Anti-CD20 antibody as consolidation therapy in a patient with primary plasma cell leukemia after high-dose therapy and autologous stem cell transplantation

In multiple myeloma (MM), circulating malignant B cells are proposed as the proliferative compartment of the disease. In view of the close relationship between multiple myeloma and primary plasma cell leukemia (PCL), an anti-CD20 antibody treatment might also be considered as consolidation for patients with PCL. A 55-year-old patient diagnosed with PCL achieved complete remission after autologous transplantation. A total of four weekly courses of rituximab (375 mg/m(2)) were administered. Prior to antibody therapy, CD20+ cells comprised 22.6% of the mononuclear cells in peripheral blood (PB) assessed by flow cytometry and were enriched by magnetic activated cell sorting (MACS). In the enriched CD20+ fraction, 0.093% clonotypic cells were detected using a quantitative polymerase chain reaction (PCR) assay based on limiting dilutions. The proportion of clonotypic cells was 0.034% in PB and 0.032% in bone marrow (BM). Rituximab depleted CD20+ cells completely in PB and BM. Tumor load in PB and BM at day 40 and in PB at day 70 did not change in comparison to prior to therapy (0.037% in PB, 0.026% in BM). At day 90, the tumor load increased to 0.066% in PB. At day 120, the patient relapsed with 0.65% CD38++/CD138+/CD20- plasma cells and furthermore no CD20+ B cells in PB. The expansion of plasma cells was accompanied by an increase in the tumor load in both compartments (PB: 0.65%, BM: 1.8%). The accumulation of plasma cells during disease progression without the reappearance of CD20+ cells did not sustain the role of circulating clonotypic B cells as proliferative compartment in our patient. However, it cannot be excluded that rituximab was not able to eradicate malignant B cells, which subsequently contributed to relapse.

Systemic capillary leak syndrome preceding plasma cell leukaemia

We report a patient with plasma cell leukaemia with systemic capillary leak syndrome, a rare disorder often associated with monoclonal gammopathy. In this patient, the manifestation of capillary leak syndrome antedated the diagnosis of plasma cell leukaemia by 5-6 months. During that time, he was repeatedly admitted to the hospital with weight gain, congestive cardiac failure, cough and anasarca in the presence of normal renal function, liver function and normal echocardiography. On presentation, a serum protein electrophoresis showed monoclonal IgG; the blood smear showed 60% plasma cells with a total count of 4.4 x 10(9)/l. A bone marrow aspirate showed replacement of the normal marrow by sheets of immature plasma cells. His systemic capillary leak syndrome initially responded to decongestive therapy with terbutaline and aminophylline but later on he became refractory to them and responded to vincristine, doxorubicin and dexamethasone (VAD) combination therapy only transiently. Danocrine and pentoxifylline, added during VAD chemotherapy, did not produce a durable response in capillary leak syndrome, which finally responded to autologous peripheral blood stem cell transplantation (PBSCT). After PBSCT, he remained free of capillary leak for 10 months without terbutaline, pentoxifylline corticosteroids, aminophylline or danocrine. His disease relapsed without recurrence of the capillary leak. He died 15 months after PBSCT and 20 months after the diagnosis of plasma cell leukaemia.

Plasma cell leukemia

Plasma cell leukemia (PCL) is a rare aggressive variant of multiple myeloma (MM) characterized by a fulminant course and poor prognosis. The median survival is measured in months. Therapy and prognosis partially depend on whether the disease presents de novo or as a secondary process involving the leukemic transformation of a previously diagnosed MM. Secondary PCL represents a terminal event for refractory/relapsed MM and is usually not responsive to any treatment modality. The optimal regimens for the treatment of primary PCL have not been firmly established. Induction with combination chemotherapy, followed by high-dose chemotherapy (preferably within the setting of a clinical trial), is the current recommended approach for eligible patients.

A pilot study of combined immunotherapy with autologous adoptive tumour-specific T-cell transfer, vaccination with CD40-activated malignant B cells and interleukin 2

