Distribution of human herpesvirus-8 latently infected cells in Kaposi's sarcoma, multicentric Castleman's disease, and primary effusion lymphoma

Human herpesvirus 8 (HHV-8, also called KSHV) is linked to the etiopathogenesis of Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). The universal presence of HHV-8 in early KS has not yet been shown. We used a mAb (LN53) against latent nuclear antigen-1 (LNA-1) of HHV-8 encoded by ORF73 to study the distribution of the cell types latently infected by HHV-8 in patch, plaque, and nodular KS, MCD, and PEL. In early KS, HHV-8 is present in <10% of cells forming the walls of ectatic vessels. In nodular KS, HHV-8 is present in cells surrounding slit-like vessels and in >90% of spindle cells, but not in normal vascular endothelium. In addition, HHV-8 colocalizes with vascular endothelial growth factor receptor-3 (VEGFR-3), a marker of lymphatic and precursor endothelium. In early KS lesions, VEGFR-3 is more extensively expressed than LNA-1, indicating that HHV-8 is not inducing the proliferation of VEGFR-3-positive endothelium directly. In MCD, HHV-8 is present in mantle zone large immunoblastic B cells. No staining for LNA-1 is seen in samples from multiple myeloma, prostate cancer, and angiosarcoma, supporting the absence of any etiological link between these diseases and HHV-8.

Kaposi's sarcoma-associated herpesvirus infection of bone marrow dendritic cells from multiple myeloma patients

Kaposi's sarcoma-associated herpesvirus (KSHV) was found in the bone marrow dendritic cells of multiple myeloma patients but not in malignant plasma cells or bone marrow dendritic cells from normal individuals or patients with other malignancies. In addition the virus was detected in the bone marrow dendritic cells from two out of eight patients with monoclonal gammopathy of undetermined significance (MGUS), a precursor to myeloma. Viral interleukin-6, the human homolog of which is a growth factor for myeloma, was found to be transcribed in the myeloma bone marrow dendritic cells. KSHV may be required for transformation from MGUS to myeloma and perpetuate the growth of malignant plasma cells.

Plasmablastic lymphomas and plasmablastic plasma cell myelomas have nearly identical immunophenotypic profiles

Plasmablastic lymphoma is an aggressive neoplasm that shares many cytomorphologic and immunophenotypic features with plasmablastic plasma cell myeloma. However, plasmablastic lymphoma is listed in the World Health Organization (WHO) classification as a variant of diffuse large B-cell lymphoma. To characterize the relationship between plasmablastic lymphoma and plasmablastic plasma cell myeloma, we performed immunohistochemistry using a large panel of B-cell and plasma cell markers on nine cases of plasmablastic lymphoma and seven cases of plasmablastic plasma cell myeloma with and without HIV/AIDS. The expression profiles of the tumor suppressor genes p53, p16, and p27, and the presence of Epstein-Barr virus (EBV) and human herpes virus type 8 (HHV-8) were also analyzed. All cases of plasmablastic lymphoma and plasmablastic plasma cell myeloma were positive for MUM1/IRF4, CD138, and CD38, and negative for CD20, corresponding to a plasma cell immunophenotype. PAX-5 and BCL-6 were weakly positive in 2/9 and 1/5 plasmablastic lymphomas, and negative in all plasmablastic plasma cell myelomas. Three markers that are often aberrantly expressed in cases of plasma cell myelomas, CD56, CD4 and CD10, were positive in 5/9, 2/5, and 6/9 plasmablastic lymphomas, and in 3/7, 1/5, and 2/7 plasmablastic plasma cell myelomas. A high Ki-67 proliferation index, overexpression of p53, and loss of expression of p16 and p27 were present in both tumors. No evidence of HHV-8 infection was detected in either neoplasm. The only significant difference between plasmablastic lymphoma and plasma cell myeloma was the presence of EBV-encoded RNA, which was positive in all plasmablastic lymphoma cases tested and negative in all plasma cell myelomas. In conclusion, most cases of AIDS-related plasmablastic lymphoma have an immunophenotype and tumor suppressor gene expression profile virtually identical to plasmablastic plasma cell myeloma, and unlike diffuse large B-cell lymphoma. These results do not support the suggestion in the WHO classification that plasmablastic lymphoma is a variant of diffuse large B-cell lymphoma.

