the cytologic differentiation and histologic stage of MM. Twelve (75%) of 16 MMs had intermediate or immature cytologic features and were histologic Stage III. With use of a polymerase chain reaction assay, we also analyzed six cases (three cyclin D1 positive, three cyclin D1 negative) for the t(11;14); one MM carried the t(11;14) and expressed cyclin D1 protein. We conclude that cyclin D1 expression occurs in approximately one-quarter of plasma cell neoplasms and correlates with the degree of cytologic differentiation and histologic stage. The relatively high frequency of cyclin D1 expression, compared with the less than 5% incidence of the t(11;14) detected by conventional cytogenetics reported in the literature, suggests that upregulation of cyclin D1 protein might be the result of mechanisms other than the t(11;14).

The Ig heavy chain gene is frequently involved in chromosomal translocations in multiple myeloma and plasma cell leukemia as detected by in situ hybridization

Chromosome rearrangement of 14q32.33 has recurrently occurred with variable partner sites, including 11q13.3, 8q24.1, 18q21.3, and 6p21.1 in multiple myeloma (MM). To assess the actual incidence of 14q32.33 translocation and to elucidate its implication in the pathogenesis of MM, we studied 42 patients with MM, plasma cell leukemia, or plasmacytoma and 5 with monoclonal gammopathy with undetermined significance (MGUS) by G-banding and molecular cytogenetic methods. Using double-color fluorescence in situ hybridization (DCFISH) with 2 Ig heavy chain (IgH) gene probes, a yeast artificial chromosome (YAC) clone containing variable region, and a phage clone containing gamma constant region, 14q32.33 translocation was detected as split signals of the IgH gene in 31 patients with plasma cell malignancies and 3 with MGUS. In contrast, of 40 patients who were assessed by G-banding, 3 (7.5%) showed the 14q+ chromosome. DCFISH detected a split of the IgH gene on interphase nuclei in 34 (73.9%) of 46 patients analyzed, whereas on metaphase spreads, it was in 22 (51.2%) of 43 patients analyzed. Interphase DCFISH was particularly useful to detect 14q32.33 translocation in 17 (65.4%) of 26 patients with normal karyotypes. Donor sites were identified in 11 of 22 patients demonstrated as carrying 14q32.33 translocation by metaphase FISH. Chromosome t(11;14)(q13.3; q32.33) was detected in 5 patients, t(8;14)(q24.1;q32.33) in 2, t(14;18)(q32.33;q21.3) in 2, and t(7;14)(q32.1;q32.33) in 1. A complex 14q32.33 translocation involving 3q and 16q24 was detected in 1 patient. Myeloma cells with t(7;14) showed myelomonocytoid surface antigen. Because rearrangements of 14q32.33 were closely associated with translocation of proto-oncogenes into the IgH gene, our findings indicate that 14q32.33 translocation with various partner chromosomes is a critical event in the pathogenesis of MM and MGUS.

[Clinical and evolutive study of plasma cell leukemia. Apropos of 9 cases]

Nine patients were diagnosed with plasma cell leukemia (PCL) from 1982-1995 at our hospital. Seven patients had primary PCL and the other two patients a secondary from. In this study the clinical and analytical features are reported, as well as the therapy and response obtained in these patients. Also, the karyotype findings in bone marrow of four of these patients are reported. At diagnosis, the most common symptom was bone pain which was associated with osteolytic lesions or diffuse bone demineralization. Analytical features were similar to those reported in other series of patients with PCL. Different therapeutical regimens were used, and VAD was the most commonly employed. Two patients underwent consolidation therapy with autologous transplantation of hemopoietic stem cells. The mean survival time was 5.5 months. Although PCL prognosis associated with chemotherapy is still poor, myeloablative therapy with hemopoietic support can increase the survival length in these patients.

Fas/Apo-1 (CD95)-mediated and CD95-independent apoptosis of malignant plasma cells

CD95 (Fas/Apo-1) mediates apoptosis in cells of various types. Expression of CD95 and its function were investigated in myeloma cells and most plasma cell lines have been found to be CD95-positive. Anti-CD95 antibody induced apoptosis in these cell lines in a manner dependent on intensity of CD95 expression. Bel-2 expression levels in these cell lines were not correlated with sensitivity to CD95-induced apoptosis. Myeloma cells from approximately 70% of cases analyzed expressed CD95, suggesting a high frequency of CD95 expression of myeloma cells. The incidence of CD95 expression in samples from extramedullary lesions were higher than those of bone marrow myeloma cells. Anti-CD95 antibody did not induce apoptosis in some freshly isolated myeloma cells despite the expression of CD95 induced apoptosis in myeloma cell lines in a manner dependent on intensity of CD95 expression. In fresh samples, intensity of CD95 expression was not correlated with apoptosis evoked by anti-CD95 antibody. Interestingly, isolated myeloma cells with an high-level expression of CD95 showed spontaneous apoptosis during in vitro incubation. This was observed in samples from cases with high serum levels of lactate dehydrogenase (LDH), suggesting that the LDH was derived from cells undergoing spontaneous apoptosis in vivo. Taken together, CD95 is expressed in most myeloma cell lines and in many freshly isolated myeloma cells. However, some of the latter escape from CD95-dependent apoptosis despite the expression of CD95. Moreover, some myeloma cells from cases with aggressive disease may undergo apoptosis in a CD95-independent manner. In this review, the significance of CD95 and apoptosis of myeloma cells are discussed.

