Seroconversion for human herpesvirus 8 during HIV infection is highly predictive of Kaposi's sarcoma

Spectrum of cancers among HIV-infected persons in Africa: The Uganda AIDS-Cancer Registry Match Study

Although more than 25 million people in sub-Saharan Africa have human immunodeficiency virus (HIV) infection, little is known regarding their cancer risk. We investigated cancer risk among persons with HIV/AIDS in Uganda using record-linkage. We linked records of 12,607 HIV-infected persons attending The AIDS Support Organization (TASO) in Kyadondo County from October 1988 through December 2002 to the Kampala Cancer Registry. We calculated standardized incidence ratios (SIRs) to identify increased cancer risks in the early (4-27 months after TASO registration), late (28-60 months), or combined (4-60 months) incidence periods. We identified 378 cancers (181 prevalent, 197 incident) among TASO participants. Of incident cancers, 137 (70%) were AIDS-defining cancers. Risk was increased in the early-incident period, compared to the general population, for the AIDS-defining cancers: Kaposi sarcoma (SIR 6.4, 95%CI 4.8-8.4), non-Hodgkin lymphoma (6.7, 1.8-17), and cervical carcinoma (2.4, 1.1-4.4). These three cancers were also increased in the combined periods. Risks of five non-AIDS-defining cancers were increased in the combined periods: Hodgkin lymphoma (5.7, 1.2-17) and cancers of the conjunctiva (SIR 4.0; 1.5-8.7), kidney (16, 1.8-58), thyroid (5.7, 1.1-16), and uterus (5.5, 1.5-14). Cancers of the breast, nasopharynx, and lung were increased either in the early or late incident periods only. Among 407 children, seven cancers were observed, of which five were Kaposi sarcoma. The application of a record-linkage design in Africa broadens the repertoire of epidemiological tools for studying HIV-infected populations. We confirm the increased risks of AIDS-defining cancers and report increased risks of a few non-AIDS-defining cancers.

Kaposi's Sarcoma-associated Herpesvirus Activation of Vascular Endothelial Growth Factor Receptor 3 Alters Endothelial Function and Enhances Infection

Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8) is the etiologic agent of Kaposi's sarcoma, an endothelial neoplasm. This gamma-herpesvirus encodes for several unique proteins that alter target cell function, including the virion envelope-associated glycoprotein B (gB). Glycoprotein B has an RGD (Arg-Gly-Asp) motif at the extracellular amino terminus region and binds to the alpha3beta1 surface integrin, which enhances virus entry. We now report that gB can activate the vascular endothelial growth factor receptor 3 (VEGFR-3) on the surface of microvascular endothelial cells and trigger receptor signaling, which can modulate endothelial migration and proliferation. Furthermore, we observed that VEGFR-3 expression and activation enhance KSHV infection and participate in KSHV-mediated transformation. These functional changes in the endothelium may contribute to the pathogenesis of Kaposi's sarcoma and suggest that interventions that inhibit gB activation of VEGFR-3 could be useful in the treatment of this neoplasm.

Human herpesvirus-8 seropositivity and clinical correlations in HIV-1-positive and highly exposed, persistently HIV-seronegative individuals in Greece

The prevalence of anti-human herpesvirus 8 (HHV-8) antibodies was retrospectively assessed in a cohort of 248 consecutive HIV-1-positive patients followed up in an academic unit in Greece during a 14-year period and in 46 highly exposed, persistently HIV-seronegative (HEPS) individuals. The impact of the initial anti-HHV-8 status on tumorgenesis and mortality was studied. The first available serum sample from the department's pool was tested. Demographics and data regarding history of sexually transmitted diseases, Hepatitis B surface antigen (HbsAg) and hepatitis C (HCV) status were collected. Patients who developed either HHV-8-related or non-HHV-8-related neoplasms during long-term follow-up were also identified. Forty-eight percent of the HIV-1-positive patients and 56% of the HEPS subjects were found anti-HHV-8-positive. No difference was observed regarding the development of HHV-8-related or non-HHV-8-related neoplasia and mortality on grounds of initial anti- HHV-8 status. Mortality was positively associated with the presence of HBsAg. HCV infection showed a trend to be more common in anti-HHV-8-positive patients. In summary, the seroprevalence of HHV-8 among HIV-1-positive patients is higher than the one reported in the Western world. The initial anti-HHV-8 status is not a prognostic factor in HIV-1-positive individuals. The high seroprevalence in HEPS individuals possibly reflects their risk-prone lifestyle. HbsAg-positive status is a long-term negative prognostic factor in HIV infection.

Risk factors for Kaposi's sarcoma among HHV-8 seropositive homosexual men with AIDS

Kaposi's sarcoma (KS) is a frequent complication of the acquired immunodeficiency syndrome (AIDS) in homosexual men. Risk factors for developing this malignancy are uncertain, other than immunosuppression and coinfection with human herpesvirus 8 (HHV-8). We therefore examined factors associated with KS in a cross-sectional analysis of 99 cases among 503 HHV-8 seropositive homosexual men with AIDS. Data were collected by computer-assisted personal interviews and medical chart reviews. HHV-8 seroreactivity was determined by enzyme-linked immunosorbent assay for antibodies against HHV-8 K8.1 glycoprotein. KS was significantly less common in blacks compared to whites [risk ratio (RR) = 0.4; 95% CI = 0.2 =0.8] and more common in subjects who had completed college (RR = 1.7; 95% CI = 1.1-2.7) or had annual income greater than dollar 30,000 (RR = 1.5; 95% CI = 1.1-2.2). KS was less common in cigarette smokers (RR = 0.6; 95% CI = 0.5-0.9) and users of crack cocaine (RR = 0.4; 95% CI = 0.1-0.8). KS was less common in bisexual men compared to men who were exclusively homosexual (estimated RR = 0.6; 95% CI = 0.4-0.9) and inversely associated with number of female partners. KS was also less common in men who had received pay for sex (RR = 0.6; 95% CI = 0.4-1.0). These cross-sectional associations could be biased by potential differences in relative timing of HHV-8 and HIV infection, a postulated determinant of KS risk. Alternatively, our findings may reflect factors protective against KS in individuals infected with HHV-8. Future research should focus on identifying practical measures for countering KS that do not increase the risk of other diseases.

Barebacking identity among HIV-positive gay and bisexual men: demographic, psychological, and behavioral correlates

OBJECTIVES

To determine the correlates associated with barebacking identity among HIV-positive gay and bisexual men.

DESIGN

An analysis of data from the baseline quantitative assessment of a randomized controlled intervention study of 1168 HIV-positive gay and bisexual men from New York City and San Francisco.

METHODS

Participants were actively and passively recruited from mainstream gay venues, AIDS service organizations, and public and commercial sex environments. Participants completed a computerized quantitative questionnaire assessing their identity as a barebacker, sexual behavior, demographic factors, psychosocial states, perceptions of health risks, and substance use.

RESULTS

Men of color were less likely to identify themselves as barebackers. Men who did identify themselves as barebackers were slightly younger. They were more likely to miss a dose of medication; report drug use (non-injection and injection); exhibit higher levels of sexual compulsivity and lower personal responsibility for safer sex; and report higher rates of unprotected insertive anal intercourse, unprotected receptive anal intercourse, and unprotected insertive oral intercourse with all partners, regardless of their HIV serostatus.

CONCLUSION

Barebacking and its corresponding behaviors pose immediate public health risks for HIV-positive gay and bisexual men. Further work is needed to understand this phenomenon more fully in relation to the psychological, sociological, biomedical, and cultural realities.

Cancer incidence patterns among adolescents and young adults in the United States

OBJECTIVE

The purpose of this study was to examine age-specific cancer incidence patterns among adolescents and young adults (ages 15--49).

