Quantitation of cell-free and cell-associated Kaposi's sarcoma-associated herpesvirus DNA by real-time PCR

Compartmentalized T cell profile in the lungs of patients with HIV-1-associated pulmonary Kaposi sarcoma

Pulmonary Kaposi sarcoma (pKS) caused by Human herpesvirus 8 (HHV-8) is a devastating form of KS in patients with advanced acquired immunodeficiency syndrome (AIDS) and is associated with increased morbidity and mortality. Blood T cells play a central role in the response of HIV-1 and HHV-8. However, little information is available on T cells in the alveolar space of HIV-1-associated pKS patients.Therefore, we examined CD8+ and CD4+ T cells in the alveolar space in comparison with the blood of patients with pKS. We recruited 26 HIV-1 positive patients with KS, including 15 patients with pKS. Bronchoalveolar lavage (BAL) cells and blood mononuclear cells were analyzed for T cell memory phenotypes, surface markers associated with exhaustion, and intracellular cytokine staining (ICS) using flow cytometry. HIV-1 and HHV-8 viral loads were measured in plasma by quantitative PCR.BAL T cells showed reduced inflammatory capacities and significantly diminished polyfunctionality compared to blood T cells from patients with pKS. This was not accompanied by increased expression of exhaustion markers, such as TIM-3 and PD-1.More importantly, we found a negative correlation between the production of MIP1-β and TNF-α in T cells in BAL and blood, indicating compartmentalised immune responses to pKS and accentuated chronic HIV-1/HHV-8 pathogenesis via T cells in the lungs of people with pKS.

Cytomegalovirus, Epstein-Barr virus and human herpesvirus 8 salivary shedding in HIV positive men who have sex with men with controlled and uncontrolled plasma HIV viremia: a 24-month longitudinal study

Background

This longitudinal study described Cytomegalovirus (CMV) DNA, Epstein-Barr (EBV) DNA and human herpesvirus 8 (HHV-8) DNA asymptomatic salivary shedding in HIV-positive men who have sex with men (MSM). We aimed to 1-analyze frequency and persistence of herpesvirus shedding, 2-correlate herpesvirus positivity and HIV viroimmunological parameters and 3-assess the association between HIV-RNA suppression and herpesvirus replication.

Methods

Herpesvirus DNA was tested with an in-house real-time PCR in 2 salivary samples obtained at T0 and T1 (24 months after T0). HIV-RNA was evaluated in the 24 months prior to T0 and in the 24 months prior to T1; MSM were classified as successfully suppressed patients (SSPs), viremic patients (VPs) and partially suppressed patients (PSPs). EBV DNA load was classified as low viral load (EBV-LVL, value ≤10,000 copies/ml) and as high viral load (EBV-HVL,> 10,000 copies/ml). Mann-Whitney U test tested the difference of the median between groups of patients. Chi-squared test and Fisher’s exact test compared categorical variables according to the frequencies. Kruskal-Wallis test compared continuous data distributions between levels of categorical variables.

Results

Ninety-two patients (median CD4+ count 575 cells/mm3, median nadir 330 CD4+ cells/mm3) were included: 40 SSPs,33 VPs and 19 PSPs. The more frequently single virus detected was EBV, both at T0 and at T1 (in 67.5 and 70% of SSPs, in 84.8 and 81.8% of VPs and in 68.4 and 73.7% of SPSs) and the most frequently multiple positivity detected was EBV + HHV-8. At T1, the percentage of CMV positivity was higher in VPs than in SSPs (36.4% vs 5%, p < 0.001), the combined shedding of HHV-8, CMV and EBV was present only in VPs (15.1%, p = 0.01 respect to SSPs) and no VPs confirmed the absence of shedding found at T0 (vs 17.5% of SSPs, p = 0.01). EBV-HVL was more frequent in VPs than in SSPs: 78.6% at T0 (p = 0.03) and 88.9% at T1 (p = 0.01).

Conclusions

The relationship between uncontrolled plasma HIV viremia and CMV, EBV, and HHV-8 shedding is multifaceted, as demonstrated by the focused association with EBV DNA load and not with its frequency and by the persistent combined detection of two oncogenic viruses as EBV and HHV-8 regardless of HIV virological control.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3591-x) contains supplementary material, which is available to authorized users.

Relationship of vitamin D insufficiency to AIDS-associated Kaposi's sarcoma outcomes: retrospective analysis of a prospective clinical trial in Zimbabwe

OBJECTIVES

The prevalence of vitamin D insufficiency in Africans with AIDS-associated Kaposi sarcoma (AIDS-KS) and the role of vitamin D in AIDS-KS progression are unknown. We hypothesized that a high prevalence of vitamin D deficiency would be found in Zimbabweans with AIDS-KS and that low baseline vitamin D would correlate with progression of AIDS-KS.

METHODS

Ninety subjects were enrolled in a prospective pilot study investigation of the effect of antiretroviral therapy in the treatment of AIDS-KS in Harare, Zimbabwe. Co-formulated abacavir, lamivudine, and zidovudine was initiated; chemotherapy was provided at the discretion of the provider. Participants were followed for 96 weeks. 25-Hydroxyvitamin D was measured in stored specimens collected at study entry. The relationship between vitamin D and clinical response was described by odds ratio and 95% confidence interval.

RESULTS

Samples were available for 85 participants; 45 (53%) subjects had inadequate (<75 nmol/l) 25-hydroxyvitamin D. HIV-1 RNA was significantly higher among those with insufficient vitamin D (4.7 vs. 4.5 log, p = 0.04). Tumor response, survival, and KS-IRIS were not associated with vitamin D (p ≥ 0.3).

CONCLUSIONS

Vitamin D insufficiency was common among Zimbabweans with AIDS-KS but not associated with outcomes after initiation of antiretroviral therapy.

