Novel association of haemophagocytic syndrome with Kaposi's sarcoma-associated herpesvirus-related primary effusion lymphoma

Recent Advances in Developing Treatments of Kaposi's Sarcoma Herpesvirus-Related Diseases

Kaposi-sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is the causative agent of several malignancies, including Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). Active KSHV replication has also been associated with a pathological condition called KSHV inflammatory cytokine syndrome (KICS), and KSHV may play a role in rare cases of post-transplant polyclonal lymphoproliferative disorders. Several commonly used herpesviral DNA polymerase inhibitors are active against KSHV in tissue culture. Unfortunately, they are not always efficacious against KSHV-induced diseases. To improve the outcome for the patients, new therapeutics need to be developed, including treatment strategies that target either viral proteins or cellular pathways involved in tumor growth and/or supporting the viral life cycle. In this review, we summarize the most commonly established treatments against KSHV-related diseases and review recent developments and promising new compounds that are currently under investigation or on the way to clinical use.

Remission of an HHV8-related extracavitary primary effusion lymphoma in an HIV-positive patient during antiretroviral treatment containing dolutegravir

Background

Human herpes virus 8 (HHV8) is the causative agent of Kaposi’s sarcoma and has been associated with an increasing number of hematologic diseases such as primary effusion lymphoma (PEL) (both classic and extracavitary form), multicentric Castleman disease and the germinotropic lymphoproliferative disorder. PEL is a rare B cell non-Hodgkin lymphoma that primarily affects immunocompromised patients; aggressive chemotherapy and antiretroviral therapy (ART) with protease inhibitors have been used, with poor results. We present a case of extracavitary PEL in an HIV-infected patient, regressed after ART initiation.

Case presentation

A 42-year-old male was admitted to the emergency room because of several months of malaise, fever and progressive deterioration of the general conditions. On physical examination soft non-painful subcutaneous masses were palpable at retronuchal, retroauricolar and thoracic regions. HIV serology resulted positive: HIV plasma viremia was 782,270 copies/mL, CD4 103 cells/mL. The excision of one of the masses, metabolically active at a positron emission tomography (PET-CT) scan, revealed an HHV8-related extracavitary PEL. HHV8 plasma viremia was 44,826 copies/mL. ART with tenofovir alafenamide/emtricitabine/dolutegravir was started together with ganciclovir for cytomegalovirus chorioretinitis. The progressive disappearance of the masses was seen after 6 weeks of ART, and a PET-CT scan resulted completely negative at 3 months. After 19 months of ART the patient was in remission of PEL, HIV viremia was undetectable (< 20 copies/mL), CD4 count was 766 cells/mL and HHV8 viremia was undetectable.

Conclusions

In this clinical case, the complete regression of PEL has been achieved after the immune recovery, as a consequence of ART introduction, without chemotherapy. It cannot be excluded that ganciclovir, used for the treatment of CMV chorioretinitis, may have contributed to the control of HHV8 replication. Whether to try or not a conservative approach in HIV-infected PEL patients must be carefully evaluated, considering the patient’s characteristics and the prognostic factors.

Macrophage Activation Syndrome

Hemophagocytic lymphohistiocytosis (HLH), or termed macrophage activation syndrome (MAS) when associated with rheumatic disorders, is a frequently fatal complication of infections, rheumatic disorders, and hematopoietic malignancies. Clinically, HLH/MAS is a life-threatening condition that is usually diagnosed among febrile hospitalized patients (children and adults) who commonly present with unremitting fever and a shock-like multiorgan dysfunction scenario. Laboratory studies reveal pancytopenia, elevated liver enzymes, elevated markers of inflammation (ESR, CRP), hyperferritinemia, and features of coagulopathy. In about 60% of cases, excess hemophagocytosis (macrophages/histiocytes engulfing other hematopoietic cell types) is noted on biopsy specimens from the bone marrow, liver, lymph nodes, and other organs. HLH/MAS has been hypothesized to occur when a threshold level of inflammation has been achieved, and genetic and environmental risk factors are believed to contribute to the hyperinflammatory state. A broad variety of infections, from viruses to fungi to bacteria, have been identified as triggers of HLH/MAS, either in isolation or in addition to an underlying inflammatory disease state. Certain infections, particularly by members of the herpesvirus family, are the most notorious triggers of HLH/MAS. Treatment for infection-triggered MAS requires therapy for both the underlying infection and dampening of the hyperactive immune response.