METHOD

Cancer incidence data for 1995--1999 from 22 population-based central cancer registries, covering about 47% of the US population, were used. Relative frequencies and average annual age-specific incidence rates per 100,000 person-year were computed for the five-year age groups from age 15--19 years through 45--49 years. Tests of significance for comparison were at a level of p<0.05.

RESULTS

The age at crossover from a predominance of non-epithelial cancers to a predominance of epithelial cancers during adolescence and young adulthood varied by gender and race. Epithelial cancer became the predominant type of tumor after age 40 years among males while it was the predominant type after age 25 years among females. There was also a shift in the top five cancer types with increasing age, which varied by race and gender. Epithelial cancers of the thyroid, breast, ovary, and cervix uteri started to increase sharply among young women in their 20s while among males epithelial cancers rarely occurred until the early 30s (ages 30--34). Cancers of the female breast, colon and rectum, and lung began to occur at an earlier age and increased more sharply among blacks than among whites. However, the incidence rates of epithelial thyroid and ovarian cancers rose more quickly among whites than blacks. Non-Hodgkin lymphoma and soft tissue sarcoma (excluded Kaposi's sarcoma) increased with age among both whites and blacks but the rates were significantly higher among blacks than among whites. Both Kaposi's sarcoma and testicular cancer incidence increased with age and peaked in the early 30s (ages 30--34). The former was significantly higher among blacks than whites while the latter was significantly higher among whites than blacks. Cervical cancer incidence leveled off when white women reached their 30s, but for black women the rate continued to rise with advancing age. Cutaneous melanoma rates were significantly higher among females than among males between the ages of 15 and 39. Conclusion Cancer incidence patterns among adolescents and young adults are distinctive. Specific cancer prevention and control strategies should be targeted accordingly and tailored to their specific needs.

Seroconcordant sexual partnerings of HIV-seropositive men who have sex with men

OBJECTIVES

To describe the sexual behaviors of HIV-positive men with their seroconcordant partners and to determine the factors associated with unprotected anal intercourse (UAI) in these sexual partnerings.

METHODS

The data were drawn from the baseline assessment of a randomized controlled intervention study of 1168 HIV-positive men who have sex with men recruited from mainstream gay venues, AIDS service organizations, and public/commercial sex environments.

RESULTS

Of the 1168 men, 596 engaged in sexual experiences with other HIV-positive men, and 371 of the 596 (62%) practised UAI with their seroconcordant partners. Those who engaged in UAI expressed less self-evaluation with regard to their unsafe sexual practices, had higher levels of hedonism associated with unsafe sex, and were more likely both to inject recreation drugs and use methamphetamine in particular. Furthermore, these participants expressed less concern with regard to HIV re-infection, infection with other sexually transmitted infections, and the transmission of pathogens causing opportunistic infections.

CONCLUSION

Our findings suggest that at least three sets of factors predispose HIV-positive men to engage in unsafe anal sexual behaviors with their concordant partners: a decreased belief that infection with other pathogens or re-infection with HIV present health problems; less evaluation of sexual activities and behaviors; more hedonistic expectations of sex and higher levels of sexual compulsivity, as well as recreational drug use with and without sex.

Profile of Patients With Kaposi's Sarcoma in the Era of Highly Active Antiretroviral Therapy

Purpose

Since the advent of highly active antiretroviral therapy (HAART), the incidence of Kaposi's sarcoma (KS) among AIDS patients has declined both nationwide and in King County, Washington. We sought to compare clinical parameters of patients diagnosed with KS in the pre-HAART (1990 to 1996) and HAART (1997 to 2002) eras.

Methods

We used patient data abstracted from the Adult/Adolescent Spectrum of HIV-Related Diseases study of Public Health—Seattle and King County.

Results

Patients diagnosed with KS in the HAART era (n = 40) were significantly more likely (P < .05) than pre–HAART-era KS patients (n = 366) to be diagnosed with alcohol problems (43% v 18%), noninjection drug use (45% v 18%), injection drug use (25% v 10%), psychosis (25% v 13%), and hypertension (13% v 2%). Although median CD4+ count and HIV-1 viral load at the time of KS diagnosis were not significantly different between the two groups, significantly fewer (P < .01) HAART-era KS patients developed opportunistic illnesses (OIs) during their follow-up. The risk of dying among KS patients diagnosed in the HAART era is significantly lower (P < .01) than for KS patients diagnosed in the pre-HAART era (hazard ratio, 0.24).

Conclusion

Although HAART-era KS patients in King County were as likely to have a depleted CD4+ cell count and high HIV-1 viral loads at the time of KS diagnosis as pre-HAART KS patients, they survived longer and fewer of them were diagnosed with other OIs. They also had an increased prevalence of substance abuse and mental illness, contributing to a dynamic and changing KS clinical profile.

Human Herpesvirus 8 (HHV-8) Infection in HIV/AIDS Patients From Santos, Brazil: Seroprevalence and Associated Factors

GOAL

The goal of this study was to evaluate the seroprevalence of human herpesvirus 8 (HHV-8) infection among HIV-infected individuals from Brazil and the associated risk factors.

STUDY

A cross-sectional survey was carried out with 497 HIV/AIDS outpatients attending the local AIDS Reference Center in Santos (southeastern Brazil) between February 1997 and January 1998 had serum samples screened for anti-HHV-8 antibodies. Patients were considered seropositive whenever reactivity was observed in at least 1 of 3 tests (immunofluorescence assays for latent nuclear and lytic antigens and orf65 recombinant antigen enzyme-linked immunosorbent assay).

RESULTS

Overall HHV-8 seroprevalence was 13.9% (95% confidence interval [CI], 10.9-17.6). HHV-8 coinfection was significantly more frequent in men (18.7%; 95% CI, 14.1-23.4) than in women (7.8%; 95% CI, 4.2-11.3) (P < 0.001). According to the mode of HIV acquisition among males, seroprevalence of HHV-8 infection was significantly higher in men who have sex with men when compared with the other groups (32.4% vs. 10.0%, P < 0.001). Multivariate logistic regression revealed HHV-8 infection among men to be independently associated with sexual orientation (adjusted odds ratio [AOR], 5.5 for homosexuals; AOR, 2.8 for bisexuals). No significant risk factor for HHV-8 infection could be demonstrated for HIV-infected women in this cohort,

CONCLUSIONS

This study provides further evidence that men who have sex with men are at higher risk of HHV-8 infection and shows that the epidemiologic pattern of this infection among HIV/AIDS patients from Santos, Brazil, is similar to that described in other countries with a low incidence of Kaposi's sarcoma.

Retrospective, longitudinal analysis of serum human herpesvirus-8 viral DNA load in AIDS-related Kaposi's sarcoma patients before and after diagnosis

Human herpesvirus 8 (HHV-8) is detected more often in patients progressing towards Kaposi's sarcoma (KS) than in patients who do not develop the disease, suggesting that the level of viremia might be associated with Kaposi's sarcoma disease and progression. Longitudinal serum samples from 19 AIDS-Kaposi's sarcoma patients, ranging from 2 years before KS till 2 years after KS diagnosis were tested. No correlation was found between viral load and progression to KS, or disease stage.