STAT3 activation by KSHV correlates with IL-10, IL-6 and IL-23 release and an autophagic block in dendritic cells

Kaposis's sarcoma associated herpesvirus (KSHV) has been reported to infect, among others, monocytes and dendritic cells DCs impairing their function. However, the underlying mechanisms remain not completely elucidated yet. Here we show that DC exposure to active or UV-inactivated KSHV resulted in STAT3 phosphorylation. This effect, partially dependent on KSHV-engagement of DC-SIGN, induced a high release of IL-10, IL-6 and IL-23, cytokines that in turn might maintain STAT3 in a phosphorylated state. STAT3 activation also correlated with a block of autophagy in DCs, as indicated by LC3II reduction and p62 accumulation. The IL-10, IL-6 and IL-23 release and the autophagic block could be overcome by inhibiting STAT3 activation, highlighting the role of STAT3 in mediating such effects. In conclusion, here we show that STAT3 activation can be one of the molecular mechanisms leading to KSHV-mediated DC dysfunction, that might allow viral persistence and the onset of KSHV-associated malignancies.

Immune reconstitution inflammatory syndrome of Kaposi's sarcoma in an HIV-infected patient

We present a case of Kaposi's sarcoma-related immune reconstitution inflammatory syndrome in an HIV-infected patient who developed fever, worsening pulmonary infiltrates with respiratory distress, and progression of skin tumors at the popliteal region and thigh that resulted in limitation on movement of the right knee joint at 3.5 months following a significant increase of CD4 count after combination antiretroviral therapy.

KSHV DNA viremia correlates with low CD4+ cell count in Italian males at the time of diagnosis of HIV infection

To evaluate the relevance and the virological and immunological markers of Kaposi sarcoma herpesvirus 8 (KSHV) viremia in Italian male patients at the time of diagnosis of infection with HIV-1, 481 men infected with HIV were recruited consecutively. The presence of KSHV DNA was evaluated in peripheral blood mononuclear cells (PBMCs) and in plasma and correlated with demographic and viro-immunological parameters. Seventy-four patients had KSHV DNA detected in PBMCs. By univariate analysis, the presence of KSHV DNA was associated significantly with unprotected homosexual relationships (P=0.003) and it was significantly higher in patients with CD4+ cell <350 (P=0.025). By multivariate analysis, homosexual relationships were associated independently with KSHV DNA in PBMCs (OR: 3.25; 95% CI: 1.1-9.7; P=0.035). Among the 74 patients with KSHV DNA detected in PBMCs, plasma samples from 60 were analyzed and 33 were positive for KSHV DNA. The CD4+ cell counts and percentages were significantly lower in patients with KSHV DNA in both PBMCs and plasma as compared to patients with only KSHV DNA in PBMCs (P=0.006 and P=0.019, respectively). Among the patients with KSHV DNA detected in PBMCs, all 13 patients with CD4+ cells count <200 had detectable levels of KSHV in their plasma. By multivariate analysis adjusted for the epidemiologic and virological parameters, low CD4+ cell count was the only independent variable associated with the presence of KSHV DNA in plasma (OR, 0.001; 95% CI: <0.001-0.001; P=0.03). In HIV-positive antiretroviral therapy-naïve males, KSHV active replication as detected by KSHV DNA in plasma was associated significantly with low CD4+ cell count.

Anal and oral human papillomavirus (HPV) infection in HIV-infected subjects in northern Italy: a longitudinal cohort study among men who have sex with men

Background

A study including 166 subjects was performed to investigate the frequency and persistence over a 6-month interval of concurrent oral and anal Human Papillomavirus (HPV) infections in Human Immunodeficiency Virus (HIV)-infected men who have sex with men (MSM).

Methods

Patients with no previously documented HPV-related anogenital lesion/disease were recruited to participate in a longitudinal study. Polymerase chain reaction (PCR) was performed to detect HPV from oral and anal swabs and to detect Human Herpes Virus 8 (HHV-8) DNA in saliva on 2 separate specimen series, one collected at baseline and the other collected 6 months later. A multivariate logistic analysis was performed using anal HPV infection as the dependent variable versus a set of covariates: age, HIV plasma viral load, CD4+ count, hepatitis B virus (HBV) serology, hepatitis C virus (HCV) serology, syphilis serology and HHV-8 viral shedding. A stepwise elimination of covariates with a p-value > 0.1 was performed.

Results

The overall prevalence of HPV did not vary significantly between the baseline and the follow-up, either in the oral (20.1 and 21.3%, respectively) or the anal specimens (88.6 and 86.3%). The prevalence of high-risk (HR) genotypes among the HPV-positive specimens was similar in the oral and anal infections (mean values 24.3% and 20.9%). Among 68 patients with either a HR, low-risk (LR) or undetermined genotype at baseline, 75% had persistent HPV and the persistence rates were 71.4% in HR infections and 76.7% in LR infections. There was a lack of genotype concordance between oral and anal HPV samples. The prevalence of HR HPV in anus appeared to be higher in the younger patients, peaking (> 25%) in the 43-50 years age group. A decrease of the high level of anal prevalence of all genotypes of HPV in the patients > 50 years was evident. HHV-8 oral shedding was positively related to HPV anal infection (p = 0.0046). A significant correlation was found between the persistence of HHV-8 shedding and HIV viral load by logistic bivariate analysis (Odds Ratio of HHV-8 persistence for 1-log increase of HIV viral load = 1.725 ± 0.397, p = 0.018).

Conclusions

A high prevalence of HPV infection was found in our cohort of HIV-infected MSM, with a negative correlation between anal HPV infection and CD4 cell count.

