Castleman's Lymphoma Research Articles

Outcomes in Kaposi's sarcoma-associated herpesvirus -associated primary effusion lymphoma and multicentric Castleman's disease in patients with human immunodeficiency virus (HIV) in a safety-net hospital system.

To describe cases of Kaposi's sarcoma-associated herpesvirus (KSHV)-associated multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) in patients with HIV from a large, safety-net hospital system in Dallas, Texas, USA. We conducted a retrospective review of patients with HIV-associated PEL and/or MCD. Twelve patients with PEL and 10 patients with MCD were identified. All patients were male and 17 of 20 were men who have sex with men; 66.7% of PEL patients and 50% of MCD patients had concurrent KS at the time of diagnosis; 42% of patients with PEL and 20% of patients with MCD died during the follow-up period. We noted improved survival in our cohort compared to previous studies, particularly in our PEL patients with a median survival of 11.4 months compared to 3-6-month median survival historically. Median follow-up time for MCD patients was 17.5 months. This improved survival is despite suboptimal antiretroviral therapy (ART) adherence at diagnosis, with only 50% of patients on ART at the time of MCD/PEL diagnosis. These data highlight the importance of early recognition of PEL and MCD, and the larger-scale efforts needed to better understand the pathogenetic drivers of clinical outcomes in patients affected by KSHV-related diseases.

Long-Term Follow-up of Hypereosinophilic Syndrome Patients Treated with Mepolizumab: A Nationwide Real-Life Study of 59 Patients

Background Mepolizumab, a humanized monoclonal antibody directed against IL-5, has proven efficacious for the treatment of FIP1L1 ∷ PDGFRA ( F/P)-negative Hypereosinophilic Syndrome (HES) in two randomized controlled trials with short term follow-up. However, both its efficacy and safety profiles on the long term are unknown. Methods All F/P-negative HES patient treated with mepolizumab in France from 2003 to 2022 in either GlaxoSmithKline-sponsored randomized trials (MHE100185 and HES200622) or long-term access programs (MHE100901 and MHE10417) were included. For each study visit, we retrospectively collected the following data: drug doses (and spacing), HES-disease status, absolute eosinophil counts (AEC), and doses of oral corticosteroids (OCS). Clinical remission (CR) was defined as the absence of symptoms related to HES. Complete hematological remission (CHR) was defined as an AEC < 0.5 x 10 9/L, and relapse by the occurrence of new or worsening of HES-related symptoms, irrespective of either AEC or increase of HES treatments. Relapse-free survival was modeled using a Kaplan-Meier method. We also assessed the rates of “super responses”, a new outcome measure defined as the combination of both CR, CHR and complete withdrawal of OCS at last follow-up. Results and discussion Data were available for 64 out of the 80 patients identified. All patients ultimately received 300mg subcutaneous mepolizumab, but 27 (45.8%) patients had initially been started on higher doses (700 or 750 mg intravenous). Five patients were excluded because of misdiagnoses despite initially high AEC and HES-mimicking presentation (IgG4-related disease (n=1), Castleman's disease (n=1), lymphoma (n=2) and STAT6 gain-of-function mutation (n=1)). Ultimately, the study population consisted of 59 patients (idiopathic HES, n=51; lymphocytic HES, n=8) with chronic HES sensitive to high-dose OCS yet who remained OCS-dependent on the long run (median [IQR] dose of OCS at baseline: 11 [9-20] mg/d). In median, patients had two organs involved, with gastro-intestinal, respiratory, and cutaneous manifestations being the most frequent symptoms. After a median follow-up of 4.5 [2.5-12.3] years, 11 patients (19%) relapsed, among whom five were clearly related to prior mepolizumab spacing to more than four weeks between injections (Figure 1). In details, most of the patients were in CR (n=55, 93%) and/or in CHR (n=56, 95%) at last follow-up, including 38 (64%) OCS-free patients who fulfilled criteria for super response. No baseline predictive factor for super response was evidenced. When focusing on the 21 (36%) patients with more than eight years of follow-up (median 14.4 [12.2-17.3] years), outcomes tended to be the same as those of the overall population. At last follow-up more than 70% of patients were able to space mepolizumab's infusions for more than four weeks (median time between two injections at last follow-up: 8 [4-11] months). Ultimately, four patients were able to discontinue mepolizumab without subsequent relapse with more than two years of follow-up. There was no new safety signal, and no patient withdrew mepolizumab due to a treatment-related adverse event. Conclusion Mepolizumab remains highly efficacious in the long-term (including in patients with more than 10 years of follow-up), enabling sustained disease remission despite tapering of OCS and spacing of injections. Very few cases of mepolizumab failure were identified, among which the leading cause was HES misdiagnosis.

