The natural history of Kaposi's sarcoma in the acquired immunodeficiency syndrome

Impact of valganciclovir therapy on severe IRIS-Kaposi Sarcoma mortality: An open-label, parallel, randomized controlled trial

INTRODUCTION

High HHV-8 viral load (VL) in Kaposi Sarcoma (KS) has been associated with Severe Immune Reconstitution Inflammatory Syndrome (Severe-IRIS-KS), which can occur after initiating cART, and leads to high mortality, particularly in patients with pulmonary involvement. We investigate if valganciclovir (as an anti-HHV-8 agent) initiated before cART reduces the mortality associated with Severe-IRIS-KS and the incidence of Severe-IRIS-KS.

METHODS

Open-label parallel-group randomized clinical trial in AIDS cART naïve patients with disseminated KS (DKS) as defined by at least two of the following: pulmonary, lymph-node, or gastrointestinal involvement, lymphedema, or ≥30 skin lesions. In the experimental group (EG), patients received valganciclovir 900 mg BID four weeks before cART and continued until week 48; in the control group (CG), cART was initiated on week 0. Non-severe-IRIS-KS was defined as: an increase in the number of lesions plus a decrease of ≥one log10 HIV-VL, or an increase of ≥50cells/mm3 or ≥2-fold in baseline CD4+cells. Severe-IRIS-KS was defined as abrupt clinical worsening of KS lesions and/or fever after ruling out another infection following cART initiation, and at least three of the following: thrombocytopenia, anemia, hyponatremia, or hypoalbuminemia.

RESULTS

40 patients were randomized and 37 completed the study. In the ITT analysis, at 48 weeks, total mortality was the same in both groups (3/20), severe-IRIS-KS attributable mortality was 0/20 in the EG, compared with 3/20 in the CG (p = 0.09), similar to the per-protocol analysis: 0/18 in the EG, and 3/19 in the control group (p = 0.09). The crude incidence rate of severe-IRIS-KS was four patients developed a total of 12 episodes of Severe-IRIS-KS in the CG and two patients developed one episode each in the EG. Mortality in patients with pulmonary KS was nil in the EG (0/5) compared with 3/4 in the CG (P = 0.048). No difference was found between groups in the number of non-S-IRIS-KS events. Among survivors at week 48, 82% achieved >80% remission.

CONCLUSIONS

Although mortality attributable to KS was lower in the EG the difference was not statistically significant.

Kaposi’s Sarcoma Lesion Progression in BKV-Tat Transgenic Mice Is Increased by Inflammatory Cytokines and Blocked by Treatment with Anti-Tat Antibodies

Kaposi’s sarcoma (KS) is an angioproliferative tumor showing an increased frequency and aggressiveness in HIV-infected subjects (AIDS-KS), due to the combined effects of inflammatory cytokines (IC), angiogenic factors, and the HIV-1 Tat protein. While the introduction of effective combined antiretroviral regimens greatly improved AIDS-KS incidence and course, it continues to be an incurable disease and the development of new rational targeted therapies is warranted. We used the BKV/Tat transgenic mouse model to evaluate the effects of IC and anti-Tat antibodies (Abs) treatment on KS-like lesions arising in BKV/Tat mice. We demonstrated here that IC-treatment increases the severity and delays the regression of KS-like lesions. Further, anti-Tat Abs reduced KS-like lesion severity developing in IC-treated mice when anti-Tat Abs were administered at an early-stage of lesion development as compared to more advanced lesions. Early anti-Tat Abs treatment also accelerated KS-like lesion regression and reduced the rate of severe-grade lesions. This effect was more evident in the first weeks after Ab treatment, suggesting that a longer treatment with anti-Tat Abs might be even more effective, particularly if administered just after lesion development. Although preliminary, these results are encouraging, and the approach deserves further studies for the development of anti-Tat Ab-based therapies for AIDS-KS. Clinical studies specifically addressing the effect of anti-Tat antibodies in treating AIDS-KS are not yet available. Nevertheless, the effectiveness of anti-Tat antibodies in controlling HIV/AIDS progression, likely due to the neutralization of extracellular Tat activities, is suggested by several cross-sectional and longitudinal clinical studies, indicating that anti-Tat Ab treatment or Tat-based vaccines may be effective to treat AIDS-KS patients or prevent the tumor in individuals at risk.

AIDS Related Kaposi's Sarcoma: A 20-Year Experience in a Clinic from the South-East of Romania

Kaposi’s sarcoma (KS) was peculiarly described in the first notified cases of the acquired immunodeficiency syndrome as an opportunistic condition. However, the medical progress and the development of active antiretroviral therapy allowed the control of the HIV/AIDS epidemic, although the features of KS have changed throughout the past decades. The purpose of our study is to assess the epidemiological and clinical features of AIDS related KS in Romanian patients. A retrospective follow-up study was achieved in a single infectious diseases’ clinic from Galati—Romania, between 2001 and 2021. Referring to 290 new HIV diagnosed cases from our clinic retained in care, the prevalence of KS was 3.4%. The main characteristics of patients with KS are a median age of 33, a predominance of males, prevalent severe systemic forms of diseases, frequent association of past or concomitant tuberculosis, and context of immune reconstruction syndrome. The mortality rate was 70%. KS has occurred in patients with delayed HIV diagnoses and inadequate adherence to therapy. Early recognition of both infections, the close monitoring of latent or symptomatic tuberculosis, improving the antiretroviral adherence and raising the access to oncologic procedures in Romanian HIV patients could improve their prognosis related to KS.

The potential impacts of early secreted antigenic target of 6 kDa of Mycobacterium tuberculosis on KSHV-infected cells

Kaposi's sarcoma-associated herpesvirus (KSHV) causes several human cancers, including Kaposi's sarcoma (KS) and primary effusion lymphoma, which are mostly seen in immunocompromised patients, such as human immunodefeciency virus (HIV)+ individuals. Tuberculosis (TB), caused by the bacterial pathogen Mycobacterium tuberculosis (Mtb), remains one of the deadliest infectious diseases in the world. The risk of developing TB is dramatically higher in people living with HIV than among those without HIV infection. Case reports link cutaneous or pulmonary KS in HIV+ patients with mycobacterial co-infections, however, impacts of Mtb infection or its products on KSHV-infected cells are not known. We report here that ESAT-6, a secreted Mtb virulence factor, induces viral reactivation from KSHV-infected cells. KSHV-infected pulmonary endothelial cells were resistant to ESAT-6 induced inhibition of cell growth. Our data demonstrate that Mtb virulence factors influence the biology of KSHV-infected cells, highlighting the need to study the interactions between these two pathogens commonly found in people living with HIV.