Molecular detection of herpesviruses

In routine molecular diagnostics, detection of herpesviruses has made a major impact. Infection with herpesviruses is indicated by demonstrating the presence of the virus in selected specimens. Rapid and reliable detection of herpesvirus DNA helps to decrease the lethality as well as the sequelae of herpesvirus infection in patients at risk. This chapter discusses specimen types and both laboratory-developed and commercially available assays useful for molecular detection of herpesviruses. To meet the need for reliable laboratory results, it is advisable to employ maximum automated and standardized kits based on reagents and standards of reproducible high quality. In the routine diagnostic laboratory, introduction of IVD/CE and/or FDA-labeled tests is preferred.

Predictors of immune reconstitution inflammatory syndrome-associated with kaposi sarcoma in mozambique: a prospective study

BACKGROUND

The impact and relevance of immune reconstitution inflammatory syndrome-associated with Kaposi sarcoma (IRIS-KS) has not been assessed in sub-Saharan African countries, where the bulk of HIV-1 and KS-associated herpesvirus (KSHV) coinfection occurs. Understanding the risk factors for developing IRIS-KS would aid in the identification and in the improvement of clinical management for high-risk patients.

METHODS

Sixty-nine consecutive HIV-1 and KSHV coinfected Mozambican adults initiating cART were prospectively followed for development of IRIS-KS over 10 months as part of a larger prospective observational study. Plasma HIV RNA, CD4 counts, anti-KSHV lytic antibodies, and plasma KSHV DNA viral load were assessed at the pre-cART visit and at 4 and 10 months after cART initiation. A survival analysis was performed to assess potential risk factors for developing IRIS-KS.

RESULTS

During the first 10 months of combined antiretroviral therapy (cART), 8 patients (8/69, 11.6%) experienced IRIS-KS at a median time of 13.8 weeks after cART initiation. Multivariate analysis identified 4 independent IRIS-KS predictors: clinical pretreatment KS [hazard ratio (HR) 91.7], detectable plasma KSHV DNA (HR 24.4), hematocrit <30% (HR 26.5), and plasma HIV-1 RNA viral load (HR 34.6 per log viral load increase). Treatment with either cART alone or with a combination of cART and systemic chemotherapy led to partial or complete clinical response in 62.5% (5/8) of IRIS-KS cases.

CONCLUSIONS

This study identified 4 independent predictors of IRIS-KS, which may help to develop screening tools aiding in the identification of patients at high risk of IRIS-KS for whom close clinical supervision is warranted.

Biscoclaurine alkaloid cepharanthine inhibits the growth of primary effusion lymphoma in vitro and in vivo and induces apoptosis via suppression of the NF-kappaB pathway

Primary effusion lymphoma (PEL) is a unique and recently identified non-Hodgkin's lymphoma that was originally identified in patients with AIDS. PEL is caused by the Kaposi sarcoma-associated herpes virus (KSHV/HHV-8) and shows a peculiar presentation involving liquid growth in the serous body cavity and a poor prognosis. As the nuclear factor (NF)-kappaB pathway is activated in PEL and plays a central role in oncogenesis, we examined the effect of a biscoclaurine alkaloid, cepharanthine (CEP) on PEL derived cell lines (BCBL-1, TY-1 and RM-P1), in vitro and in vivo. An methylthiotetrazole assay revealed that the cell proliferation of PEL cell lines was significantly suppressed by the addition of CEP (1-10 microg/ml). CEP also inhibited NF-kappaB activation and induced apoptotic cell death in PEL cell lines. We established a PEL animal model by intraperitoneal injection of BCBL-1, which led to the development of ascites and diffuse infiltration of organs, without obvious solid lymphoma formation, which resembles the diffuse nature of human PEL. Intraperitoneal administration of CEP inhibited ascites formation and diffuse infiltration of BCBL-1 without significant systemic toxicity in this model. These results indicate that NF-kappaB could be an ideal molecular target for treating PEL and that CEP is quite useful as a unique therapeutic agent for PEL.

A 6-aminoquinolone compound, WC5, with potent and selective anti-human cytomegalovirus activity

We identified a 6-aminoquinolone compound, WC5, that inhibits human cytomegalovirus (HCMV) replication with a selectivity index of approximately 500. WC5 also showed activity against drug-resistant HCMV strains. In contrast, it did not significantly affect the replication of human herpesvirus 6 and 8 and was approximately 10-fold less active against murine cytomegalovirus. Thus, WC5 may represent a lead for the development of new, potent, and selective anti-HCMV compounds.

Human herpesvirus 8 acute infection of endothelial cells induces monocyte chemoattractant protein 1-dependent capillary-like structure formation: role of the IKK/NF-kappaB pathway

Human herpesvirus 8 (HHV-8) is considered the causative agent of Kaposi sarcoma, a highly vascularized neoplasm characterized by spindle-shaped cells of endothelial origin and inflammatory cell infiltration. The cell transforming ability of HHV-8 has been associated with the activation of NF-kappaB, a nuclear factor playing a pivotal role in promoting inflammation and cell proliferation; however, little is known about NF-kappaB activation during acute HHV-8 infection. In the present study, we used a recently established in vitro model of HHV-8 acute productive infection in endothelial cells to investigate the effect of HHV-8 on NF-kappaB activity and function. HHV-8 rapidly and potently induced NF-kappaB activity in endothelial cells via stimulation of the IkappaB kinase (IKK). Following IKK activation, HHV-8 selectively triggered the production of high levels of monocyte chemoattractant protein 1 (MCP-1), whereas it did not affect the expression of other NF-kappaB-dependent proinflammatory proteins, including TNF-alpha, IL-8, and RANTES. Deletion of NF-kappaB-binding sites in the MCP-1 enhancer resulted in significant inhibition of HHV-8-induced transcription. Furthermore, MCP-1 production was accompanied by virus-induced capillary-like structure formation at early stages of infection. The results suggest that HHV-8-induced MCP-1 may play an important role in promoting inflammation and pathogenic angiogenesis typical of HHV-8-associated lesions.

