Detection of Kaposi's sarcoma-associated herpesvirus in peripheral blood cells in human immunodeficiency virus infection: association with Kaposi's sarcoma, CD4 cell count, and HIV RNA levels

Comparison of Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus viral load in peripheral blood mononuclear cells and oral fluids of HIV-negative individuals aged 3-89 years from Uganda

We previously found that age, sex and malaria were associated with KSHV in individuals from Uganda. In this study, we have evaluated these same factors in relation to EBV in the same specimens. Overall, 74% (oral fluids) and 46% (PBMCs) had detectable EBV. This was significantly higher than observed for KSHV (24% oral fluids and 11% PBMCs). Individuals with EBV in PBMCs were more likely to have KSHV in PBMCs (P = 0.011). The peak age for detection of EBV in oral fluids was 3-5 years while that of KSHV was 6-12 years. In PBMCs, there was a bimodal peak age for detection of EBV (at 3-5 years and 66 + years) while for KSHV there was a single peak at 3-5 years. Individuals with malaria had higher levels of EBV in PBMCs compared to malaria-negative individuals (P = 0.002). In summary, our results show that younger age and malaria are associated with higher levels of EBV and KSHV in PBMCs suggesting malaria impacts immunity to both gamma-herpesviruses.

Antiretroviral Therapy for HIV-Associated Cutaneous Kaposi's Sarcoma: Clinical, HIV-Related, and Sociodemographic Predictors of Outcome

Kaposi's sarcoma (KS) is an AIDS-defining malignancy that can improve or worsen with antiretroviral therapy (ART). We aimed at identifying clinical, HIV-related, and sociodemographic factors associated with either progression or nonprogression (regression or stable disease) of ART-treated HIV-associated KS in patients with limited cutaneous disease. We conducted a prospective cohort study of ART-treated HIV-associated KS cases. Clinical, HIV-related, and sociodemographic variables were collected at baseline, and patients were followed up to determine treatment outcomes. Cox regression, linear mixed effects model, and Spearman's rank correlation were used for analysis. Half (50%) of the study participants had KS regression or stable disease, whereas the other half (50%) had disease progression during the treatment and follow-up period. Among the data analyzed, presence of KS nodules at baseline (hazard ratio = 5.47; 95% confidence interval = 1.32-22.65; p = .02) was an independent predictor of poor treatment outcome. Progressors and nonprogressors were indistinguishable in the changes they experienced in the HIV plasma viral load and CD4 counts as a result of ART. Even when cutaneous presentation is limited, the presence of nodular morphotype KS lesions should be considered an indicator for combined ART plus chemotherapy. Temporal trends in CD4 counts and HIV viral loads did not correlate with treatment outcome in ART-treated HIV-associated KS.

Reactivation and Lytic Replication of Kaposi's Sarcoma-Associated Herpesvirus: An Update

The life cycle of Kaposi’s sarcoma-associated herpesvirus (KSHV) consists of two phases, latent and lytic. The virus establishes latency as a strategy for avoiding host immune surveillance and fusing symbiotically with the host for lifetime persistent infection. However, latency can be disrupted and KSHV is reactivated for entry into the lytic replication. Viral lytic replication is crucial for efficient dissemination from its long-term reservoir to the sites of disease and for the spread of the virus to new hosts. The balance of these two phases in the KSHV life cycle is important for both the virus and the host and control of the switch between these two phases is extremely complex. Various environmental factors such as oxidative stress, hypoxia, and certain chemicals have been shown to switch KSHV from latency to lytic reactivation. Immunosuppression, unbalanced inflammatory cytokines, and other viral co-infections also lead to the reactivation of KSHV. This review article summarizes the current understanding of the initiation and regulation of KSHV reactivation and the mechanisms underlying the process of viral lytic replication. In particular, the central role of an immediate-early gene product RTA in KSHV reactivation has been extensively investigated. These studies revealed multiple layers of regulation in activation of RTA as well as the multifunctional roles of RTA in the lytic replication cascade. Epigenetic regulation is known as a critical layer of control for the switch of KSHV between latency and lytic replication. The viral non-coding RNA, PAN, was demonstrated to play a central role in the epigenetic regulation by serving as a guide RNA that brought chromatin remodeling enzymes to the promoters of RTA and other lytic genes. In addition, a novel dimension of regulation by microPeptides emerged and has been shown to regulate RTA expression at the protein level. Overall, extensive investigation of KSHV reactivation and lytic replication has revealed a sophisticated regulation network that controls the important events in KSHV life cycle.