HHV-8-associated haemophagocytic lymphohistiocytosis in a patient with advanced AIDS

We present a patient with advanced AIDS admitted with recurrent shock of unclear aetiology, fevers, altered mental status and refractory cytopenias. His case posed a diagnostic challenge because evaluation of septic shock in the setting of advanced AIDS requires a time-consuming work-up for broad infectious aetiologies that can delay consideration of other diagnoses, including primary or secondary haemophagocytic lymphohistiocytosis (HLH). After this patient did not improve with supportive care and empiric antimicrobials, there was concern for HLH given that he met ≥5 of the HLH consortium criteria. He underwent bone marrow biopsy, which was non-diagnostic. Empiric therapy for HLH was initiated, but unfortunately, the patient died. Autopsy revealed extensive haemophagocytosis in the spleen, bone marrow and liver, confirming the diagnosis of HLH. Postmortem, his soluble CD-25 returned 18 890 pg/mL (<1033 pg/mL), and his serum HHV-8 PCR resulted positive. The diagnosis was HLH secondary to Human Herpes Virus 8 (HHV-8) in a patient with advanced AIDS.

Case report of a primary effusion lymphoma successfully treated with oral valganciclovir after failing chemotherapy

Primary effusion lymphoma is a rare non-Hodgkin lymphoma that presents with pleural effusions and lacking of tumour mass. It is universally associated with human herpesvirus 8 (HHV8) and is more frequent among immunosuppressed patients. There is no standard treatment, chemotherapy and anti-HIV therapy have been used with poor results, but there is still no strong evidence supporting the use of valganciclovir. We present the case of a HIV positive man that presented with pleural effusion compatible with primary effusion lymphoma and positivity for HHV8 DNA in blood. Bortezomib-containing treatment protocol was started, but the disease progressed within the chemotherapy. Therefore, treatment with oral valganciclovir was decided and the patient achieved a sustained radiological complete response. HHV8 DNA turned negative 6 months after starting the treatment with valganciclovir.

KSHV targeted therapy: an update on inhibitors of viral lytic replication

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi’s sarcoma, primary effusion lymphoma and multicentric Castleman’s disease. Since the discovery of KSHV 20 years ago, there is still no standard treatment and the management of virus-associated malignancies remains toxic and incompletely efficacious. As the majority of tumor cells are latently infected with KSHV, currently marketed antivirals that target the virus lytic cycle have shown inconsistent results in clinic. Nevertheless, lytic replication plays a major role in disease progression and virus dissemination. Case reports and retrospective studies have pointed out the benefit of antiviral therapy in the treatment and prevention of KSHV-associated diseases. As a consequence, potent and selective antivirals are needed. This review focuses on the anti-KSHV activity, mode of action and current status of antiviral drugs targeting KSHV lytic cycle. Among these drugs, different subclasses of viral DNA polymerase inhibitors and compounds that do not target the viral DNA polymerase are being discussed. We also cover molecules that target cellular kinases, as well as the potential of new drug targets and animal models for antiviral testing.

Sustained complete remission of primary effusion lymphoma with adjunctive ganciclovir treatment in an HIV-positive patient

Primary effusion lymphoma (PEL) is one of the least common of the AIDS-related lymphomas, accounting for less than 1-4% of cases. Clinical manifestations depend on the extent and distribution of disease and, as in the majority of patients no detectable mass lesion is found, symptoms are related to fluid accumulation, dyspnoea (pleural or pericardial effusions), abdominal distension (ascites) or joint swelling. The median survival after diagnosis, even with aggressive chemotherapy, remains poor and remissions are often of short duration. We present the case of a 31-year-old man with AIDS and diagnosis of PEL, in whom sustained and complete remission of the tumour was achieved with adjunctive ganciclovir therapy. Since the disease is so uncommon, there is a paucity of data to guide the treatment of these patients; ganciclovir might be a potential antiviral therapeutic option, as demonstrated by the 2-year remission achieved in our patient.

Debate around infection-dependent hemophagocytic syndrome in paediatrics

Background

Hemophagocytic syndrome (HPS) is clinically defined as a combination of fever, liver dysfunction, coagulation abnormalities, pancytopenia, progressive macrophage proliferation throughout the reticuloendothelial system, and cytokine over-production, and may be primary or secondary to infectious, auto-immune, and tumoral diseases. The most consistent association is with viral infections but, as it is still debated whether any micro-organisms are involved in its pathogenesis, we critically appraised the literature concerning HPS and its relationship with infections.