The Incidence of Kaposi Sarcoma Among Injection Drug Users With AIDS in the United States

Some studies report increased prevalence of human herpesvirus 8 (HHV-8), the causative agent of Kaposi sarcoma (KS), among injection drug users (IDUs), suggesting that HHV-8 may be transmitted through blood-borne or other exposures common in this population. Since an elevated HHV-8 prevalence in IDUs would likely lead to increased KS incidence, KS incidence was studied in IDUs and non-IDU's with AIDS. AIDS-related KS cases were identified using linked US AIDS and cancer registry data for 25,891 women, 47,782 heterosexual men, and 90,616 men who have sex with men (MSM). KS arose in 7099 persons with AIDS. KS incidence was highest for MSM (5.7 per 100 person-years), substantially lower for heterosexual men (0.7 per 100 person-years), and lowest for women (0.4 per 100 person-years). After adjustment for age, race, registry location, and year of AIDS onset, relative risks for KS associated with injection drug use were 1.3 (95% CI, 0.9-1.8) among women, 1.1 (0.7-1.6) among heterosexual men, and 0.9 (0.8-0.9) among MSM. It is concluded that injection drug use was not associated with an increased risk of AIDS-related KS. Thus, these data suggest that IDUs' risk of acquiring HHV-8, through needle sharing or other behaviors related to injection drug use, is low.

Seroprevalence of Human Herpesvirus 8 Infection in Northern Thailand

BACKGROUND

Human herpesvirus 8 (HHV-8) is associated with Kaposi sarcoma (KS) in patients with acquired immunodeficiency syndrome (AIDS) and KS, classical KS, or endemic KS. Because human immunodeficiency virus (HIV) infections and HIV/AIDS are common in Thailand but KS is very rare (only 0.2% of reported patients with AIDS in Thailand had KS), we determined the HHV-8 seroprevalence among populations who were HIV positive or at risk of HIV infection.

METHODS

A total of 992 persons from 2 populations underwent testing for lytic antibodies to HHV-8 using an immunofluorescence assay involving a BCBL-1 cell line at serum dilutions of 1 : 50 and 1 : 100. Serum specimens with positive results were titered to end points. Subjects included approximately 400 married couples in which the husband was HIV positive and the wife was HIV positive (200 couples) or HIV negative (200 couples). In addition, 200 HIV-negative men from a sexually transmitted diseases (STD) clinic were studied.

RESULTS

The antibody prevalence was 24.2% in the total population. The prevalence was higher among HIV-negative men (13.0%) but was similar among HIV-positive women (27.9%) and HIV-negative women (23.8%). The HHV-8 seroprevalence among wives whose husbands were HIV-1 positive did not differ according to their husband's HHV-8 status. There was no association between HHV-8 seroprevalence and reported sexual behavior or STD history.

CONCLUSION

Despite the rarity of KS among patients with AIDS in Thailand, HHV-8 infections are common and do not appear to be frequently transmitted sexually in these populations.

Tumorigenesis by human herpesvirus 8 vGPCR is accelerated by human immunodeficiency virus type 1 Tat

Human herpesvirus 8 (HHV-8), also called Kaposi's sarcoma (KS) herpesvirus, can cause KS but is inefficient. Untreated human immunodeficiency virus type 1 (HIV-1) coinfection is a powerful risk factor. The HHV-8 chemokine receptor, vGPCR (ORF74), activates NF-kappaB and NF-AT, and their levels of activation are synergistically increased by HIV-1 Tat. Transgenic vGPCR mice develop KS-like tumors. A cell line derived from one such tumor expresses vGPCR and forms tumors in nude mice. Here we show that transfection of DNA encoding HIV-1 tat (but not a transactivation-defective mutant) into these tumor cells increases NF-kappaB and NF-AT activation levels and accelerates tumor formation. Tumorigenesis was also accelerated when Tat DNA was transfected into normal cells and the transfected cells were mixed with the tumor cells and injected into a single site. Tumorigenesis was also increased when the two cell types were injected at separate sites, suggesting that tumorigenesis is accelerated by Tat through soluble factors.

Amino acid residue at position 13 in HLA-DR beta chain plays a critical role in the development of Kaposi's sarcoma in AIDS patients

BACKGROUND

In 1994 human herpesvirus 8 (HHV-8) was identified as the causative agent of Kaposi's sarcoma (KS). Moreover, the crucial role of HLA molecules in determining susceptibility to several infections was recognized.

OBJECTIVES

To evaluate the influence of HLA-DRB1 polymorphism in KS susceptibility among HHV-8 infected AIDS patients.

DESIGN

A matched case-control study was designed to identify possible biological and environmental risk factors for HIV associated KS. Cases were defined as any AIDS patient with a clinical diagnosis of KS and controls as any AIDS patient with an indicative disease other than KS or with CD4 cells counts < 200 x 10 cells/l, diagnosed at +/- 4 months after case diagnosis. Each case was matched with two controls by sex, age and transmission category.

METHODS

HHV-8 serostatus was determined by immunofluorescence assay for the latency associated antigen encoded by Orf73, ELISA for Orf73 and ELISA for the lytic antigen Orf65. DRB1 typing was carried out with a commercially available PCR-sequence specific primer assay.

RESULTS

Comparison of marker frequencies in HHV-8 infected AIDS patients with or without KS showed a positive association between KS and HLA-DRB1 alleles containing phenylalanine at position 13 [odds ratio (OR), 2.24; P = 0.016]. A negative association was observed when the residue at the same position was glycine (OR, 0.16; P = 0.009).

CONCLUSION

These observations suggest a possible role for HLA-DRB1 in the development of KS in HHV-8 infected individuals with HIV co-infection. Progression to KS in HHV-8 infected AIDS patients may also depend on host factors controlling the immune response.

Multicentric Castleman's disease and Kaposi's sarcoma in a cyclosporin treated, HIV-1 negative patient: case report

Background

Multicentric Castleman's disease (MCD) is a rare disease, but is more frequent in AIDS patients. MCD has only been reported twice before in patients receiving immunosuppressive therapy after renal transplantation, and never in patients receiving immunosuppressive therapy without transplantation. About half of the cases of MCD are human herpesvirus 8 (HHV8) – related, in contrast to Kaposi's sarcoma, a more common complication arising after immunosuppression, where the virus is found in virtually all cases.

Case presentation

We report a HIV-1 negative, non-transplant patient who developed HHV8-associated multicentric Castleman's disease and Kaposi's sarcoma after 17 years of immunosuppressive treatment with cyclosporin A for a minimal change nephropathy. Chemotherapy with liposomal doxorubicin resolved both symptoms of multicentric Castleman's disease and Kaposi's sarcoma in this patient. A concomitant decline in the HHV8 viral load in serum/plasma, as determined by a quantitative real-time PCR assay, was observed.

Conclusions

Multicentric Castleman's disease can be a complication of cyclosporin A treatment. Both multicentric Castleman's disease and Kaposi's sarcoma in this patient were responsive to liposomal doxorubicin, the treatment of choice for Kaposi's sarcoma at the moment, again suggesting a common mechanism linking both disorders, at least for HHV8-positive multicentric Castleman's disease and Kaposi's sarcoma.

HHV8 viral load measurements can be used to monitor effectiveness of therapy.

Risk factors for high anti-HHV-8 antibody titers (> or =1:51,200) in black, HIV-1 negative South African cancer patients: a case control study

BACKGROUND

Infection with human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the necessary causal agent in the development of Kaposi's sarcoma (KS). Infection with HIV-1, male gender and older age all increase risk for KS. However, the geographic distribution of HHV-8 and KS both prior to the HIV/AIDS epidemic and with HIV/AIDS suggest the presence of an additional co-factor in the development of KS.

METHODS

Between January 1994 and October 1997, we interviewed 2576 black in-patients with cancer in Johannesburg and Soweto, South Africa. Blood was tested for antibodies against HIV-1 and HHV-8 and the study was restricted to 2191 HIV-1 negative patients. Antibodies against the latent nuclear antigen of HHV-8 encoded by orf73 were detected with an indirect immunofluorescence assay. We examined the relationship between high anti-HHV-8 antibody titers (> or =1:51,200) and sociodemographic and behavioral factors using unconditional logistic regression models. Variables that were significant at p = 0.10 were included in multivariate analysis.