Identification of Human Herpesvirus 8 Sequences in Conjunctiva Intraepithelial Neoplasia and Squamous Cell Carcinoma of Ugandan Patients

The incidence of squamous cell carcinoma of the conjunctiva is particularly high in sub-Saharan Africa with temporal trends similar to those of Kaposi sarcoma (KS). Human herpesvirus type 8 (HHV8), has not yet been investigated in conjunctiva tumors. In this study biopsies and PBMCs of conjunctiva neoplasia patients along with nonneoplastic conjunctiva tissues have been analyzed for HHV8 sequences by PCR targeting ORF26. All amplimers were subjected to nucleotide sequencing followed by phylogenetic analysis. HHV8 DNA has been identified in 12 out of 48 (25%) HIV-positive, and in 2 out of 24 (8.3%) HIV-negative conjunctiva neoplastic tissues and in 4 out of 33 (12.1%) PBMC samples from conjunctiva neoplasia diseased patients as well as in 4 out of 60 (6.7%) nontumor conjunctiva tissues. The viral load ranged from 1 to 400 copies/10(5) cells. Phylogenetic analysis showed that the majority of HHV8 ORF26 amplimers clustered with subtypes R (n = 11) and B2 (n = 6). This variant distribution is in agreement with that of HHV8 variants previously identified in Ugandan KS cases. The presence of HHV8 in conjunctiva tumors from HIV-positive patients warrants further studies to test whether HHV8 products released by infected cells may have paracrine effects on the growth of conjunctiva lesions.

Differences in Kaposi sarcoma-associated herpesvirus-specific and herpesvirus-non-specific immune responses in classic Kaposi sarcoma cases and matched controls in Sicily

Kaposi sarcoma (KS) might develop because of incompetent immune responses, both non-specifically and specifically against the KS-associated herpesvirus (KSHV). Peripheral blood mononuclear cells from 15 classic (non-AIDS) KS cases, 13 KSHV seropositives (without KS) and 15 KSHV-seronegative controls were tested for interferon-γ T-cell (enzyme-linked immunospot [Elispot]) responses to KSHV-latency-associated nuclear antigen (LANA), KSHV-K8.1 and CMV/Epstein-Barr virus (EBV) peptide pools. The forearm and thigh of each participant was also tested for delayed-type hypersensitivity (DTH) against common recall antigens. Groups were compared with Fisher exact test and multinomial logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI). A KSHV Elispot response was detected in 10 (67%) classic KS cases, 11 (85%) KSHV seropositives (without KS) and two (13%) seronegative controls. All four cases with KSHV-LANA responses had current KS lesions, whereas five of six cases with KSHV-K8.1 responses had no lesions (P = 0.048). No case responded to both LANA and K8.1. Compared with the seronegative controls, the risk for classic KS was inversely related to DTH in the thigh (OR 0.71, 95% CI 0.55-0.94, P = 0.01), directly associated with DTH in the forearm (OR 1.35, 95% CI 1.02-1.80, P = 0.04) and tended to be increased fivefold per KSHV Elispot response (OR 5.13, 95% CI 0.86-30.77, P = 0.07). Compared with KSHV seropositives (without KS), the risk for classic KS was reduced fivefold (OR 0.20, CI 0.03-0.77, P = 0.04) per KSHV response. The CMV/EBV Elispot responses were irrelevant. Deficiency of both KSHV-specific and KSHV-non-specific immunity is associated with classic KS. This might clarify why Kaposi sarcoma responds to immune reconstitution.

AIDS-related Kaposi's sarcoma: epidemiological, diagnostic, treatment and control aspects in sub-Saharan Africa

Until the 1980s, little attention had been accorded to endemic Kaposi's sarcoma (KS), a neoplasm noted in several parts of Southern Europe and the African continent but with relatively slow progression, except in children and young adults. Furthermore, therapeutic approaches based on surgery, radiation and topical treatment were of limited efficacy, mostly used to overcome the disabling and stigmatizing effects of the disease. With the emergence of the HIV/AIDS epidemic, and the profound impact of KS on AIDS-related mortality, the pathogenesis of KS has been better studied, and the realisation that a virus (KS-associated Herpesvirus or Human Herpesvirus 8, or KSHV/HHV-8), combined with immunosuppression and cytokine-induced growth, was responsible for the development of this disease has led to novel therapeutic approaches. These are unfortunately still highly toxic, require careful monitoring, and are expensive, thus limiting their use in most parts of Africa. However, the use of highly active antiretroviral therapy (HAART), which has led to a considerable decline in KS incidence in populations of industrialized countries, constitutes the best hope for the control of this stigmatizing and lethal disease in Africa. Trials comparing different regimens of antiretroviral drugs in combination with systemic chemotherapeutic agents are urgently needed.