Association of polymorphisms in NFκB1 promoter and NFκBIA gene with the development of antibodies against HHV-8 in HIV-infected individuals

Human gammaherpesvirus 8 (HHV-8) is the etiologic agent of Kaposi's sarcoma, multicentric Castleman's disease and primary effusion lymphoma. Like other herpesviruses, the HHV-8 may exhibit latent or lytic cycle, both regulated by viral and host factors. Regarding host factors, we analysed the association of polymorphisms in NFkB1 promoter (NFkB1-94 ins/del ATTG) and NFκBIA gene (NFκBIA 3′UTR A→G) with the development of antibodies against latent or lytic antigens from HHV-8. The ins/del [OR 7.9 (95% CI 3.3–19.1), p < 0.001], AG [OR 12.3 (95% CI 4.3–34.9) p < 0.001], GG [OR 9.4 (95% CI 3.2–27.9), p < 0.001], ins/del + AG [OR 94.5 (95% CI 9.6–924.4), <0.0001], ins/del + GG [OR 50.4 (95% CI 5.2–482.2, p < 0.0001] and G allele [OR 3.3 (95% CI 2.0–5.6), p < 0.001] were strongly related with the presence of antibodies to lytic antigens. This is the first association of polymorphisms in NFκB1 promoter and NFκBIA gene with the development of antibodies against HHV-8.

Kaposi's Sarcoma in Lung Transplantation: A Decade's Single-Centre Case Series

Purpose Human herpes virus 8 (HHV8) is associated with Kaposi's sarcoma, multicentric Castleman's disease and Primary Effusion Lymphoma. Behaving as an opportunistic virus, immune-compromised patients, including solid organ transplant recipients, are disproportionately affected. The aim of our study was to review all the cases of HHV8 related disease in our lung transplant population. Methods We retrospectively evaluated the incidence of KS and HHV8 associated lymphoproliferative disorders among all lung transplant recipients at our centre, from January 2008 to December 2017. Clinical data of these patients were collected, taking into account time of onset, donor/recipient HHV8 serology, treatments and outcomes. Results Four out of 203 (2%) patients developed KS (Table 1). Disseminated forms of KS occurred through HHV8 infection from a seropositive donor (D+/R-); both patients initially complained of aspecific symptoms (fever and malaise) and presented with pancytopenia and very high HHV8 DNAemia. We observed a very aggressive progression of KS, and patient 3 died 4 weeks after the fourth dose of liposomal doxorubicin due to an untreatable mycotic infection. By contrast, KS due to viral reactivation (i.e., D-/R+) was milder, limited to the skin and responded to modifications in the immunosuppressive regimens. Interestingly, the recipient of the liver harvested from patient 4’s donor developed another serious HHV8 related disease (i.e., Castelman's disease, investigation currently ongoing at another transplant centre). Conclusion We suggest implementation of D/R serological screening for HHV-8 before transplantation, in order to identify patients at risk of developing HHV-8 related diseases, improve clinical and virological surveillance and possibly individualize immune-suppressive therapy. For the time being, in the absence of a systematic screening, we strongly recommend to report index cases as soon as possible to regional allocation systems in order to identy other recipients potentially at risk.

Kaposi's Sarcoma-Associated Herpesvirus Latency Locus Renders B Cells Hyperresponsive to Secondary Infections.