Multiple gastric involvement by myeloid antigen CD13-positive non-secretory plasma cell leukaemia

Gastrointestinal tract involvement is a rare complication of plasma cell neoplasia. We present a case of non-secretory type primary plasma cell leukaemia (PCL) with multiple gastric involvement. Dual surface antigen analysis of bone marrow cells revealed that atypical plasma cells coexpressed CD38 and myeloid antigen CD13. Upper gastrointestinal endoscopy disclosed multiple submucosal masses in the body of the stomach. Endoscopic biopsy specimens showed marked infiltration of atypical plasma cells consistent with a diagnosis of gastric involvement by PCL. Since CD13 antigen is identical to aminopeptidase N, a membrane-bound glycoprotein thought to be involved in the process of tumour invasion, CD13 expression on neoplastic plasma cells may be related to the gastric involvement in this patient.

Biologic effects of anti-interleukin-6 murine monoclonal antibody in advanced multiple myeloma

In patients with advanced multiple myeloma (MM) there is an excess of production of interleukin-6 (IL-6) in vivo, and elevated serum levels are associated with plasmablastic proliferative activity and short survival. These data prompted us to perform a clinical trial with a murine anti-IL-6 monoclonal antibody (MoAb) to neutralize the excess of this putatively deleterious factor in these patients. Ten MM patients with extramedullary involvement frequently were treated with anti-IL-6 MoAb. The MoAb was administered intravenously to 9 patients; 1 patient with malignant pleural effusion received intrapleural therapy. Of the 3 patients who succumbed to progressive MM after less than 1 week of treatment (including the only 1 treated locally), 2 with evaluable data exhibited marked inhibition of plasmablastic proliferation. Among the 7 patients remaining more homogeneous receiving the anti-IL-6 MoAb for more than 1 week, 3 had objective antiproliferative effect marked by a significant reduction of the myeloma cell labelling index within the bone marrow. One of these 3 patients achieved a 30% regression of tumor mass. However, none of the patients studied achieved remission or improved outcome as judged by standard clinical criteria. Of major interest, objective antiproliferative effects were associated with complete inhibition of C-reactive protein (CRP) synthesis and low daily IL-6 production in vivo. On the other hand, the lack of effect in 4 patients was associated with a higher IL-6 production and inability of the MoAb to neutralize it. Anti-IL-6 was also associated with resolution of low-grade fever in all the patients and with worsening thrombocytopenia and mild neutropenia. The generation of human antibodies to Fc fragment of the murine anti-IL-6 MoAb observed in 1 patient was associated with dramatic progression. These data show that anti-IL-6 MoAb can suppress the proliferation of myeloma cells and underscore the biologic role of IL-6 for myeloma growth in vivo. Furthermore, suppression of CRP and worsening of neutropenia/thrombocytopenia both indicate that IL-6 is critically involved in acute-phase responses and granulopoiesis/thrombopoiesis.

Expression of the Fas antigen on primary human leukemia cells

The antigen defined by the monoclonal antibody anti-Fas can mediate apoptosis, is associated with the receptor for tumor necrosis factor, and is expressed on a limited number of human tissues. In this study we analyzed the expression of Fas on primary human leukemic cells and on mononuclear cells from other hematologic disorders. A total of 95 samples of blood or bone marrow were studied by indirect immunofluorescence. These samples included the normal controls, 47 cases of acute myelogenous leukemia (AML), 11 cases of acute lymphoblastic leukemia (ALL), 21 cases of leukemic lymphoma, seven cases of chronic myelogenous leukemia (CML), five cases of plasma cell leukemia or multiple myeloma, and five cases of myelodysplastic or myeloproliferative syndromes. Normal controls were negative without exception. Among AML, 13/47 cases (28%) were positive; among ALL, 1/11 cases (9%) was positive; among leukemic lymphomas, 3/21 cases (14%) were positive. In a case of plasma cell leukemia which strongly expressed the Fas antigen, we demonstrated that the antibody mediates cell lysis, which was synergistically enhanced by the addition of rabbit complement. In patients with AML, Fas positivity had no obvious clinical relevance. Taken together, our results show that approximately 30% of cases of AML and occasionally other leukemias express the Fas antigens, whereas normal controls are negative in our test system. These findings may be useful in the treatment of refractory leukemias or may permit the purging of autologous transplants.