KSHV G-protein coupled receptor vGPCR oncogenic signaling upregulation of Cyclooxygenase-2 expression mediates angiogenesis and tumorigenesis in Kaposi's sarcoma

Kaposi's sarcoma-associated herpesvirus (KSHV) vGPCR is a constitutively active G protein-coupled receptor that subverts proliferative and inflammatory signaling pathways to induce cell transformation in Kaposi's sarcoma. Cyclooxygenase-2 (COX-2) is an inflammatory mediator that plays a key regulatory role in the activation of tumor angiogenesis. Using two different transformed mouse models and tumorigenic full KSHV genome-bearing cells, including KSHV-Bac16 based mutant system with a vGPCR deletion, we demostrate that vGPCR upregulates COX-2 expression and activity, signaling through selective MAPK cascades. We show that vGPCR expression triggers signaling pathways that upregulate COX-2 levels due to a dual effect upon both its gene promoter region and, in mature mRNA, the 3'UTR region that control mRNA stability. Both events are mediated by signaling through ERK1/2 MAPK pathway. Inhibition of COX-2 in vGPCR-transformed cells impairs vGPCR-driven angiogenesis and treatment with the COX-2-selective inhibitory drug Celecoxib produces a significant decrease in tumor growth, pointing to COX-2 activity as critical for vGPCR oncogenicity in vivo and indicating that COX-2-mediated angiogenesis could play a role in KS tumorigenesis. These results, along with the overexpression of COX-2 in KS lesions, define COX-2 as a potential target for the prevention and treatment of KSHV-oncogenesis.

Kaposi's Sarcoma: A Clinico-Pathologic Overview

A careful overview of the classical appearances of Kaposi's sarcoma (KS) as well as of its variants were reviewed from the clinical and pathological point of view. The growth phases (stages) and the cellular patterns were histopathologically compared with emphasis on the developmental progression of disease as well as mitotic activity. Other morphological aspects were also assessed such as the features of the early phases and the incidence of hyaline bodies. One hundred and forty-three lesions from 96 patients mostly of the Italian sporadic type were investigated. A complete list of those entities which should be considered in differential diagnosis is shown and the dilemma of whether KS is a neoplasia or a hyperplasia is discussed.

HIV-associated Kaposi sarcoma and related diseases

: The search for the etiologic agent for Kaposi sarcoma led to the discovery of Kaposi sarcoma-associated herpesvirus (KSHV) in 1994. KSHV, also called human herpesvirus-8, has since been shown to be the etiologic agent for several other tumors and diseases, including primary effusion lymphoma (PEL), an extracavitary variant of PEL, KSHV-associated diffuse large B-cell lymphoma, a form of multicentric Castleman disease, and KSHV inflammatory cytokine syndrome. KSHV encodes several genes that interfere with innate and specific immunity, thwart apoptosis, enhance cell proliferation and cytokine production, and promote angiogenesis, and these play important roles in disease pathogenesis. HIV is an important cofactor in Kaposi sarcoma pathogenesis, and widespread use of antiretroviral therapy has reduced Kaposi sarcoma incidence. However, Kaposi sarcoma remains the second most frequent tumor arising in HIV-infected patients in the United States and is particularly common in sub-Saharan Africa. KSHV prevalence varies substantially in different populations. KSHV is secreted in saliva, and public health measures to reduce its spread may help reduce the incidence of KSHV-associated diseases. Although there have been advances in the treatment of Kaposi sarcoma, KSHV-multicentric Castleman disease, and PEL, improved therapies are needed, especially those that are appropriate for Kaposi sarcoma in resource-poor regions.

Human Immunodeficiency Virus-Negative-Associated Lymphangioma-like Kaposi's Sarcoma with Variable Clinical PresentationsA Case Report

Lymphangioma-like Kaposi's sarcoma (LLKS) is a rare histologic variant of KS. Kaposi's sarcoma is also known as human herpesvirus type 8. The clinical presentation of the LLKS lesion is highly unusual and similar to that of classic KS but with multinodular vascular tumors and lymphedema. We present a 63-year-old native Haitian man with multiple slowly progressive exophytic ulcerated lesions covering more than 60% of his left lower extremity with no systemic involvement. Much confusion surrounded the clinical presentation of these wounds, and we postulated several differential diagnoses. Herein we describe the evaluation, clinical appearance, and progression of LLKS. Due to the rarity of LLKS, treating physicians need to be aware of the clinical presentation and diagnostic criteria of this variant. Despite being incurable, early diagnosis of LLKS can lead to long-term treatment options and a major reduction in symptoms.

Lymphangiectatic Kaposi's sarcoma in a patient with AIDS

Kaposi's sarcoma is a malignant disease that originates in the lymphatic endothelium. It has a broad spectrum of clinical manifestations. Its four distinct clinical forms are: classic, endemic, iatrogenic and epidemic Kaposi's sarcoma. In non-HIV-associated Kaposi's sarcoma, the disease is typically limited to the lower extremities, but in immunodeficient patients, it is a multifocal systemic disease. The clinical course of the disease differs among patients, ranging from a single or a few indolent lesions to an aggressive diffuse disease. Advanced Kaposi's sarcoma lesions, typically those on the lower extremities, are often associated with lymphedema. In this paper, we report a case of a patient with a rare form of AIDS-associated Kaposi sarcoma called lymphangiectatic Kaposis's sarcoma.

HIV/AIDS Related Respiratory Diseases

Lungs are the most commonly involved organ by HIV/AIDS related diseases, and pulmonary infections are the main reasons for the increasing death rate from AIDS. Pathogens of HIV related pulmonary infections include parasites, fungi, mycobacteria, viruses, bacteria and toxoplasma gondii. According to international reports, pathogens have different geographical distribution, which is also closely related to the socioeconomic status of the region to produce varied AIDS related diseases spectra. For instance, in the United States, pneumocystis carnii pneumonia (PCP), tuberculosis and recurrent bacterial pneumonia (at least twice within 1 year) occur frequently in HIV infected patients. An international report published 10 years ago indicated that PCP is the most common and serious pulmonary opportunistic infections in HIV infected patients. Now its incidence has dropped with the application of antiretroviral treatment and preventive measures. PCP will continue to occur initially in patients who are aware of their HIV infection. In addition, HIV related viral and parasitic infections have been reported both domestically and internationally. In this section, the clinical manifestations and imaging findings of HIV related pulmonary infections are analyzed and discussed, which provide effective diagnosis basis, so as to reduce the incidence of HIV-related pulmonary infections.

Kaposi's sarcoma in patients with and without human immunodeficiency virus infection, in a tertiary referral centre in Kenya

The clinical features of Kaposi's sarcoma (KS), in patients with and without HIV infection, were investigated in a tertiary referral centre in Kenya between 1997 and 1999. Although 186 cases were identified prospectively, the data analysis was restricted to the 91 (49%) cases who had pathological confirmation of Kaposi's sarcoma and documented HIV serostatus. Among these 91 subjects (58% of whom were male), the age-group holding the largest number of KS cases was that of individuals aged 31-40 years; most of the paediatric cases were aged 6-10 years. The ratio of HIV-seropositives to HIV-seronegatives was 8.5:1 for the adult cases and 0.9:1 for the paediatric. Of the signs and symptoms of Kaposi's sarcoma seen at presentation, only peripheral lympadenopathy was found to be significantly associated with underlying HIV infection (P = 0.05). The median survival was 104 days. It is apparent that, as the HIV epidemic advances in regions of the world with endemic KS, the clinical presentation and natural history of the endemic KS are blending with those of the epidemic or AIDS-associated disease, leading to a reduction in the mean age of the cases and a nearly identical incidence in men and women. In regions of the world where patients have ready access to such chemotherapy, the impact of treatment with highly active antiretroviral drugs on the incidence and natural history of KS has been dramatic. It will be important to monitor the clinico-pathological features of KS in the developing world, as more active antiretroviral regimens become available in clinical practice there.