Kaposi's sarcoma-associated herpesvirus: clinical, diagnostic, and epidemiological aspects

Kaposi's sarcoma-associated herpesvirus (KSHI) is one of the few viruses proven to be associated with tumorigenesis in humans. Its causal association with all clinical and epidemiological variants of Kaposi's sarcoma (KS) is well established. KSHV is also involved in the pathogenesis of primary effusion lymphoma (PEL) and a subset of multicentric Castleman's disease (MCD). Possible associations of KSHV with other clinical settings have been extensively examined. The findings from several of these studies are contradictory and are yet to be resolved. Concentrated effort over the last decade, since the initial discovery of KSHV, led to the development of several experimental systems that resulted in a better comprehension of the biological characteristics of KSHV and set the stage for the understanding of mechainisms by which diseases are induced by the virus. The development of molecular, histological, and serological tools for KSHV diagnosis allowed researchers to track the transmission and to study the epidemiology of KSHV. These assays have been applied, in particular in ambiguous cases, in order to confirm clinically and pathologically based diagnoses. Here, we review the advances in the clinical, experimental, diagnostic, and epidemiological research of KSHV.

Evidence for both lytic replication and tightly regulated human herpesvirus 8 latency in circulating mononuclear cells, with virus loads frequently below common thresholds of detection

To address whether human herpesvirus 8 (HHV-8) DNA in peripheral blood mononuclear cells (PBMCs) might be the product of latent or lytic infection and to shed light on sporadic detection of HHV-8 DNA in individuals seropositive for the virus, we studied the frequency of infected cells, total virus load, and virus load per infected cell in PBMCs from men coinfected with HHV-8 and human immunodeficiency virus (HIV), some of whom had Kaposi's sarcoma. The low frequencies of infected cells detected (fewer than one per million cells in some individuals) suggest that the prevalence of the virus in circulating leukocytes was underestimated in previous studies that employed more conventional sampling methods (single, small-volume specimens). Mean virus loads ranged from 3 to 330 copies per infected PBMC; these numbers can represent much higher loads in individual lytically infected cells (>10(3) genomes/cell) in mixtures that consist predominantly of latently (relatively few genomes) infected cells. The presence in some subjects of high HHV-8 mean genome copy numbers per infected cell, together with viral DNA being found in plasma only from subjects with positive PBMCs, supports earlier suggestions that the virus can actively replicate in PBMCs. In some individuals, mean virus loads were less than 10 genomes per infected cell, suggesting a tightly controlled purely latent state. HHV-8 genome copy numbers are substantially higher in latently infected cells derived from primary effusion lymphomas; thus, it appears that HHV-8 is able to adopt more than one latency program, perhaps analogous to the several types of Epstein-Barr virus latency.

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.

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.

Human herpesvirus-8 (Kaposi's sarcoma-associated virus) ORF50 increases in vitro cell susceptibility to human immunodeficiency virus type 1 infection

ORF50, an immediate-early gene of human herpesvirus-8 (HHV-8), encodes a transactivating protein necessary for virus reactivation and lytic replication. ORF50 was reported recently to synergize with human immunodeficiency virus type 1 (HIV-1) tat at a post-transcriptional level. To study the effects of these molecular interactions on HIV replication and biology, cellular clones stably transformed with ORF50 were obtained by transfection of cell lines of different origin. These clones were infected subsequently with HIV. Experiments showed that ORF50 enhances HIV replication in T and B cells (Jurkat and BC-3 cells) and induces susceptibility and transient permissiveness in non-susceptible glial (A172) cells. Upregulation of viral receptors and co-receptors did not account for increased sensitivity to HIV infection and therefore the action of ORF50 might be modulated by the intracellular environment. Interestingly, non-susceptible cells transformed with ORF50 showed transient production of HIV particles that could spread to adjacent cells by direct contact. These findings show that HHV-8 ORF50 has an enhancing effect on HIV replication in vitro and suggest that the two viruses might interact in co-infected patients.