Clinical features associated with COVID-19 outcome in multiple myeloma: first results from the International Myeloma Society data set

The primary cause of morbidity and mortality in patients with multiple myeloma (MM) is an infection. Therefore, there is great concern about susceptibility to the outcome of COVID-19-infected patients with MM. This retrospective study describes the baseline characteristics and outcome data of COVID-19 infection in 650 patients with plasma cell disorders, collected by the International Myeloma Society to understand the initial challenges faced by myeloma patients during the COVID-19 pandemic. Analyses were performed for hospitalized MM patients. Among hospitalized patients, the median age was 69 years, and nearly all patients (96%) had MM. Approximately 36% were recently diagnosed (2019-2020), and 54% of patients were receiving first-line therapy. Thirty-three percent of patients have died, with significant geographic variability, ranging from 27% to 57% of hospitalized patients. Univariate analysis identified age, International Staging System stage 3 (ISS3), high-risk disease, renal disease, suboptimal myeloma control (active or progressive disease), and 1 or more comorbidities as risk factors for higher rates of death. Neither history of transplant, including within a year of COVID-19 diagnosis, nor other anti-MM treatments were associated with outcomes. Multivariate analysis found that only age, high-risk MM, renal disease, and suboptimal MM control remained independent predictors of adverse outcome with COVID-19 infection. The management of MM in the era of COVID-19 requires careful consideration of patient- and disease-related factors to decrease the risk of acquiring COVID-19 infection, while not compromising disease control through appropriate MM treatment. This study provides initial data to develop recommendations for the management of MM patients with COVID-19 infection.

The role of Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) in lymphoproliferative diseases

The Kaposi's sarcoma-associated herpesvirus (KSHV), also called human herpesvirus 8 (HHV-8), has been found to be present in a limited subset of lymphoproliferative disorders. Among these are the primary effusion lymphomas, formerly designated body cavity-based lymphomas, a rare type of malignant lymphoma which possesses an unusual set of clinical and biologic features, suggesting that they represent a distinct disease entity. This virus is also present in a large proportion of cases of multicentric Castleman's disease, particularly those associated with HIV-infection. In addition, KSHV has been implicated in the pathogenesis of multiple myeloma, where it has been identified in bone marrow adherent cells but not in the neoplastic myeloma plasma cell population. However, the latter finding remains controversial. The discovery of KSHV in a subset of malignant lymphomas has allowed the development of lymphoma cell lines which now serve as biological reagents for propagating the virus, as a substrate for serologic assays, and as a model system for pathobiologic studies. This review discusses the features of KSHV-associated lymphoproliferative disorders and the evidence supporting its role in the pathogenesis of these diseases.

Plasmablastic lymphoma in HIV-positive patients: an aggressive Epstein-Barr virus-associated extramedullary plasmacytic neoplasm

AIDS-associated aggressive B-cell lymphomas often have plasmacytoid features. Plasma cell neoplasms in HIV patients were commonly described to have atypical morphology and an aggressive clinical course in the literature. We reviewed 14 cases of neoplasms with marked plasmacytic differentiation in HIV-positive patients to determine their clinicopathologic features. Of these, 13 of 14 had homogeneous morphology and were generally CD45(+), CD20-, PAX-5-, and CD138(+). All were positive for Epstein-Barr virus-encoded RNA (EBER) but lacked EBV late membrane proteins (LMP). Human herpes virus 8 (HHV8) DNA was detected in 6 of 10 cases by nested PCR, but HHV8 latent nuclear antigen (LNA) was absent. The 13 patients ranged in age from 28 to 44 years (median, 41 years) (11 male patients; 2 female patients). All patients had extramedullary and 11 of 13 had extranodal tumor at the initial presentation; 2 had distant marrow involvement. The most commonly involved location was the oral cavity (6 of 13 cases), followed by bone and soft tissue (4 of 13), and the gastrointestinal tract (3 of 13). All 11 patients with follow-up died within 34 months (median, 7 months). The 14th patient who had a nodal disease with more undifferentiated morphology and expression of the HHV8 LNA protein was alive without disease at last follow-up (>72 months), probably representing a novel HHV8(+) lymphoma. We conclude that most plasmacytic tumors in HIV-positive individuals are extramedullary, clinically aggressive EBV(+) tumors identical to plasmablastic lymphoma that does not have the clinical features of plasma cell myeloma.