Differential expression of interleukin-2 receptors (alpha and beta chain) in mature lymphoid neoplasms

We investigated the expression of interleukin-2 receptors (IL-2R) in 60 adult patients with mature lymphoid neoplasms by flow cytometric analysis, using two monoclonal antibodies, anti-Tac for IL-2R alpha-chain (IL-2R alpha) and Mik-beta 1 for IL-2R beta-chain (IL-2R beta). Among B-cell malignancies, IL-2R alpha was found in 13/25 (52%) cases of chronic lymphocytic leukemia (CLL) and its variants, 3/14 (21%) of a heterogeneous group of non-Hodgkin's lymphoma (NHL) and none of the plasma cell diseases. IL-2R beta was not observed in any of B-cell neoplasms. IL-2R alpha was more frequently expressed in CD11b(+) B-cell neoplasms than in CD11b(-) (P < 0.05). In T-cell disorders, all three cases of adult T-cell leukemia/lymphoma expressed IL-2R alpha but not IL-2R beta. IL-2R beta was detected in 3/8 cases of CLL and 2/3 of NHL and none of these cases expressed IL-2R alpha. CD8(+) malignant T-cells commonly displayed IL-2R beta. These data indicate that the IL-2R alpha and IL-2R beta in mature lymphoid neoplasms was expressed independently each other and was associated with the particular phenotypical characteristics of neoplastic cells, respectively.

IgE plasma cell leukemia successfully treated with combination VAD (vincristine, doxorubicin, dexamethasone) and MP (melphalan, prednisolone) followed by interferon-alpha

A 69-year-old woman with IgE/kappa plasma cell leukemia (PCL) was treated with a sequential combination of VAD (vincristine, doxorubicin, dexamethasone) and MP (melphalan, prednisolone) followed by interferon-alpha (IFN alpha). A complete remission was achieved for 14 months. Maintenance therapy with IFN alpha has continued for an additional 10 months. IgE PCL is extremely rare. The biological characteristics of the myeloma cells, including surface marker, adhesion molecule, karyotype, DNA analysis, and the response to various cytokines, are presented.

Production of monoclonal antibodies specific for antigens derived from tissue of chinook salmon (Oncorhynchus tshawytscha) affected with plasmacytoid leukemia

Two distinct monoclonal antibodies (MAB) were prepared for testing with kidney, spleen, and retrobulbar tissue imprints made from chinook salmon (Oncorhynchus tshawytscha) affected with plasmacytoid leukemia. (PL). Hybridomas were prepared from mice immunized with whole and lysed cells purified from renal or retrobulbar PL-positive tissues, which had been obtained from naturally and experimentally infected fish from British Columbia, Canada. The MAB reacted with at least 4 morphologically different cell types; fluorescence was associated with the plasma membrane and cytoplasm. The MAB also reacted with kidney imprints made from chinook salmon affected with a PL-like lymphoproliferative disease in California, indicating that these 2 diseases might be caused by a similar agent. The MAB did not react with any of the kidney or spleen imprints made from wild chinook salmon collected from a river in Ontario, Canada.

[Preliminary study of immunophenotype of multiple myeloma cells]

Using the alkaline phosphatase-anti-alkaline phosphatase (APAAP) technique, plasma cells from multiple myeloma (MM, 23 cases), plasma cell leukemia (PCL, 2 cases) and reactive plasmacytosis (RP, 13 cases) were immunophenotyped with a panel of monoclonal antibodies (McAb). The results showed that McAbCD38 was strongly positive in high percentage of MM and RP cases and the CD9 was the next. 9/23 MM expressed CD10. Our results might indirectly support that CD10 is a malignant marker of MM with poor prognosis, a concept proposed by Durie. The results were (1) all RP but 1 acute monocytic leukemia related to RP were CD10 negative. (2) In our series 2 cases of plasma cell leukemia (PCL) expressed CD10; (3) 4 MM cases survived more than 2 years were CD10 negative. A few MM cases also expressed other surface markers of pre-B and B lymphocyte, such as CD19, CD20, CD22, HLA-DR, cytoplasmic mu chain. CD20 was positive in 4/21 MM and negative in all RP cases. 7/22 MM expressed HLA-DR, and 1/13 RP did so, among them there was a significant difference. HLA-DR seems to be another malignant marker of plasma cells. 1 MM expressed CD8, and 1 PCL highly expressed CD4 indicating PCL might be heterogeneous. Lymphoid stem cells may be involved in MM and PLC. We conclude that multiple myeloma cells have different immunophenotypes and CD10, CD20 and HLA-DR may help to differentiate MM from RP.