Absence of HBV and HCV, HTLV-I and -II, and human herpes virus-8 activation after allogeneic RBC transfusion in patients with advanced HIV-1 infection

BACKGROUND

The Viral Activation Transfusion Study was a prospective, randomized, double-blind comparison of transfusion with WBC-reduced versus non-WBC-reduced RBCs to HIV+ patients. The primary study characterized the effect of transfusion on HIV and CMV activation by monitoring viral load changes. The present study analyzed HBV, HCV, HTLV-I and -II, and human herpes virus-8 (HHV-8) viral load before and after transfusion to evaluate the further hypothesis that global immune stimulation following allogeneic RBC transfusion results in activation and increased viral proliferation of chronic viral infections other than HIV and CMV.

STUDY DESIGN AND METHODS

Baseline samples from 519 to 523 subjects were screened for HBV, HCV, HTLV-I and -II, and HHV-8 infection, and baseline, serial weekly, and quarterly blood samples from infected subjects in the non-WBC-reduced arm were evaluated for changes from baseline in viral nucleic acid and ALT levels.

RESULTS

Seroprevalence of HBV, HCV, HTLV-I and -II, and HHV-8 was 68, 25, 5, and 30 percent, respectively. No significant induction of HBV, HCV, HHV-8, or HTLV-I and -II viral replication following allogeneic transfusion of non-WBC-reduced blood was observed. A significant, albeit small, association was observed between transfusion and ALT.

CONCLUSIONS

Based on these results and our previous finding that no adverse effect on HIV and CMV viral load and disease progression results from allogeneic transfusion, no evidence is found to support the selective use of WBC-reduced blood components for HIV-infected patients.

HIV-1 RNA and viral load

Viral load monitoring has become the standard of care in clinical practice to assess risk for disease progression and to monitor treatment response. Furthermore, viral load monitoring has contributed greatly to the understanding of HIV disease pathogenesis and response to various antiretroviral regimens, and has broadened its applications to include blood bank screening. The assays that are currently available are more sensitive, precise, and robust. There is now a better understanding of their limitations and the clinical scenarios and assay performance issues that result in variations of viral load results.

Human herpesvirus 8, Kaposi's sarcoma, and associated conditions

HHV-8 is a recently identified human herpes virus that can produce tumors, most often in immune compromised hosts. The virus is most closely associated with Kaposi's sarcoma, but is also clearly associated with primary effusion lymphomas and multicentric Castleman's disease. The prevalence of HHV-8 infection varies considerably, but is highest among men who have sex with men and others with histories of sexually transmitted diseases and high numbers of lifetime sexual partners. HHV-8 is shed in saliva, and less commonly in genital secretions. Treatment of HHV-8 associated diseases includes reversal of immune compromise either via discontinuation of immunosuppressives or immune reconstitution via antiretroviral regimens. Specific antiviral drug inhibit HHV-8 replication, and can result in responses in certain HHV-8-associated conditions.

Detection of DNA of lymphotropic herpesviruses in plasma of human immunodeficiency virus-infected patients: frequency and clinical significance

The frequency and clinical significance of detection of DNA of cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), HHV-7, and HHV-8 in plasma were investigated by PCR. The plasma was obtained from 120 selected human immunodeficiency virus (HIV)-infected patients, of whom 75 had AIDS-related manifestations, 32 had primary HIV infection (PHI), and 13 had asymptomatic infections. Nested PCR analysis revealed that none of the lymphotropic herpesviruses tested were found in patients with PHI, in asymptomatic HIV-positive individuals, or in HIV-negative controls. By contrast, DNA of one or more of the viruses was found in 42 (56%) of 75 patients with AIDS-related manifestations, including CMV disease (CMV-D) or AIDS-related tumors. The presence of CMV DNA in plasma was significantly associated with CMV-D (P < 0.001). By contrast, EBV detection was not significantly associated with AIDS-related lymphomas (P = 0.31). Interestingly, the presence of HHV-8 DNA in plasma was significantly associated with Kaposi's sarcoma (KS) disease (P < 0.001) and with the clinical status of KS patients (P < 0.001). CMV (primarily), EBV, and HHV-8 were the viruses most commonly reactivated in the context of severe immunosuppression (P < 0.05). In contrast, HHV-6 and HHV-7 infections were infrequent at any stage of disease. In conclusion, plasma PCR was confirmed to be useful in the diagnosis of CMV-D but not in that of tumors or other conditions possibly associated with EBV, HHV-6, and HHV-7. Our findings support the hypothesis of a direct involvement of HHV-8 replication in KS pathogenesis, thus emphasizing the usefulness of sensitive and specific diagnostic tests to monitor HHV-8 infection.