Primary prophylaxis with lamivudine of hepatitis B virus reactivation in chronic HbsAg carriers with lymphoid malignancies treated with chemotherapy

Hepatitis B virus (HBV) reactivation of various degrees of severity, including fulminant hepatitis, may develop in 20-50% of hepatitis B virus surface antigen (HbsAg)-positive patients undergoing immunosuppressive or cytostatic treatment. Lamivudine is a nucleoside analogue that can directly suppress HBV replication. We have performed a pilot study to test the efficacy and tolerability of lamivudine as a primary prophylaxis of HBV reactivation in 20 consecutive patients treated for haematological malignancies, mainly of lymphoid origin. Lamivudine, 100 mg/d, was given orally from the start until 1 month after the end of chemotherapy, which included corticosteroids and/or purine analogues in 85% of cases. It was well tolerated and did not cause any unexpected reduction of cytostatic drugs dosages. The chemotherapy programme was completed in all patients without modifications. A transient threefold increase in serum amylase was observed in one case. HBV-DNA levels decreased in six out of six patients (P = 0.039) and ALT levels in five out of six patients (P = 0.057) whose serum levels were abnormal at the onset of therapy. Two patients developed transient hepatitis. HBV reactivation was documented in only one of these patients who had stopped lamivudine 1 month before. No signs of HBV reactivation were detected both during and after treatment in 18 patients with a median follow-up of 6 months (range 3-12). Thus, primary prophylaxis with lamivudine may be a well tolerated and effective method to reduce the frequency of chemotherapy-induced HBV reactivation in chronic HBsAg carriers.

Plasmablastic lymphoma with MYC translocation: evidence for a common pathway in the generation of plasmablastic features

Plasmablastic lymphoma, which is considered a subtype of diffuse large B-cell lymphoma, shares many similar morphological and immunophenotypic features with plasmablastic transformation of plasma cell myeloma. In the setting of human immunodeficiency virus (HIV) infection, both types of neoplasms can be associated with Epstein-Barr virus (EBV), thus making their distinction challenging. Moreover, the biological relationship between these entities remains unclear. We report four unique cases of plasmablastic lymphoma occurring in the setting of HIV infection that had overlapping clinical and genetic features with plasma cell myeloma. We reviewed the clinical, morphological, and cytogenetic findings and performed immunohistochemistry, in situ hybridization for EBV, chromosome analysis, and fluorescent in situ hybridization (FISH) using the MYC break-apart rearrangement probe. All patients were males with a median age of 45 years. In addition to extra-nodal disease, plasmablastic morphology, and phenotype typical of plasmablastic lymphoma, three of the four cases also showed clinical findings overlapping with plasma cell myeloma, that is, monoclonal serum immunoglobulin and lytic bone lesions. Furthermore, these cases showed complex cytogenetic changes that are more commonly observed in plasma cell myeloma. A unique feature was the presence of MYC (8q24.1) rearrangement confirmed by FISH in all four cases. MYC translocation has been associated with tumor progression in multiple myeloma but has only rarely been previously reported in plasmablastic lymphoma. These cases show a clinical and biological relationship between plasmablastic lymphoma and the plasmablastic variant of plasma cell myeloma. Dysregulation of MYC may be a common genetic mechanism that imparts plasmablastic morphology and aggressive clinical course to B-cell neoplasms at a later stage of differentiation.