Kaposi's sarcoma-associated herpesvirus (KSHV) induces B cell hyperplasia and neoplasia, such as multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL). To explore KSHV-induced B cell reprogramming in vivo, we expressed the KSHV latency locus, inclusive of all viral microRNAs (miRNAs), in B cells of transgenic mice in the absence of the inhibitory FcγRIIB receptor. The BALB/c strain was chosen as this is the preferred model to study B cell differentiation. The mice developed hyperglobulinemia, plasmacytosis, and B lymphoid hyperplasia. This phenotype was ameliorated by everolimus, which is a rapamycin derivative used for the treatment of mantle cell lymphoma. KSHV latency mice exhibited hyperresponsiveness to the T-dependent (TD) antigen mimic anti-CD40 and increased incidence of pristane-induced inflammation. Lastly, the adaptive immunity against a secondary infection with Zika virus (ZIKV) was markedly enhanced. These phenotypes are consistent with KSHV lowering the activation threshold of latently infected B cells, which may be beneficial in areas of endemicity, where KSHV is acquired in childhood and infections are common.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) establishes latency in B cells and is stringently linked to primary effusion lymphoma (PEL) and the premalignant B cell hyperplasia multicentric Castleman's disease (MCD). To investigate potential genetic background effects, we expressed the KSHV miRNAs in BALB/c transgenic mice. BALB/c mice are the preferred strain for B cell hybridoma development because of their propensity to develop predictable B cell responses to antigen. The BALB/c latency mice exhibited a higher incidence of B cell hyperplasia as well as sustained hyperglobulinemia. The development of neutralizing antibodies against ZIKV was augmented in BALB/c latency mice. Hyperglobulinemia was dampened by everolimus, a derivative of rapamycin, suggesting a role for mTOR inhibitors in managing immune activation, which is hallmark of KSHV infection as well as HIV infection.

De Novo Human Herpesvirus 8 Tumors Induced by Rituximab in Autoimmune or Inflammatory Systemic Diseases.

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma (KS)-associated herpesvirus, is involved in KS and other tumors, including multicentric Castleman's disease and primary effusion lymphoma. Rituximab (RTX) is currently used for the treatment of several autoimmune or inflammatory diseases and humoral organ transplant rejection. De novo HHV-8 tumors induced by RTX used for these indications have not been reported previously. This study was undertaken to evaluate de novo HHV-8 tumors induced by RTX. In this retrospective study, we investigated the clinical, virologic, and pathologic features of 5 HIV-negative male patients with HHV-8 tumors induced by RTX therapy. Patients were all immunocompromised by previous treatments, which consisted of steroids and/or immunosuppressive agents, and received RTX for insufficient response, disease progression, or transplant rejection. They developed HHV-8 tumors a median of 4 months after beginning treatment with RTX (range 3-13 months). Four patients had at least 1 risk factor for HHV-8, including a high Fitzpatrick skin phototype (of >3) (n= 3) and homosexuality (n = 1). Four patients developed KS (all 4 had skin lesions and 2 had visceral involvement), and 1 patient developed a solid primary effusion lymphoma. RTX was discontinued in all patients, and immunosuppressants were reduced when feasible. After a median follow-up of 20 months, 2 patients died. Remission of KS was complete in 1 patient and partial in 1 patient, and 1 patient had progression. Our findings indicate that patients who have a high skin phototype and are at risk of HHV-8 should be carefully screened for HHV-8 before RTX therapy. The safety of RTX, especially in nonlymphomatous disorders, should be carefully evaluated in patients at risk of HHV-8 tumors.

Diversity of human herpesvirus 8 genotypes in patients with AIDS and non-AIDS associated Kaposi's sarcoma, Castleman's disease and primary effusion lymphoma in Argentina.

HHV-8 genotypes are distributed heterogeneously worldwide. The variable K1 gene and the conserved ORF26E region serve to genotype. The aim of the study was to characterize HHV-8 isolates from patients with AIDS, classical, and iatrogenic KS, primary effusion lymphoma and Castleman's disease and one organ donor from Argentina by analysis of ORFK1 and ORF26E regions. DNA was extracted from fresh or paraffin embedded biopsies, blood, and saliva samples and submitted to HHV-8 PCR. Phylogenetic analyses of ORFK1 showed that subtypes C (C1, C2, and C3), B1 and A (A1, A2, and A3) were present in 70.8%, 16.7%, and 12.5% of cases, respectively. Analyses of ORF26E fragment revealed that most strains (45.8%) were subtype A/C while the remaining fall into K, J, B2, R, and D subtypes. Linkage between ORFK1-ORF26E subtypes corresponded to reported relationships, except for one strain that clustered with B1 (K1 African) and D (ORF26E Asian-Pacific) subtypes. This research reveals predominance of subtype C, a broad spectrum of HHV-8 genotypes and reports the first isolation of the African B genotype in Argentina.