Lytic and latent antigens of the human gammaherpesviruses Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus induce T-cell responses with similar functional properties and memory phenotypes

The cellular immunity against Kaposi's sarcoma-associated herpesvirus (KSHV) is poorly characterized and has not been compared to T-cell responses against other human herpesviruses. Here, novel and dominant targets of KSHV-specific cellular immunity are identified and compared to T cells specific for lytic and latent antigens in a second human gammaherpesvirus, Epstein-Barr virus. The data identify a novel HLA-B57- and HLA-B58-restricted epitope in the Orf57 protein and show consistently close parallels in immune phenotypes and functional response patterns between cells targeting lytic or latent KSHV- and EBV-encoded antigens, suggesting common mechanisms in the induction of these responses.

High prevalence of multiple human herpesviruses in saliva from human immunodeficiency virus-infected persons in the era of highly active antiretroviral therapy

Human immunodeficiency virus (HIV) infection is associated with an increased risk for human herpesviruses (HHVs) and their related diseases. Methods for limiting the transmission of HHVs require a better understanding of the prevalence and infectiousness of oral HHVs in HIV-infected patients. We performed quantitative PCR to investigate the prevalence, quantity, risk, and correlates of salivary HHVs from 58 HIV-seropositive individuals in a case control study. HHVs were significantly more prevalent in the salivas of HIV-seropositive persons than in those of the controls (odds ratios [ORs], 4.2 to 26.2; P<or=0.008). In HIV-infected patients, Epstein-Barr virus (EBV), human herpesvirus 8 (HHV-8), cytomegalovirus (CMV), and herpes simplex virus type 1 (HSV-1) were detected in 90%, 57%, 31% and 16% of samples, respectively, compared with 48%, 24%, 2%, and 2%, respectively, of samples from controls. Multiple HHVs were observed in 71% of HIV-seropositive persons and only 16% of controls (OR, 13.0; 95% confidence interval, 5.29 to 32.56). HIV-positive patients had significantly higher EBV loads than HIV-negative persons (P<0.0001). HIV-infected patients with CD4 counts above 200 cells/microl had increased probability for having HHV-8 in saliva (P=0.009) compared with patients whose counts were less than 200. In contrast, HSV-1, EBV, and CMV were detected more often when CD4 counts were low. High salivary HHV loads were detected for those (n=7) with oral lesions. These findings suggest that saliva is a potential risk factor for the acquisition of multiple HHVs, and several host factors may function to accelerate HHV reactivation or replication in patients with HIV infection.

Comparisons between capillary zone electrophoresis and real-time PCR for quantification of circulating DNA levels in human sera

BACKGROUND

Recently, some research results showed that the circulating DNA in serum or plasma had potential for the molecular diagnosis and prognosis of certain cancers. Several methods have been employed for the quantification of circulating DNA. However, the circulating DNA levels obtained by various methods exhibited considerable differences. Additionally, these methods were labor-extensive and time-consuming, and not suitable for the quantification of circulating DNA in numerous samples due to the use of commercial DNA extraction kits for the purification of circulating DNA. We presented a new method for the quantification of circulating DNA in sera by capillary zone electrophoresis (CZE) with laser-induced fluorescence detection (LIF).

METHODS

In the present work, we want to make comparison between CZE-LIF assay and real time PCR for the quantification of circulating DNA levels. Linearity, intra and inter variability of two methods were evaluated.

RESULTS

The intra and inter variability of circulating DNA quantification by real-time PCR were 7.3% and 14.92%, respectively. In CZE assay the intra and inter variability were 4.19% and 6.91%, respectively. The R.S.D. values of the same coated capillary and different coated capillaries were 5.14% and 9.02%, respectively. Our data showed that the circulating DNA levels obtained by two methods had a good correlation. Moreover, we further confirmed that blood samples collection, serum preparation and other treatment procedures had a significant impact on the DNA levels in sera.

CONCLUSION

Our data further illustrated that CZE-LIF is a simple, rapid and sensitive method for the quantification of circulating DNA in human sera, and well suitable for the analysis of a large number of samples in clinical diagnosis.

Effusion and solid lymphomas have distinctive gene and protein expression profiles in an animal model of primary effusion lymphoma

Lymphoma usually forms solid tumours in patients, and high expression levels of adhesion molecules are observed in these tumours. However, Kaposi's sarcoma-associated herpesvirus (KSHV)-related primary effusion lymphoma (PEL) does not form solid tumours and adhesion molecule expression is suppressed in the cells. Inoculation of a KSHV-associated PEL cell line into the peritoneal cavity of severe combined immunodeficiency mice resulted in the formation of effusion and solid lymphomas in the peritoneal cavity. Proteomics using two-dimensional difference gel electrophoresis and DNA microarray analyses identified 14 proteins and 105 genes, respectively, whose expression differed significantly between effusion and solid lymphomas. Five genes were identified as having similar expression profiles to that of lymphocyte function-associated antigen 1, an important adhesion molecule in leukocytes. Among these, coronin 1A, an actin-binding protein, was identified as a molecule showing high expression in solid lymphoma by both DNA microarray and proteomics analyses. Western and northern blotting showed that coronin 1A was predominantly expressed in solid lymphomas. Moreover, KSHV-encoded lytic proteins, including viral interleukin-6, were highly expressed in effusion lymphoma compared with solid lymphoma. These data demonstrate that effusion and solid lymphomas possess distinctive gene and protein expression profiles in our mouse model, and suggest that differences in gene and protein expression between effusion and solid lymphomas may be associated with the formation of effusion lymphoma or invasive features of solid lymphoma. Furthermore, the results obtained using this combination of proteomics and DNA microarray analyses indicate that protein synthesis partly reflects, but does not correlate strictly with, mRNA production.