Discussion

Infection-dependent HPS has been widely observed, but there are no data concerning its incidence in children. A better understanding of the pathophysiology of HPS may clarify the interactions between the immune system and the variously implicated potential infectious agents. Epstein-Barr virus (EBV) infection has been prominently associated with HPS, with clonal proliferation and the hyperactivation of EBV-infected T cells. However, a number of other viral, bacterial, fungal, and parasitic infections have been reported in association with HPS. In the case of low-risk HPS, corticosteroids and/or intravenous immunoglobulin or cyclosporine A may be sufficient to control the biological process, but etoposide is recommended as a means of reversing infection-dependent lymphohistiocytic dysregulation in high-risk cases.

Summary

HPS is a potential complication of various infections. A polymerase chain reaction search for infectious agents including EBV, cytomegalovirus and Leishmania is recommended in clinical settings characterised by non-remitting fever, organomegaly, cytopenia and hyperferritinemia.

Diagnosing visceral leishmaniasis and HIV/AIDS co-infection: a case series study in Pernambuco, Brazil

HIV/AIDS-associated visceral leishmaniasis may display the characteristics of an aggressive disease or without specific symptoms at all, thus making diagnosis difficult. The present study describes the results of diagnostic tests applied to a series of suspected VL cases in HIV-infected/AIDS patients admitted in referral hospitals in Pernambuco, Brazil. From a total of 14 eligible patients with cytopenias and/or fever of an unknown etiology, and indication of bone marrow aspirate, 10 patients were selected for inclusion in the study. Diagnosis was confirmed by the following examinations: Leishmania detection in bone marrow aspirate, direct agglutination test, indirect immunofluorescence, rK39 dipstick test, polymerase chain reaction and latex agglutination test. Five out of the ten patients were diagnosed with co-infection. A positive direct agglutination test was recorded for all five co-infected patients, the Leishmania detection and latex agglutination tests were positive in four patients, the rK39 dipstick test in three, the indirect immunofluorescence in two and a positive polymerase chain reaction was recorded for one patient. This series of cases was the first to be conducted in Brazil using this set of tests in order to detect co-infection. However, no consensus has thus far been reached regarding the most appropriate examination for the screening and monitoring of this group of patients.

Human herpesvirus 8-associated neoplasms: the roles of viral replication and antiviral treatment

PURPOSE OF REVIEW

In this review, we highlight the importance of human herpesvirus 8 (HHV-8) lytic replication and the potential for antiviral therapies to prevent or treat HHV-8-related neoplasms.

RECENT FINDINGS

Diseases caused by HHV-8 infection include Kaposi sarcoma, multicentric Castleman disease (MCD), and primary effusion lymphoma (PEL), which occur primarily in patients with HIV infection. Kaposi sarcoma is the most common AIDS-associated malignancy worldwide. MCD and PEL occur less commonly but, like Kaposi sarcoma, are associated with poor treatment outcomes. Like all herpesviruses, HHV-8 is capable of either latent or lytic infection of cells. Although HHV-8 infection of tumor cells is predominately latent, accumulating data point to the importance of both lytic phase viral gene products and production of infectious virus. Antiviral agents that target herpesvirus DNA synthesis, such as ganciclovir, inhibit HHV-8 lytic replication and can prevent Kaposi sarcoma. Several HIV protease inhibitors may interfere with tumor growth and angiogenesis, and one protease inhibitor, nelfinavir, directly inhibits HHV-8 replication in vitro.

SUMMARY

Controlled trials are indicated to determine the clinical utility of antiviral suppression of HHV-8 replication, and identify the optimal antiretroviral regimens, for the prevention and treatment of Kaposi sarcoma.

