Clinical Characteristics and Outcomes of Patients With Primary Plasma Cell Leukemia in the Era of Novel Agent Therapy

OBJECTIVE

To evaluate the clinical outcomes of patients with primary plasma cell leukemia (pPCL) defined by 5% or greater clonal circulating plasma cells on peripheral blood smear and treated with novel agent induction therapies.

PATIENTS AND METHODS

A cohort of 68 patients with pPCL diagnosed at the Mayo Clinic in Rochester, Minnesota, from January 1, 2000, to December 31, 2019, and treated with novel agent induction therapies was evaluated.

RESULTS

The median follow-up was 46 (95% CI, 41 to 90) months. The median bone marrow plasma cell content was 85% (range, 10% to 100%) and median clonal circulaitng plasma cell percentage on the peripheral blood smear was 26% (range, 5% to 93%). There was a preponderance of t(11;14) primary cytogenetic abnormality in this cohort. The median time to next therapy (TTNT) and overall survival (OS) for all patients with pPCL patients in this cohort was 13 (95% CI, 9 to 17) and 23 (95% CI, 19 to 38) months, respectively. However, when stratified by cytogenetic risk, the median TTNT and OS were 16 and 51 months for standard risk vs 9 and 19 months for high risk (P=.01 for OS).

CONCLUSION

Primary plasma cell leukemia remains an aggressive disease with poor prognosis despite novel agent-based therapies. Some patients have better than expected survival and this phenomenon may be influenced by the absence of high-risk cytogenetics. Newer treatment regimens are needed to improve the prognosis of this devastating disease.

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.

Plasma Cell Leukemia – the Forgotten Dis­ease

BACKGROUND

Plasma cell leukemia (PCL) is a rare dis-ease and possibly the most aggressive form of monoclonal gammopathy. It is classified into two forms -  primary PCL that occurs without a previously identifiable multiple myeloma stage, and secondary PCL that develops from previously dia-gnosed multiple myeloma. These two forms have different cytogenetic and molecular profiles, but both forms have an aggressive clinical course. Combinations of different therapeutic approaches includ-ing autologous stem cell transplantation and currently proteasome inhibitors and immunomodulatory drugs are used to treat PCL. Current dia-gnostic criteria, developed in the 1970s, may underestimate PCL prevalence; thus, prospective re-evaluation is be-ing considered.

PURPOSE

The aim of this study is to review all available information about PCL with an emphasis on dia-gnostics, treatment, and circulat-ing plasma cells features.

CONCLUSION

Although PCL is rare, it is quite a severe dis-ease. Current treatments us-ing the latest therapeutics have prolonged patient survival. However, due to the low incidence of PCL, information about the dis-ease is very limited and comes mostly from small retrospective studies. Further studies of PCL are needed, because new information could increase in patient survival and our understand-ing of its pathogenesis. Key words plasma cell leukemia -  multiple myeloma -  plasma cells -  cytogenetics -  treatment This work was supported by grant NV18-03-00203. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submited: 2. 11. 2018 Accepted: 18. 11. 2018.

Risk of acute myeloid leukemia and myelodysplastic syndrome after autotransplants for lymphomas and plasma cell myeloma

BACKGROUND

Exposures to DNA-damaging drugs and ionizing radiations increase risks of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

METHODS

9028 recipients of hematopoietic cell autotransplants (1995-2010) for Hodgkin lymphoma (HL; n = 916), non-Hodgkin lymphoma (NHL; n = 3546) and plasma cell myeloma (PCM; n = 4566), reported to the CIBMTR, were analyzed for risk of subsequent AML or MDS.