Nationwide registry-based analysis of cancer clustering detects strong familial occurrence of Kaposi sarcoma

Many cancer predisposition syndromes are rare or have incomplete penetrance, and traditional epidemiological tools are not well suited for their detection. Here we have used an approach that employs the entire population based data in the Finnish Cancer Registry (FCR) for analyzing familial aggregation of all types of cancer, in order to find evidence for previously unrecognized cancer susceptibility conditions. We performed a systematic clustering of 878,593 patients in FCR based on family name at birth, municipality of birth, and tumor type, diagnosed between years 1952 and 2011. We also estimated the familial occurrence of the tumor types using cluster score that reflects the proportion of patients belonging to the most significant clusters compared to all patients in Finland. The clustering effort identified 25,910 birth name-municipality based clusters representing 183 different tumor types characterized by topography and morphology. We produced information about familial occurrence of hundreds of tumor types, and many of the tumor types with high cluster score represented known cancer syndromes. Unexpectedly, Kaposi sarcoma (KS) also produced a very high score (cluster score 1.91, p-value <0.0001). We verified from population records that many of the KS patients forming the clusters were indeed close relatives, and identified one family with five affected individuals in two generations and several families with two first degree relatives. Our approach is unique in enabling systematic examination of a national epidemiological database to derive evidence of aberrant familial aggregation of all tumor types, both common and rare. It allowed effortless identification of families displaying features of both known as well as potentially novel cancer predisposition conditions, including striking familial aggregation of KS. Further work with high-throughput methods should elucidate the molecular basis of the potentially novel predisposition conditions found in this study.

A role for virally induced reactive oxygen species in Kaposi's sarcoma herpesvirus tumorigenesis

AIMS

Kaposi's sarcoma (KS), caused by the Kaposi's sarcoma herpesvirus (KSHV), is an AIDS-associated cancer characterized by angiogenesis and proliferation of spindle cells. Rac1-activated reactive oxygen species (ROS) production has been implicated in KS tumorigenesis. We used an animal model of KSHV-induced Kaposi's sarcomagenesis (mECK36) to study the role of ROS in KS and the efficacy of N-acetyl l-cysteine (NAC) in inhibiting or preventing KS.

RESULTS

Signaling by the KSHV early lytic gene viral G protein-coupled receptor (vGPCR) activated ROS production in mECK36 cells via a Rac1-NADPH oxidase pathway. Induction of the lytic cycle in KSHV-infected KS spindle cells upregulated ROS along with upregulation of vGPCR expression. We also found that expression of the major latent transcript in 293 cells increased ROS levels. ROS scavenging with NAC halted mECK36 tumor growth in a KSHV-specific manner. NAC inhibited KSHV latent gene expression as well as tumor angiogenesis and lymphangiogenesis. These effects correlated with the reduction of vascular endothelial growth factor (VEGF), c-myc, and cyclin D1, and could be explained on the basis of inhibition of STAT3 tyrosine phosphorylation. NAC prevented mECK36 de novo tumor formation. Molecular analysis of NAC-resistant tumors revealed a strong upregulation of Rac1 and p40(PHOX).

INNOVATION AND CONCLUSION

Our results demonstrate that ROS-induction by KSHV plays a causal role in KS oncogenesis by promoting proliferation and angiogenesis. Our results show that both ROS and their molecular sources can be targeted therapeutically using NAC or other Food and Drug Administration (FDA)-approved inhibitors for prevention and treatment of AIDS-KS.

Update on imaging of non-infectious musculoskeletal complications of HIV infection

Acquired immunodeficiency syndrome (AIDS) results from infection with human immunodeficiency virus (HIV), producing an immunodeficient state and severe pathology across multiple organ systems. Musculoskeletal involvement is particularly prevalent in this population with both infectious and non-infectious complications encountered, but it is suggested that the latter will affect 72% of HIV-infected individuals. In this review we aim to provide an update on the imaging characteristics of the non-infectious manifestations. The conditions include HIV-related arthritis as well as various malignancies, myositis, anaemia, osteonecrosis, rhabdomyolysis, hypertrophic osteoarthropathy and therapy-related side effects. For the clinician, the diagnostic challenge lies in differentiating disease-related symptoms from therapy-related side effects, particularly when clinical and laboratory features can be non-specific. This is especially difficult following the widespread introduction of highly active anti-retroviral therapy (HAART). Imaging investigations and MRI in particular have proven vital for facilitating early diagnosis and enabling prompt treatment. Furthermore, wider availability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has allowed whole-body assessment for staging and treatment response of malignancy. Understanding the pathogenesis of the various conditions and recognising their imaging features is essential for the clinical radiologist.

Kaposi's sarcoma and its associated herpesvirus

Kaposi's sarcoma (KS) is the most common cancer in HIV-infected untreated individuals. Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8 (HHV8)) is the infectious cause of this neoplasm. In this Review we describe the epidemiology of KS and KSHV, and the insights into the remarkable mechanisms through which KSHV can induce KS that have been gained in the past 16 years. KSHV latent transcripts, such as latency-associated nuclear antigen (LANA), viral cyclin, viral FLIP and viral-encoded microRNAs, drive cell proliferation and prevent apoptosis, whereas KSHV lytic proteins, such as viral G protein-coupled receptor, K1 and virally encoded cytokines (viral interleukin-6 and viral chemokines) further contribute to the unique angioproliferative and inflammatory KS lesions through a mechanism called paracrine neoplasia.

Treatment for leiomyosarcoma and leiomyoma in children with HIV infection

BACKGROUND

Smooth muscle tumour (SMT) composed of leiomyoma and leiomyosarcoma recently has been described in many HIV-infected children. Leiomyosarcoma has become the second most frequent malignancy in children with HIV infection or other immunodeficiency diseases in the United States. Although leiomyosarcoma accounts for only 2% to 4% of childhood soft tissue sarcomas, the prognosis is poor in HIV-infected compared with non-infected patients. The development of Epstein-Barr virus (EBV)-associated SMT in children with acquired immunodeficiency virus (AIDS) decreases health, reduces quality of life, and often results in death. Some researchers, therefore, ascribe cause of death to SMT in the majority of these cases, not to AIDS. Currently, the optimal therapeutic strategy is controversial and there is a need to identify the efficacy and safety of different interventions for AIDS-associated SMT on overall survival and disease-free survival in children.

OBJECTIVES

To assess the effectiveness of current therapeutic interventions for previously untreated children with AIDS-associated leiomyoma and leiomyosarcoma

SEARCH STRATEGY

We searched the following electronic databases by subject headings and text words:Cochrane HIV/AIDS Group trials register (November 2009); Cochrane Central Register of Controlled Trials on Cochrane Library (Issue 4, 2009); MEDLINE (January 1966 to November 2009); EMBASE (January 1985 to November 2009); NLMGateway database and AEGIS; Chinese Biomedical Disc (CBMDisc 1978 to November 2009); VIP (1989 to present); and China National Knowledge Infrastructure (CNKI 1994 to 2009). We also searched physicians data query protocols, proceedings, and abstracts from AIDS and cancer conferences, and the reference lists from identified trials for unidentified trials to discover any unpublished or currently on-going relevant trials. All the trials were searched by comprehensive electronic databases or hand searching. The search was not limited by language.