Efficient Infection of a Human B Cell Line with Cell-Free Kaposi's Sarcoma-Associated Herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) is causatively linked to two B cell lymphoproliferative disorders, multicentric Castleman's disease and primary effusion lymphoma. Latently infected B cells are a major KSHV reservoir, and virus activation from tonsillar B cells can result in salivary shedding and virus transmission. Paradoxically, human B cells (primary and continuous) are notoriously refractory to infection, thus posing a major obstacle to the study of KSHV in this cell type. By performing a strategic search of human B cell lymphoma lines, we found that MC116 cells were efficiently infected by cell-free KSHV. Upon exposure to recombinant KSHV.219, enhanced green fluorescent protein reporter expression was detected in 17 to 20% of MC116 cells. Latent-phase transcription and protein synthesis were detected by reverse transcription-PCR and detection of latency-associated nuclear antigen expression, respectively, in cell lysates and individual cells. Selection based on the puromycin resistance gene in KSHV.219 yielded cultures with all cells infected. After repeated passaging of the selected KSHV-infected cells without puromycin, latent KSHV was maintained in a small fraction of cells. Infected MC116 cells could be induced into lytic phase with histone deacetylase inhibitors, as is known for latently infected non-B cell lines, and also selectively by the B cell-specific pathway involving B cell receptor cross-linking. Lytic-phase transition was documented by red fluorescent protein reporter expression, late structural glycoprotein (K8.1A, gH) detection, and infectious KSHV production. MC116 cells were CD27(-)/CD10(+), characteristic of transitional B cells. These findings represent an important step in the establishment of an efficient continuous B cell line model to study the biologically relevant steps of KSHV infection. Kaposi's sarcoma-associated herpesvirus (KSHV) causes two serious pathologies of B cells, the antibody-producing cells of the immune system. B cells are a major reservoir for KSHV persistence in the body. Paradoxically, in the laboratory, B cells are extremely difficult to infect with KSHV; this problem greatly hinders scientific analysis of B cell infection. We describe our search for and successful identification of a stable human B cell line that can be efficiently infected by KSHV. Upon infection of these cells, the virus goes into a quiet latent phase, a characteristic feature of many herpesvirus infections. The virus can be triggered to enter an active lytic phase by treatments known to stimulate normal B cell functions. These findings suggest that the new B cell line will be a valuable model in which to study KSHV infection of this major target cell type.

A case report of syndrome of inappropriate antidiuretic hormone secretion with Castleman's disease and lymphoma.

BackgroundSyndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common cause of hyponatremia in hospitalized patients and is often described in patients with small-cell carcinoma of the lung. In this report, we described both Castleman’s disease and lymphoma coexisting in one patient with SIADH.Case presentationA 70-year-old Chinese woman with a history of diabetes mellitus and insulin therapy had severe hyponatremia and gastrointestinal symptoms. Through a series of examinations, common causes such as pulmonary carcinoma were excluded. An abdominal mass was detected by computed tomography. Although the peripheral lymph node biopsy showed the pathological result as Castleman’s disease, the pathology of the abdominal lymph node revealed diffuse large B-cell lymphoma. After chemotherapy, the hyponatremia was treated during a period of follow-up.ConclusionThis patient presented with the rare clinical condition of inappropriate antidiuretic hormone secretion alongside Castleman’s disease and lymphoma. Asymptomatic hyponatremia may persist for some time suggesting that clinical physicians should pay attention to the mild cases of hyponatremia. We also hypothesized that Castleman’s disease is a condition of pre-lymphoma with both having the ability to cause SIADH. The possibility of lymphoma as well as Castleman’s disease triggering the development of SIADH should also be taken into consideration for conducting recurrent biopsies.

Pulmonary manifestations of human herpesvirus-8 during HIV infection

Human herpesvirus (HHV)-8 is an oncogenic gamma herpesvirus that was first described in 1994 in Kaposi sarcoma lesions. HHV-8 is involved in the pathophysiological features of multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL), both rare B-cell lymphoproliferative diseases. HHV-8-related tumours occur almost exclusively in immunocompromised patients, mostly those with HIV infection. Combined antiretroviral therapies have reduced the incidence of Kaposi sarcoma but not MCD and PEL. HHV-8-related diseases frequently exhibit pulmonary involvement, which may indicate the disease. Kaposi sarcoma in the lung is often asymptomatic but may require specific therapy. It mostly shows cutaneous or mucosal involvement. Patients with typical MCD present fever and lymphadenopathy associated with interstitial lung disease without opportunistic infection. Specific treatment may be urgent. PEL provokes a febrile, lymphocytic-exudative pleural effusion, without a pleural mass on computed tomography scan. Rapid diagnosis prevents unnecessary examinations and leads to specific, rapid treatment. Therapy is complex, combining antiretroviral therapy and chemotherapy.