RESULTS

335 MDS/AML cases were diagnosed posttransplant (3.7%). Variables associated with an increased risk for AML or MDS in multivariate analyses were: (1) conditioning with total body radiation versus chemotherapy alone for HL (HR = 4.0; 95% confidence interval [1.4, 11.6]) and NHL (HR = 2.5 [1.1, 2.5]); (2) ≥3 versus 1 line of chemotherapy for NHL (HR = 1.9 [1.3, 2.8]); and (3) subjects with NHL transplanted in 2005-2010 versus 1995-1999 (HR = 2.1 [1.5, 3.1]). Using Surveillance, Epidemiology and End Results (SEER) data, we found risks for AML/MDS in HL, NHL and PCM to be 5-10 times the background rate. In contrast, relative risks were 10-50 for AML and approximately 100 for MDS in the autotransplant cohort.

CONCLUSIONS

There are substantial risks of AML and MDS after autotransplants for HL, NHL and PCM.

Plasma Cell Leukemia: A Report on Three Patients

Three patients with plasma cell leukemia are reported. Two of them had a previous history of myeloma; the third one started with a plasma cell leukemia. Diagnosis was made from the required presence of 20% plasma cells in the peripheral blood. In all 3 cases, bone marrow aspiration and peripheral blood showed plasma cells strongly positive for acid phosphatase and alpha-naphthyl acetate esterase, and negative for periodic acid-Schiff. The first patient was treated with a polychemotherapy regimen that included vincristine, cyclophosphamide, chlorambucil and prednisone, and the second patient with melphalan and prednisone; the third one, who started with plasma cell leukemia, received total body irradiation at the dose of 600 rad. The results of the therapy and survival time, which was never more than 3 months, are in accord with other reports in the literature.

Human metapneumovirus in haematopoietic stem cell transplantation recipients: a case series and review of the diagnostic and therapeutic approach

Human metapneumovirus (hMPV) is a paramyxovirus that causes respiratory tract infections ranging from mild upper airway infection to severe pneumonia. Patients with haematological disease, especially haematopoietic stem cell transplantation (HSCT) recipients, are more likely to develop more severe infections. We describe three cases of hMPV infection in HSCT patients. The most reliable diagnostic procedure for hMPV is multiplex ligation-dependent probe amplification (MLPA) on a nasopharyngeal swab. Sensitivity and specificity of MLPA to detect hMPV is high and time to diagnosis is short. A number of other respiratory pathogens can be tested in one test run. Treatment is mainly supportive and only a few antiviral agents are available for treating paramyxovirus infections. Ribavirin and immunoglobulins were reported to be effective in cases of HSCT patients with hMPV pneumonia but their efficacy has not been studied in randomised trials.

Primary Plasma Cell Leukemia in the Era of Novel Agents: A Multicenter Study of the Japanese Society of Myeloma

We investigated the treatment and outcome of Japanese patients with primary plasma cell leukemia (pPCL) in the era of novel agents and analyzed the risk factors affecting survival. Among 3,318 patients with symptomatic multiple myeloma (MM), 38 patients were diagnosed with pPCL. The median overall survival (OS) of the pPCL patients was 2.85 years, which was significantly extended compared with that in previous reports. The proportion of patients treated with novel agents was 61%. The OS of the patients treated with novel agents was significantly extended compared with that of patients treated without novel agents according to the generalized Wilcoxon test (2.85 vs. 1.16 years, p = 0.049). This statistical finding suggests that treatment with novel agents could have prevented early death in the patients with pPCL. Age was the only statistically significant prognostic factor associated with an inferior OS (hazard ratio 4.57). Five patients received maintenance therapy with novel agents, and their OS tended to be longer than that of the other patients without maintenance (4.45 vs. 2.85 years). Unlike MM, OS for pPCL has not been improved significantly over the last decade, especially in elderly patients. Therefore, it is important to establish the treatment strategy, particularly after induction treatment.

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.