RESULTS

Of the 2191 HIV-1 negative patients who did not have Kaposi's sarcoma, 854 (39.0%) were positive for antibodies against HHV-8 according to the immunofluorescent assay. Among those seropositive for HHV-8, 530 (62.1%) had low titers (1:200), 227 (26.6%) had medium titers (1:51,200) and 97 (11.4%) had highest titers (1:204,800). Among the 2191 HIV-1 negative patients, the prevalence of high anti-HHV-8 antibody titers (> or =1:51,200) was independently associated with increasing age (p-trend = 0.04), having a marital status of separated or divorced (p = 0.003), using wood, coal or charcoal as fuel for cooking 20 years ago instead of electricity (p = 0.02) and consuming traditional maize beer more than one time a week (p = 0.02; p-trend for increasing consumption = 0.05) although this may be due to chance given the large number of predictors considered in this analysis.

CONCLUSIONS

Among HIV-negative subjects, patients with high anti-HHV-8 antibody titers are characterized by older age. Other associations that may be factors in the development of high anti-HHV-8 titers include exposure to poverty or a low socioeconomic status environment and consumption of traditional maize beer. The relationship between these variables and high anti-HHV-8 titers requires further, prospective study.

Use of HIV protease inhibitors to block Kaposi's sarcoma and tumour growth

HIV protease inhibitors are antiretroviral drugs that block the enzyme required for production of infectious viral particles. Although these agents have been designed to selectively bind to the catalytic site of HIV protease, evidence indicates that other cellular and microbial enzymes and pathways are also affected. It has been reported that patients treated with highly active anti-retroviral therapy (HAART) containing a protease inhibitor may be at reduced risk of Kaposi's sarcoma (KS) and some types of non-Hodgkin lymphomas; some disease regressions have also been described. Here we review recent data showing that several widely used protease inhibitors, including indinavir, saquinavir, ritonavir, and nelfinavir, can affect important cellular and tissue processes such as angiogenesis, tumour growth and invasion, inflammation, antigen processing and presentation, cell survival, and tissue remodelling. Most of these non-HIV-related effects of protease inhibitors are due to inhibition of cell invasion and matrix metalloprotease activity, or modulation of the cell proteasome and NFkappaB. These elements are required for development of most tumours. Thus, by direct and indirect activities, protease inhibitors can simultaneously block several pathways involved in tumour growth, invasion, and metastasis. These findings indicate that protease inhibitors can be exploited for the therapy of KS and other tumours that occur in both HIV-infected and non-infected individuals. A multicentre phase II clinical trial with indinavir in non-HIV-associated KS is about to start in Italy.

Correlates of human herpesvirus-8 seropositivity among U.S. military members recently infected with human immunodeficiency virus

BACKGROUND

Human herpesvirus 8 (HHV-8), the cause of Kaposi's sarcoma, is common among HIV-infected persons. The exact route of transmission of HHV-8 in various populations is still debated.

GOAL

The goal was to define the correlates of HHV-8 infection among men recently infected with human immunodeficiency virus.

STUDY DESIGN

Three hundred forty-two HIV-infected U.S. military men were evaluated using a questionnaire regarding potential risk factors and laboratory data, including HHV-8, herpes simplex virus 2 (HSV-2), syphilis, hepatitis B, and hepatitis C serologies.

RESULTS

The seroprevalence of HHV-8 was 32%. HHV-8 was significantly associated with hepatitis B seropositivity (odds ratio [OR], 2.44; 95% confidence interval [CI], 1.5-4.1), and black ethnicity was negatively associated with HHV-8 (OR, 0.6; 95% CI, 0.3-0.9) in the multivariate analysis. HHV-8 was not associated with drug use or hepatitis C seropositivity. Among men who have sex with men (MSM), HHV-8 infection correlated with hepatitis B seropositivity (OR, 2.2; 95% CI, 1.1-4.3) and HSV-2 (OR, 2.6; 95% CI, 1.4-4.9). Among heterosexuals, the correlates of HHV-8 were different; blacks as compared with whites (OR, 0.3; 95% CI, 0.1-0.8) and married versus single status (OR, 0.4; 95% CI, 0.2-0.9) were associated with a lower rate of HHV-8 infection. Among heterosexuals, hepatitis B, HSV-2, and sexual behaviors were not associated with HHV-8.

CONCLUSION

This study suggests that the seroprevalence of HHV-8 is increased in both MSM and heterosexual men with HIV infection, and that the route(s) of HHV-8 acquisition might be different between MSM and heterosexuals.

Human herpesvirus 8: current issues

Although human herpesvirus 8 (HHV-8) is the etiologic agent of Kaposi sarcoma (KS), there are no formal guidelines for the clinical management of HHV-8 infection. In patients infected with human immunodeficiency virus (HIV), highly active antiretroviral therapy (HAART) is the best tool for the prevention of KS. In patients who have undergone transplantation, KS is often managed by curtailing immunosuppressive therapies, despite the potential adverse consequences for graft survival. Interventions related to HHV-8 infection might improve the management of KS in immunocompromised patients. However, knowledge from HHV-8 research cannot yet be translated into clinically useful interventions. Achieving clinical utility will require the commercial development of diagnostic tools currently available only in research settings and the evaluation of potential interventions. Such interventions might include the use of HHV-8 diagnostics to identify patients at high risk and to aid in the early detection of KS, prophylaxis with antiherpes drugs to prevent KS, treatment of KS with antiherpes drugs, and donor/recipient screening for organ transplantation.

Molecular genetics of Kaposi's sarcoma-associated herpesvirus (human herpesvirus-8) epidemiology and pathogenesis

Kaposi's sarcoma had been recognized as unique human cancer for a century before it manifested as an AIDS-defining illness with a suspected infectious etiology. The discovery of Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8, in 1994 by using representational difference analysis, a subtractive method previously employed for cloning differences in human genomic DNA, was a fitting harbinger for the powerful bioinformatic approaches since employed to understand its pathogenesis in KS. Indeed, the discovery of KSHV was rapidly followed by publication of its complete sequence, which revealed that the virus had coopted a wide armamentarium of human genes; in the short time since then, the functions of many of these viral gene variants in cell growth control, signaling apoptosis, angiogenesis, and immunomodulation have been characterized. This critical literature review explores the pathogenic potential of these genes within the framework of current knowledge of the basic herpesvirology of KSHV, including the relationships between viral genotypic variation and the four clinicoepidemiologic forms of Kaposi's sarcoma, current viral detection methods and their utility, primary infection by KSHV, tissue culture and animal models of latent- and lytic-cycle gene expression and pathogenesis, and viral reactivation from latency. Recent advances in models of de novo endothelial infection, microarray analyses of the host response to infection, receptor identification, and cloning of full-length, infectious KSHV genomic DNA promise to reveal key molecular mechanisms of the candidate pathogeneic genes when expressed in the context of viral infection.