SELECTION CRITERIA

We searched for published or unpublished randomised controlled trials (RCTs) or controlled clinical trials (CCTs) of therapy for leiomyosarcoma and leiomyoma in children with AIDS.

DATA COLLECTION AND ANALYSIS

Two authors screened the results of the search independently to select relevant studies. The full text of all potentially relevant studies was retrieved and the qualities were assessed by the two authors using predetermined criteria. No eligible RCTs or CCTs were identified.

MAIN RESULTS

We were unable to find any RCTs or CCTs of interventions for treating AIDS-associated SMT in children.

IMPLICATIONS FOR CLINICAL PRACTICE

We could not find any RCTs or CCTs of intervention for treating AIDS-associated SMT in children with HIV infection, and currently, the clinical practice of treating SMT in HIV-infected children is based on descriptive studies and simply situational analyses. Thus there is insufficient evidence to establish the efficacy and acceptability of these interventions, and we recommend a case-by-case treatment of patients until evidence becomes available.

IMPLICATIONS FOR RESEARCH

In future, high-quality RCTs are urgently needed before any final conclusion can be drawn. Rigorously designed, multicenter, randomised, double-blind controlled trials are required to evaluate these interventions as a way of improving the survival and decreasing mortality in that population. Policy makers and researchers should prioritise funding for these trials to increase the quantity and quality of such studies and provide strong evidence for the effectiveness of therapies for AIDS-associated SMTs. Meanwhile, safety and adverse events should be critically assessed by standardized monitoring or an effective self-report system, and attention should be paid to long-term adverse effects in children with HIV infection.

Anterior Segment and External Ocular Disorders Associated with Human Immunodeficiency Virus Disease

The eye is a common site for complications of human immunodeficiency virus (HIV) infection. Although cytomegalovirus retinitis remains the most prevalent of the blinding ocular disorders that can occur in individuals with the acquired immunodeficiency syndrome (AIDS), several important HIV-associated disorders may involve the anterior segment, ocular surface, and adnexae. Some of these entities, such as Kaposi sarcoma, were well described, but uncommon, before the HIV epidemic. Others, like microsporidial keratoconjunctivitis, have presentations that differ between affected individuals with HIV disease and those from the general population who are immunocompetent. The treatment of many of these diseases is challenging because of host immunodeficiency. Survival after the diagnosis of AIDS has increased among individuals with HIV disease because of more effective antiretroviral therapies and improved prophylaxis against, and treatment of, opportunistic infections. This longer survival may lead to an increased prevalence of anterior segment and external ocular disorders. In addition, the evaluation and management of disorders such as blepharitis and dry eye, which were previously overshadowed by more severe, blinding disorders, may demand increased attention, as the general health of this population improves. Not all individuals infected with HIV receive potent antiretroviral therapy, however, because of socioeconomic or other factors, and others will be intolerant of these drugs or experience drug failure. Ophthalmologists must, therefore, still be aware of the ocular findings that develop in the setting of severe immunosuppression. This article reviews the spectrum of HIV-associated anterior segment and external ocular disorders, with recommendations for their evaluation and management.

In vivo-restricted and reversible malignancy induced by human herpesvirus-8 KSHV: a cell and animal model of virally induced Kaposi's sarcoma

Transfection of a Kaposi's sarcoma (KS) herpesvirus (KSHV) Bacterial Artificial Chromosome (KSHVBac36) into mouse bone marrow endothelial-lineage cells generates a cell (mECK36) that forms KS-like tumors in mice. mECK36 expressed most KSHV genes and were angiogenic, but they didn't form colonies in soft agar. In nude mice, mECK36 formed KSHV-harboring vascularized spindle cell sarcomas that were LANA+/podoplanin+, overexpressed VEGF and Angiopoietin ligands and receptors, and displayed KSHV and host transcriptomes reminiscent of KS. mECK36 that lost the KSHV episome reverted to nontumorigenicity. siRNA suppression of KSHV vGPCR, an angiogenic gene upregulated in mECK36 tumors, inhibited angiogenicity and tumorigenicity. These results show that KSHV malignancy is in vivo growth restricted and reversible, defining mECK36 as a biologically sensitive animal model of KSHV-dependent KS.

Long-term complete remission of laryngeal Kaposi's sarcoma after palliative radiotherapy

BACKGROUND

A 43-year-old Caucasian man presented with enlarged right laterocervical lymph nodes, and a 6-month history of diarrhea and 9 kg weight loss. His previous medical history was unremarkable. Physical examination and a cervical CT scan showed several indistinct necrotic right laterocervical lymph nodes of 4 cm maximal diameter, but with no lesions of the respiratory or digestive tracts.

INVESTIGATIONS

Physical examination, cervical CT scan, laterocervical lymph node biopsy, laboratory tests, and endoscopy.

DIAGNOSIS

Clinical stage 4 AIDS with stage T0 I1 S1 epidemic AIDS-related Kaposi's sarcoma of the laterocervical lymph nodes and, subsequently, the larynx.

MANAGEMENT

Highly active antiretroviral treatment (stavudine, didanosine, and nelfinavir), tracheotomy, and palliative radiotherapy.

Epstein-Barr Virus Infection-Associated Smooth-Muscle Tumors in Patients with AIDS

BACKGROUND

The aim of our study is to describe the unusual clinical manifestations of smooth-muscle tumors (SMTs) in patients with acquired immunodeficiency virus (AIDS) and to demonstrate the association between Epstein-Barr virus (EBV) infection and SMTs.

METHODS

Nine patients with AIDS and SMTs were characterized at Chulalongkorn Hospital (Bangkok, Thailand) from 2001 through 2003. Tumor tissues suitable for immunohistochemical analysis and in situ hybridization were assayed for SMTs and EBV, respectively. Plasma and serum samples were tested for EBV by real-time quantitative polymerase chain reaction and serologic analysis.

RESULTS

The study included 8 adults and 1 child (3 males and 6 females). All patients had CD4 cell counts of <200 cells/microL. By the end of the study, 3 patients had died, and 6 patients had survived. The sites of SMTs were the epidura (5 intracranial and 4 intraspinal SMTs), vocal cords (2), adrenal glands (2), abdominal wall (2), iris (1), liver (1), lung (1), orbit (1), and thigh (1). Seven patients had multicentric SMTs involving intracranial sites only (4 SMTs), extra- and intracranial sites (3), or extracranial sites only (2), which occurred either concurrently or sequentially. We found evidence of EBV infection, as determined by in situ hybridization, in all SMTs. Furthermore, EBV DNA was detectable in plasma samples from 2 patients. The results of serologic analysis were consistent with past EBV infection.

CONCLUSIONS

SMTs in patients with AIDS typically arise in multiple and very unusual sites that are not often observed in SMTs among immunocompetent individuals. Our series also suggests association between EBV infection and SMTs in patients with AIDS. The exact role of EBV in smooth-muscle oncogenesis awaits further study.