Secondary plasma cell leukemia

Plasma cell leukemia (PCL) is a rare disease and is the least common variant of multiple myeloma accounting for 2-3% of all plasma cell dyscrasias. We report a patient who was diagnosed with multiple myeloma, 12 months earlier; he was treated with VBCMP, VCMP regime, and after 12 months he presented of high grade fever, weakness, palpitations, loss of appetite, bone pains, dyspnea. Initial evaluation revealed plasmacytosis with blood plasma cell count of 13 860/mm³. His hemoglobin (Hb) was 8.4 mg/dL, platelets were 45 000/mm³ and total leukocyte count (TLC) was 23 100/mm³ (60% plasma cells). Bone marrow examination revealed 90% plasmablastic cells. Serum LDH was high at 3117 U/L and serum calcium was also elevated at 9.1 mg/dL. A diagnosis of PCL was made and the patient was started on treatment with VAD regime along with supportive care. Patient condition deteriorated very quickly, despite treatment and he died on the third day. A detailed report of this case and a review of PCL is presented here.

[Plasma cell leukemia: a highly aggressive monoclonal gammopathy with a very poor prognosis]

Plasma cell leukemia (PCL) is an aggressive variant of multiple myeloma and is characterized by the presence of greater then 20% absolute number of plasma cells circulating in the peripheral blood. PCL represents approximately 2-4% of all MM diagnosis and exists in two forms: primary PCL (PPCL, 60% of cases) presents de novo; whereas secondary PCL (SPCL, accounts for the remaining 40%) consists of a leukemic transformation in patients with a previously diagnosed MM. Because the mechanisms contributing to the pathogenesis of PCL are not fully understood, immunophenotyping, genetic evaluation (conventional karyotype, FISH, GEP and array-CGH), and immunohistochemistry are very important tools to investigate why plasma cells escape from bone marrow and become highly aggressive. Since treatment with standard agents and steroids is poorly effective, a combination of new drugs as part of the induction regimens and haematopoietic stem cell transplantation (autologous and allogeneic approaches) may overcome the poor prognosis exhibited by PCL patients.

Marrow transplantation for malignant plasma cell disorders: summary of the Seattle experience

28 patients with plasma cell malignancies received marrow transplants from identical twins (N = 8), HLA-identical family members (N = 15), HLA partially-matched relatives (N = 3) or cryopreserved autologous marrow (N = 2). Treatment regimens included cyclophosphamide (CY) and total body irradiation (TBI) for 15 patients and busulphan (BU) and CY for 13 patients. 3 of 8 twins are alive, 2 without disease at 24 and 34 months, and 1 is alive and well at 116 months without evidence of disease except for at small residual monoclonal protein spike. 12 of the 18 allografted patients died of transplant-related causes and 2 died of progressive disease. 4 of 18 allograft recipients are alive; 2 are free of disease at 16 and 15 months, 1 is alive at 6 months without disease except for persistent monoclonal Kappa protein. 1 patient is alive with residual marrow involvement and a persistent IGA lambda monoclonal protein at 7 months. 1 of the 2 autograft recipients is alive 2 months after transplant and is not yet evaluable for tumor response and the other patient died early of transplant-related complications. Both CY + TBI and BU + CY resulted in remissions in patients with advanced plasma cell malignancies. However, the optimal treatment regimen and timing of transplantation remain to be determined.

A retrospective analysis of thirty-one cases of plasma cell leukemia from a single center in China

BACKGROUND/AIMS

The study was undertaken to understand the characteristic of plasma cell leukemia (PCL) in China.

METHODS

We reviewed and compared medical data of 22 primary PCL, 9 secondary PCL and 461 multiple myeloma (MM) diagnosed at our institute from January 2000 to January 2008.

RESULTS

The median onset ages of primary and secondary PCL patients were 49.5 and 56 years, respectively. PCL patients presented with a low peripheral blood plasmacytosis, extensive involvement of visceral organs and poor residual bone marrow function, without severe renal insufficiency. Seventeen of twenty-one PCL patients had abnormal karyotypes, mostly complex and hypodiploid or pseudodiploid. The deletion of 13q was frequent in primary and secondary PCL (57.1 and 42.9%, respectively). There was a significant difference in survival among primary PCL, secondary PCL and MM (median 14, 2 and 37 months, respectively, p = 0.0000).