Possible role of human herpesvirus 8 in the lymphoproliferative disorders in common variable immunodeficiency

Patients who have common variable immunodeficiency (CVID) and granulomatous/lymphocytic interstitial lung disease (GLILD) are at high risk for early mortality and B cell lymphomas. Infection with human herpes virus type 8 (HHV8), a B cell lymphotrophic virus, is linked to lymphoproliferative disorders in people who have secondary immunodeficiencies. Therefore, we determined the prevalence of HHV8 infection in CVID patients with GLILD. Genomic DNA isolated from peripheral blood mononuclear cells was screened by nested- and real time-quantitative PCR (QRT-PCR) for the presence of HHV8 genome. It was positive in 6/9 CVID patients with GLILD (CVID-GLILD), 1/21 CVID patients without GLILD (CVID-control), and no patients receiving intravenous gamma globulin (n = 13) or normal blood donors (n = 20). Immunohistochemistry (IHC) demonstrated expression of the latency-associated nuclear antigen-1 (LANA-1) in the biopsies of the lung, liver, and bone marrow of four patients with CVID-GLILD. One CVID-GLILD patient developed a B cell lymphoma during the course of the study. QRT-PCR demonstrated high copy number of HHV8 genome and IHC showed diffuse staining for LANA-1 in the malignant lymph node. HHV8 infection may be an important factor in the pathogenesis of the interstitial lung disease and lymphoproliferative disorders in patients with CVID.

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.

Human Herpesvirus 8 DNA in Serum During Seroconversion in Allogeneic Bone Marrow Transplant Recipients

To determine the prevalence of human herpesvirus 8 (HHV-8) infection, the rate of HHV-8 seroconversion, and the presence of serum HHV-8 DNA after bone marrow transplantation (BMT), we evaluated sera from 187 Italian BMT donor-recipient pairs. Antibodies to lytic and latent HHV-8 antigens were detected by immunofluorescence. Sera of donor-recipient pairs who seroconverted were examined by real-time polymerase chain reaction (RT-PCR). Before BMT, 24 (13%) of 187 donors and 20 (11%) of 187 recipients were seropositive; after BMT, 28 (15%) of 187 recipients were seropositive. Seroconversion occurred in 19 (11%) of 167 recipients seronegative at baseline: 14 (9%) from 149 seronegative donors and five (28%) from 18 seropositive donors (relative risk of seroconversion with BMT from a seropositive donor = 2.96, 95% confidence interval = 1.21 to 7.25; P = .02, two-sided Fisher's exact test). One donor and two recipients who seroconverted after BMT were positive for HHV-8 by RT-PCR. No HHV-8-related complications were observed after a median follow-up of 6 years. BMT-associated HHV-8 seroconversion is relatively common in seronegative recipients from seropositive donor, but factors other than BMT may also contribute to seroconversion.

Effect of prophylactic valacyclovir on the presence of human herpesvirus DNA in saliva of healthy individuals after dental treatment

Human herpesviruses (HHVs) are ubiquitous pathogens that intermittently reactivate from latency. Transmission is believed to be facilitated by their frequent appearance in saliva. This study sought to understand the factors that influence the appearance of these viruses in saliva by examining the prevalence, pattern, and quantity of all eight HHVs in saliva of immunocompetent adults with a history of recurrent oral herpes simplex virus (HSV) infections following dental treatment and antiviral therapy. Valacyclovir or matched placebo was given (2 g twice on the day of treatment and 1 g twice the following day) to 125 patients in a randomized, double-blind controlled trial. Saliva, collected on the day of dental treatment and 3 and 7 days later, was analyzed using real-time quantitative PCR. At all visits, HHVs coinfected saliva. Over the course of the week, the DNAs of HHV-6 and HHV-7 were detected significantly more often (97% to 99% of patients) than Epstein-Barr virus (EBV; 64.8%), HSV-1 (13.0%), HHV-8 (3.2%), cytomegalovirus (2.4%), HSV-2 (0%), and varicella-zoster virus (0%), irrespective of drug treatment (P < 0.002). Mean genome copy numbers were highest for HSV-1 and HHV-6. Dental treatment did not influence asymptomatic viral shedding patterns. However, valacyclovir treatment resulted in significantly fewer patients shedding EBV at both postoperative visits compared with placebo (P < 0.008). These results suggest that HHVs are simultaneously present in the saliva of healthy adults at levels that could facilitate transmission, and valacyclovir therapy decreases the prevalence of EBV in saliva but has little effect on HHV-6 and HHV-7.

Viral load of human herpesvirus 8 (HHV-8) in the circulatory blood cells correlates with clinical progression in a patient with HHV-8-associated solid lymphoma with aids-associated Kaposi's sarcoma

We encountered a case of a rapidly progressive HHV-8-associated solid lymphoma with AIDS-associated Kaposi's sarcoma (KS). HHV-8 DNA load in whole blood cells was analyzed quantitatively by real-time PCR using amplification of the HHV-8-encoded ORF26 gene. Ours is the first observation that the rapid increase in the HHV-8 viral load (from 1.9x10(4) copies/microg to 1.6x10(6) copies/microg in 40 days) in conjunction with low CD4+ cell counts was accompanied by an accelerated clinical disease progression. The results indicate that the quantity of circulating HHV-8 is measurable with real-time PCR and can provide clinically useful information.