Viral infections associated with haemophagocytic syndrome

Haemophagocytic syndrome (HPS) or haemophagocytic lymphohistiocytosis (HLH) is a rare disease caused by a dysfunction of cytotoxic T cells and NK cells. This T cell/NK cell dysregulation causes an aberrant cytokine release, resulting in proliferation/activation of histiocytes with subsequent haemophagocytosis. Histiocytic infiltration of the reticuloendothelial system results in hepatomegaly, splenomegaly, lymphadenopathy and pancytopenia ultimately leading to multiple organ dysfunctions. Common clinical features include high fevers despite broad spectrum antimicrobials, maculopapular rash, neurological symptoms, coagulopathy and abnormal liver function tests. Haemophagocytic syndrome can be either primary, i.e. due to an underlying genetic defect or secondary, associated with malignancies, autoimmune diseases (also called macrophage activation syndrome) or infections. Infectious triggers are most commonly due to viral infections mainly of the herpes group, with EBV being the most common cause. HPS can be fatal if untreated. Early recognition of the clinical presentation and laboratory abnormalities associated with HPS and prompt initiation of treatment can be life saving. HPS triggered by viral infections generally does not respond to specific antiviral therapy but may be treated with immunosuppressive/immunomodulatory agents and, in refractory cases, with bone marrow transplantation. Copyright © 2010 John Wiley & Sons, Ltd.

Molecular biology of Kaposi's sarcoma-associated herpesvirus and related oncogenesis

Kaposi's Sarcoma-associated Herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is the most recently identified human tumor virus,and is associated with the pathogenesis of Kaposi's sarcoma and two lymphoproliferative disorders known to occur frequently in AIDS patients-primary effusion lymphoma and multicentric Castleman disease. In the 15 years since its discovery, intense studies have demonstrated an etiologic role for KSHV in the development of these malignancies. Here, we review the recent advances linked to understanding KSHV latent and lytic life cycle and the molecular mechanisms of KSHV-mediated oncogenesis in terms of transformation, cell signaling, cell growth and survival, angiogenesis, immune invasion and response to microenvironmental stress, and highlight the potential therapeutic targets for blocking KSHV tumorigenesis.

Primary effusion lymphoma involving three body cavities

Primary effusion lymphoma (PEL) is a human herpes virus-8 (HHV8)-associated large-cell non-Hodgkin lymphoma localized in body cavities and presenting as pleural, peritoneal, or pericardial lymphomatous effusions. It typically affects immunocompromised patients and usually involves only one body site. We describe herein a case of PEL affecting three body cavity sites in an immunocompetent patient. A 69-year-old HIV-negative man presented with upper gastrointestinal bleeding and ascites. An examination of the fluid by cytology showed large atypical lymphocytes with abundant basophilic cytoplasm, either central or eccentric nuclei having irregular outlines, and multiple prominent nucleoli. The neoplastic cells showed positive staining for CD45, CD3, HHV8 latent nuclear antigen (LNA), and Epstein-Barr virus-encoded RNA. A diagnosis of PEL was rendered. Despite chemotherapy and valganciclovir, the disease progressed to involve the pleural and pericardial cavities and the patient died 5 months following the initial diagnosis. Although PEL is a B-cell lymphoma, it is usually of null phenotype by immunohistochemistry, and can rarely aberrantly express T-cell markers, as seen in the current case. The key to the diagnosis of PEL rests on identifying HHV8 in the neoplastic cells. Therefore, restricting the term of PEL only to those cases that are HHV8 positive is important in order to differentiate PEL from other lymphomas that can present as serous effusions and that carry, in general, a more favorable prognosis than PEL.

Successful treatment with liposomal doxorubicin for widespread Kaposi's sarcoma and human herpesvirus-8 related severe hemophagocytic syndrome in a patient with acquired immunodeficiency syndrome

Hemophagocytic syndrome (HPS) sometimes occurres in patients with acquired immunodeficiency syndrome (AIDS). Human herpesvirus-8 (HHV-8)/Kaposi's sarcoma (KS)-associated herpesvirus has so far been recognized as a trigger of HPS in immunosuppressed subject. We describe a 39-year-old man with AIDS who had widespread mucocutaneous and pulmonary KS and severe HPS. No opportunistic infections or neoplasias were detected except for KS. HHV-8-DNA could be detected in this patient by polymerase chain reaction (PCR) in the serum. Clinical symptoms and cytopenia originating from HPS were reduced by pulse therapy of corticosteroid, antibiotics, and virucides, but recurred with dose reduction of the steroid. Mucocutaneous tumors, edema, and dyspnea had progressed rapidly at this time. Liposomal doxorubicin was given and showed marked effects on both mucocutaneous and plural tumors. HPS also subsided and the serum HHV-8 DNA level markedly decreased after initial treatment with liposomal doxorubicin. HHV-8 clearance with liposomal doxorubicin has recently been reported. Liposomal doxorubicin suppressed not only the widespread KS tumors, but also HHV-8 viremia resulting in decreased HPS in this patient.