CONCLUSION

Overall, primary and secondary PCL are different disorders with distinct natural histories and survival.

Efficacy and safety of bortezomib in patients with plasma cell leukemia

BACKGROUND

The prognosis of patients with plasma cell leukemia (PCL), an aggressive variant of multiple myeloma (MM), is usually poor. Bortezomib is the first proteasome inhibitor approved for the treatment of advanced MM. Currently available information regarding the role of bortezomib in PCL is scanty and derives from anecdotal, single-case reports.

METHODS

The authors conducted a retrospective survey of unselected Italian patients with primary or secondary PCL who were treated with bortezomib outside of clinical trials. Twelve evaluable patients were recorded who had received bortezomib for 1 to 6 cycles as either a single agent or variously combined with other drugs. Three patients were treated with bortezomib as frontline therapy, and 9 patients received bortezomib after 1 to 4 lines of chemotherapy, including autologous stem cell transplantation and thalidomide.

RESULTS

According to the International uniform response criteria of the International Myeloma Working Group, 5 partial responses (defined as a reduction in M-protein of >50%), 4 very good partial responses (defined as a reduction of >90% in M-protein), and 2 complete responses (defined as negative immunofixation) were achieved, for a response rate of 92%. Responses did not appear to be influenced by previous treatments or by other clinical or biologic parameters, including chromosome 13 deletion or the combination of bortezomib with other drugs. The median progression-free and overall survivals after bortezomib were 8 months and 12 months, respectively. At the time of last follow-up, 8 patients were alive 6 to 21 months after treatment with bortezomib, 4 of whom were in very good partial or complete responses. Grade 3/4 hematologic or neurologic toxicities (graded according to the Common Terminology Criteria for Adverse Events [CTCAE; version 3]) were reported to occur in 9 patients and 1 patient, respectively, whereas 6 patients experienced possible or documented infections.

CONCLUSIONS

Bortezomib appears to be an effective drug for PCL that could significantly improve the usually adverse clinical outcome of these patients.

Molecular events contributing to cell death in malignant human hematopoietic cells elicited by an IgG3-avidin fusion protein targeting the transferrin receptor

We have previously reported that an anti-human transferrin receptor IgG3-avidin fusion protein (anti-hTfR IgG3-Av) inhibits the proliferation of an erythroleukemia-cell line. We have now found that anti-hTfR IgG3-Av also inhibits the proliferation of additional human malignant B and plasma cells. Anti-hTfR IgG3-Av induces internalization and rapid degradation of the TfR. These events can be reproduced in cells treated with anti-hTfR IgG3 cross-linked with a secondary Ab, suggesting that they result from increased TfR cross-linking. Confocal microscopy of cells treated with anti-hTfR IgG3-Av shows that the TfR is directed to an intracellular compartment expressing the lysosomal marker LAMP-1. The degradation of TfR is partially blocked by cysteine protease inhibitors. Furthermore, cells treated with anti-hTfR IgG3-Av exhibit mitochondrial depolarization and activation of caspases 9, 8, and 3. The mitochondrial damage and cell death can be prevented by iron supplementation, but cannot be fully blocked by a pan-caspase inhibitor. These results suggest that anti-hTfR IgG3-Av induces lethal iron deprivation, but the resulting cell death does not solely depend on caspase activation. This report provides insights into the mechanism of cell death induced by anti-TfR Abs such as anti-hTfR IgG3-Av, a molecule that may be useful in the treatment of B-cell malignancies such as multiple myeloma.

