Kaposi's sarcoma-associated herpesvirus viremia is associated with the progression of classic and endemic Kaposi's sarcoma

In order to gain further insight on the role of Kaposi's sarcoma-associated herpesvirus (KSHV) in classic and endemic Kaposi's sarcoma (KS) pathogenesis, we aimed to determine (i) whether KSHV is detectable in peripheral blood mononuclear cells (PBMCs), (ii) which PBMCs subpopulation harbor the virus, (iii) which clinical, histologic, and immunologic parameters are associated with KSHV viremia in a population of classic and endemic KS. KSHV viremia and various immunologic parameters were screened on 81 patients. KSHV viremia was positive in 58% of the patients. KSHV was detected in B cells, T cells, and monocytes. CD34+ cells depleted in circulating endothelial cells (CECs) were never infected and 50% of the patients tested had CECs infected by KSHV. We observed a significant increase of IL-2 and IFN-gamma production by CD4 T cells and an increase of IFN-gamma production by CD8 T cells compared to control patients. KS progression (P = 0.001) and KS staging (P = 0.03) were significantly and independently associated with positive KSHV viremia. Our results show that there is no specific immunosuppression in classic or endemic KS. We showed that KSHV can be detected within CECs and that KSHV viremia could be an indicator of circulating mature or precursor spindle cells.     

Further confirmation of the association of human herpesvirus 8 with Kaposi's sarcoma

Recently, a new herpesvirus-like DNA sequence named Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) has been isolated from almost all cases of Kaposi's sarcoma (KS). It has not been found in most benign and malignant cutaneous hemangioproliferative disorders other than KS. To further verify the specificity of the association of this new viral DNA with KS, we examined in total 42 cases of vascular neoplasms of endothelial derivation using nested polymerase chain reaction (PCR) for the presence of a 233-bp segment of this KSHV/HHV8 on paraffin-embedded specimens. In our investigation, we added an additional step to conventional PCR protocol that uses UV light to pretreat all the PCR regeants except Taq DNA polymerase and the target DNA to eliminate the false positives caused by trace contamination. All 15 cases of typical KS, both AIDS and non-AIDS related, as well as 4 cases of atypical vascular tumors suspicious of KS, were positive for this KSHV/HHV8 DNA sequence. The remaining 23 cases of hemangioproliferative disorders other than KS, including angiosarcoma, capillary hemangioma, angiolymphoid hyperplasia with eosinophilia, epithelioid hemangioma, histiocytoid hemangioma, hemangioendothelioma, and microvenous hemangioma, were negative for HHV8. These results confirm the previous observation that KSHV/HHV8 is specific for KS within hemangioproliferative cutaneous disorders, and PCR for detection of KSHV/HHV8 might be used as an additional diagnostic tool in distinguishing KS.     

KSHV/HHV8-associated primary cutaneous plasmablastic lymphoma in a patient with Castleman's disease and Kaposi's sarcoma

Abstract:  We report a unique case of Kaposi's sarcoma (KS)-associated herpesvirus (KSHV)/human herpesvirus (HHV)8-associated lymphoma in a 56-year-old man with a history of acquired immune deficiency syndrome, Castleman's disease, KS, and idiopathic thrombocytopenic purpura. Three months following the diagnosis of KS affecting a left cervical lymph node and Castleman's disease with bone marrow involvement, he presented with a subcutaneous, tender lesion on his left arm. A skin biopsy demonstrated a superficial and deep, interstitial-nodular infiltrate of severely atypical lymphoid cells showing plasmacytoid features, numerous mitotic figures, and frequent individual apoptotic tumor cells. The morphologic features were those of plasmablastic lymphoma (PBL). Immunohistochemical study showed that the lymphoma cells strongly expressed CD45, CD30, and KSHV/HHV8 latency-associated nuclear antigen. KSHV/HHV8 was also detected in the biopsy sections of the patient's KS and Castleman's disease. Epstein–Barr virus in situ hybridization was diffusely positive. In situ hybridization demonstrated κ-light chain restriction. Although KSHV/HHV8 has been individually associated with KS, Castleman's disease, and PBL, this appears to be the first reported case in which all three entities were present simultaneously in one person, suggesting a critical role of KSHV/HHV8 as a common denominator in the pathogenesis of these diseases.     