Imaging Dose-dependent Pharmacokinetics of an RGD-Fluorescent Dye Conjugate Targeted to αvβ3 Receptor Expressed in Kaposi's Sarcoma

Dynamic fluorescence images were obtained from xenografts bearing a subcutaneous human Kaposi's sarcoma (KS1767) immediately following the intravenous injection of an integrin-receptor targeting Cy5.5-c(KRGDf) at a dose ranging from 0.75 to 6 nmol/mouse. The fluorescence images were acquired using an intensified charge-coupled device system and were analyzed with a three-compartment pharmacokinetic (PK) model to determine uptake parameters in the tumor and normal tissue regions of interest as a function of administered dose. Our results show that the uptake of Cy5.5-c(KRGDf) in tumor regions were: (i) significantly greater than the contralateral normal tissue regions; (ii) linearly increased with dose of Cy5.5-c(KRGDf) up to 1.5 nmol/mouse; and (iii) blocked by preinjection of c(KRGDf). Above doses of 1.5 nmol/mouse, the uptake no longer increased with dose, suggesting integrin receptor saturation. In normal tissues, the PK uptake parameters were not influenced by Cy5.5-c(KRGDf) dose nor by the preadministration of c(KRGDf).

Cutaneous markers of HIV infection

Despite the development of laboratory methods, dermatological symptoms are a basic index of the presence and physical course of HIV infection. HIV infection usually undergoes a long latent period, proceeds to a period of immunodeficiency-related symptoms, and ends in an advanced immunodeficiency state characterized by opportunistic infections and neoplasms. Occasionally, dermatological manifestations can be the first signs of asymptomatic disease, indices of advanced immunodeficiency, or symptoms of opportunistic infections or neoplasms. The variety of symptoms and signs for the skin during the course of HIV infection is a consequence of the progressing immunodeficiency and therefore indicates the underlying disorder. The use of these manifestations is a challenge for clinical praxis.

Kaposi's sarcoma associated herpesvirus G protein-coupled receptor immortalizes human endothelial cells by activation of the VEGF receptor-2/ KDR

The G protein-coupled receptor oncogene (vGPCR) of the Kaposi's sarcoma (KS) associated herpesvirus (KSHV), an oncovirus implicated in angioproliferative neoplasms, induces angiogenesis by VEGF secretion. Accordingly, we found that expression of vGPCR in human umbilical vein endothelial cells (HUVEC) leads to immortalization with constitutive VEGF receptor-2/ KDR expression and activation. vGPCR immortalization was associated with anti-senescence mediated by alternative lengthening of telomeres and an anti-apoptotic response mediated by vGPCR constitutive signaling and KDR autocrine signaling leading to activation of the PI3K/AKT pathway. In the presence of the KS growth factor VEGF, this mechanism can sustain suppression of signaling by the immortalizing gene. We conclude that vGPCR can cause an oncogenic immortalizing event and recapitulate aspects of the KS angiogenic phenotype in human endothelial cells, pointing to this gene as a pathogenic determinant of KSHV.

Treatment of Kaposi's sarcoma--an update

Kaposi's sarcoma (KS) is an angioproliferative disease of multifactorial origin arising in different clinic-epidemiologic forms, which show the same histopathological features. It generally starts as a hyperplastic reactive-inflammatory and angiogenic process, which may evolve into monomorphic nodules of KS cells that can be clonal (late-stage lesions) and resemble a true sarcoma. Infection with the human herpesvirus 8, cytokine- and angiogenic factor-induced growth together with an immuno-dysregulated state represent fundamental conditions for the development of this tumor. Several local therapies are used to eradicate early and confined skin lesions, whereas widely disseminated, progressive or symptomatic disease requires a more aggressive treatment. Although different chemotherapeutic agents have been used to treat aggressive KS, the growing understanding of the pathogenetic factors participating in KS development has provided a strong rationale for using less- or non-cytotoxic agents that block the mechanisms involved in KS pathogenesis. The angiogenic nature of KS makes it particularly suitable for using therapies based on anti-angiogenic agents. Of note on this goal, recent studies indicate that the highly active anti-retroviral therapy, including at least one human immunodeficiency virus (HIV) protease inhibitor (PI), is associated with a dramatic decrease in the incidence of AIDS-KS and with a regression of KS in treated individuals. Consistent with this, results from preclinical studies indicate that PIs have potent and direct anti-angiogenic and anti-KS activities, suggesting that they should be further investigated, alone or combined with other therapies, as a novel treatment for KS in both HIV seropositive or seronegative individuals.

Dermatological aspects of angiogenesis

Neovascularization is vital for the growth of tumours, providing a lifeline for sustenance and waste disposal. Tumour vessels can grow by sprouting, intussusception or by incorporating bone marrow-derived endothelial precursor cells into growing vessels. Recent advances in vascular biology have identified some key factors that control vascular growth, and have led to the hypothesis that in normal tissues vascular quiescence is maintained by the dominant influence of endogenous angiogenesis inhibitors over angiogenic stimuli. In contrast, increased secretion of angiogenic factors and the down-regulation of endogenous angiogenesis inhibitors induce tumour angiogenesis. Vascular quiescence in the skin seems to be primarily maintained by a balance between the endogenous angiogenesis inhibitors thrombospondin 1 and thrombospondin 2 and the potent proangiogenic factor vascular endothelial growth factor A. Inhibiting tumour growth by controlling angiogenesis is an intriguing approach with great potential for the treatment of vascular tumours such as haemangioma, Kaposi's sarcoma and solid cutaneous tumours such as squamous cell carcinoma, melanoma and basal cell carcinoma. In this review, the role of angiogenesis and more recent topics such as lymphangiogenesis in cutaneous tumour growth, invasion and metastasis will be discussed.

Human immunodeficiency virus type-1 activates lytic cycle replication of Kaposi's sarcoma-associated herpesvirus through induction of KSHV Rta

Human immunodeficiency virus type-1 (HIV-1) infection dramatically increases the risk of development of Kaposi's sarcoma (KS) in individuals infected with Kaposi's sarcoma-associated herpesvirus (KSHV). In a primary effusion lymphoma (PEL) tissue culture model system, HIV-1 replication potently induced the lytic replication of KSHV and led to the secretion of soluble factors capable of inducing lytic KSHV replication in bystander cells. Here we demonstrate that HIV induces KSHV lytic replication through activation of the KSHV Rta. HIV gene expression activated the KSHV Rta promoter following viral infection or after transfection of proviral DNA. Although HIV-1 Tat has previously been implicated as an activator of KSHV lytic replication, Tat alone was unable to activate lytic replication and failed to activate the Rta promoter. We conclude that HIV activates KSHV lytic replication by inducing the KSHV Rta promoter and that factors other than HIV-1 Tat are required to mediate this effect.

Antitumorigenic effects of HIV protease inhibitor ritonavir: inhibition of Kaposi sarcoma

Treatment of patients with human immunodeficiency virus (HIV) protease inhibitors such as ritonavir can result in increases in CD4(+) T-cell counts that are independent of a reduction in HIV-1 viral load. This lack of correlation between the 2 has led to the identification of additional effects of ritonavir that potentially alter HIV disease pathogenesis. Our previous studies indicated that ritonavir directly affects immune cell activation, proliferation, and susceptibility to apoptosis. We show here that ritonavir inhibited the activation and proliferation of primary endothelial cells and decreased the production of tumor necrosis factor alpha (TNF-alpha) interleukin 6 (IL-6), IL-8, and vascular endothelial growth factor, factors that all contribute to tumor neovascularization and to the development of Kaposi sarcoma (KS) lesions. Ritonavir also suppressed the expression of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and E-selectin, which correlated with a functional decrease in leukocyte adhesion. Transcriptional activation of nuclear factor-kappaB, as induced by the KS-promoting factor TNF-alpha, the HIV-1 Tat protein, or the human herpesvirus 8 protein ORF74, was inhibited by ritonavir. KS-derived cell lines underwent apoptosis in vitro after treatment with ritonavir at concentrations that are obtained in clinical therapy (3-15 microM). In a KS mouse xenotransplantation model, ritonavir inhibited tumor formation and progression by KS-derived cells. Taken together, these data suggest that ritonavir has antineoplastic effects that are independent from its ability to inhibit the HIV protease.