Therapy of AIDS-associated Kaposi's sarcoma: targeting pathogenetic mechanisms

Only a small number of the many agents with the potential to inhibit factors known to stimulate KS growth have been tested clinically, and many were investigated at a time when treatment options for HIV infection were relatively ineffective. The failure of some of these agents to induce KS regression may not signify failure to achieve a relevant biologic effect in all cases, but may simply mean that in a neoplasm that expresses a broad array of growth factors, inhibition of a single factor may be insufficient to achieve tumor regression. Moreover, agents that inhibit angiogenesis may be expected to stabilize tumors rather then eradicate them, but tumor stabilization is a difficult endpoint to quantify. In fact, given the redundancy of growth factors believed to be involved in KS development, it is perhaps remarkable that members of several classes of agents (eg, a synthetic retinoid, an MMPI, thalidomide, IL-12) have induced KS regression in a substantial minority of patients. It is likely, however, that drug combinations that target several pathogenetic mechanisms will be more effective than will single drugs in suppressing KS growth. A particular need. especially in the early evaluation of therapies aimed at specific pathogenic targets, is the development of assays to measure specific biologic effects (eg, changes in the activity of signal transduction pathways within tumor biopsy specimens) related to the agent's putative mechanism of action. Greater availability and clinical application of these types of markers of biologic efficacy may speed the identification of potentially active agents that could then be "fast tracked" into larger efficacy trials and combination studies.

Cancer incidence in adolescents and young adults in the United States, 1992-1997

PURPOSE

To examine cancer incidence patterns among adolescents and young adults in the United States.

METHODS

Cancer incidence data from 26 population-based central cancer registries for 1992-1997 were used. Individual cancers were grouped into specific diagnostic groups and subgroups using an integrated classification scheme. The integrated scheme was developed for this study and was based on the most commonly used schemes in population-based epidemiologic studies: Surveillance, Epidemiology, and End Results Program's site groups, International Classification of Childhood Cancer, and International Agency for Research on Cancer's Histological Groups for Comparative Studies. Percent distributions and age-specific incidence rates per million population were computed for adolescents (aged 15-19 years) and young adults (aged 20-24 years) by gender.

RESULTS

The data for 26,010 cancer cases were examined. Among 15-19-year-olds, the five most common cancers were Hodgkin's disease, leukemia, cancer in the brain and other nervous system, bone cancer, and non-Hodgkin's disease. Among 20-24-year-olds, the five most common cancers were Hodgkin's disease, testicular cancer, thyroid cancer, melanoma of the skin, and leukemia. The proportions and rates of the histologic subtypes for most of the common cancers changed with advancing age. For example, among 15-19-year-olds, acute lymphocytic leukemia accounted for approximately 60% of leukemias in males and 50% in females. Among 20-24-year-olds, however, the corresponding percentages of acute lymphocytic leukemia were 37% in males and 31% in females. For ovarian cancer, the germ cell tumor was the most common subtype (54.6% of all ovarian cancers) among 15-19-year-olds. In contrast, ovarian carcinoma was the predominant subtype (70.4%) among 20-24-year-olds. For both age groups, the incidence rates of nodular Hodgkin's disease, melanoma of the skin, and thyroid cancer were significantly greater in females than in males.

CONCLUSIONS

Cancer incidence patterns among adolescents and young adults are distinctive. In these age groups, a transition from predominantly pediatric histologic subtypes to adult subtypes was observed for Hodgkin's disease, leukemia, ovarian cancer, and soft tissue sarcoma. Gender differences were found for Hodgkin's disease, melanoma of the skin, and thyroid cancer.

Relationship of Kaposi sarcoma (KS)-associated herpesvirus viremia and KS disease in Zimbabwe

The relationship between Kaposi sarcoma-associated herpesvirus (KSHV) viremia and KS disease was investigated in 500 subjects who received treatment in Harare, Zimbabwe. Subjects were grouped by results of human immunodeficiency virus (HIV) type 1 serological tests, KS diagnosis, and KS clinical stage. The plasma KSHV DNA concentration was associated with concomitant KS and HIV-1 infection (AIDS-KS; P<.001) and AIDS-KS clinical stage (P=.01). Plasma KSHV DNA levels were greater in AIDS-KS than in matched HIV-1-seronegative KS (P=.04). The plasma KSHV DNA level was not associated with age, sex, systemic symptoms, or CD4+ lymphocyte count. Plasma and peripheral blood mononuclear cell KSHV DNA concentrations were linearly related (r2=.44; P<.001), and the nucleotide sequence of the K1 gene highly variable region was identical in both compartments. These findings provide evidence that KSHV viremia is common in advanced AIDS-KS in Zimbabwe and suggest a relationship between KSHV lytic replication and untreated HIV-1 infection.

Human Herpesvirus 8: Biology and Role in the Pathogenesis of Kaposi's Sarcoma and Other AIDS-related Malignancies

Human herpesvirus type 8, or Kaposi's sarcoma-associated herpesvirus (KSHV), is the only known human g(2) herpesvirus (rhadinovirus) and the most recently discovered tumor virus. KSHV is associated with Kaposi's sarcoma and two other lymphoproliferative disorders in the AIDS setting: primary effusion lymphoma and the plasma cell variant of multicentric Castleman's disease. This review offers an update on the epidemiology and the role of KSHV genes in the development of disease.

Human herpesvirus 8 investigations: a role in the clinical management of Kaposi's sarcoma?

Kaposi's sarcoma (KS) is a vascular tumour associated with infection by human herpesvirus 8 (HHV-8). Most of the recent studies on KS have focused on the epidemiology and molecular biology of HHV-8. However, the contribution of virological investigations into HHV-8 to the clinical management of KS has been poorly evaluated so far. From a diagnostic point of view, HHV-8 currently appears as a useful tool for distinguishing KS from its mimics. Seroconversion to antibodies against HHV-8 may predict the development of KS in susceptible individuals, and reduction of HHV-8 viraemia is associated with therapies effective against KS. Further prospective studies are still required to determine the role of serological or genotypic investigations into HHV-8 in the prevention of KS and in KS response to therapy.

Gene expression profile of AIDS-related Kaposi's sarcoma

BACKGROUND

Kaposi's Sarcoma (KS) is a proliferation of aberrant vascular structures lined by spindle cells, and is caused by a gammaherpes virus (HHV8/KSHV). Its course is aggravated by co-infection with HIV-1, where the timing of infection with HIV-1 and HHV8 is important for the clinical outcome.

METHODS

In order to better understand the pathogenesis of KS, we have analysed tissue from two AIDS-KS lesions, and from normal skin by serial analysis of gene expression (SAGE). Semi-quantitative RT-PCR was then used to validate the results.

RESULTS

The expression profile of AIDS-related KS (AIDS-KS) reflects an active process in the skin. Transcripts of HHV8 were found to be very low, and HIV-1 mRNA was not detected by SAGE, although it could be found using RT-PCR. Comparing the expression profile of AIDS-KS tissue with publicly available SAGE libraries suggested that AIDS-KS mRNA levels are most similar to those in an artificially mixed library of endothelial cells and leukocytes, in line with the description of KS lesions as containing spindle cells with endothelial characteristics, and an inflammatory infiltrate. At least 64 transcripts were found to be significantly elevated, and 28 were statistically downregulated in AIDS-KS compared to normal skin. Five of the upregulated mRNAs, including Tie 1 and sialoadhesin/CD169, were confirmed by semi-quantitative PCR to be elevated in additional AIDS-KS biopsies. Antibodies to sialoadhesin/CD169, a known marker of activated macrophages, were shown to specifically label tumour macrophages.

CONCLUSION

The expression profile of AIDS-KS showed 64 genes to be significantly upregulated, and 28 genes downregulated, compared with normal skin. One of the genes with increased expression was sialoadhesin (CD169). Antibodies to sialoadhesin/CD169 specifically labelled tumour-associated macrophages, suggesting that macrophages present in AIDS-KS lesions belong to a subset of human CD169+ macrophages.