Cyclin D1 and retinoblastoma protein expression in Kaposi's sarcoma

Cyclins are implicated in the induction and control of the cell cycle. Cyclin D1 regulates G1-phase progression by phosphorylation of the retinoblastoma protein (pRb). The Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV) contains and transcribes an open reading frame with sequence similarities to cellular D-type cyclins. The KSHV-cyclin protein is associated with kinase activity capable of phosphorylating pRb in vitro. Here, we study for the first time the endogenous cyclin Dl and Rb protein expression in Kaposi's sarcoma (KS) tissue. Twenty-four consecutive biopsies of AIDS-related (n=21) and classical (n=3) KS were studied by immunohistochemistry with monoclonal antibodies against cyclin Dl and pRb. We detected cyclin Dl in 1 of 13 patch/plaque stage, in 4 of 5 nodular stage and in 3 of 6 visceral KS lesions. By Western blot analysis, this cellular cyclin Dl monoclonal antibody did not cross-react with the purified KSHV-cyclin protein. The pRb was consistently detected in 24 of 24 KS lesions. In summary, early KS lesions rarely have detectable expression of endogenous cyclin Dl. Advanced and disseminated KS lesions tend to have overexpression of endogenous cyclin Dl. Therefore, cellular cyclin Dl expression appears to correlate with tumor progression in KS. The endogenous cyclin Dl is antigenically distinct from the KSHV-cyclin homolog. The pRb, which may serve as a substrate for KSHV-cyclin, is found in all KS lesions examined.     

Search for Kaposi's sarcoma-associated virus DNA in hemangioproliferative disorders and cutaneous malignant lymphoma

Recently, a Kaposi's sarcoma-associated herpesvirus (KSHV) was discovered. We evaluated by PCR 14 paraffin-embedded specimens with the histological diagnosis of endemic, classic and HFV-associated Kaposi's sarcoma (KS) for the presence of the KSHV DNA sequence. In addition, biopsies of adjacent, histologically unaffected skin, peripheral-blood mononuclear cells (PBMCs) of HIV-infected KS patients, PBMCs of one classic KS patient, and specimens of patients with hemangioproliferative disorders other than KS as well as samples of cutaneous T-and B-cell lymphoma were analyzed for KSHV. In all cases of KS, independent of the KS subtype, KSHV was detected in lesional skin. No KSHV was found in biopsies of the adjacent unaffected skin or PBMCs of HFV-infected KS patients. We found KSHV in the PBMCs of a patient with classical KS. All specimens of cutaneous T-and B-cell lymphomas or lymphomatoid papulosis were negative for KSHV. In addition, the samples with hemangioproliferative disorders other than KS were negative for KSHV. There was one borderline case of KS or acroangiodermatitis that was positive for KSHV. Additional histological sections and clinical evaluation confirmed the diagnosis of classic KS. In summary, the data indicate that PCR for KSHV should be a useful diagnostic tool in cases of hemangioproliferative disorders.     

Infection of circulating CD34+ cells by HHV-8 in patients with Kaposi's sarcoma.