Plasma-cell type Castleman’s disease of the neck and lymphocyte-depletion Hodgkin lymphoma associated with intestinal intussusception in an AIDS patient

A 36-year-old man was diagnosed with plasma-cell type Castleman's disease with the presentation of recurrent lymphadenpathy of the neck. HIV infection was not suspected or confirmed until esophageal candidiasis developed one year later. Meanwhile, surgery was performed for intestinal intussusception and obstruction caused by lymphocyte-depletion Hodgkin lymphoma. However, he died of rapidly progressive pneumonia and disseminated intravascular coagulation associated with intracerebral hemorrhage, which occurred 6 months later during the course of chemotherapy. This case suggests that HIV infection should be considered in patients who present with plasma-cell type Castleman's disease or lymphocyte-depletion Hodgkin lymphoma with extra-nodal involvement in order to conduct appropriate diagnosis and initiate treatment for HIV infection.

Abstract A211: A phase I study of MABp1, a first-in-human, first-true human monoclonal antibody against the IL-1 in patients with advanced cancers.

Abstract Background: IL-1 is associated with pathological inflammatory responses, including inflammation that supports a malignant phenotype in the tumor microenvironment. Targeting IL-1α may reduce tumor potential by undermining one or more aspects of tumor-driven angiogenesis, tissue matrix remodeling and metastasis. MABp1 is a true human therapeutic antibody generated by a natural human immune response and was cloned directly from a human peripheral B lymphocyte. MABp1 binds IL-1α with high-affinity and is a potent blocker of IL-1α biological activity. Blocking IL-1α activity using MABp1 may be a safe and effective means of interrupting the chronic inflammatory response that supports tumor growth and invasiveness. Methods: This is an open label, first-in-man, phase I trial of MABp1 in patients with advanced cancers both metastatic and refractory to standard of care treatment. The trial included two dosing arms: arm A (4 levels of MABp1, administered once every 3 weeks); arm B consisted of the highest dose concentration in arm A administered once every 2 weeks. The trial followed a 3+3 design. Pharmacokinetics was measured at pre-screening and on days 1 (post-infusion), 8 and 15 during each cycle for the first 3 cycles and on day 1 of each subsequent cycle post-infusion. Pharmacodynamic sampling of CRP, IL-6 and IL-1 receptor antagonist (IL-1RA) occurred at screening and on days 1, 8 and 15 of each cycle. Results: Thirty-six patients were enrolled in arm A. Enrollment in arm B, the biweekly dosing cohort, is still ongoing. Pharmacokinetic investigation of patients in the highest dosing cohort of arm A showed an average peak serum concentration of 80 micrograms per milliliter, with a half-life of approximately 3 days. The most common possibly drug related adverse events (AEs) included 7 patients with grade I-II proteinuria (19%), 5 patients with grade I nausea (14%), and 4 patients with grade I-II fatigue (11%). A maximum dose of 3.75 mg/kg was reached on arm A, the highest dose concentration, with one dose-limiting toxicity (DLT) of a possibly drug-related infection. Of the 36 patients enrolled in arm A, 6 patients had (17%) had stable disease for &amp;gt;6 months (colorectal (CRC), Castleman's lymphoma, rectal, non-small cell lung (NSCLC), neuroendocrine, pseudomyxoma peritonei. One patient with KRAS+ CRC had a PR (−33% by RECIST) and continued on study for 18 months. Low IL-1RA at baseline (&amp;lt;400 pg/ml) was associated with patients with PR or on study &amp;gt;6 months. Conclusions: MABp1 was well tolerated with minimal AEs at the 3.75 mg/kg dose given every 3 weeks. MABp1 showed evidence of anti-tumor activity and altered disease progression in CRC, NSCLC, and other tumor subtypes. Reducing tumor-driven inflammation through IL-1α antagonism may be an effective disease modifying anti-cancer agent in advanced stage disease. Patient responses and an association of positive outcomes with low baseline IL1-RA levels support this finding. Further study is warranted in advanced cancers with MABp1. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A211.