Stimulation of Kaposi's sarcoma-associated herpesvirus viremia during hematopoietic stem cell mobilization with filgrastim

The effects of hematopoietic stem cell (HSC) mobilization on Kaposi's sarcoma-associated herpesvirus (KSHV) were evaluated in three KSHV and human immunodeficiency virus type 1 co-infected subjects. KSHV DNA was not detected in purified CD34+ cell preparations from the period of filgrastim treatment. However, two of 3 subjects had transiently increased cell-free plasma KSHV DNA during filgrastim treatment. Peak plasma KSHV DNA (2,600 and 4,300 copies/mL) occurred on day 4 and declined to below the limit of detection by day 7. These findings suggest that, although CD34+ cell preparations do not have evidence of KSHV infection, HSC mobilization may stimulate KSHV replication in other cellular compartments that contribute to KSHV viremia.

Real-time Fluorescent PCR Techniques to Study Microbial-Host Interactions

This chapter describes how real-time polymerase chain reaction (PCR) performs and how it may be used to detect microbial pathogens and the relationship they form with their host. Research and diagnostic microbiology laboratories contain a mix of traditional and leading-edge, in-house and commercial assays for the detection of microbes and the effects they impart upon target tissues, organs, and systems. The PCR has undergone significant change over the last decade, to the extent that only a small proportion of scientists have been able or willing to keep abreast of the latest offerings. The chapter reviews these changes. It discusses the second-generation of PCR technology-kinetic or real-time PCR, a tool gaining widespread acceptance in many scientific disciplines but especially in the microbiology laboratory.

Immune reconstitution inflammatory syndrome associated with Kaposi sarcoma during potent antiretroviral therapy

Rapidly progressive Kaposi sarcoma (KS) lesions with lymphadenopathy and tissue swelling occurred in a patient during antiretroviral treatment, despite an increased CD4(+) lymphocyte count and decreased HIV-1 level and KS-associated herpesvirus replication, suggesting immune reconstitution inflammatory syndrome. Inflammation resolved coincident with decreases in the CD4(+) lymphocyte count during paclitaxel treatment, whereas KS cleared only after prolonged antiretroviral therapy and chemotherapy.

Inhibition of infection and replication of human herpesvirus 8 in microvascular endothelial cells by alpha interferon and phosphonoformic acid

Infection of endothelial cells with human herpesvirus 8 (HHV-8) is an essential event in the development of Kaposi's sarcoma. When primary microvascular endothelial cells (MECs) were infected with HHV-8 at a low multiplicity of infection, considerable latent replication of HHV-8 occurred, leading to a time-dependent increase in the percentage of virus-infected cells that was accompanied by cellular spindling and growth to a high density with loss of contact inhibition. Only a low percentage of MECs supported lytic replication of HHV-8 and produced infectious virus. Phosphonoformic acid blocked production of infectious virus but did not inhibit the rapid expansion of latently infected MECs. Pretreatment of MECs with alpha interferon (IFN-alpha) prior to infection effectively reduced HHV-8 viral gene expression, latent replication, and production of infectious virus. High levels of the double-stranded RNA activated protein kinase (PKR) were expressed in HHV-8-infected cells, and incubation with IFN-alpha increased PKR expression more in virus-infected cells than in uninfected cells. MECs that were immortalized with simian virus 40 large-T antigen differed from nonimmortalized MECs in their response to infection with HHV-8 and demonstrated that cells with elevated levels of expression of antiviral transcripts expressed viral transcripts at reduced levels. These studies demonstrate that MECs respond to HHV-8 with enhanced expression of cellular antiviral genes and that augmentation of innate antiviral defenses with IFN-alpha is a more effective strategy than inhibition of viral lytic replication to protect MECs from infection with HHV-8 and to restrict proliferation of virus-infected MECs.

Real-time PCR in the microbiology laboratory

Use of PCR in the field of molecular diagnostics has increased to the point where it is now accepted as the standard method for detecting nucleic acids from a number of sample and microbial types. However, conventional PCR was already an essential tool in the research laboratory. Real-time PCR has catalysed wider acceptance of PCR because it is more rapid, sensitive and reproducible, while the risk of carryover contamination is minimised. There is an increasing number of chemistries which are used to detect PCR products as they accumulate within a closed reaction vessel during real-time PCR. These include the non-specific DNA-binding fluorophores and the specific, fluorophore-labelled oligonucleotide probes, some of which will be discussed in detail. It is not only the technology that has changed with the introduction of real-time PCR. Accompanying changes have occurred in the traditional terminology of PCR, and these changes will be highlighted as they occur. Factors that have restricted the development of multiplex real-time PCR, as well as the role of real-time PCR in the quantitation and genotyping of the microbial causes of infectious disease, will also be discussed. Because the amplification hardware and the fluorogenic detection chemistries have evolved rapidly, this review aims to update the scientist on the current state of the art. Additionally, the advantages, limitations and general background of real-time PCR technology will be reviewed in the context of the microbiology laboratory.

Co-detection and discrimination of six human herpesviruses by multiplex PCR-ELAHA

BACKGROUND

Herpesviruses are a significant cause of human morbidity. Traditional approaches to the identification of these viruses require infectious or at least antigenic virus. Multiplex PCR (mPCR) is capable of simultaneously amplifying a range of targets from a single preparation of nucleic acids and when combined with a suitable detection assay, it is capable of discriminating each of the amplicons.

OBJECTIVES

Several methods have been described in the literature, however, they lack one or more significant design features required to suitably control a routinely applied nucleic acid amplification assay. We aimed to design a multiplex herpesvirus PCR that could co-amplify eight human herpesvirus targets plus an internal control (IC) molecule in a single tube.

STUDY DESIGN

Primers were designed to target the DNA polymerase genes of each of the human herpesviruses. Synthetic controls were developed to act as templates for the evaluation of assay sensitivity and specificity and for development of an in-house competitive quantitative PCR. Amplicon was discriminated using a simplified enzyme linked amplicon hybridisation assay (ELAHA).