Human herpesvirus type 8 (HHV-8) has been identified as the most likely candidate to be involved in the development of Kaposi's Sarcoma (KS). HHV-8 has been associated with all forms of KS, primary effusion lymphoma, and multicentric Castleman's disease and detected in various non-neoplastic cells. Its presence in cells of the different hemopoietic lineages has not yet been investigated in a comprehensive and systematic manner. In this study we searched for the presence of HHV-8 in different subpopulations of peripheral blood mononuclear cells (PBMC) from patients with classic and AIDS-associated KS, as well as from HIV-1 sero-positive and sero-negative persons without KS. Thirty-four samples of PBMC were isolated from 30 patients. Subpopulations were isolated with immunomagnetic beads. Polymerase chain reaction for HHV-8 DNA was performed on PBMC and subpopulations with a primer pair selected from ORF26 of the viral genome. Polymerase chain reaction products were subsequently Southern blotted and hybridized. In patients with KS, HHV-8 DNA was detected in nine of 11 (81%) CD19+ cells, four of 11 (36%) CD2+ cells, three of 11 (27%) CD14+ cells, and nine of 11 (81%) of the remaining depleted cell populations (DP) that contain CD34 positive cells. In a subsequent set of experiments HHV-8 DNA was detected in 10 of 12 (83%) CD34 positive cell fractions. All cell subpopulations from the non-KS group were HHV-8 negative, with the exception of one positive B cell sample obtained from an HIV-infected patient. Our data demonstrate that in peripheral blood HHV-8 is detectable not only in CD19+ cells, as previously reported, but also in other cells, including T cells, monocytes, and cells devoid of specific lineage markers. We also show for the first time that CD34+ cells in peripheral blood of KS patients are a predominant HHV-8-harboring population, suggesting that they represent an additional important reservoir for this virus in vivo.     

HIV-associated Kaposi's sarcoma

Kaposi's sarcoma (KS) is a multifocal vascular tumor that occurs most commonly in patients who have immunosuppression caused by HIV. KS-associated herpes virus (human herpes virus 8, KSHV) has been identified as the causative agent. There are marked geographic differences in the prevalence of both KS and seropositivity to KSHV. The incidence of the tumor has shown a marked decline in first-world countries with the widespread use of effective antiretroviral therapy. The most effective anthracycline is pegylated liposomal doxorubicin; however, few developing countries, where KS prevalence is highest, can afford to use these agents.     

The influence of highly active antiretroviral therapy on AIDS-associated Kaposi's sarcoma

To assess the clinical and biological benefit of highly active antiretroviral therapy on AIDS-associated Kaposi's sarcoma (KS), 13 patients with AIDS-associated Kaposi's sarcoma (five pulmonary KS and eight cutaneous KS) were prospectively followed for a mean duration of 12 months. Six patients were treated with specific anti-KS chemotherapy before or simultaneously with the introduction of antiretroviral therapy. Clinical response was assessed according to the AIDS Clinical Trial Group (ACTG) criteria. CD4 cell counts, plasma HIV-1 RNA and human herpesvirus 8 (HHV-8) viraemia were measured at baseline and at different points. Among patients with pulmonary KS, we observed three complete responses (CR), one partial response (PR) and one progression. The median survival time after the diagnosis of pulmonary KS was 15 months with a median duration of the response after the discontinuation of specific chemotherapy for KS of 8 months. Among patients with cutaneous KS, we observed four CR, three PR and one stable response. A complete response was significantly associated with a reversal in HHV-8 viraemia (five of six vs. one of six; P = 0.02, Mann-Whitney test).     

Kaposi's sarcoma and other manifestations of human herpesvirus 8

Kaposi's sarcoma (KS) was described by Moritz Kaposi in 1872 and was known for an entire century as a rare disorder of older men usually of Eastern European, Mediterranean, and/or Jewish origin. In the early 1980s, the prevalence of KS began to increase dramatically and soon became the most common malignancy in patients with AIDS, especially those who were male homosexuals. In 1994, a new human herpesvirus (HHV) was found to be present in almost 100% of KS lesions. This virus was found to be a gammaherpesvirus, closely related to Epstein-Barr virus, and was designated HHV-8. Subsequently, HHV-8 DNA was found in almost all specimens of classic KS, endemic KS, and iatrogenic KS, as well as epidemic KS (ie, AIDS KS). It is now believed that HHV-8 is necessary, but not sufficient, to cause KS and that other factors such as immunosuppression play a major role. The use of highly active antiretroviral therapy (HAART) since 1996 has markedly reduced the prevalence of AIDS KS in western countries, but because 99% of the 40 million patients with AIDS in the world cannot afford HAART, KS is still a very common problem. Primary effusion lymphoma and multicentric Castleman's disease are also thought to be due to HHV-8. Although HHV-8 DNA has been described in a number of other cutaneous disorders, there is little evidence that HHV-8 is of etiologic significance in these diseases. The mechanism by which HHV-8 causes KS, primary effusion lymphoma, and multicentric Castleman's disease is not well understood but is thought to involve a number of molecular events, the study of which should further our understanding of viral oncology. (J Am Acad Dermatol 2002;47:641-55.) Learning objective: At the completion of this learning activity, participants should be familiar with Kaposi's sarcoma and other manifestations of human herpesvirus 8.     