Angiogenic effects of extracellular human immunodeficiency virus type 1 Tat protein and its role in the pathogenesis of AIDS-associated Kaposi's sarcoma

The Tat protein of human immunodeficiency virus (HIV) type 1 is a transactivator of viral gene expression that is required for virus replication and spread. Moreover, Tat is released by acutely HIV-infected cells via a leaderless secretory pathway and in a biologically active form that exerts effects on both HIV-infected and uninfected cells from different organs and systems. This review focuses on the activities of extracellular Tat protein on endothelial cells, on angiogenesis, and on the pathogenesis of AIDS-associated angioproliferative diseases such as Kaposi's sarcoma. In particular, we discuss results from different groups indicating that Tat mimics the proangiogenic activities of extracellular matrix molecules and that it enhances the effects of angiogenic factors.

Reactivation and role of HHV-8 in Kaposi's sarcoma initiation

Kaposi's sarcoma (KS) is an angioproliferative disease occurring in several clinical-epidemio-logic forms but all associated with infection by the human herpesvirus-8 (HHV-8). At least in early stages, KS is a reactive disease associated with a state of immune dysregulation characterized by CD8+ T-cell activation and production of Th1-type inflammatory cytokines (IC) that precedes lesion development. In fact, evidence indicates that IC can trigger lesion formation by inducing the activation of endothelial cells that leads to adhesion and tissue extravasation of lymphomonocytes, spindle cell formation, and angiogenesis, and HHV-8 reactivation that, in turn, leads to virus spread to all circulating cell types and virus dissemination into tissues. Due to virus escape mechanisms and deficient immune responses toward HHV-8, virus reactivation and spread are not controlled by the immune system but induce immune responses that may paradoxically exacerbate the reactive process. The virus is recruited into "activated" tissue sites where it finds an optimal environment for growth. In fact, viral load is very low in early lesions, whereas almost all spindle cells are infected in late-stage lesions. Although early KS is a reactive process of polyclonal nature that can regress, in time and in the presence of immunodeficiency, it can progress to a true sarcoma. This is likely due to the long-lasting expression of HHV-8 latency genes in spindle cells associated with the deregulated expression of oncogenes and oncosuppressor genes and, for AIDS-KS, with the effects of the HIV-1 Tat protein.

Human herpesvirus-8 and Kaposi's sarcoma: relationship with the multistep concept of tumorigenesis

Kaposi's sarcoma (KS) develops through discrete inflammatory-angiogenic stages of polyclonal nature (early-stage lesions) to monomorphic nodules of spindle-shaped cells that can be clonal (late-stage lesions) and resemble true sarcomas. Molecular and epidemiological studies indicate that development of KS is tightly associated with infection by the human herpesvirus-8 (HHV-8). However, only individuals with specific conditions of immunodysregulation develop KS. In these individuals the systemic and tissue increase of Th-1-type cytokines (IC) reactivate HHV-8 infection, leading to increased viral load, antibody titers, and an expanded cell tropism that precedes the clinical appearance of KS. Recruitment of the virus into tissues by infected monocytes and other cell types is facilitated by the endothelial cell activation due to IC. In clinical lesions, HHV-8 infection increases with lesion stage and in late-stage lesions most of the spindle cells are latently infected, whereas only few lyrically infected cells are present, suggesting that latent genes may have a role in the transformation of the early inflammatory-hyperplastic lesion into a real sarcoma. The development of tumors, however, is regulated through a multistep process based on the acquisition by cells of several different capabilities leading to malignant growth. Here we review the available data on the expression of HHV-8-encoded genes in primary KS lesions and, in view of their biological activity, analyze their potential function in different steps of tumorigenesis. By this pragmatic approach interesting insights into potential key functions of HHV-8-encoded genes are found and steps of potential cooperativity with other viral factors (HIV-1-Tat) in the pathogenesis of KS are identified.

Human herpesvirus-8-transformed endothelial cells have functionally activated vascular endothelial growth factor/vascular endothelial growth factor receptor

Kaposi's sarcoma is a vascular tumor commonly associated with human immunodeficiency virus (HIV)-1 and human herpesvirus (HHV-8) also known as Kaposi's sarcoma-associated herpesvirus. The principal features of this tumor are abnormal proliferation of vascular structures lined with spindle-shaped endothelial cells. HHV-8 may transform a subpopulation of endothelial cells in vitro via viral and cellular gene expression. We hypothesized that among the cellular genes, vascular endothelial growth factors (VEGFs) and their cognate receptors may be involved in viral-mediated transformation. We have shown that HHV-8-transformed endothelial cells (EC-HHV-8) express higher levels of VEGF, VEGF-C, VEGF-D, and PlGF in addition to VEGF receptors-1, -2, and -3. Furthermore, antibodies to VEGF receptor-2 inhibited cell proliferation and viability. Similarly, inhibition of VEGF gene expression with antisense oligonucleotides inhibited EC-HHV-8 cell proliferation/viability. The growth and viability of primary endothelial cells and a fibroblast cell line however were unaffected by either the VEGF receptor-2 antibody or the VEGF antisense oligodeoxynucleotides. VEGF and VEGF receptors are thus induced in EC-HHV-8 and participate in the transformation. Inhibitors of VEGF may thus modulate the disease process during development and progression.

Kaposi's sarcoma: clinico-pathological analysis of human immunodeficiency virus (HIV) and non-HIV associated cases

Kaposi s sarcoma (KS) is a angioformative lesion that classically occurs in elderly Eastern European and Mediterranean males but is also common in immunosuppressed individuals particularly human immunodeficiency virus (HIV)-infected patients. This study investigates the clinical and histopathological features of 47 patients with Kaposi s sarcoma from a teaching hospital in Sydney, Australia, in which 44 cases had adequate clinical follow-up information over a 10-year period. Most of the lesions were of late stage (37/47 cases; 79%), consisting of 11 cases of plaque stage KS and 26 cases of nodular stage KS with only 10 cases of early or patch stage KS. The majority of the HIV-positive cases (23/33; 70%) and all of the HIV-negative (14/14; 100%) cases had late stage lesions (p=0.020; X 2 -test). The histopathological features that were more common in the KS lesions of HIV-negative patients were lesional cell mitosis (p=0.0002), single cell necrosis (p=0.001), apoptosis (p=0.0001) and single cell anaplasia (p=0.0001). The KS lesions in HIV-positive patients tended to have dissecting blood vessels (14/33 cases; 42%) unlike those seen in HIV-negative patients (0/14 cases; 0%) (p=0.004). Most HIV-positive cases (30/33; 90%) were males (p=0.0068); and all these patients (33/33 cases; 100%) were <60 years old, in contrast to HIV-negative patients (1/11 cases; 9%) (p=0.0001). HIV status does not affect the occurrence of multiplicity of KS lesions. However, extracutaneous or visceral KS lesions were more likely to occur in HIV-positive patients (p=0.027). The number of cases of histologically proven KS cases has decreased markedly over the recent 5 year period of 1995-1999 (n=14), which was less than half of the number of the preceding 5 year period, 1990-1994 (n=33). In summary, there are distinct differences in the clinical and histopathological features of Kaposi s sarcoma lesions in HIV-positive and HIV-negative patients. Despite the recent discovery of the HHV8 virus as the initiating and promoting factor of most of the KS lesions, these differences indicated that there might be different mechanisms that occur in HIV-positive and HIV-negative patients in the development of this lesion.