New approaches to the treatment of human herpesvirus 8-associated disease

Human herpesvirus 8 (HHV-8, also known as Kaposi sarcoma-associated herpesvirus or KSHV) is the etiologic agent of Kaposi sarcoma (KS) and primary effusion lymphoma (PEL), as well as many cases of Castleman disease. Despite significant advances in understanding the biology and natural history of these diseases, current treatment options have important limitations, and strategies to prevent their development in high-risk individuals are lacking. This article reviews the scope of HHV-8-associated disease, as well as the efficacy of current treatment options. Finally, novel approaches to treatment and prevention are described, including antiviral agents, targeted molecular therapy and a combination of these modalities.

Comparison of human herpes virus 8 related primary effusion lymphoma with human herpes virus 8 unrelated primary effusion lymphoma-like lymphoma on the basis of HIV: report of 2 cases and review of 212 cases in the literature

BACKGROUND

Primary lymphomatous effusion is a rare lymphoma that arises in the body cavity and has a peculiar proliferative form, lacking a tumor. This primary lymphomatous effusion includes human herpes virus 8 (HHV8)-related primary effusion lymphoma (PEL) and HHV8-unrelated PEL-like lymphoma. We attempted to clarify the nature of the primary lymphomatous effusion.

METHODS

Using 'PEL' and 'body cavity-based lymphoma' (BCBL) as key words, reports written in English were collected from PubMed. Primary lymphomatous effusion was defined as BCBL with primary effusion and without tumor at onset. Adding our 2 PEL-like lymphoma cases, each case was studied as to the patients' and lymphomas' characteristics, therapy and survival time. Moreover, each item was compared among four groups according to the presence of HHV8 and HIV.

RESULTS

In 214 cases investigated, there was no difference in proliferation, but an apparent difference in age, gender, phenotype, effectiveness and prognosis among the four groups.

CONCLUSIONS

Both PEL and PEL-like lymphoma are thought to be characterized by a peculiar proliferation, regardless of the presence of HHV8. Dividing PEL or PEL-like lymphoma into two subgroups on the basis of HIV presentation might also be appropriate.

The use of antiviral drugs in the prevention and treatment of Kaposi sarcoma, multicentric Castleman disease and primary effusion lymphoma

Kaposi sarcoma-associated herpesvirus [KSHV, also known as human herpesvirus 8 (HHV-8)] is the most recently identified member of the human herpesvirus family. Kaposi sarcoma (KS), primary effusion lymphoma, and multicentric Castleman disease are all associated with KSHV infection. Although the incidence of KS has declined dramatically in areas with access to highly active antiretroviral therapy, it remains the most common AIDS-associated malignancy in the developed world and is one of the most common cancers in developing nations. Current treatment options for KSHV-associated disease are ineffective, unavailable, or toxic to many affected persons. A growing body of basic science, preclinical, and observational data suggests that antiviral medications may play an important role in the prevention and treatment of KSHV-associated disease.

The pleiotropic effects of Kaposi's sarcoma herpesvirus

Kaposi's sarcoma herpesvirus (KSHV), or human herpesvirus 8 (HHV8), is an essential factor in the pathogenesis of Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). Case reports suggest an occasional involvement in bone marrow hypoplasia and haemophagocytic syndrome, but other disease associations are unconfirmed or controversial. KSHV-associated disease is of particular importance in immunosuppressed individuals, in particular in patients with HIV infection and transplant recipients. KSHV establishes a latent infection in the majority of infected cells in KS, MCD, and PEL, but lytic replication occurs in a small fraction of infected cells. Viral proteins expressed during both the latent and the lytic phase of the viral life cycle contribute to the pathogenesis of KSHV-associated diseases.

Fatal HHV-8-Associated Hemophagocytic Syndrome in an HIV-Negative Immunocompetent Patient With Plasmablastic Variant of Multicentric Castleman Disease (Plasmablastic Microlymphoma)