RESULTS AND CONCLUSIONS

For routine diagnostic use we reduced the number of herpesviral targets from 8 to 6 in order to maintain adequate clinical sensitivity. The ELAHA proved more sensitive than agarose gel electrophoresis. Additionally, 36 cytomegalovirus positive patients were examined with an in-house quantitative PCR-ELAHA which was developed to confirm that that the mPCR's co-detection limit of 10(2) copy of synthetic template per millilitre was relevant for use in detecting virus from clinical samples. The mPCR-ELAHA was then applied to the screening of 174 patient specimens resulting in a specificity of 98% and a sensitivity of 93%. This preliminary study demonstrated that the mPCR-ELAHA was a complete approach to the detection of herpesviruses from a range of clinical samples and disease states.

Human herpesvirus 8 load in matched serum and plasma samples of patients with AIDS-associated Kaposi's sarcoma

Human herpesvirus 8 (HHV-8) (or Kaposi's sarcoma [KS]-associated herpesvirus) is associated with all forms of KS. HHV-8 DNA load in peripheral blood mononuclear cells (PBMCs) of KS patients has been shown to correlate with the clinical stage of the disease. Studies have been done to assess the HHV-8 viral load in different sample types from KS patients and its clinical relevance. This paper describes the design and evaluation of a quantitative real-time (TaqMan) PCR assay for routine diagnosis of HHV-8 infection. The linear dynamic range was 5 to 5 x 10(6) copies of HHV-8 DNA (r(2) > 0.99). The assay is very sensitive, specific, and easily reproducible (less than 2% variability) and can be used for different clinical samples, such as serum, plasma, and PBMCs. The question of which clinical sample, serum or plasma, is preferable for HHV8 DNA testing was addressed, using this newly developed real-time PCR assay. From 85 patients with diagnosed AIDS-KS, matched plasma and serum samples were collected. Of the 85 patients tested, 35 were positive for HHV-8 DNA in both plasma and serum (41%), 8 were positive in serum but not plasma, and 7 had detectable HHV-8 DNA only in plasma. The HHV-8 load was similar in both plasma and serum, and no significant difference was found. However, more inhibition was seen in the plasma samples with the use of a system quality control, seal herpesvirus type 1. Therefore, our results suggest that serum is the preferred material for HHV-8 load testing, since there is less possible hindrance in the amplification than with plasma.

Rhesus monkey rhadinovirus (RRV): construction of a RRV-GFP recombinant virus and development of assays to assess viral replication

Rhesus monkey rhadinovirus (RRV) is a gamma-2-herpesvirus that is closely related to Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8). Lack of an efficient culture system to grow high titers of virus, and the lack of an in vivo animal model system, has hampered the study of KSHV replication and pathogenesis. RRV is capable of replicating to high titers on fibroblasts, thus facilitating the construction of recombinant rhadinoviruses. In addition, the ability to experimentally infect naïve rhesus macaques with RRV makes it an excellent model system to study gamma-herpesvirus replication. Our study describes, for the first time, the construction of a GFP-expressing RRV recombinant virus using a traditional homologous recombination strategy. We have also developed two new methods for determining viral titers of RRV including a traditional viral plaque assay and a quantitative real-time PCR assay. We have compared the replication of wild-type RRV with that of the RRV-GFP recombinant virus in one-step growth curves. We have also measured the sensitivity of RRV to a small panel of antiviral drugs. The development of both the recombination strategy and the viral quantitation assays for RRV will lay the foundation for future studies to evaluate the contribution of individual genes to viral replication both in vitro and in vivo.

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.

Detection and quantitation of Kaposi's sarcoma-associated herpesvirus (KSHV) by a single competitive-quantitative polymerase chain reaction

Kaposi's sarcoma-associated herpesvirus is a novel herpesvirus linked to AIDS-related neoplasms. Currently it is difficult to evaluate the number of virions in viral preparation or in samples obtained from patients with Kaposi's sarcoma (KS), since no protocol for determining the plaque forming units of KSHV exists. We constructed a fragment of a different size than the target viral DNA to carry out a competitive-quantitative PCR. Both fragment and viral DNA were added to a single PCR reaction to compete for the same set of primers. By knowing the amount of the competitor added to the reaction, we could determine the number of viral DNA molecules. We used this assay successfully to detect and quantify KSHV genomes from KS skin biopsies and pleural effusion lymphoma, and from different viral preparations. To date, this is the most convenient and economic method that allows an accurate and fast viral detection/quantitation with a single PCR.

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.

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.

Laboratory diagnosis of human herpesvirus 8 infection in humans

Human herpesvirus 8 (HHV-8) is causally associated with Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease. Serological and molecular biology assays are used to investigate the biology of this virus in different populations and diseases. Serological assays are mainly used to study the prevalence of the viral infection and to predict the diagnosis of Kaposi's sarcoma and other HHV-8-associated cancers. The appearance of antibodies against lytic antigens precedes the appearance of antibodies against latent antigens, probably explaining the lower sensitivity of assays based on latent HHV-8 antigens. The lack of international reference serum panels is presently the major bottleneck for further progress in the field of HHV-8 serology. Molecular biological assays are an absolute requirement for both the diagnosis and the follow-up of HHV-8 infection. Qualitative methods have been particularly useful to elucidate the mode of transmission and the causal association between HHV-8 and HHV-8-associated diseases. Quantitative methods have become an essential tool to monitor the progression of the infection and the effects of antiviral therapies. This review analyzes the performance of the different serological and molecular biological assays available at present. The main conclusion is that more research is needed to define the most useful laboratory tests for the diagnosis of HHV-8 infection and to establish the clinical role of such tests.