Injection of human herpesvirus-8 in human skin engrafted on SCID mice induces Kaposi's sarcoma-like lesions

Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) has been implicated in the development of Kaposi's sarcoma (KS) and several B-cell lymphoproliferative diseases. Serologic and molecular genetic association data has implicated HHV-8 as the causal agent of KS, but its role in the development of KS lesions is not understood. To examine the etiology of KS, HHV-8 was injected into normal human skin transplanted onto SCID mice. Injection of HHV-8 induced lesion formation that is morphologically and phenotypically consistent with KS, including the presence of angiogenesis and spindle-shaped cells latently infected with HHV-8. These findings suggest that HHV-8 is indeed the etiologic agent of KS, and that the virus plays an important role in initiation of this disease.     

Infection with Kaposi's sarcoma-associated herpesvirus among families of patients with classic Kaposi's sarcoma

BACKGROUND: Classic Kaposi's sarcoma (CKS) primarily affects elderly Mediterranean or Eastern European men. Incidence rates of CKS in Israel are among the world's highest. In practically all cases, antibodies against Kaposi's sarcoma-associated herpesvirus (KSHV) can be detected. A relatively high seroprevalence rate of KSHV in Israel generally correlates with the incidence of CKS. A sexual mode of virus transmission is recognized among homosexual men, whereas the precise transmission routes in the heterosexual population and those with CKS are still unclear. OBJECTIVE: To better assess the transmission routes of KSHV in Israeli patients with CKS and their first-degree relatives as compared with a control group. DESIGN: Serum was collected from all study participants and tested for KSHV antibodies by means of latent and lytic immunofluorescence assays. An open reading frame 65 (ORF65) Western blot assay was applied as a confirmatory tool. SETTING: Three dermatological departments in Israel. PATIENTS: Sixty-four Jewish patients with CKS, 143 of their first-degree relatives, and 186 hospital-based control subjects. RESULTS: Seropositivity to KSHV was detected in 62 (96.9%) of the patients with CKS, in 56 (39.2%) of their first-degree relatives, and in only 21 (11.3%) of the hospital controls (P<.001). The specific relationship with the index patient (spouse, offspring, or sibling) had no significant effect on the prevalence of serpositivity in the family members. CONCLUSION: Our serologic evidence of familial clustering of KSHV infection suggests a predominantly nonsexual horizontal transmission route of the virus.     

Lymphedematous HIV-associated Kaposi's sarcoma

BACKGROUND: Advanced Kaposi's sarcoma is frequently associated with chronic lymphedema (cLO). The histopathological features of lymphedematous HIV-associated KS (KS) are poorly documented and the co-existence of fibroma-like nodules in lymphedematous KS is under-recognized. The aims of this study were to assess the clinicopathological spectrum and diagnostic difficulties associated with lymphedematous KS and to highlight the clinicopathological profile of fibroma-like nodules. In addition, the pathogenesis of fibroma-like nodules and cLO is revisited. MATERIALS AND METHODS: Prospective 17-month clinicopathological study of all biopsies from patients with lymphedematous KS. RESULTS: Seventy-four biopsies, the majority from the lower limbs, from 41 patients were evaluated. Nineteen, 14, five and three patients had one, two, three or four biopsies each, respectively. In 14 biopsies, there was poor clinicopathological correlation of KS stage. Exclusive lesional KS (patch, plaque, nodule or lymphangioma-like) was identified in 29 biopsies; 23 and eight biopsies demonstrated KS or fibroma-like morphology and the adjacent dermis demonstrated cLO. There was variable intratumoral and peritumoral venous compression and lymphatic dilatation. Fourteen biopsies demonstrated cLO exclusively. Smaller fibroma-like nodules lacked KS spindle cells, whereas >5 mm nodules demonstrated focal KS spindle cell proliferation and aggregation on extensive sectioning. The subcutis of 42 biopsies demonstrated variable fibrosis, hemosiderin deposits, lymphocytes, plasma cells, KS, interstitial granular material and pools of lymph fluid. Subcutaneous abscesses were identified in six biopsies. All biopsies had variable epidermal features of cLO. CONCLUSIONS: cLO influences clinicopathological correlation of KS stage and may also mask the presence of KS and the co-existence of subcutaneous abscesses. Smaller fibroma-like nodules are hypothesized to be a manifestation of cLO that have the potential to acquire the characteristics of KS. Lymphatic and venous obstruction, protein-rich interstitial fluid, tissue hemosiderin and subcutaneous infection are hypothesized to play a combined role in the evolution and perpetuation of cLO.     