Evaluation of T cells as carriers for systemic measles virotherapy in the presence of antiviral antibodies

Neutralizing antiviral antibodies (Abs) can hinder systemic virotherapy. Here, we used activated T cells as carriers to deliver oncolytic measles viruses (MV) to multiple myeloma xenografts in the presence of anti-MV antibodies (Abs). Virus-infected T cells expressing measles H/F fusogenic envelope glycoproteins could efficiently transfer MV infection by heterofusion, even after exposure to virus-inactivating anti-MV antisera. Severe-combined immunodeficiency (SCID) mice bearing subcutaneous or disseminated human myeloma xenografts were given MV-luciferase (MV-Luc) or MV-Luc-infected T cells intravenously. Indium111 labeling indicated that 1-2% of the virus-infected T cells trafficked to tumors. Preinfected T cells fused with tumor cells in vivo and transferred MV-Luc to tumor xenografts where intratumoral viral spread was monitored non-invasively using bioluminescent imaging. In mice passively immunized with high titers of measles immune serum, intravenous virus and cell delivery were both inhibited. Decreasing the amount of measles immune serum given to mice permitted tumor infection by virus-infected T cells and cell-free virus. In conclusion, virus-loaded T cells may facilitate systemic measles virotherapy in the presence of antiviral Abs and they warrant further investigation as potential MV cell carriers.

Management of patients with multiple myeloma in the era of COVID-19 pandemic: a consensus paper from the European Myeloma Network (EMN)

Patients with multiple myeloma (MM) seem to be at increased risk for more severe COVID-19 infection and associated complications due to their immunocompromised state, the older age and comorbidities. The European Myeloma Network has provided an expert consensus statement in order to guide therapeutic decisions in the era of the COVID-19 pandemic. Patient education for personal hygiene and social distancing measures, along with treatment individualization, telemedicine and continuous surveillance for early diagnosis of COVID-19 are essential. In countries or local communities where COVID-19 infection is widely spread, MM patients should have a PCR test of nasopharyngeal swab for SARS-CoV-2 before hospital admission, starting a new treatment line, cell apheresis or ASCT in order to avoid ward or community spread and infections. Oral agent-based regimens should be considered, especially for the elderly and frail patients with standard risk disease, whereas de-intensified regimens for dexamethasone, bortezomib, carfilzomib and daratumumab should be used based on patient risk and response. Treatment initiation should not be postponed for patients with end organ damage, myeloma emergencies and aggressive relapses. Autologous (and especially allogeneic) transplantation should be delayed and extended induction should be administered, especially in standard risk patients and those with adequate MM response to induction. Watchful waiting should be considered for standard risk relapsed patients with low tumor burden, and slow biochemical relapses. The conduction of clinical trials should continue with appropriate adaptations to the current circumstances. Patients with MM and symptomatic COVID-19 disease should interrupt anti-myeloma treatment until recovery. For patients with positive PCR test for SARS-CoV-2, but with no symptoms for COVID-19, a 14-day quarantine should be considered if myeloma-related events allow the delay of treatment. The need for surveillance for drug interactions due to polypharmacy is highlighted. The participation in international COVID-19 cancer registries is greatly encouraged.

Oncolytic measles virus targets high CD46 expression on multiple myeloma cells

OBJECTIVE

Multiple myeloma (MM) is an incurable B cell malignancy and novel therapeutics are urgently needed. Live attenuated measles virus (MV) has potent oncolytic activity against MM tumor xenografts. The virus is tumor selective and preferentially targets cells that express high levels of CD46 receptors. However, CD46 levels on MM have not previously been evaluated. In this study, we investigated the potential of CD46 as a target for MM therapy and correlated surface levels of CD46 on MM cells with their susceptibility to MV-induced cytopathic effects.

MATERIALS AND METHODS

CD46 expression on neoplastic plasma cells (PCs) and nonplasma cells (NPCs) from 38 MM patients was analyzed by flow cytometry and receptor numbers were quantitated using BD QuantiBRITE PE beads.