Effect of multiple herpesvirus infections on the progression of HIV disease in a cohort of HIV seroconverters

The effects of herpesviruses infection on the progression of HIV disease remain controversial, with some studies showing accelerated progression and others showing no effect. Furthermore, the effect of concurrent infection with more than one herpesvirus on the progression of HIV disease has never been investigated. To this end, the rates of progression of HIV disease were determined after stratifying for the presence of up to five different herpesvirus infections. The study population consisted of 359 HIV-infected persons for whom the date of seroconversion was estimated (part of the Italian Seroconversion Study). One serum sample from each participant was tested for antibodies to five herpesviruses: HSV-2, CMV, HHV-6, HHV-7, and HHV-8. Univariate analysis showed that HSV-2 and HHV-8 were significantly associated with progression to AIDS, yet when adjusting for age at HIV seroconversion and for the presence of the other herpesvirus infections, only HHV-8 infection showed a significant association. The age-adjusted risk of progression to AIDS with Kaposi's sarcoma increased with the number of herpesvirus infections and was significant in individuals with four infections. The risk of progression to AIDS without Kaposi's sarcoma also increased with the number of infections, although not significantly. Similar results were found when considering CD4+ cell count <200 x 10(6) cells/L as the endpoint. Concurrent infection with more than one herpesvirus does not appear to have a significant effect on the course of HIV disease, except for the known association between HHV-8 and Kaposi's sarcoma. However, even after excluding Kaposi's sarcoma from the AIDS-defining endpoints, a slightly increased risk for participants with four herpesvirus infections remained.

Kaposi's sarcoma-like tumors in a human herpesvirus 8 ORF74 transgenic mouse

The product of human herpesvirus 8 (HHV-8) open reading frame 74 (ORF74) is related structurally and functionally to cellular chemokine receptors. ORF74 activates several cellular signaling pathways in the absence of added ligands, and NIH 3T3 cells expressing ORF74 are tumorigenic in nude mice. We have generated a line of transgenic (Tg) mice with ORF74 driven by the simian virus 40 early promoter. A minority (approximately 30%) of the Tg mice, including the founder, developed tumors resembling Kaposi's sarcoma (KS) lesions, which occurred most typically on the tail or legs. The tumors were highly vascularized, had a spindle cell component, expressed VEGF-C mRNA, and contained a majority of CD31(+) cells. CD31 and VEGF-C are typically expressed in KS. Tumors generally (but not always) occurred at single sites and most were relatively indolent, although several mice developed large visceral tumors. ORF74 was expressed in a minority of cells in the Tg tumors and in a few other tissues of mice with tumors; mice without tumors did not express detectable ORF74 in any tissues tested. Cell lines established from tumors expressed ORF74 in a majority of cells, expressed VEGF-C mRNA, and were tumorigenic in nude mice. The resultant tumors grew rapidly, metastasized, and continued to express ORF74. Cell lines established from these secondary tumors also expressed ORF74 and were tumorigenic. These data strongly suggest that ORF74 plays a role in the pathology of KS and confirm and extend previous findings on the tumorigenic potential of ORF74.

Risk factors for Kaposi's sarcoma in men seropositive for both human herpesvirus 8 and human immunodeficiency virus

OBJECTIVE

To identify risk factors for Kaposi's sarcoma (KS) among men seropositive for both human herpesvirus 8 (HHV-8) and HIV.

DESIGN

Cross-sectional study of 91 HHV-8 seropositive, HIV seropositive men who have sex with men (57 with KS), and 70 controls at lower risk for KS.

METHODS

Patients received clinical evaluations. Blood, oral fluids, semen, rectal brush, rectal swab, and urine were collected, and tests for HHV-8 were performed.

RESULTS

Men with KS were more likely to have HHV-8 DNA in peripheral blood mononuclear cells (PBMC) than men without KS [35.1 versus 5.9%, odds ratio (OR), 8.6, 95% confidence interval (CI), 1.9-39.9]. The prevalence of HHV-8 DNA in oral fluids was similar for the two groups (37.0 versus 32.4%; OR, 1.2; 95% CI, 0.5-3.0). HHV-8 DNA was rarely detected in specimens of other types from these men, or in any specimens from the 70 controls. Among men with KS, HHV-8 DNA in PBMC was associated with new KS lesions (OR, 4.5; 95% CI, 1.4-14.5), and HHV-8 DNA in oral fluids was associated with oropharyngeal KS lesions (OR, 3.1; 95% CI, 1.0-10.1). Men with high HHV-8 antibody titers were more likely to have KS (OR, 9.6; 95% CI, 1.2-78.2), but were less likely to have new KS lesions (OR, 0.2; 95% CI, 0.0-1.1) or HHV-8 DNA in PBMC (OR, 0.2; 95% CI, 0.0-1.6) or oral fluids (OR, undefined; = 0.001).

CONCLUSIONS

In HHV-8- and HIV-seropositive men, HHV-8 DNA is associated with KS. Among men without KS, HHV-8 DNA is most commonly found in oral fluids. High HHV-8 antibody titers may protect against circulating HHV-8 and new KS lesions.

Calibrated real-time PCR assay for quantitation of human herpesvirus 8 DNA in biological fluids

Accurate laboratory tests for the diagnosis of active human herpesvirus 8 (HHV-8) infection are becoming essential to study the pathogenesis of HHV-8-associated tumors and for the clinical management of HHV-8-infected individuals. We have developed a highly sensitive, calibrated quantitative real-time PCR assay for the measurement of cell-free HHV-8 DNA in body fluids, based on the addition of a synthetic DNA calibrator prior to DNA extraction. The calibrator controls each sample for the presence of PCR inhibitors, determines a cutoff value of sensitivity for negative samples, and normalizes positive samples for the efficiency of DNA recovery. The assay shows a wide dynamic range of detection (between 1 and 10(6) viral genome equivalents/reaction) and a high degree of accuracy even in the presence of high amounts (up to 1 micro g) of human genomic DNA. Moreover, the assay has a very high sensitivity (lower detection limit, 10 genome equivalents/ml) and a high degree of reproducibility and repeatability with a coefficient of variation (CV) of <15 and 23%, respectively. Furthermore, the use of the calibrator improves the accuracy of quantitation and decreases the intersample variability (CV, 9 and 6%, respectively). The sensitivity and specificity of the assay were tested with a series of clinical specimens obtained from patients affected by various HHV-8-related diseases, as well as from a wide number of controls. In conclusion, our calibrated real-time PCR assay provides a reliable high-throughput method for quantitation of HHV-8 DNA in clinical and laboratory specimens.

Mechanisms of expression of HHV8, EBV and HPV in selected HIV-associated oral lesions

Opportunistic DNA viruses, particularly members of the herpesvirus family, are frequently the aetiological agents of HIV-associated oral lesions. Oral lesions common to the early phase of the AIDS epidemic, including Kaposi's sarcoma (KS), oral aphthous ulceration, AIDS-associated oral lymphoma, and oral hairy leukoplakia (OHL), have been tested for the prevalence of Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV). While EBV DNA is detected by PCR in all of these lesions, abundant viral replication can only be detected in OHL. In OHL, a novel state of EBV infection has been discovered with concurrent expression of replicative and transforming proteins, with all of these proteins contributing to the development of the lesion. Activation of signalling pathways and up-regulation of the viral receptor, proliferative and antiapoptotic genes by these proteins induce several of the histological features common to OHL, such as acanthosis and hyperproliferation. In contrast to other permissive herpesvirus infections, expression of EBV transforming proteins within the permissively infected OHL tissue enables epithelial cell survival and may enhance viral replication. Detection of KSHV in these HIV-infected individuals has been localized only to their saliva. Replicative and latent KSHV gene products have been detected in association with the development of oral KS lesions. EBV, but not human cytomegalovirus (HCMV), has been detected by PCR in minor salivary gland biopsies of HIV-associated salivary gland disease. Human papillomaviruses (HPV) are associated with oral warts in HIV-positive individuals; a diagnosis that appears to be increasing in frequency in the era of highly active antiretroviral therapy. To date, there appears to be little increase in the incidence of HPV-associated oral cancer. The mechanisms of interaction between HIV and HPV are not fully understood. Expression of viral gene products is clearly important and necessary for the development of multiple AIDS-associated oral lesions.