Virus-associated hemophagocytic syndrome (VAHS) triggered by HHV-8 is extremely rare and has been reported only in 9 immunocompromised patients. We report the first case of HHV-8-associated VAHS in an HIV-negative, immunocompetent patient with plasmablastic variant (plasmablastic microlymphoma) of multicentric Castleman disease (MCD). This 61-year-old man presented with fever, cough, and bilateral inguinal lymphadenopathy. Biopsy of the right inguinal lymph node revealed plasmablastic MCD with nodular aggregates of plasmablasts expressing IgM, MUM1, HHV-8 latency-associated nuclear antigen, and viral interleukin-6. These plasmablasts were monotypic for Iglambda light chain expression but not Igkappa. All the B-cell clonality assays, including IgH-FR2, IgH-FR3, DH-JH, Igkappa, and Iglambda PCR, showed a polyclonal pattern. His serum human interleukin-6 level was markedly elevated and was negative for EBV acute infection/reactivation. The marrow aspirate showed florid hemophagocytosis. His disease progressed rapidly to multisystemic illness, and he died of acute respiratory failure in 1 month. Our case showed that HHV-8 might trigger VAHS in an immunocompetent patient with plasmablastic MCD. We speculated that our patient developed VAHS under the cytokine storm associated with the proliferating HHV-8-infected plasmablasts, similar to the EBV-triggered VAHS in patients with EBV-associated T-cell lymphoma.

Serous effusions in malignant lymphomas: A review

Serous effusions are a common complication of lymphomas. Although the frequency of pleural effusion is 20-30% in non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD), the involvement of peritoneal and pericardial cavities is uncommon. Among lymphoma subtypes, T-cell neoplasms, especially the lymphoblastic lymphomas, more frequently involve the serous fluids. The thoracic duct obstruction and impaired lymphatic drainage appear to be the primary mechanism for pathogenesis of pleural effusion in HD and direct pleural infiltration is the predominant cause in NHL. There is wide variation in rate of positive cytologic findings of NHL in pleural effusion (22.2-94.1%). Cytologic features of specific lymphoma subtypes such as lymphoblastic lymphoma, follicular center cell lymphoma, including Burkitt-type lymphoma, marginal zone lymphoma, MALT lymphoma, and anaplastic large-cell lymphoma, etc., have been described in the literature. The differential diagnostic problems of lymphomas in serous effusions include reactive lymphocytoses, early involvement by lymphomatous process, small round-cell tumors (SRCT), and presence of look-alike of Reed-Sternberg cells. To overcome these difficulties, various ancillary studies, including immunocytochemistry (ICC), morphometry, flow cytometry (FCM), and cytogenetics/molecular genetics (PCR, in-situ hybridization, and Southern blotting), have been performed on effusion specimens. ICC not only distinguishes lymphomas from reactive lymphocytoses and SRCTs, it significantly modifies the morphologic diagnosis to achieve a better classification of lymphomas. Combined morphology and immunophenotyping by FCM, has a sensitivity as well as specificity of 100%. Morphometry also distinguishes reactive lymphocytoses from malignant lymphoma with a high degree of sensitivity (>85%) and specificity (>95%). Limitations of individual ancillary techniques can be overcome by using multiple parameters. Although lymphomas rarely present as serous effusions without the involvement of other thoracic and extrathoracic sites, a small group of lymphomas called primary effusion lymphomas (PEL) exhibit exclusive or dominant involvement of serous cavities, without a detectable solid tumor mass. This body cavity based lymphoma (BCBL) is a distinct clinicopathologic entity and is found predominantly in AIDS patients with preexisting Kaposi sarcoma. In the absence of obstructive or infiltrative tumor mass, its pathogenesis has been attributed to stimulation by vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF), leading to vascular leakage. Cytomorphologically, PEL is usually a large-cell lymphoma, which appears to bridge features of large-cell immunoblastic and anaplastic large-cell lymphoma (ALCL). Most of these cases comprise a unique subgroup of B-cell lymphoma, with features of both high-grade anaplastic and B-immunoblastic lymphoma, but T-cell and/or natural killer cell immunophenotypes are described. Its association with various viral DNAs has been studied in detail by molecular techniques. Pleural effusion due to lymphomas, either primary or otherwise, is considered as one of the factors adversely influencing overall survival. The presence of pleural effusion at the time of presentation is not only associated with extremely poor outcome of lymphomas, it is also a predictor of disease relapse after chemotherapy and decreased survival. When the patients of lymphomatous pleural effusions with and without mediastinal mass present in respiratory distress, thoracocentesis is the initial diagnostic and therapeutic choice in these patients. In such situations, cytology along with ancillary studies not only gives a quick diagnosis of lymphoma, but also offers prognostically significant information such as classification of lymphomas, its grade and immunophenotype, and presence/absence of viral DNAs and tumor lysis syndrome.