Most B-cell malignancies are incurable diseases and therefore warrant new therapeutic approaches. In a pilot study, we tested the feasibility and safety of combined immunotherapy consisting of adoptive transfer of autologous tumour-specific T cells, low-dose interleukin 2 (IL-2) and a cellular vaccine of CD40-activated plasma cell leukaemia (PCL) cells in a patient who failed tandem repeat stem cell transplantation and idiotype vaccination. Autologous tumour-specific T cells for adoptive T-cell transfer were propagated in vitro by repetitive stimulation with autologous ex vivo CD40-activated PCL cells. CD40-activated PCL cells for vaccination were similarly generated ex vivo by co-culture with CD40 ligand transfectants. Autologous T cells (5 x 108 and 2.5 x 109 for two separate treatment cycles) generated ex vivo and cytotoxic against autologous tumours were infused and well tolerated by the patient. Fever and myalgias were closely related to IL-2 injections and no other adverse effects were observed. A temporary decrease of PCL cells in peripheral blood was seen after the first cycle of adoptive T-cell therapy, tumour cell vaccination and low-dose IL-2. Tumour progression was associated with tumour cells that (1) expressed a complex karyotype, (2) demonstrated loss of MHC class II, and (3) did not induce autologous tumour-specific T-cell lines ex vivo. We demonstrated the safety and feasibility in combining autologous tumour-specific T-cell therapy with low-dose IL-2 and that clinical trials based on the use of CD40-activated autologous tumour cell vaccines are warranted in patients with CD40-activated autologous tumour cells, either as a vaccine or for ex vivo stimulation of autologous T cells.

Long-term survival in primary plasma cell leukemia after therapy with VAD, autologous blood stem cell transplantation and interferon-alpha

Primary plasma cell leukemia (PCL) is a rare form of plasma cell neoplasm with a poor prognosis. Conventional melphalan-based treatments have been most disappointing. We report the case of a 62-year-old man with a primary form of PCL treated with VAD combination achieving an objective response, and who received high-dose melphalan and autologous peripheral blood stem cell (PBSC) transplantation followed by interferon-alpha. During the remission time, lasting for 3 years, an infiltration by large granular lymphocytes (LGL) was noted in peripheral blood. However, when the number of LGL declined, a bone marrow relapse was observed. The treatment for PCL and the possible role of these LGL on tumor cell control after autologous PBSC transplantation are discussed.

Long-lasting complete remission in plasma cell leukemia after aggressive chemotherapy and CD34-selected autologous peripheral blood progenitor cell transplant: molecular follow-up of minimal residual disease

Plasma cell leukemia is a rare disease associated with very poor survival with standard treatment. We report a patient affected by plasma cell leukemia treated with aggressive chemotherapy and autologous CD34-selected PBPC who achieved a complete remission now lasting more than 2 years. Molecular studies confirmed the presence of minimal residual disease (MRD) despite the absence of disease activity. High-dose chemotherapy with stem cell rescue may be applied to selected patients considering the impact of the treatment on survival. The meaning of molecular MRD in this setting is unclear.

Selective apoptosis of neoplastic cells by the HLA-DR-specific monoclonal antibody

The human major histocompatibility complex (MHC) class II molecule-specific monoclonal antibody (mAb) 8D1 can induce apoptosis of tumor cells expressing HLA-DR molecules on their surface. This effect is associated with a cross-linking of HLA-DR, since monovalent Fab fragments of 8D1 cannot mediate cytotoxicity unless they are anchored to a solid support. Anti-neoplastic activity of 8D1 is highly selective, i.e. the mAb affects neither the viability nor the function of non-malignant HLA-DR+ cells. These findings raise the possibility of a selective antibody-based anti-tumor therapy of class II positive blood cell neoplasm.

A single step density gradient separation for large scale enrichment of mobilized peripheral blood progenitor cells collected for autotransplantation

Peripheral blood leukocytes are becoming the preferred source of hematopoietic progenitor/stem cells for autologous transplantation. However, in vitro purging procedures are complex and expensive when applied to peripheral blood progenitor cells harvests. This is mainly due to the large quantities of nucleated cells present in leukapheresis collections. Aiming to reduce total cellularity without significant loss of CD34+ cells, we developed an in vitro cell separation procedure based on ficoll/metrizoate gradient used at a final density of 1.067 g/ml. To obtain this density, standard Lympho-prep (1.077 g/ml) was diluted with normal saline solution (NaCl 9 g/l). Twenty-six leukapheresis collections (median cellularity 21.1 x 10(9), range 2.8-60) from 14 patients with non-Hodgkin's lymphoma, multiple myeloma or plasma cell leukemia were processed (median two leukaphereses per patient). Mean (+/- s.d.) recovery of total nucleated cells, CD34+ cells and CFU-GM was 20.9 +/- 10%, 74.7 +/- 22% and 70.5 +/- 19%, respectively. Cumulative per patient progenitor cell recovery was always above 50%, and as high as 80% in 10/14 patients, while total cellularity was reduced to a median 21.5% (10-33%) of pre-separation values. Contaminating neoplastic cells, identified by immunofluorescence in five collections, were reduced by 1-2 logs. The results indicate that our density gradient separation is an effective method to reduce total cellularity prior to immunological purging, without significant loss of progenitor cells.