Micronodular Kaposi's sarcoma - a new variant of classic-sporadic Kaposi's sarcoma

Kaposi's sarcoma (KS) in its classic-sporadic form is a rare vascular neoplasm affecting predominantly elderly men of Jewish or Mediterranean origin. Women are very rarely affected by KS. The tumor manifests itself most commonly with brownish macular or infiltrated oval lesions on the lower legs in both genders. Human herpesvirus 8 (HHV-8) has recently been demonstrated to be etiologically linked to KS. We report a 51-year-old HIV-seronegative Caucasian woman with an unusual, previously not described variant of KS which presented with small (3 mm in diameter) scattered firm red papules on her right arm. The histology with nodular spindle cell tumor expressing endothelial markers, the demonstration of serum antibodies against HHV-8 and the presence of viral nucleic acids in the lesional tissue proved the diagnosis of the nodular stage of KS. An indolent course characterized by clinically identical seasonal recurrences, even after surgical treatment and cryosurgery, was observed during the follow-up period of 9 years. We propose the term 'micronodular KS' for this unusual clinical variant of KS mimicking capillary hemangioma.     

Human herpesvirus 8 (HHV-8) in familial Kaposi's sarcoma

Human herpesvirus 8 (HHV-8) has been detected in various epidemiological forms of Kaposi's sarcoma (KS). Since familial KS cases are exceedingly rare and the occurrence of familial KS in siblings has thought to depend rather on genetic factors than on a viral factor, familial KS has not been investigated for the presence of HHV-8. To investigate whether HHV-8 is present also in this rare form of KS, we examined tumor biopsies of 2 siblings with familial KS for the presence of HHV-8 specific DNA sequences by a nested PCR protocol. HHV-8 DNA sequences could be detected in KS specimens of both patients. Sequence analysis revealed an identical DNA sequence of HHV-8 in KS tissue of both siblings, but the sequence in our cases differs in one base pair at position 67 from the previously published HHV-8 KS330Bam fragment. The findings indicate that besides the yet poorly defined genetical factors involved in the pathogenesis of KS, HHV-8 may act as a cofactor also in familial KS. In addition, our data demonstrate that HHV-8 is found in all epidemiological forms of KS, including the rarely occurring familial KS. Familial KS may act as a further model to study the interaction of an oncogenic virus with genetic host factors in the context of a neoplastic disorder.     

Classic Kaposi's sarcoma treated with topical rapamycin

Kaposi's sarcoma (KS) is an angioproliferative disorder caused by human herpesvirus 8 (HHV‐8). Current research efforts have focused on the study of the relative role of KSHV‐encoded genes in Kaposi's sarcomagenesis in order to identify novel mechanism‐based therapies for patients suffering from this tumor. Although several viral genes have potential for KS pathogenesis, compelling data point to the KSHV‐encoded G protein‐coupled receptor (vGPCR) as a leading candidate viral gene for the initiation of KS. Interestingly, the oncogenic potential of vGPCR seems to correlate with its capacity to activate the mammalian target of rapamycin (mTOR) signaling pathway. Rapamycin, the prototypical inhibitor of the mTOR signaling pathway, has recently emerged as an effective treatment for KS when administered orally. In this case report, we present an immunocompetent patient with KS lesions treated with topical rapamycin achieving clinical and histologic healing after 16 weeks of treatment. The topical application of rapamycin could be a novel therapeutic option for the treatment of KS.     