[Epidemiology of human herpes virus 8 (HHV-8) or the herpes virus associated with Kaposi's sarcoma (KSHV)]

Human herpesvirus 8 (HHV-8), also called Kaposi's sarcoma-associated herpesvirus (KSHV), is not a ubiquitous virus. In countries with a low viral seroprevalence (< 5% in adult general population) as the USA, Northern Europe and Asia, the infection concerns essentially homosexual men. In this latter population, the viral transmission seems to occur during sex. In endemic countries (HHV-8 seroprevalence between 10-70% in the adult general population) as in the Mediterranean basin (Italy, Greece), and Africa (East and Central Africa), men, women and children are infected. In these countries, HHV-8 seroprevalence increases with age and often reaches adult rates before the end of puberty. Viral transmission, in general endemic populations, seems to occur from mother to child and between sibs whereas heterosexual transmission appears to concern essentially groups at risk for sexual transmitted diseases. Saliva is a major reservoir of HHV-8.

Development of real-time NASBA assays with molecular beacon detection to quantify mRNA coding for HHV-8 lytic and latent genes

BACKGROUND

Human herpesvirus-8 (HHV-8) is linked to the pathogenesis of Kaposi's sarcoma (KS), and the HHV-8 DNA load in peripheral blood mononuclear cells (PBMC) is associated with the clinical stage of KS. To examine the expression of HHV-8 in PBMC, four HHV-8 mRNA specific NASBA assays were developed

METHODS

We have developed four quantitative nucleic acid sequence-based amplification assays (NASBA-QT) specifically to detect mRNA coding for ORF 73 (latency-associated nuclear antigen, LANA), vGCR (a membrane receptor), vBcl-2 (a viral inhibitor of apoptosis) and vIL-6 (a viral growth factor). The NASBA technique amplifies nucleic acids without thermocycling and mRNA can be amplified in a dsDNA background. A molecular beacon is used during amplification to enable real-time detection of the product. The assays were tested on PBMC samples of two AIDS-KS patients from the Amsterdam Cohort.

RESULTS

For all four assays, the limit of detection (LOD) of 50 molecules and the limit of quantification (LOQ) of 100 molecules were determined using in vitro transcribed RNA. The linear dynamic range was 50 to 10(7) molecules of HHV-8 mRNA. We found HHV-8 mRNA expression in 9 out of the 10 tested samples.

CONCLUSION

These real-time NASBA assays with beacon detection provide tools for further study of HHV-8 expression in patient material.

Retrospective analysis of HHV-8 viremia and cellular viral load in HIV-seropositive patients receiving interleukin 2 in combination with antiretroviral therapy

The combination of interleukin 2 (IL-2) and antiretroviral therapy (ART) represents an emerging strategy in the treatment of patients infected with HIV. Aside from its immunomodulatory role, however, IL-2 may induce replication of human herpesvirus 8 (HHV-8)/Kaposi sarcoma (KS)–associated herpesvirus. We retrospectively evaluated HHV-8 plasma viremia and cellular load, as well as anti–HHV-8 antibody titers, in sequential samples from 84 patients receiving ART alone or in combination with IL-2. At baseline, HHV-8 plasma viremia was present only in 2 HHV-8–seropositive patients in whom KS subsequently developed during or immediately after termination of IL-2 therapy. The level of viremia increased during follow-up and peaked at the time of the clinical manifestation of KS. Moreover, transient peaks of HHV-8 viremia were temporally associated with administration of IL-2. HHV-8 plasma viremia was never detected in the other 47 patients receiving IL-2 nor in 35 controls treated only with ART. Thus, IL-2 therapy seems safe in most patients infected with both HIV and HHV-8, except for those with detectable HHV-8 viremia, who may not be eligible for IL-2 treatment.

Vascular endothelial growth factor levels in serum do not increase following HIV type 1 and HHV8 seroconversion and lack correlation with AIDS-related Kaposi's sarcoma

The utility of vascular endothelial growth factor (VEGF) concentrations in serum as a predictive marker for AIDS-KS was studied. Sera were obtained from 40 homosexual men who seroconverted for HIV-1 and HHV8 prior to or during their participation in the Amsterdam Cohort Studies (1984-2000). We designed an ELISA to detect VEGF and measured VEGF prior to either infection, at HIV-1 and HHV8 seroconversion, after both infections, at AIDS-KS diagnosis (n = 11), and in the most recently available serum sample. The geometric mean serum VEGF concentration was 81.5 pg/ml in those with AIDS-KS and 80.4 pg/ml in those with AIDS but without KS. Median serum VEGF concentrations did not differ between the time points described above. Higher VEGF concentrations in serum were observed at higher CD4(+) cell counts. Serum concentrations of VEGF were not influenced by HIV-1 or HHV8 infection or by the conditions leading to AIDS-KS. Sequential measurement of VEGF in serum is not expected to contribute to the prediction or therapeutic monitoring of AIDS-KS.

Update on Kaposi's sarcoma and other HHV8 associated diseases. Part 1: epidemiology, environmental predispositions, clinical manifestations, and therapy

Kaposi's sarcoma (KS) is a mesenchymal tumour involving blood and lymphatic vessels. Only recently has the pathogenesis of this extraordinary neoplasm been elucidated. Viral oncogenesis and cytokine-induced growth together with some state of immunocompromise represent important conditions for this tumour to develop. In 1994, a novel virus was discovered and termed human herpesvirus 8 (HHV8), also known as Kaposi's sarcoma-associated herpes virus, which can be found in all types of KS, whether related to HIV or not. In the era of highly active antiretroviral therapy (HAART), the incidence of AIDS-KS has considerably declined, probably due to enhanced immune reconstitution and anti-HHV8-specific immune responses. If HAART is able to prevent spreading of KS, local therapy of KS may become an essential component of patient management. Part 1 of the review covers the epidemiology, environmental predispositions, clinical manifestations, and therapy of KS. Newer treatments such as pegylated liposomal anthracyclines and experimental strategies are discussed. We also present rationales and graduated treatment algorithms for local and systemic therapy in patients with KS to appropriately meet the challenges of this extraordinary neoplasm. Part 2, to be published next month, will summarise recent insights in the pathogenesis of KS and will discuss other HHV8-related diseases such as Castleman's disease and primary effusion lymphoma.

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.

HHV-8 infection: a model for reactivation and transmission

The rapid pace of knowledge about HHV-8 since its discovery has been one of the most exciting aspects of medical virology in the last decade. As outlined in this review, the discovery by Drs Chang and Moore of this virus has opened up a broad field of biology with interesting contrasts between current epidemiological data for Kaposi's sarcoma and the cell biology of this gamma herpesvirus. In particular, we summarise the paucity of virological data supporting genital sites of replication and emphasise detection of HHV-8 in the oropharynx. Hopefully continued study will address many of the critical questions that exist today regarding how this infection is transmitted and acquired.

Kaposi's sarcoma and human herpesvirus 8 infection do not protect HIV-1 infected homosexual men from AIDS dementia complex

OBJECTIVE

To examine the association between Kaposi's sarcoma (KS), human herpes virus 8 (HHV8) and AIDS dementia complex (ADC).

DESIGN

A total of 599 HIV-1 infected homosexual men participated in a prospective cohort study (Amsterdam, 1984-1996).