RESULTS

Results showed that malignant PCs expressed significantly higher levels of CD46 receptors compared to NPCs (p < 0.0001). The mean CD46 receptor numbers on PCs and NPCs were 49,130/cell and 7,340/cell, respectively. Potent cytopathic effects of extensive intercellular fusion were observed in measles-infected PCs but not in NPCs. The extent of MV-induced cytopathic effects of cell fusion correlated with CD46 expression levels on the MM cells. Normal plasma cells do not overexpress CD46 and colony-forming assays demonstrated that MV was not cytotoxic to normal bone marrow progenitor cells.

CONCLUSION

The present study establishes CD46 as a surface antigen that is expressed more abundantly on primary MM cells compared to normal hematopoietic cells of various lineages in the bone marrow, making CD46 a promising surface marker for targeted cytoreductive therapy of MM.

Radioiodide imaging and radiovirotherapy of multiple myeloma using VSV(Delta51)-NIS, an attenuated vesicular stomatitis virus encoding the sodium iodide symporter gene

Multiple myeloma is a radiosensitive malignancy that is currently incurable. Here, we generated a novel recombinant vesicular stomatitis virus [VSV(Delta51)-NIS] that has a deletion of methionine 51 in the matrix protein and expresses the human sodium iodide symporter (NIS) gene. VSV(Delta51)-NIS showed specific oncolytic activity against myeloma cell lines and primary myeloma cells and was able to replicate to high titers in myeloma cells in vitro. Iodide uptake assays showed accumulation of radioactive iodide in VSV(Delta51)-NIS-infected myeloma cells that was specific to the function of the NIS transgene. In bg/nd/xid mice with established subcutaneous myeloma tumors, administration of VSV(Delta51)-NIS resulted in high intratumoral virus replication and tumor regression. VSV-associated neurotoxicity was not observed. Intratumoral spread of the infection was monitored noninvasively by serial gamma camera imaging of (123)I-iodide biodistribution. Dosimetry calculations based on these images pointed to the feasibility of combination radiovirotherapy with VSV(Delta51)-NIS plus (131)I. Immunocompetent mice with syngeneic 5TGM1 myeloma tumors (either subcutaneous or orthotopic) showed significant enhancements of tumor regression and survival when VSV(Delta51)-NIS was combined with (131)I. These results show that VSV(Delta51)-NIS is a safe oncolytic agent with significant therapeutic potential in multiple myeloma.

Vesicular stomatitis virus: a potential therapeutic virus for the treatment of hematologic malignancy

Certain strains of vesicular stomatitis virus (VSV) have been shown to be oncolytic in a wide variety of solid tumors. In the present study, we tested the leukemolytic properties of VSV using established leukemia cell lines and primary patient material. VSV efficiently killed essentially all leukemic cell lines. In contrast, however, normal clonogenic bone marrow progenitor cells and peripheral blood cells were remarkably refractory to infection by VSV. By exploiting this large difference in susceptibility to infection we successfully purged contaminating leukemic cells from cultures of peripheral blood progenitor cells (PBPC) using VSV. VSV was also able to infect and kill leukemic cells in primary samples taken from patients with multiple myeloma (MM). This study demonstrates the potential utility of VSV in the treatment, both ex vivo and in vivo, of hematologic malignancies.

Patient cytomegalovirus seropositivity with or without reactivation is the most important prognostic factor for survival and treatment-related mortality in stem cell transplantation from unrelated donors using pretransplant in vivo T-cell depletion with anti-thymocyte globulin