Therapeutic options for human herpesvirus-8/Kaposi's sarcoma-associated herpesvirus-related disorders

Human herpesvirus-8/Kaposi's sarcoma-associated herpesvirus infection is associated with three proliferative disorders in immunocompromised patients - Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease. These disorders often develop in patients with advanced AIDS who present a number of therapeutic challenges, underscoring the importance of continuing efforts dedicated to basic and clinical research in this field. In the era of highly active antiretroviral therapy, the incidence of AIDS and Kaposi's sarcoma has considerably decreased, presumably due to enhanced anti-Kaposi's sarcoma-associated herpesvirus immune responses, whereas the situation with primary effusion lymphoma and multicentric Castleman's disease is more complex. Based on advances in the understanding of Kaposi's sarcoma-associated herpesvirus-related disorders and availability of antiretroviral agents, current and future therapeutic approaches will be discussed.

Transmission and disease association of Kaposi's sarcoma-associated herpesvirus: recent developments

PURPOSE OF REVIEW

Kaposi's sarcoma-associated herpesvirus or human herpesvirus 8, common in sub-Saharan Africa and around the Mediterranean Sea but rare in most other countries, is known to be transmitted in childhood within families in endemic regions, and through sexual contacts among high-risk groups in Western countries. Nevertheless recent developments on other modes of transmission of the virus have been made during the last years and are summarized in this review. Furthermore, recent published disease associations are discussed.

RECENT FINDINGS

The last year has seen research addressing the question of parenteral transmission, sexual transmission through heterosexual contact, transmission of Kaposi's sarcoma-associated herpesvirus-infected cells from organ donors to recipient, as well as the first suggestion that host genetic factors may facilitate infection in childhood. Additional clinical manifestations of infection with the virus such as primary pulmonary hypertension and germinotropic lymphoproliferative disorder have been identified.

SUMMARY

Evidence of Kaposi's sarcoma-associated herpesvirus transmission other than between homosexual adults and during childhood - namely transmission through heterosexual contact or injection drug use - is growing although these issues are still incompletely analysed and far away from being fully understood. Despite our increasing knowledge on transmission and disease associations of the virus, implications on the clinical management of associated diseases and public health have to be further evaluated in the coming years.

Remission of HHV-8 and HIV-associated multicentric Castleman disease with ganciclovir treatment

Multicentric Castleman disease (MCD) is a lymphoproliferative disorder associated with human herpesvirus 8 (HHV-8) infection among persons with human immunodeficiency virus (HIV) infection. Treatment often includes chemotherapy, and progression to non-Hodgkin lymphoma frequently occurs. MCD is characterized in part by active HHV-8 replication, and many of the symptoms of MCD may be attributable to viral gene products. We describe the effect of ganciclovir on the clinical and virologic course of MCD in a series of 3 case reports. Two patients experienced a reduction in the frequency of episodic flares of MCD and detectable HHV-8 DNA with intravenous or oral ganciclovir, whereas the third patient recovered from an acute episode of renal and respiratory failure with intravenous ganciclovir therapy. These data provide in vivo evidence for the utility of antiviral agents against HHV-8 in the management of MCD.

Candidiasis-associated hemophagocytic lymphohistiocytosis in a patient infected with human immunodeficiency virus

We describe a patient with acquired immunodeficiency syndrome who developed candidiasis-associated hemophagocytic lymphohistiocytosis (HLH), and we review the previously reported cases of this unusual clinical syndrome in patients infected with human immunodeficiency virus (HIV). HLH appears to follow a fulminant course in HIV-infected patients, which warrants an aggressive diagnostic and therapeutic approach. HIV itself may play a role in the pathogenesis of HLH, which is usually associated with opportunistic infections or malignancies. Therapy is usually directed at supportive care and treatment of the underlying disorders, although initiation of antiretroviral therapy may improve the eventual outcome in some cases.

Human herpesvirus 8-associated hemophagocytic lymphohistiocytosis in human immunodeficiency virus-infected patients

We retrospectively reviewed 5 cases of hemophagocytic lymphohistiocytosis (HL) associated with human herpesvirus 8 (HHV-8) reactivation in human immunodeficiency virus (HIV)-infected patients. All patients had clinical and biological features characteristic of HL. Pulmonary symptoms were present in all patients and were frequently life threatening. The mean number of HL episodes was 6. Four patients had HL-associated Kaposi sarcoma, and 3 had multicentric Castleman disease. The mean CD4 cell count was 200 cells/mm(3). HIV loads were stable in all patients. All patients had high levels of HHV-8 in peripheral blood mononuclear cells during attacks, and a significant increase in this parameter before the attacks was seen in 3 patients. Although 2 patients died of HL, 3 are still alive and receiving etoposide therapy (mean follow-up, 3 years). HHV-8-related HL is associated with life-threatening symptoms and biological HHV-8 reactivation, and it may be controlled in the long term by etoposide therapy combined with highly active antiretroviral therapy.