Serous fluid cytology of multicentric Castleman’s disease and other lymphoproliferative disorders associated with Kaposi sarcoma‐associated herpes virus: a review with case reports

The aim of this study is to describe and review the cytological features of Kaposi sarcoma-associated herpes virus (KSHV) related entities, such as multicentric Castleman's disease (MCD), plasmablastic-lymphoma (PBL) and primary effusion lymphoma (PEL), which all may present as body cavity effusions. Serous fluid cytology of MCD and PBL has not, to our knowledge, thus far been described. Although different in nature, MCD, PBL and PEL are characterized by similar morphological features. Body cavity effusions from four different patients with previously known or unknown KSHV-related lymphoproliferations have been examined by routine cytology, immunocytochemistry (IC) and polymerase chain reaction (PCR). MCD, PBL and PEL are all characterized by increased cellularity, comprising mainly lymphoid and plasmacytoid cells with variable proportions of immunoblasts. Immunocytochemistry and PCR results show the MCD to be CD138 and KSHV positive, CD30 negative, IgM, IgH and lambda restricted but IgH polyclonal. PBL was CD138 positive, kappa restricted, weakly positive with VS38 and over 80% positive with MIB 1. PEL was CD45, EMA, CD138, KSHV, p53 and CD3 positive, CD20, EBV, CD30, CD2, CD4, ALK1, epithelial and mesothelial markers negative, and PCR monoclonal B-cell expanded (Ig-kappa bands). Cytological examination of effusions in KSHV-related lymphoproliferative disorders may show similar morphological features but clonality studies and immunocytochemistry are very helpful in distinguishing between these rare benign and malignant lymphoproliferative diseases.

HHV-8 linked to Kaposi's sarcoma, Castleman's disease and primary effusion lymphoma in a HIV-1-infected man

HHV-8 linked to Kaposi’s sarcoma, Castleman’s disease and primary effusion lymphoma in a HIV-1-infected man Alain Bestawros a, Mohamed-Rachid Boulassel b, Rene P. Michel c, Jean-Pierre Routy b,∗ a Department of Internal Medicine, Montreal General Hospital and McGill University Health Centre, Montreal, Canada b Division of Hematology and Immunodeficiency Service, Royal Victoria Hospital and McGill University Health Centre, Monterial, Canada c Department of Pathology, Royal Victoria Hospital and McGill University Health Centre, Montreal, Canada

Kaposi's sarcoma-associated herpesvirus immune modulation: an overview

Kaposi's sarcoma-associated herpesvirus (KSHV) is the most recently discovered human herpesvirus. It is the aetiological agent of Kaposi's sarcoma (KS), a tumour frequently affecting AIDS patients not receiving treatment. KSHV is also a likely cause of two lymphoproliferative diseases: multicentric Castleman's disease and primary effusion lymphoma. The study of KSHV offers exciting challenges for understanding the mechanisms of virus pathogenesis, including those involved in establishing infection and dissemination in the host. To facilitate these processes, approximately one-quarter of KSHV genes encode cellular homologues or unique proteins that have immunomodulatory roles in cytokine production, apoptosis, cell signalling and the immunological synapse. The activities of these molecules are considered in the present review and the positions of their genes are mapped from a complete KSHV genome sequence derived from a KS biopsy. The understanding gained enables the significance of different components of the immune response in protection against KSHV infection to be evaluated. It also helps to unravel the complexities of cellular and immunological pathways and offers the potential for exploiting viral immunomodulators and derivatives in disease therapy.

Reactive Oxygen Species (ROS) Are Induced by vFLIP and Regulate NF-kB Activation in KSHV-Infected Primary Effusion Lymphoma Cells.

Reactive Oxygen Species (ROS) act as second messengers in various cellular signaling cascades. While high levels of ROS induce oxidative stress response and cause cell death, lower levels of ROS in cancer cells can actually promote neoplastic growth and survival. ROS can activate the NF-kB pathway either through activation of the canonical IKK complex or through tyrosine phosphorylation of IkB alpha in a cell-specific manner. Recently it was shown that Epstein-Barr Virus (EBV) increased the amount of ROS in Burkitt's lymphoma cells through the actions of its EBER mRNA and viral proteins EBNA2 and LMP1. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human gamma-herpesvirus that is the etiologic agent of Kaposi's sarcoma, multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL). We investigated whether KSHV also increases ROS levels in PEL cells. We demonstrate that PEL cell lines have higher levels of intracellular ROS than uninfected cells, and highly activated MAPK, a downstream target of ROS. Since KSHV viral FLICE-inhibitory protein (vFLIP) activates NF-kB in PELs, we examined whether ROS is involved in this signaling pathway. We show that vFLIP potently induced ROS after treatment with doxycycline in vFLIP-inducible Namalwa cells. Inhibition of ROS by an antioxidant PDTC led to a reduction in NF-kB activity in PEL cells. These data suggest that reactive oxygen is a possible signaling mechanism downstream of vFLIP, which mediates NF-kB activation and PEL survival. Furthermore, antioxidants may be useful as pharmacological agents in the treatment of PEL.