Primary plasma cell leukemia: report of 17 new cases treated with autologous or allogeneic stem-cell transplantation and review of the literature

Primary plasma cell leukemia (PPCL) is a rare hematologic malignancy characterized by the proliferation of plasma cells in blood, bone marrow, and other organs in the absence of established multiple myeloma. PPCL has a poor prognosis when treated with conventional therapy for multiple myeloma. We describe here 17 new cases of PPCL who underwent stem-cell transplantation (SCT) (2 cases observed by the authors and 15 cases from the International Bone Marrow Transplant Registry [IBMTR]). The first case was diagnosed in a 21-year-old male who presented with leukocytosis and acute renal failure. He was treated with hyper-CVAD, entered complete remission, and then proceeded to high-dose chemotherapy with peripheral stem-cell support. He is currently in complete remission 23 months after initial diagnosis and 19 months after autologous SCT. The second case was observed in a 31-year-old male who presented with leukocytosis and hepatic infiltration with plasma cells. He was treated with VAD chemotherapy and underwent allogeneic bone marrow transplantation from his HLA-identical sister. He remained in complete remission for 3 years and then developed progressive refractory disease, dying 7 years after the initial diagnosis. In addition to these 2 cases, 15 further unpublished cases of PPCL from the IBMTR are reported here (treated between 1993 and 2001, 6 by autologous and 9 by allogeneic transplantation). Finally, the features of PPCL, the outcome, published data of SCT for PPCL, and indications for treatment are discussed.

Consolidation therapy with autologous blood stem cell transplantation in a patient with primary plasma cell leukaemia

Primary plasma cell leukaemia (PPCL) is a rare form of plasma cell dyscrasia. Conventional melphalan-based treatment is often ineffective, with a reported median survival of 2-7 months only. We report a 53-year-old man with PPCL who was treated with four cycles of combination chemotherapy including vincristine, adriamycin and dexamethasone that resulted in a good partial remission. High-dose melphalan 200 mg/m2 and autologous peripheral blood stem cell (PBSC) rescue was then given 6 months after diagnosis. Maintenance interferon-alpha was started 8 weeks after transplantation with good drug compliance. Complete remission was achieved and molecular remission was documented 11 months after autologous PBSC transplantation. In conclusion, high-dose therapy followed by autologous stem cell rescue is a feasible option for PPCL that can result in a reasonably sustained remission.

Low cost autologous peripheral blood stem cell transplantation performed in a municipal hospital for a patient with plasma cell leukaemia

Autologous peripheral blood stem cell transplantation (PBSCT) is a costly procedure. In India, the cost varies from US$20000 to 25000 and most patients cannot afford it. Using several cost-cutting measures, we were able to treat a patient with plasma cell leukaemia by autologous PBSCT. A 42-year-old-male presented with plasma cell leukaemia. He was treated with VAD therapy, followed by high-dose cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) for mobilization of peripheral blood stem cells. The patient was conditioned with high dose melphalan, followed by autologous PBSCT. The procedure was performed in a municipal hospital in which there was no prior experience with stem cell transplantation. Costs were reduced by: (i) using oral medication whenever possible; (ii) having a relative of the patient prepare his food under medical guidance; (iii) starting G-CSF on day 7 rather than on day 1; (iv) short-term storage of the PBSC in an ordinary refrigerator at 4 degrees C without cryopreservation; (v) infusing a large number of CD34+ cells, which shortened the time to engraftment; (vi) delegating many of the functions of a marrow transplant nurse to a resident physician. The cost of transplantation was thereby reduced to about US$ 6000, with successful engraftment by day +13. The patient remained in remission for 7 months, after which he relapsed and was treated with chemotherapy and electron beam radiation to the skin.

Relapsed plasma cell leukaemia presenting with aggressive extramedullary plasmacytomas in the meninges and testis--a missed opportunity for induction CNS prophylaxis

After initial treatment, a 54-year-old male with plasma cell leukaemia developed extramedullary relapse in the testis and meninges without evidence of bone marrow involvement. We postulate that the central nervous system (CNS) and testis may have served as sanctuary sites for the disease during initial treatment. A role for CNS prophylaxis in plasma cell leukaemia is suggested.

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.