Combined chemotherapy including high-dose methotrexate in KSHV/HHV8-associated primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare KSHV/HHV8-associated high-grade non-Hodgkin's lymphoma (NHL) of B-cell origin, characterized by serous effusions in body cavities. Most patients are HIV-infected homosexual men with severe immunosuppression and other KSHV/HHV8-associated diseases such as Kaposi's sarcoma (KS). The prognosis is poor with a median survival of less than 6 months in most cohorts. The achievement of a sustained complete remission is rare. High-dose chemotherapy regimens are warranted to improve complete remission rate and survival. Seven patients with AIDS-associated PEL were treated with a combined chemotherapy including high-dose methotrexate followed by leucovorin rescue. In all cases, KSHV/HHV8 sequences were detected in the effusion samples using quantitative PCR assays. Five patients had a pre-existing KS, associated in three cases with multicentric Castleman's disease (MCD). Upon diagnosis, 6 patients received antiretroviral therapy, which was maintained during chemotherapy in 5 of them. At time of analysis, 3 out of 7 patients were in complete remission 18, 26, and 78 months after PEL diagnosis. Three patients died with a progressive PEL at 22, 67, and 153 days after diagnosis, and 1 patient died 9 months after PEL diagnosis with a MCD-associated plasmablastic NHL. Complete remission was obtained in 3 out of 7 patients treated for AIDS-associated PEL with combined chemotherapy containing high-dose methotrexate.

Severe pancytopenia and hemophagocytosis after HHV-8 primary infection in a renal transplant patient successfully treated with foscarnet

We report the occurrence of human herpesvirus (HHV)-8 primary infection in an adult male kidney recipient. Four months after transplantation, the patient developed visceral Kaposi sarcoma, and 1 month later he presented with progressive and severe peripheral cytopenia, in the presence of a normocellular or hypercellular bone marrow (BM) with hemophagocytosis. HHV-8 was the sole pathogen detected by polymerase chain reaction either in the serum or in the BM. HHV-8 latent nuclear antigen was detected in immature progenitor cells from the BM. Immunosuppressive therapy was reduced, and the patient was treated with foscarnet for 2 weeks, leading to a dramatic normalization of blood cell counts, concomitantly with the disappearance of HHV-8 viremia. At the end of antiviral therapy, the patient received chemotherapy, and Kaposi sarcoma regressed in 2 months. Severe peripheral cytopenia may be a posttransplant complication after HHV-8 infection, for which treatment with foscarnet seems appropriate.

Spectrum of Kaposi's sarcoma-associated herpesvirus, or human herpesvirus 8, diseases

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), discovered in 1994, is a human rhadinovirus (gamma-2 herpesvirus). Unlike other human herpesviruses (herpes simplex virus, Epstein-Barr virus, varicella-zoster virus, cytomegalovirus, HHV-6, and HHV-7), it is not widespread in the general population and has many unique proteins. HHV-8 is strongly associated with all subtypes of Kaposi's sarcoma (KS), multicentric Castleman's disease, and a rare form of B-cell lymphoma, primary effusion lymphoma. In addition, HHV-8 DNA sequences have been found in association with other diseases, but the role of the virus in these diseases is largely unconfirmed and remains controversial. The seroprevalence of HHV-8, based on detection of latent and lytic proteins, is 2 to 5% in healthy donors except in certain geographic areas where the virus is endemic, 80 to 95% in classic KS patients, and 40 to 50% in HIV-1 patients without KS. This virus can be transmitted both sexually and through body fluids (e.g., saliva and blood). HHV-8 is a transforming virus, as evidenced by its presence in human malignancies, by the in vitro transforming properties of several of its viral genes, and by its ability to transform some primary cells in culture. It is not, however, sufficient for transformation, and other cofactors such as immunosuppressive cytokines are involved in the development of HHV-8-associated malignancies. In this article, we review the biology, molecular virology, epidemiology, transmission, detection methods, pathogenesis, and antiviral therapy of this newly discovered human herpesvirus.