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

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

Viral load of human herpesvirus 8 in peripheral blood of human immunodeficiency virus-infected patients with Kaposi's sarcoma

Viral load is an important marker of activity of viral diseases for a number of viruses. We wished to evaluate whether the viral load of human herpesvirus 8 (HHV-8) in peripheral blood was a consistent feature of Kaposi's sarcoma (KS) patients and whether the viral load correlated with human immunodeficiency virus (HIV) RNA levels, CD4 counts, and/or the HHV-8 seroreactivity. Fifty-four consecutive plasma samples from 14 patients with KS were evaluated for HHV-8 viral load by quantitative real-time PCR. Samples were analyzed at the start of highly active antiretroviral therapy (HAART) and at different intervals during treatments. The median HHV-8 DNA load before HAART treatment was 8,998 (ranging from 170 to 40,100) copies/ml and 12,270 (ranging from 40 to 142,575) copies/ml during HAART. There were both increasing and decreasing trends. There was an association between HHV-8 DNA and HIV RNA viral loads (odds ratio [OR] = 5.40; 95% confidence interval [95% CI], 1.54 to 18.98) and between HHV-8 viral load and CD4 cell counts (OR = 7.24; 95% CI, 1.30 to 40.35). High HHV-8 viral load was also correlated with the titers of antibodies to the lytic HHV-8 antigen detected with immunofluorescence (P < 0.01), but not with antibodies to the latent HHV-8 antigen. In conclusion, we found that HHV-8 viremia in KS is associated with HIV viral load, CD4 cell counts, and lytic HHV-8 serological reactivity. HHV-8 viral load monitored by real time PCR might be useful for determination HHV-8 viral load during the follow-up of KS patients.

HHV-8 infection in patients with AIDS-related Kaposi's sarcoma in Brazil

The aims of the present study were to determine the prevalence of human herpesvirus type 8 (HHV-8) in HIV-positive Brazilian patients with (HIV+/KS+) and without Kaposi's sarcoma (HIV+/KS-) using PCR and immunofluorescence assays, to assess its association with KS disease, to evaluate the performance of these tests in detecting HHV-8 infection, and to investigate the association between anti-HHV-8 antibody titers, CD4 counts and staging of KS disease. Blood samples from 66 patients, 39 HIV+/KS+ and 27 HIV+/KS-, were analyzed for HHV-8 viremia in peripheral blood mononuclear cells by PCR and HHV-8 antigenemia for latent and lytic infection by immunofluorescence assay. Positive samples for latent nuclear HHV-8 antigen (LNA) antibodies were titrated out from 1/100 to (1/4)09,600 dilution. Clinical information was collected from medical records and risk behavior was assessed through an interview. HHV-8 DNA sequences were detected by PCR in 74.3% of KS+ patients and in 3.7% of KS- patients. Serological assays were similar in detecting anti-LNA antibodies and anti-lytic antigens in sera from KS+ patients (79.5%) and KS- patients (18.5%). HHV-8 was associated with KS whatever the method used, i.e., PCR (odds ratio (OR) = 7.4, 95% confidence interval (CI) = 2.16-25.61) or anti-LNA and anti-lytic antibodies (OR = 17.0, 95%CI = 4.91-59.14). Among KS+ patients, HHV-8 titration levels correlated positively with CD4 counts (rho 0.48, P = 0.02), but not with KS staging. HHV-8 is involved in the development of KS in different geographic areas worldwide, as it is in Brazil, where HHV-8 is more frequent among HIV+ patients. KS severity was associated with immunodeficiency, but no correlation was found between HHV-8 antibody titers and KS staging.

Evaluation of the human herpesvirus 8 DNA load in blood and Kaposi's sarcoma skin lesions from AIDS patients on highly active antiretroviral therapy

OBJECTIVES

To evaluate the human herpesvirus 8 (HHV-8) DNA load in peripheral blood mononuclear cells (PBMC) and Kaposi's sarcoma (KS) skin lesions of subjects with AIDS and to correlate these measures with the tumour load.

DESIGN

Assessment of the HHV-8 DNA load was performed every 3 months in PBMC and every 6 months in KS skin lesions from seven subjects with AIDS who were receiving highly active antiretroviral therapy (HAART).