Kaposi's sarcoma in renal transplant patients: experience at the Cruces Hospital in Bilbao

BACKGROUND: Kaposi's sarcoma (KS) in renal transplant recipients (RTRs) probably arises from a complex interplay of multiple factors. OBJECTIVE: In order to analyze the prevalence of KS in patients transplanted at the Cruces Hospital in Bilbao, together with their clinical features, treatment, and etiologic factors, we performed a study using the registry of RTRs in our center. METHODS: The records of 1,230 kidney transplant patients at the Cruces Hospital between 1979 and 1998 were reviewed. Immunosuppressive therapy was reduced once a diagnosis of KS was made. A nested polymerase chain reaction was used to detect human herpesvirus 8 (HHV-8) DNA in the biopsy tissue. The DNA was extracted from fresh tissue (n = 2) or from formalin-fixed, paraffin-embedded specimens (n = 5). RESULTS: Six cases of KS were diagnosed. All patients with cutaneous KS improved with a reduction in immunosuppressive drugs. HHV-8 was detected in 100% (2/2) of the frozen biopsies and 20% (1/5) of the formalin-fixed samples investigated. CONCLUSIONS: Our experience indicates that a continuous state of immunodeficiency is important for the development of KS in RTRs. The association, previously described between HHV-8 and transplant-associated KS, also exists in the studied population.     

Looking for the target cell of Kaposi's sarcoma-associated herpesvirus

The level of Kaposi's sarcoma-associated herpesvirus (KSHV) cellular viremia in patients with Kaposi's sarcoma could be related to both the tumor burden and its progression. The origin of the spindle cell, the hallmark cell of Kaposi's sarcoma, is still debated. Two hypotheses may be formulated, favoring a lymphatic endothelial cell or an endothelial-cell precursor evolving into a lymphatic phenotype, both preferentially targeted by KSHV.     

Kaposi's sarcoma in Nigeria

BACKGROUND: The prevalence of Kaposi's sarcoma (KS) in parts of Africa has been on the increase as a result of the human immunodeficiency virus (HIV) infection pandemic. However, there is a paucity of information for Nigeria. OBJECTIVE: To describe the clinical and epidemiological characteristics of cutaneous KS in patients with HIV-infection in Benin City, Nigeria. METHODS: All patients presenting to the dermatology and infectious diseases clinics of the University of Benin Teaching Hospital, or admitted to its medical wards, within the period July 2000-June 2005 were examined retrospectively in a chart review for KS. Diagnosis of HIV was based upon ELISA testing. The CD4(+) cell counts were performed using the Dyna Bead method and KS was diagnosed histologically. RESULTS: In our survey, 31 patients, representing 0.84% of all new HIV patients seen during the study period, had cutaneous KS. There were 19 males and 12 females, giving a male to female ratio of 1.6 : 1. The mean age was 36.3 +/- 9 years; mean CD4(+) count was 127 +/- 14 cells/dl. The lower limbs (74.2%), trunk (48.4%) and the face (22.6%) were the most frequent sites affected. The lesions were solitary in three patients (9.7%) and multiple in 28 patients (90.3%). CONCLUSION: The prevalence of HIV-related KS is increasing in Nigeria. There is an increase in the number of women being diagnosed with this form of KS, probably owing to more females having HIV disease.     

The pathobiology of Kaposi's sarcoma: advances since the onset of the AIDS epidemic

Since the perplexing early Kaposi's sarcoma (KS) observations at the dawn of the acquired immunodeficiency syndrome epidemic, KS has been extensively studied, revealing a complex disease. The identification and complete elucidation of the genome of its causal agent, the KS-associated herpesvirus/human herpesvirus 8, have shed important insights into the pathobiology of this disease. The purpose of this review is to describe the scientific advances and understanding of KS over the past three decades.