Real-time PCR in virology

The use of the polymerase chain reaction (PCR) in molecular diagnostics has increased to the point where it is now accepted as the gold standard for detecting nucleic acids from a number of origins and it has become an essential tool in the research laboratory. Real-time PCR has engendered wider acceptance of the PCR due to its improved rapidity, sensitivity, reproducibility and the reduced risk of carry-over contamination. There are currently five main chemistries used for the detection of PCR product during real-time PCR. These are the DNA binding fluorophores, the 5' endonuclease, adjacent linear and hairpin oligoprobes and the self-fluorescing amplicons, which are described in detail. We also discuss factors that have restricted the development of multiplex real-time PCR as well as the role of real-time PCR in quantitating nucleic acids. Both amplification hardware and the fluorogenic detection chemistries have evolved rapidly as the understanding of real-time PCR has developed and this review aims to update the scientist on the current state of the art. We describe the background, advantages and limitations of real-time PCR and we review the literature as it applies to virus detection in the routine and research laboratory in order to focus on one of the many areas in which the application of real-time PCR has provided significant methodological benefits and improved patient outcomes. However, the technology discussed has been applied to other areas of microbiology as well as studies of gene expression and genetic disease.

Development of a real-time polymerase chain reaction assay for the diagnosis of human herpesvirus-6 infection and application to bone marrow transplant patients

A quantitative real-time PCR assay was developed for human herpesvirus-6 (HHV-6) genome based on TaqMan technology. After choosing a region of interest into the U65-U66 genes of HHV-6 genome, its nucleotide sequence was determined among four HHV-6 strains (one variant A and three variants B) to exclude a variability of sensitivity due to interstrain sequence differences. A plasmid containing HHV-6 target sequences identical to those of reference type viruses was constructed with the aim of standardisation. This HHV-6 genomic quantitation assay has a threshold sensitivity of ten copy equivalents (EqCop) per reaction. In order to test the feasibility of this assay directly on human samples, the technique was applied to the quantitation of HHV-6 genome in 30 blood samples from healthy subjects as well as 31 blood samples and three samples of cerebrospinal fluid (CSF) from 21 bone marrow transplant (BMT) recipients and four patients with a haematological disease but not treated by bone marrow transplantation. HHV-6 load ranged between 0.00015 and 0.0008 equivalent DNA copy number (EqCop) per 100 peripheral blood mononuclear cells (PBMCs) in healthy subjects whereas it ranged from <10 to 7500 EqCop per 100 PBMCs, and from <10 to 415,820 EqCop per 100 microl of whole CSF in patients. The efficacy of treatment with antiherpetic drug was associated with a decrease of the viral load in the CSF of one patient. This method leads to relevant results in term of range of quantitation, sensitivity, and safety against contamination by amplicons, and might constitute a useful tool for the follow-up of BMT recipients particularly in the presence of antiherpetic therapy.

Highly sensitive Taqman PCR detection of Puumala hantavirus

An increasing number of clinical cases of Hantavirus infections have been reported from various regions in Asia, Europe and North America. Hantaviruses (family Bunyaviridae, genus Hantavirus) are enveloped and possess a single-stranded trisegmented RNA genome of negative polarity. Rodents or insectivores are natural hosts of hantaviruses and transmit the virus to humans chiefly by aerosolisation. These viruses are the causative agents of haemorrhagic fever with renal and pulmonary syndromes. In the northeast of France, Puumala hantavirus causes, every year, more than 150 mild forms of haemorrhagic fever with a renal syndrome known as nephropathia epidemica. Serological tests may lack sensitivity for diagnosing early stages of infection and virus isolation is limited because it grows poorly in cell culture. Since reverse transcription (RT)-PCR amplification is an efficient method for detecting viral genomes in patient specimens, we developed an assay using a Taqman probe and compared it with the classical RT-PCR amplification. To achieve this goal, a Puumala strain was grown in Vero E6 cells and RNA extracted from the culture supernatant. We found that the semi-nested RT-PCR detected a minimal amount of 300 TCID(50) mL(-1), while the Taqman PCR allowed detection of less than 10 TCID(50) mL(-1 )and provided a quantitative analysis.

Relationship of human herpesvirus 8 peripheral blood virus load and Kaposi's sarcoma clinical stage

OBJECTIVE

To determine the relationship between human herpesvirus 8 (HHV-8 or Kaposi's sarcoma-associated herpesvirus) peripheral blood virus load and Kaposi's sarcoma (KS) clinical stage.

DESIGN

Blinded, cross-sectional analysis of peripheral blood HHV-8 DNA levels in persons with AIDS-related KS in Harare, Zimbabwe.

METHODS

Subjects were stratified by KS clinical stage. The amount of HHV-8 DNA in plasma and peripheral blood mononuclear cells (PBMC) was determined by quantitative real-time PCR amplification of the HHV-8 open reading frame 26.

RESULTS

Thirty-one HIV-1/HHV-8-coinfected persons were studied: 26 subjects had histologically confirmed KS (one stage II, 11 stage III and 14 stage IV) and five subjects had antibodies to HHV-8 but did not have KS. The age, CD4 lymphocyte count and plasma HIV-1 RNA levels were similar in all groups. HHV-8 DNA was detected in the plasma of all HHV-8-infected subjects (range < 2.4 to 5.2 log10 copies/ml), but plasma HHV-8 DNA levels were not associated with KS disease stage. In contrast, the amount of HHV-8 DNA in PBMC (range < 0.7 to 4.5 log10 copies/microg) was strongly associated with KS clinical stage (P = 0.005). Among stage IV KS cases, there was a linear relationship between plasma and PBMC HHV-8 DNA levels (r2 = 0.42; P = 0.01).

CONCLUSION

The strong association observed between the extent of KS disease and the levels of HHV-8 DNA in PBMC provides further evidence for a relationship between HHV-8 virus load and KS pathogenesis.