We evaluated the cytomegalovirus (CMV) serostatus as a risk factor for survival and treatment-related mortality (TRM) in 125 patients allografted from an unrelated donor between 1994 and 1999. All patients received pretransplant in vivo T-cell depletion using rabbit anti-thymocyte globulin (ATG). Only one patient had primary graft failure and severe grade III/IV graft-versus-host disease occurred in 14% of the patients. The overall survival (OS) at 3 years was 70% for CMV-negative patients (n = 76) and 29% in the seropositive cohort (n = 49) (P > 0.001). In multivariate analyses, CMV seropositivity remained an independent negative prognostic factor for OS (RR: 2.1; CI: 1.2-3.8; P = 0.014), apart from age > 20 years (RR: 2.74; CI: 1.2-3.8; P = 0.004) and late leucocyte engraftment (RR: 2.4; CI: 1.2-4.9; P = 0.015). The TRM for all patients was 27%. Despite monitoring for CMV antigenaemia and preemptive therapy with ganciclovir when reactivation occurred, seropositive patients had a three times higher risk of fatal treatment-related complications than seronegative patients. In multivariate analyses, CMV seropositivity remained the strongest independent negative factor for TRM (RR: 5.3; CI: 1.9-14.6; P = 0.002), followed by age > 20 years (RR: 4.8; CI: 1.3-18.1; P = 0.02) and delayed leucocyte engraftment (RR: 3.6; CI: 1.2-11; P = 0.02). The TRM was identical in seropositive patients with (n = 27) or without (n = 22) CMV reactivation (44% versus 50%). We conclude that CMV seropositivity, despite preemptive ganciclovir therapy and even without reactivation, is a major negative prognostic factor for survival as well as for TRM in unrelated stem cell transplantation using pretransplant in vivo T-cell depletion with ATG.

Molecular quantification of viral load in plasma allows for fast and accurate prediction of response to therapy of Epstein-Barr virus-associated lymphoproliferative disease after allogeneic stem cell transplantation

Epstein-Barr virus lymphoproliferative disease (EBV-LPD) following allogeneic stem cell transplantation (allo-SCT) has a poor prognosis. We used a sensitive real-time polymerase chain reaction (PCR) assay for quantitative detection of EBV-DNA in plasma and serially measured EBV-DNA levels to assess the response to treatment in allo-SCT recipients with EBV-LPD. Fourteen allo-SCT recipients with EBV-LPD who received a T cell-depleted (TCD) sibling (n = 5) or matched unrelated donor (n = 9) graft were monitored from the time of EBV-LPD diagnosis, during therapy and assessment of clinical response. Seven patients had complete responses of EBV-LPD to therapy, of whom 21% (3 out of 14) survived beyond 6 months from EBV-LPD diagnosis. Clinically responding patients showed a rapid decline of EBV-DNA plasma levels within 72 h from the start of therapy. In contrast, all clinical non-responders showed an increase of EBV-DNA levels. Absolute EBV-DNA levels at the time of EBV-LPD diagnosis did not predict for response, but the pattern of EBV-DNA levels within 72 h from the start of therapy (> 50% decrease versus increase) strongly predicted for clinical response (P = 0.001). Quantitative monitoring of EBV-DNA levels from the start of and during therapy for EBV-LPD rapidly and accurately predicts for response to therapy as early as within 72 h. It may thus provide a powerful tool to adjust and select treatment in individuals with EBV-LPD following allo-SCT.

Antibodies to Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in patients with multiple myeloma

Kaposi's sarcoma-associated herpesvirus (KSHV) serologic assays were used to detect specific antibodies to KSHV lytic and latent antigens in 27 patients with multiple myeloma, 27 control patients with other cancers, and 50 random blood donors. Antibodies to KSHV recombinant minor capsid antigen orf65 were found in 81% of patients with multiple myeloma, 22% of control patients with other cancers, and 6% of the blood donors. Antibodies to KSHV latent nuclear antigens were found in 52% of patients with multiple myeloma, 26% of control patients with other cancers, and 2% of the blood donors. All of the 11 patients with progressive multiple myeloma were KSHV-seropositive. Antibodies to Epstein-Barr virus nuclear antigen 1 were present in 89% of patients with multiple myeloma, 93% of control patients with other cancers, and 88% of the blood donors. These data support the possible association of KSHV infection with multiple myeloma, particularly with progressive disease.