Human herpes virus 8 in HIV and non-HIV infected patients with pulmonary arterial hypertension in France

Kaposi's sarcoma-associated herpesvirus or human herpesvirus 8 (HHV8) is a vasculotrope virus associated with Kaposi's sarcoma, HIV-associated Castleman's disease and primary effusion lymphoma. Other associations, in particularly multiple myeloma, have been clearly disproved by additional analysis after initial positive reports [1]. Cool et al. [2] have recently demonstrated the presence of HHV8 in the lungs of patients with pulmonary arterial hypertension (PAH) ascertained by immunochemistry with antibody directed against latency-associated nuclear antigen 1 (LANA-1) and polymerase chain reaction assay to detect the viral cycline gene of HHV8. In that study, evidence of HHV8 was found in 10 out of 16 patients with idiopathic PAH, in one out of three patients with PAH related to HIV infection, and in none of 12 patients with PAH related to other conditions. The authors suggested a role for HHV8 in the development of PAH [2]. Later, the presence of HHV8 antibodies, against a structural HHV8 protein called K8.1 and against LANA-1, was tested in plasma samples from non-HIV-infected German patients with PAH, but no difference was found between patients and controls [3]. In addition, HHV8-DNA sequences were not detected by polymerase chain reaction in nine PAH lungs studied in Japan, indicating that other factors than HHV8 are more likely to be the cause of PAH in that population [4]. Moreover, whereas the geographical distribution of Kaposi's sarcoma mirrors HHV8 prevalence, it seems unlikely for PAH in which no ethnic predisposition has been observed to date. As Mediterranean countries have higher prevalence rates of HHV8 infection, we studied a cohort of French patients with PAH in order to test whether there were possible links between HHV8 and PAH in this country. The aim of the study was to evaluate the prevalence of HHV8 antibodies in plasma samples from HIV and non-HIV-infected patients with PAH. Ninety-three patients with PAH were enrolled in the study: 47 with idiopathic or familial PAH, 34 with PAH related to HIV infection, and 12 with PAH associated with other conditions. Antibodies directed against LANA-1 were detected using an immunofluorescence assay on the primary effusion lymphoma BC-3 cell line, and the positive samples were confirmed using an immunofluorescence assay that detects antibodies to HHV8 lytic antigens (KSHV IgG IFA; Biotrin, Dublin, Ireland). HHV8 antibodies were detected in one out of 47 [2.1%; confidence interval (CI) 0–6.3%] patients with idiopathic or familial PAH and in two out of 12 (16.7%; CI 0–38.7%) patients with PAH related to other conditions. In the 34 patients with PAH related to HIV infection, eight had HHV8 antibodies (23.5%; CI 9.3–37.8%). These results indicate that the prevalence of antibodies for HHV8 in HIV-infected and non-HIV-infected patients with PAH is similar to that previously reported for corresponding individuals without PAH. The seroprevalence of HHV8 in healthy individuals in France has been estimated at 2%, and between 22 and 35% among HIV-infected individuals from the United States and northern Europe using LANA tests [5,6]. This suggests that there is no trend in favour of an increased serological evidence of HHV8 infection in PAH in HIV-infected patients or in non-HIV-infected patients. In addition, a reduced immunological response to viruses has never been reported in PAH, and there is no scientific basis supporting the hypothesis of a defective humoral response to HHV8, which could explain the low prevalence of HHV8-specific antibodies in plasma samples of PAH patients. Our present results are based on serological evidence of HHV8 infection, and one may hypothesize that HHV8 infection could be restricted to patients’ lungs. However, such compartmentalized HHV8 infection without serological evidence has not been reported to date. We conclude that there is no evidence in favour of an association between PAH and HHV8 in a French cohort of HIV-seropositive and seronegative patients.