Activation of matrix-metalloproteinase-2 and membrane-type-1-matrix-metalloproteinase in endothelial cells and induction of vascular permeability in vivo by human immunodeficiency virus-1 Tat protein and basic fibroblast growth factor

Previous studies indicated that the Tat protein of human immunodeficiency virus type-1 (HIV-1) is a progression factor for Kaposi's sarcoma (KS). Specifically, extracellular Tat cooperates with basic fibroblast growth factor (bFGF) in promoting KS and endothelial cell growth and locomotion and in inducing KS-like lesions in vivo. Here we show that Tat and bFGF combined increase matrix-metalloproteinase-2 (MMP-2) secretion and activation in endothelial cells in an additive/synergistic manner. These effects are due to the activation of the membrane-type-1-matrix-metalloproteinase and to the induction of the membrane-bound tissue inhibitor of metalloproteinase-2 (TIMP-2) by Tat and bFGF combined, but also to Tat-mediated inhibition of both basal or bFGF-induced TIMP-1 and -2 secretion. Consistent with this, Tat and bFGF promote vascular permeability and edema in vivo that are blocked by a synthetic MMP inhibitor. Finally, high MMP-2 expression is detected in acquired immunodeficiency virus syndrome (AIDS)-KS lesions, and increased levels of MMP-2 are found in plasma from patients with AIDS-KS compared with HIV-uninfected individuals with classic KS, indicating that these mechanisms are operative in AIDS-KS. This suggests a novel pathway by which Tat can increase KS aggressiveness or induce vasculopathy in the setting of HIV-1 infection.

Biology of Kaposi's sarcoma

Kaposi's sarcoma (KS) is an angioproliferative disease occurring in several different clinical-epidemiological forms that, however, share the same histological traits and are all associated with infection by the human herpesvirus 8 (HHV8). KS initiates in a context of immune dysregulation characterised by CD8+ T cell activation and the production of Th1-type cytokines that induce a generalised activation of endothelial cells leading to adhesion and tissue extravasation of lympho-monocytes, spindle cell formation and angiogenesis. These phenomena are triggered or enhanced by infection with HHV8 that, in turn, is reactivated by the same cytokines. Productively-infected circulating cells are recruited into 'activated' tissue sites where HHV8 finds an optimal environment for establishing a persistent, latent infection of KS spindle cells (KSC). HHV8 dissemination is favoured by virus escape mechanisms and immune dysregulation, and leads to immune responses that are not effective against the virus but, paradoxically, exacerbates the reactive process. Although early KS is a reactive process of polyclonal nature that can regress, in time it can progress in to a true sarcoma. The progression of KS appears to be due to the deregulated expression of oncogenes and oncosuppressor genes, to the long-lasting expression of the HHV8 latency genes and, for AIDS-KS, is promoted by the proliferative and angiogenic effects of the HIV-1 Tat protein.

Targeted inhibition of calcineurin signaling blocks calcium-dependent reactivation of Kaposi sarcoma-associated herpesvirus

Kaposi sarcoma-associated herpesvirus (KSHV) is associated with KS, primary effusion lymphoma (PEL), and multicentric Castleman disease. Reactivation of KSHV in latently infected cells and subsequent plasma viremia occur before the development of KS. Intracellular signaling pathways involved in KSHV reactivation were studied. In latently infected PEL cells (BCBL-1), KSHV reactivation in single cells was determined by quantitative flow cytometry. Viral particle production was determined by electron microscope analyses and detection of minor capsid protein in culture supernatants. Agents that mobilized intracellular calcium (ionomycin, thapsigargin) induced expression of KSHV lytic cycle-associated proteins and led to increased virus production. Calcium-mediated virus reactivation was blocked by specific inhibitors of calcineurin-dependent signal transduction (cyclosporine, FK506). Similarly, calcium-mediated virus reactivation in KSHV-infected dermal microvascular endothelial cells was blocked by cyclosporine. Furthermore, retroviral transduction with plasmid DNA encoding VIVIT, a peptide specifically blocking calcineurin-NFAT interactions, inhibited calcium-dependent KSHV reactivation. By contrast, chemical induction of lytic-phase infection by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate was blocked by protein kinase C inhibitors, but not by calcineurin inhibitors. In summary, calcineurin-dependent signal transduction, an important signaling cascade in vivo, induces calcium-dependent KSHV replication, providing a possible target for the design of antiherpesvirus strategies in KSHV-infected patients.

Tat-induced platelet-activating factor synthesis contributes to the angiogenic effect of HIV-1 Tat

This study shows that human umbilical cord vein-derived endothelial cells (HUVEC) stimulated with HIV-1 Tat synthesized platelet-activating factor (PAF), a phospholipid mediator of inflammation that possesses angiogenic properties. The synthesis of PAF by HUVEC stimulated with Tat was dose and time dependent. Moreover, in vitro experiments were performed to evaluate whether migration of HUVEC induced by Tat was dependent on the synthesis of PAF. It was found that the cell motility induced by Tat was inhibited by WEB 2170, a specific PAF receptor antagonist. In vivo, the neoangiogenesis induced by Tat was also inhibited by WEB 2170 in a murine model, in which matrigel subcutaneously injected was used as substratum for angiogenesis. These results suggest that the synthesis of PAF by endothelial cells mediates, at least in part, the angiogenic activity of Tat by promoting the endothelial cell migration.

A case series of acquired immunodeficiency syndrome patients with initial neoplastic diagnoses of intraoral Kaposi's sarcoma

BACKGROUND

Oral Kaposi's sarcoma (KS) may represent the initial clinical manifestation of immunosuppression in human immunodeficiency virus disease. This article reviews the treatment provided to these patients and the outcome of the disease and provides the opportunity to assess the impact of improvements in the medical therapy of acquired immunodeficiency syndrome on disease outcome.

METHODS

A tumor registry was examined to identify patients in whom oral KS was the first neoplastic diagnosis.

RESULTS AND CONCLUSIONS

Thirty-seven cases of oral KS representing 1.9% of all cases of KS were identified as the first malignant diagnosis in patients with acquired immunodeficiency syndrome. Patients with oral KS have limited survival; the cause of death is either infection or malignancy. In our study, the palate was the most common site of primary involvement in the oral cavity. Recently diagnosed patients remained alive longer than those diagnosed earlier, and the patients with the most recently diagnosed cases were alive at the completion of the study, suggesting that medical management of human immunodeficiency virus has improved with new therapies.