Polymerase chain reaction detection of Kaposi's sarcoma-associated herpesvirus-optimized protocols and their application to myeloma

Since its discovery in 1994, KSHV (also called human herpesvirus-8 or HHV8) has been implicated in a variety of disorders. Although the association of KSHV with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease has been well established, its presence in some other diseases, such as multiple myeloma, remains controversial. Because most KSHV studies are based on polymerase chain reaction (PCR) analysis, the conflicting data may be attributable to variations in the methods, primer sets, and target sequences selected. To establish an efficient and reliable PCR approach for KSHV detection we designed eight sets of primers to six regions (ORFK1, ORFK2, ORFK9, ORK26, ORF72, and ORF74) of the KSHV genome using appropriate database and software. The detection sensitivity of these primers was carefully assessed and their reliability was strictly validated in a series of positive (15 KS and PEL samples) and negative (16 lymphoid tissues) controls. We found that primer sets to the ORFK9 region showed the highest sensitivity, whereas primer sets to ORFK1 and ORF74 showed the lowest sensitivity. Primer sets to ORFK9, ORF26 and ORF72 regions detected all of the positive cases, whereas other primer sets showed varying detection rates or nonspecific bands. All 16 negative controls were negative with all primer sets. However, six of 16 negative controls became positive when we used nested PCR targeting ORF26. Therefore, multiple target KSHV sequences increase the detection efficiency, while nested PCR protocols are likely to introduce false positivity. Using ORFK9, ORF26 and ORF72 primer sets, we screened bone marrow biopsies from 18 cases of multiple myeloma, and failed to detect any KSHV sequences. This finding supports the conclusion that KSHV is not associated with multiple myeloma. Indeed, our results further confirm that although KSHV is universally present in Kaposi's sarcoma and primary effusion lymphoma, it is not ubiquitious.

Bortezomib and the increased incidence of herpes zoster in patients with multiple myeloma

BACKGROUND

Bortezomib has significantly advanced the treatment of patients with multiple myeloma (MM). However, considering that most patients with MM are elderly, bortezomib-related morbidity should be thoroughly studied to ensure the safe use of this drug. Herpes zoster has been reported as a possible adverse event associated with bortezomib because a major target of bortezomib, nuclear factor-kappaB, is known to be involved with T-cell immunity.

PATIENTS AND METHODS

We performed a retrospective analysis of the incidence of herpes zoster among 282 patients treated with a bortezomib-containing regimen.

RESULTS

During the patients' pre-bortezomib treatment (median, 2.14 years), the incidence of herpes zoster was 11% (31 of 282 patients). However, after the patients were treated with bortezomib, the incidence increased to 22.3% (63 of 282 patients), of which almost all occurrences were within the first 3 cycles (median duration, 41 days). The time interval from diagnosis to bortezomib initiation date was shorter in herpes zoster-positive patients than in herpes zoster-negative patients (2.14 +/- 1.87 years vs. 3.38 +/- 2.95 years; P = .002). Disease duration, previous herpes zoster infection, disease stage and type of myeloma, and the type and intensity of previous treatments failed to show any relationship with herpes zoster. These findings suggest that longer history of disease and treatments did not affect the occurrence of herpes zoster, nor did the type of bortezomib regimens or their toxicities.

CONCLUSION

Bortezomib can increase the incidence of herpes zoster regardless of disease duration, previous treatments, and concomitantly administered drugs. Thus, the occurrence of herpes zoster should be monitored during bortezomib treatment.

Targeted Measles Virus Vector Displaying Echistatin Infects Endothelial Cells via αvβ3 and Leads to Tumor Regression