METHODS

The risk for ADC in patients with prior KS or HHV8 infection was estimated using the Cox proportional hazards method with adjustments for antiretroviral medication and low CD4 cell counts.

RESULTS

Of the 599 participants, 290 (48.4%) had HHV8 antibodies, 99 (16.5%) had KS and 30 (5.0%) had ADC. ADC was diagnosed in 5.2% of participants with KS and 5.0% of those without KS, and in 4.8% of HHV8 seropositive compared to 5.2% seronegative individuals and thus was not associated with KS or HHV8 infection. Using a time-dependent Cox proportional hazards analysis with the date of KS as risk factor, the risk for ADC was 2.7 [95% confidence interval (CI), 0.92-7.96; P = 0.07) and when only definite ADC was considered it was 3.5 (95% CI, 1.00-12.26;P = 0.05). After adjusting for decreases in CD4 cell count and use of medication, the hazards ratio for participants with KS to develop ADC was 2.0 (95% CI, 0.66-5.77; P = 0.23) and 2.6 (95% CI, 0.73-9.12; P = 0.14), respectively. HHV8 seropositivity, adjusted for the same variables, showed a risk for ADC of 0.85 (95% CI, 0.41-1.77;P = 0.66) and for definite ADC 0.69 (95% CI, 0.27-1.73; P = 0.42). The expected neuroprotective effects of antiretroviral medication were observed.

CONCLUSIONS

KS or HHV8 does not significantly influence the risk for developing ADC in a group with a uniform risk for developing KS therefore we recommend caution in searching for a KS-associated or HHV8-derived therapy for ADC.

Prevalence, incidence and correlates of HHV-8/KSHV infection and Kaposi's sarcoma in renal and liver transplant recipients

BACKGROUND

To determine whether the incidence of HHV-8/KSHV infection and the risk of developing KS among organ transplant recipients differ by type of organ transplanted, we calculated the rate of HHV-8/KSHV seroconversion and the risk of developing KS among renal and liver transplant recipients.

METHODS

The study population consisted of renal and liver transplant recipients recruited in two transplant centres in Rome, Italy. Both pre-transplant and post-transplant serum samples were available for all participants. The prevalence of HHV-8/KSHV infection before transplantation was calculated. To determine risk factors for infection, we calculated ORs and 95% CI. Seroconversion rates (i.e. attack rates) after transplantation were also calculated. Differences in attack rates were calculated using a binomial test for proportions.

RESULTS

Of the 130 participants, 21 (16.1%) were HHV-8/KSHV-positive before transplantation. Women were more likely to be infected than men, whereas no difference was observed by type of organ transplanted. Of the 109 initially negative individuals, 13 (11.9%) developed anti-HHV-8/KSHV antibodies after transplantation. The incidence of HHV-8/KSHV infection tended to be higher among liver transplant recipients. Four renal transplant recipients and none of the liver transplant recipients developed KS after transplantation. The risk of KS was higher among recipients who were already HHV-8/KSHV-positive before transplantation.

CONCLUSIONS

HHV-8/KSHV seroconversion rates appear to be higher among liver transplant recipients, compared to renal transplant recipients. However, renal transplant recipients tend to have a higher risk of KS. HHV-8/KSHV reactivation appears to play a greater role on the risk of KS than incident infections.

Is the time from HIV seroconversion a determinant of the risk of AIDS after adjustment for updated CD4 cell counts?

OBJECTIVE

To evaluate the effect of time from seroconversion to a given CD4 cell count on progression to AIDS after that count after adjusting for updated CD4 cell counts.

METHODS

Using pooled data from 19 seroconverter cohorts, we examined the association between the time from a CD4 <500 cells/mm 3, (<350, <200) to the first AIDS-defining event and time from seroconversion to that CD4 threshold. We adjusted for age, gender, exposure category, and HIV test interval in Cox models stratified by cohort. We estimated the residual effect of time from seroconversion, adjusting for updated CD4 cell counts. A cause-specific competing-risks model was then used to evaluate this residual effect on progression to each AIDS-defining disease. Analyses were censored on December 31, 1995.

RESULTS

Of 3825, 3006, and 1804 individuals reaching CD4 thresholds of 500, 350, and 200, respectively, 1274, 1192, and 985, respectively, developed AIDS. We found a significant effect of time from seroconversion on the risk of AIDS even after adjusting for updated CD4 counts. For individuals reaching a CD4 threshold of 350 cells/mm 3, a 1-year increase from seroconversion was associated with an increase in risk of AIDS of 6% (3%-9%) ( p =.01). This effect appeared to be nonlinear. In the first 4 years, a 1-year increase from seroconversion was associated with an 11% increase in the risk of AIDS, but there was no apparent increase in risk after 4 years. The residual effect of time from seroconversion was significantly heterogeneous ( p =.002), with respect to the risk of individual AIDS-defining diseases. Findings were similar for CD4 thresholds of 500 and 200 cells/mm 3, respectively.

CONCLUSIONS

We found a small, statistically significant, residual effect of time from seroconversion on the risk of AIDS. In practical terms, when considering an infected individual's risk of AIDS from a given CD4 cell count, there is little to be gained from knowing the time of seroconversion. However, this effect differs significantly among specific AIDS-defining diseases.

Virologic and immunologic parameters that predict clinical response of AIDS-associated Kaposi's sarcoma to highly active antiretroviral therapy

The purpose of the work was to assess the predictive value of biologic factors on the efficacy of highly active antiretroviral therapy alone or combined with chemotherapy on AIDS-associated Kaposi's sarcoma. Twenty-six AIDS-Kaposi's sarcoma patients who started therapy with protease inhibitors were investigated. No baseline chemotherapy was associated with less severe initial clinical status. Median follow-up was 652 d. The main outcome measures were as follows: best Kaposi's sarcoma clinical response; Kaposi's-sarcoma-associated herpesviral load in peripheral blood mononuclear cells using real-time quantitative polymerase chain reaction (non-detectable if less than 100 copies per microg); human immunodeficiency viral charge in plasma (non-detectable if less than 200 copies per ml); and CD4 lymphocyte count. Time to undetectable Kaposi's-sarcoma-associated herpesviral load, time to undetectable human immunodeficiency viral charge, and time to CD4 >or= 150 per microl were also recorded over time, from 2 mo measurements. Patients were staged according to the AIDS Clinical Trials Group-based tumor, immune, systemic staging system criteria. At baseline, Kaposi's sarcoma was progressive for 25 (96%) of the 26 enrolled patients. Complete or partial response to highly active antiretroviral therapy alone or combined with chemotherapy was achieved in 22 patients (85%). Median time to clinical response was estimated at 251 d. Clinical response was faster in patients without chemotherapy at baseline (p = 0.003) as well as in patients not previously treated with reverse transcriptase inhibitors (p = 0.0012). Using univariable analyses, predictive factors of clinical response were undetectable Kaposi's-sarcoma-associated herpesviremia (p = 0.013), undetectable human immunodeficiency viremia (p = 0.03), and relative variation of CD4 lymphocytes (p = 0.004). Using multivariable analysis, undetectable Kaposi's-sarcoma-associated herpesviremia (p = 0.009) and relative variation of CD4 (p = 0.005) were independently selected as having a predictive value for clinical response. Occurrence of nondetection of either Kaposi's-sarcoma-associated herpesvirus or human immunodeficiency virus was not associated with baseline CD4 value. Kaposi's-sarcoma-associated herpesvirus quantitative viral charge is an independent predictive factor of the efficacy of highly active antiretroviral therapy on AIDS-Kaposi's sarcoma. Our results support immune reconstitution as a mechanism of response of Kaposi's sarcoma to highly active antiretroviral therapy.