Cytokine-mediated growth promotion of Kaposi's sarcoma and primary effusion lymphoma

Kaposi's sarcoma (KS) is an angioproliferative disease particularly frequent and aggressive in patients with AIDS but occurring also in post-transplant patients or in immunocompetent individuals of certain geographic areas. At least in its early stages, KS behaves as a reactive hyperplastic process mediated by inflammatory cytokines and angiogenic factors triggered or exacerbated by human herpesvirus-8 (HHV-8) infection. The HIV Tat protein appears to be responsible for the highly aggressive nature of AIDS-KS. Over time, however, KS may evolve into a true sarcoma in association with the expression of oncogenes and/or HHV-8 latency genes endowed with growth and anti-apoptotic properties. HHV-8 infection is also associated with primary effusion lymphoma (PEL), a rare tumor that similarly develops more frequently in the setting of HIV infection. HHV-8 latency genes are likely to contribute to the neoplastic phenotype of PEL cells, whose growth in vivo may require cytokines and factors from the host, or encoded by the virus.

Activity of thalidomide in AIDS-related Kaposi's sarcoma

PURPOSE

To assess the toxicity and activity of oral thalidomide in Kaposi's sarcoma (KS) in a phase II dose-escalation study.

PATIENTS AND METHODS

Human immunodeficiency virus (HIV)-seropositive patients with biopsy-confirmed KS that progressed over the 2 months before enrollment received an initial dose of 200 mg/d of oral thalidomide in a phase II study. The dose was increased to a maximum of 1,000 mg/d for up to 1 year. Anti-HIV therapy was maintained during the study period. Toxicity, tumor response, immunologic and angiogenic factors, and virologic parameters were assessed.

RESULTS

Twenty patients aged 29 to 49 years with a median CD4 count of 246 cells/mm(3) (range, 14 to 646 cells/mm(3)) were enrolled. All patients were assessable for toxicity, and 17 for response. Drowsiness in nine and depression in seven patients were the most frequent toxicities observed. Eight (47%; 95% confidence interval [CI], 23% to 72%) of the 17 assessable patients achieved a partial response, and an additional two patients had stable disease. Based on all 20 patients treated, the response rate was 40% (95% CI, 19% to 64%). The median thalidomide dose at the time of response was 500 mg/d (range, 400 to 1,000 mg/d). The median duration of drug treatment was 6.3 months, and the median time to progression was 7.3 months.

CONCLUSION

Oral thalidomide was tolerated in this population at doses up to 1,000 mg/d for as long as 12 months and was found to induce clinically meaningful anti-KS responses in a sizable subset of the patients. Additional studies of this agent in KS are warranted.

Exercise and the immune system: regulation, integration, and adaptation

Stress-induced immunological reactions to exercise have stimulated much research into stress immunology and neuroimmunology. It is suggested that exercise can be employed as a model of temporary immunosuppression that occurs after severe physical stress. The exercise-stress model can be easily manipulated experimentally and allows for the study of interactions between the nervous, the endocrine, and the immune systems. This review focuses on mechanisms underlying exercise-induced immune changes such as neuroendocrinological factors including catecholamines, growth hormone, cortisol, beta-endorphin, and sex steroids. The contribution of a metabolic link between skeletal muscles and the lymphoid system is also reviewed. The mechanisms of exercise-associated muscle damage and the initiation of the inflammatory cytokine cascade are discussed. Given that exercise modulates the immune system in healthy individuals, considerations of the clinical ramifications of exercise in the prevention of diseases for which the immune system has a role is of importance. Accordingly, drawing on the experimental, clinical, and epidemiological literature, we address the interactions between exercise and infectious diseases as well as exercise and neoplasia within the context of both aging and nutrition.

Variant genotypes of FcγRIIIA influence the development of Kaposi's sarcoma in HIV-infected men

Disturbances in inflammatory cytokine production and immune regulation coupled with human herpesvirus-8 (HHV-8) infection underlie the current understanding of the pathogenesis of Kaposi's sarcoma (KS), the most common HIV-associated malignancy. The low affinity Fc gamma receptors (FcγR) for IgG link humoral and cellular immunity by mediating interaction between antibodies and effector cells, such as phagocytes and natural killer cells. We examined the frequency of polymorphic forms of the low affinityFcγRs, FcγRIIA,FcγRIIIA, and FcγRIIIB in 2 cohorts of HIV-infected men with KS and found that theFcγRIIIA genotype exerts a significant influence on susceptibility to or protection from KS. The FF genotype was underrepresented in patients with KS, whereas the VF genotype was associated with development of KS. A similar association was observed between FcγRIIIA genotypes and HHV-8 seropositivity. These observations suggest a possible role forFcγRIIIA in the development of KS during HIV infection.

Variant genotypes of FcγRIIIA influence the development of Kaposi's sarcoma in HIV-infected men

Disturbances in inflammatory cytokine production and immune regulation coupled with human herpesvirus-8 (HHV-8) infection underlie the current understanding of the pathogenesis of Kaposi's sarcoma (KS), the most common HIV-associated malignancy. The low affinity Fc gamma receptors (FcγR) for IgG link humoral and cellular immunity by mediating interaction between antibodies and effector cells, such as phagocytes and natural killer cells. We examined the frequency of polymorphic forms of the low affinityFcγRs, FcγRIIA,FcγRIIIA, and FcγRIIIB in 2 cohorts of HIV-infected men with KS and found that theFcγRIIIA genotype exerts a significant influence on susceptibility to or protection from KS. The FF genotype was underrepresented in patients with KS, whereas the VF genotype was associated with development of KS. A similar association was observed between FcγRIIIA genotypes and HHV-8 seropositivity. These observations suggest a possible role forFcγRIIIA in the development of KS during HIV infection.

HIV-1-trans-activating (Tat) protein: both a target and a tool in therapeutic approaches

Tat proteins (trans-activating proteins) are present in all known lentiviruses and are early RNA binding proteins that regulate transcription. Tat from the human immunodeficiency virus type-1 is a protein comprising 86 amino acids and encoded by 2 exons. The first 72 amino acids are encoded by exon 1 and exhibit full trans-activating activity. The second exon encodes a 14-amino-acid C-terminal sequence that is not required for trans-activation but does contain an RGD motif, which is important in binding to alphavbeta3 and alpha5beta1 integrins. Tat has an unusual property for a transcription factor; it can be released and enter cells freely, yet still retain its activity, enabling it to up-regulate a number of genes. Tat also has an angiogenic effect; it is a potent growth factor for Kaposi sarcoma-derived spindle cells, and, separately, it has been shown to bind to a specific receptor, Flk-1/KDR, on vascular smooth muscle cells, as well as to integrin-like receptors present on rat skeletal muscle cells and the lymphocyte cell line H9. It appears that the basic domain of tat is important, not only for translocation but also for nuclear localisation and trans-activation of cellular genes. As such, targeting of tat protein or, more simply, the basic domain provides great scope for therapeutic intervention in HIV-1 infection. There is also opportunity for tat to be used as a molecular tool; the protein can be manipulated to deliver non-permeable compounds into cells, an approach that already has been employed using ovalbumin, beta-galactosidase, horseradish peroxidase, and caspase-3.