METHODS

The HHV-8 DNA load was determined by a quantitative-competitive PCR using 0.2 microg of DNA from PBMC or KS skin biopsies. Staging of KS was performed by evaluating the number and type of cutaneous KS lesions.

RESULTS

The three subjects with the most extensive and active (nodular) KS had the highest amounts of HHV-8 DNA in KS skin lesions and the lowest CD4 T cell counts (< 200 x 10(6)/l). In contrast, the four other subjects with regressing KS while on HAART had a low viral load in their KS lesions. All but one subject who also had multicentric Castleman's disease had low amounts of HHV-8 DNA in PBMC.

CONCLUSION

There is a strong relationship between the tumour burden and the HHV-8 viral load in KS skin lesions of subjects with AIDS, reinforcing the causal link between this herpesvirus and AIDS-related KS.

Autocrine nerve growth factor is essential for cell survival and viral maturation in HHV-8-infected primary effusion lymphoma cells

High levels of nerve growth factor (NGF) are found in sera from individuals infected with human herpesvirus 8 (HHV-8). BC-1 and BCBL-1 cells are primary effusion lymphoma-derived B-cell lines; BC-1 cells are infected by HHV-8 and the Epstein-Barr virus (EBV), and BCBL-1 cells are infected only by HHV-8. Both cells express NGF receptors and produce NGF, whereas RAMOS cells (a B-cell line that is negative for HHV-8 and EBV) express NGF receptors but do not produce detectable NGF. Neutralization of endogenous NGF results in cell growth inhibition and apoptosis in BCBL-1 cells and, to a minor extent, in BC-1 cells. When the HHV-8 lytic cycle is induced in BCBL-1 cells by tetradecanoyl phorbol acetate (TPA), an initial reduction of endogenous NGF production is observed, and many cells undergo apoptosis. However, at 48 hours, TPA-treated cells produce significantly more NGF than untreated controls, and a subsequent recovery of cell viability is observed. Consistent with this finding, the addition of exogenous NGF or anti-NGF antibodies to TPA-treated cells reduces or increases, respectively, the rate of apoptosis in response to TPA. Finally, electron microscopy of TPA-treated BCBL-1 cells shows that the addition of exogenous NGF increases the number of cells producing and releasing complete virions as compared with the controls (25% versus 5%). On the contrary, NGF neutralization leads to the production of defective viral progeny in about 2% of cells. These data indicate that NGF is essential for both cell survival and virus maturation in HHV-8-infected cell lines. (Blood. 2000;95:2905-2912)

Viral Load Monitoring in HIV Infection

Measurement of HIV-1 viral load is now an accepted part of clinical practice for the determination of clinical prognosis and antiretroviral effectiveness in HIV infection. Consensus guidelines have been published on the appropriate use of this testing. Furthermore, recent advances in molecular technology have improved the sensitivity and reproducibility of viral load assays, and these improved assays have provided new insight into the pathogenesis of HIV disease. This article reviews new issues affecting viral load quantification, including viral subtypes, sex, compartmental differences, and other covariables.

Human herpesvirus 8 (Kaposi's sarcoma-associated herpesvirus) infection in men receiving treatment for HIV-1 infection

OBJECTIVE

To determine the prevalence of human herpesvirus 8 (HHV-8) infection in men treated for HIV-1 infection in Denver, Colorado.

DESIGN

Cross-sectional analysis

METHODS

Blood samples were obtained from 216 HIV-1-infected men. Antibody to latency-associated nuclear antigen (LANA) was detected by an immunofluorescent assay and the presence of HHV-8 in peripheral blood mononuclear cells (PBMC) was detected by polymerase chain reaction amplification.

RESULTS

Among HIV-1-infected men who did not have Kaposi's sarcoma (KS), prevalence of HHV-8 infection was 46% (95% confidence interval [CI], 0.39-0.52). LANA seropositivity was common both among subjects with KS and subjects without KS (69% versus 42%; p = .06), but detection of HHV-8 DNA in peripheral blood was strongly associated with a diagnosis of KS (44% versus 10%; p = .001). In a univariate analysis of study subjects without KS, neither the odds of LANA seropositivity nor detection of HHV-8 DNA in PBMC was significant for CD4+ lymphocyte count, HIV-1 virus load, the use of three drug antiretroviral regimens or the prior occurrence of non-KS AIDS-related conditions.

CONCLUSION

Although antibodies to HHV-8 are common among HIV-1-infected men, detection of HHV-8 DNA in PBMC is uncommon and is associated with a diagnosis of Kaposi's sarcoma.