Consolidation therapy with autologous stem cell transplantation in plasma cell leukemia after VAD, high-dose cyclophosphamide and EDAP courses: a report of three cases and a review of the literature

Plasma cell leukemia (PCL) is a rare lymphoproliferative disorder characterized by a malignant proliferation of plasma cells in blood and bone marrow. Treatment of primary PCL has been mostly disappointing. Three patients with primary PCL are described who received high-dose melphalan with autologous PBSC support after vincristine, doxorubicine and dexamethasone (VAD), high-dose cyclophosphamide, and etoposide, cisplatinum, dexamethasone and cytosine arabinoside (EDAP) courses. All patients were in CR post-transplantation. One patient relapsed after 3 months; the other patients are still in CR, after 14 and 26 months, respectively. These results in conjunction with data from the literature suggest that intensive chemotherapy for PCL is promising.

[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.

Effective autologous peripheral blood stem cell transplantation in plasma cell leukemia followed by T-large granular lymphocyte expansion: a case report

We report a case of de novo plasma cell leukemia, resistant to standard VMD (vincristine, mitoxantrone, dexamethasone) and CVP (cyclophosphamide, vincristine and prednisone) protocols, treated with a chemotherapy intensification regimen (high-dose cyclophosphamide, modified EDAP, Dexa-BEAM) and peripheral blood stem cell transplantation, performed using fractionated total body irradiation and high dose melphalan. The patient is currently alive and well, in very good partial remission 12 months after transplant and 22 months after diagnosis, disclosing a significant proportion of bone marrow and peripheral blood CD3+, CD8+, CD57+, HLA-Dr+ large granular lymphocytes with cytotoxic activity against neoplastic plasma cells.

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.

Long-term disease-free survival after autologous bone marrow transplantation in a primary plasma cell leukaemia: detection of minimal residual disease in the transplant marrow by third-complementarity-determining region-specific probes

Primary plasma cell leukaemia (PPCL) is a rare form of plasma cell neoplasm. Treatments of PPCL have been most disappointing. A patient with PPCL received high-dose melphalan plus total body irradiation and autologous bone marrow transplantation (ABMT). By using third-complementarity-determining region (CDRIII)-specific probes, minimal residual disease (MRD) was detected in remission marrow, collected 1 month before ABMT. MRD was no longer detected by CDRIII-specific probes 6, 19 and 26 months after transplantation. The patient remained in complete remission up to 59 months after ABMT.

[Multiple myeloma: a proper selection of the treatment regimen for an individual patient]

The importance of distinguishing accurately between patients with asymptomatic or stable monoclonal gammopathies and those with overt multiple myeloma cannot be overemphasized. Most patients with asymptomatic monoclonal gammopathy will remain stable without treatment, but in some overt multiple myeloma may develop after several to many years of observation. Multiple myeloma is a malignant disease of the bone marrow plasma cells. Most patients die of progressive disease despite chemotherapy. Thus, accurate differentiation between asymptomatic monoclonal gammopathy and multiple myeloma is essential. Given a diagnosis of overt myeloma, how does the physician decide which treatment regimen to use for an individual patient? Based on the risk assessment, age considerations and risk benefit consideration for the patient, the most proper selection of treatment regimen should be done. Until we can identify a group of patients who will survive longer, intensive therapy, including stem cell transfusion, should be done with caution.

[Successful VEP-IFN-alpha therapy in a case of non-secretory plasma cell leukemia (BJ-kappa type)]

Plasma cell leukemia is a rare disorder with poor prognosis. We present a case of non-secretory primary plasma cell leukemia (Bence-Jones kappa type), which was treated successfully by VEP-IFN-alpha therapy. A 82-year old man was admitted to Kanazawa Medical University in May 1991, because of emaciation and dehydration. Clinical findings showed decreased level of gamma-globulin (IgG, IgA and IgM were all decreased markedly), hypercalcemia, renal dysfunction and increased serum beta-2 microglobulin. The peripheral blood leukocyte count was 30,100/microliters with 64% plasma cells, and 80.4% plasma cells were also observed in the bone marrow. Only light chain-kappa was detected in plasma cells by an immunohistochemical staining method, but immunoelectrophoresis showed no M-bow either in serum or urine. Electron microscopy revealed typical plasma cells with prominently developed rough endoplasmic reticulum. From these results, the diagnosis of non-secretory primary plasma cell leukemia was established. He was treated with VEP-IFN-alpha regimen, and plasma cells decreased markedly in both peripheral blood and bone marrow. Serum immunoglobulin recovered to within the normal range. After 6 courses of VEP-IFN-alpha, complete remission was achieved and the remission was maintained until he died of an unrelated event, bronchial obstruction due to misswallowing, in April 1992.