Targeting tumor-associated vascular endothelium by replication-competent viral vectors is a promising strategy for cancer gene therapy. Here we describe the development of a viral vector based on the Edmonston vaccine strain of measles virus targeted to integrin alpha(v)beta3, which is expressed abundantly on activated but not quiescent vascular endothelium. We displayed a disintegrin, M28L echistatin that binds with a high affinity to integrin alpha(v)beta3 on the COOH terminus of the viral attachment (H) protein and rescued the replication-competent recombinant virus by reverse genetics. The new targeted virus was named measles virus echistatin vector (MV-ERV). Its native binding to CD46 was purposefully retained to allow virus infection of tumor cells expressing this receptor. MV-ERV correctly displayed echistatin on the outer surface of its envelope and produced interesting ring formation phenomena due to cell detachment upon infection of susceptible Vero cells in vitro. MV-ERV grew to 10(6) plaque-forming units/mL, slightly lower than the parental Edmonston strain of measles virus (MV-Edm), but it selectively infected Chinese hamster ovary cells expressing integrin alpha(v)beta3. It also selectively infected both bovine and human endothelial cells on matrigels and unlike MV-Edm, MV-ERV infected newly formed blood vessels in chorioallantoic membrane assays. In animal models, MV-ERV but not the control MV-Edm caused the regression of s.c. xenografts of resistant multiple myeloma tumors (MM1) in severe combined immunodeficient mice. The tumors were either completely eradicated or their growth was significantly retarded. The specificity, potency, and feasibility of MV-ERV infection clearly show the potential use of MV-ERV in gene therapy for targeting tumor-associated vasculature for the treatment of solid tumors.

Low dose and gene gun immunization with a hepatitis C virus nonstructural (NS) 3 DNA-based vaccine containing NS4A inhibit NS3/4A-expressing tumors in vivo

The hepatitis C virus (HCV) protease and helicase encompasses the nonstructural (NS) 3 protein and the cofactor NS4A, which targets the NS3/4A-complex to intracellular membranes. We here evaluate the importance of NS4A in NS3-based genetic immunogens. A full-length genotype 1 NS3/4A gene was cloned into a eucaryotic expression vector in the form of NS3/4A and NS3 alone. Transient transfections revealed that the inclusion of NS4A increased the expression levels of NS3. Subsequently, immunization with the NS3/4A gene primed 10- to 100-fold higher levels of NS3-specific antibodies as compared to immunization with the NS3 gene. Humoral responses primed by the NS3/4A gene had a higher IgG2a/IgG1 ratio (>20) as compared to the NS3 gene (3.0), suggesting a T helper 1-skewed response. Low dose i.m. (10 microg) immunization with the NS3/4A gene inhibited the growth of NS3/4A-expressing tumor cells in vivo, whereas the NS3 gene alone or NS3 protein did not. We then evaluated the efficiency of the NS3/4A gene administered by the gene gun, at the same doses used for humans, in priming cytotoxic T lymphocyte (CTL) responses. Three to four 4 microg doses of the NS3/4A gene primed CTL at a precursor frequency of 2-4%, which inhibited the growth of NS3/4A-expressing tumor cells in vivo. Thus, NS4A enhances the expression levels and immunogenicity of NS3, and an NS3/4A gene delivered transdermally could be a therapeutic vaccine candidate.

Plasmablastic cytomorphologic features in plasma cell neoplasms in immunocompetent patients are significantly associated with EBV

Multiple myeloma (MM) is rarely associated with Epstein-Barr virus (EBV) irrespective of HIV status, in contrast with its morphologic mimic, plasmablastic lymphoma, which occurs mainly in immunocompromised patients with frequent EBV association. Among 58 consecutive immunocompetent patients, we found plasmablastic cytomorphologic features in 2 of 4 with plasmacytomas and 14 (26%) of 54 with MM. Of the tumors, 4 (7%; 1 plasmacytoma and 3 MMs) were EBV-encoded RNA (EBER)-positive with plasmablastic cytomorphologic features in 3. The patient with plasmacytoma was disease free for 75 months, and the remaining 3 patients with MM died at 15, 74, and 97 months, respectively; the median survival of patients with EBER- MM was 12 months. EBV+ tumors were associated with plasmablastic cytomorphologic features and high labeling indices. Rare EBER+ plasmablastic plasma cell tumors exist in immunocompetent patients. These tumors may have been driven by EBV to gain the plasmablastic cytomorphologic features and high proliferation fraction. A large cohort study is needed to clarify the prognostic impact of EBV on immunocompetent patients with MM.