Primary effusion lymphoma in HIV-infected patients with multicentric Castleman's disease

Multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) are two B-cell lymphoproliferative diseases associated with Kaposi's sarcoma-associated herpes virus/human herpesvirus-8 (KSHV/HHV-8). Although MCD is considered a prelymphoma state, it is not known whether a pathogenetic link exists between MCD and PEL. This paper reports the clinico-pathological features of four cases of PEL (two pericardial, one pleural, and one peritoneal) developing in the context of HIV-associated MCD. Effusions, lymph nodes, spleen, and additional tissues from three autopsies were examined for morphology/immunophenotype, search for HHV-8 DNA, and assessment of immunoglobulin heavy chain gene (IgH) configuration using polymerase chain reaction (PCR)-based techniques. MCD and PEL samples contained HHV-8 DNA. Clonal IgH rearrangements were detected only in PEL, whereas MCD tissues were polyclonal. Light-chain immunostaining confirmed B-cell clonality in PEL (two lambda, one kappa, one not tested) and polyclonality in MCD. The autopsies revealed different morphological variants of visceral KS and multi-organ atypical infiltrates exhibiting immunoblastic/plasmablastic features reminiscent of PEL morphology, with a restriction of lambda-positive cells. In two cases, using microdissection and IgH PCR analysis, multiple/discrete bands were found in the infiltrates, compatible with polyclonality/oligoclonality. The case showing an oligoclonal IgH ladder contained a rearrangement of identical junctional size to the PEL clone; however, further analysis with PEL-derived clonotypic primers and sequencing of PCR products showed no amplification and nucleotide diversity, respectively, indicating that the two B-cell populations examined were clonally unrelated. These data show that MCD and PEL may co-exist in HIV-infected patients, suggesting a relevant association between these two HHV-8-related disorders. Although a definite clonal relationship between MCD and PEL was not demonstrated, it is hypothesized that in some MCD cases, within expanded polyclonal B-cell populations secondary to HHV-8 infection, clonal expansions may occur that localize into a body cavity, i.e. PEL.

Kaposi's sarcoma-associated herpesvirus: from cell biology to pathogenesis.

Kaposi's sarcoma-associated herpesvirus (KSHV or HHV-8) is linked to the etiopathogenesis of Kaposi's sarcoma, a plasma-blastic variant of Castleman's disease and primary effusion lymphoma. KSHV is related to a number of non-human primate viruses. Only a limited number of KSHV proteins are expressed in tumor cells. Here we discuss the putative role of these proteins in KSHV pathogenesis.

Human herpesvirus-8 in lymphomatous and nonlymphomatous body cavity effusions developing in Kaposi's sarcoma and multicentric Castleman's disease.

Human herpesvirus-8 (HHV-8) has been associated with Kaposi's sarcoma, multicentric Castleman's disease and primary effusion lymphoma. Kaposi's sarcoma and multicentric Castleman's disease patients may develop body cavity effusions that, unlike primary effusion lymphoma, are poorly characterized. To better define these effusions, pleural and peritoneal fluids derived from 12 human immunodeficiency virus-seropositive and one seronegative patients affected by Kaposi's sarcoma or multicentric Castleman's disease were analyzed by a combination of morphologic, immunophenotypic, and DNA analyses, including polymerase chain reaction amplification of HHV-8, Epstein-Barr virus, and immunoglobulin heavy-chain (IgH) gene sequences. In addition, HHV-8 serologic status was assessed by using an immunofluorescence assay. All patients were adult men with high antibody titers to HHV-8; 11 of the 13 patients were homosexual/bisexual. Effusions revealed monocyte/macrophage-rich infiltration (10 patients) or large-cell lymphoma with CD45(+)/non-T/non-B phenotype (three of 13 patients); polymerase chain reaction analysis showed the presence of HHV-8 sequences (nine of 13 patients), germline IgH (seven of 12 patients) or clonal IgH rearrangements (four of 12 patients), and rarely Epstein-Barr virus sequences (two of 12 patients). In the setting of HHV-8 infection, two effusion types may occur. One fulfills the criteria for HHV-8-positive PEL (lymphoma-morphology, HHV-8-DNA(+), IgH rearrangement). The other seems more reminiscent of an HHV-8-associated nonneoplastic process (monocyte-macrophage morphology, HHV-8-DNA(+/-), germline IgH). Interestingly, a single case of the latter effusion type harbored a B-cell monoclonal proliferation, which suggests the hypothesis that a prelymphomatous effusion may precede overt body cavity lymphoma.