High amounts of circulating interleukin (IL)-6 in the form of monomeric immune complexes during anti-IL-6 therapy. Towards a new methodology for measuring overall cytokine production in human in vivo

A patient with plasma cell leukemia was treated with anti-interleukin (IL)-6 monoclonal antibodies (mAb) for 2 months. Using chromatography on protein A-Sepharose, anti-murine-IgG-Sepharose, anti-IL-6-mAb-Sepharose and gel filtration at pH 2.3, we have demonstrated that the anti-IL-6 mAb, by preventing the binding of IL-6 to its cell membrane receptor and its renal elimination, has induced huge amounts of IL-6 to circulate in the form of monomeric immune complexes. By using this observation, we have developed a mathematical modelling that allows the determination of the overall daily production of IL-6 in this patient, which was in the range of 15 micrograms per day. Overall in vivo production of cytokines has never been evaluated in animals or in humans before.

Murine anti-interleukin-6 monoclonal antibody therapy for a patient with plasma cell leukemia

A patient with primary plasma cell leukemia resistant to chemotherapy was treated for 2 months with daily intravenous injections of anti-interleukin-6 (IL-6) monoclonal antibodies (MoAbs). The patient's clinical status improved throughout the treatment and no major side effects were observed. Serial monitoring showed blockage of the myeloma cell proliferation in the bone marrow (from 4.5% to 0% myeloma cells in the S-phase in vivo) as well as reduction in the serum calcium, serum monoclonal IgG, and the serum C-reactive protein levels. The serum calcium and serum monoclonal IgG corrected by approximately 30%, whereas the C-reactive protein corrected to undetectable levels during treatment. No major side effects developed, although both platelet and circulating neutrophil counts decreased during anti-IL-6 therapy. A transient immunization was detected 15 days after the initiation of the treatment, which could explain the recovery of myeloma cell proliferation after 2 months of treatment (2% myeloma cells in the S phase). In conclusion, this first anti-IL-6 clinical trial demonstrated the feasibility of injecting anti-IL-6 MoAbs, and also a transient tumor cytostasis and a reduction in IL-6-related toxicities. It gave insight into the major biologic activities of IL-6 in vivo and may serve as a basis for further development of anti-IL-6 therapy in myeloma and other IL-6-related diseases.

Plasma cell leukemia and hyperviscosity syndrome

A 56-year-old man had dyspnea, weight loss, hemoptysis, and a generalized bleeding diathesis. Physical examination disclosed hepatosplenomegaly, congestive heart failure, and multiple sites of bleeding. Severe anemia, thrombocytopenia, rouleaux formation, and a leukocytosis with circulating immature plasma cells were observed, along with azotemia, hyperuricemia, and marked elevation of total proteins with a monoclonal IgG kappa spike. The finding of increased serum viscosity confirmed the clinical impression of the hyperviscosity syndrome. Emergency plasma exchange produced marked improvement in the clinical manifestations of hyperviscosity syndrome. Systemic chemotherapy resulted in a partial remission of the disease, but the patient ultimately died of complications of treatment. In this review, we discuss the diagnosis and management of the hyperviscosity syndrome.

Plasma cell leukemia

In summary, plasma cell leukemia is a rare disorder that can develop spontaneously or evolve in patients with multiple myeloma. The diagnosis is based on laboratory features, including a plasmacytosis exceeding 2 X 10(9)/L or 20% of the differential cell count. Primary plasma cell leukemia should also be considered when fewer plasma cells are present provided that a clonal proliferation is documented. Most clinical characteristics are similar in both types of plasma cell leukemia. Lymphadenopathy and hepatosplenomegaly are more common in the primary form, and lytic bone lesions are more frequent in the secondary form. Patients with primary plasma cell leukemia may initially respond better to chemotherapy, including single agent drugs commonly used in multiple myeloma. However, resistant disease is expected, and most data suggest a median survival of less than 6 months in both types of leukemia. Because patients with primary plasma cell leukemia are in better condition, intensive chemotherapy and approaches such as bone marrow transplantation should be considered, especially in younger patients.

Treatment of plasma cell neoplasm with recombinant leukocyte A interferon and human lymphoblastoid interferon

Thirty cases of plasma cell neoplasms (24 multiple myeloma, one plasma cell leukemia, and three primary macroglobulinemia) were treated with two kinds of highly purified alpha-interferons, recombinant human leukocyte interferon (rIFN-alpha A) (16 cases) and human lymphoblastoid interferon (HLBI) (14 cases). Partial remission (PR) was obtained in two of 16 evaluable cases treated with rIFN-alpha A and in two of 12 evaluable cases treated with HLBI. If minor response (MR) was included, responses were observed in seven (31.3%) and six (50%), respectively. Response (PR + MR) was noted in 38% of 21 previously treated patients and 71% of seven previously untreated patients. Side-effects were noted in more than two-thirds of the patients. They included fever, malaise, nausea/anorexia and myelosuppression. Thus, these two kinds of highly purified alpha-interferon were effective in plasma cell neoplasm, producing unequivocal response in 14.3% of the cases without unacceptable side-effects.