HHV-8 Antibodies Research Articles

Human Herpesvirus 8 Seropositivity in Rural Uganda: Maturation of Sero-epidemiological Studies

Human herpesvirus 8 (HHV8, also called Kaposi sarcoma [KS]–associated herpesvirus) is a necessary but insufficient cause of KS [1]. KS is a major public health problem in Africa, where it was endemic before the human immunodeficiency virus (HIV) infection epidemic [2], accounting for up to 18% of cancers in adults in some regions, including parts of Uganda, the Congo, and Rwanda [3]. The disease was known to occur in children [4], intuitively suggesting that HHV8 could be transmitted during childhood. Currently, KS is the most common cancer in men and the second most common cancer in women and children in Uganda, highlighting the dramatic impact of the HIV infection epidemic on KS incidence [5]. The discovery of HHV8 in 1994 [1] and subsequent development of antibody assays with reasonable sensitivity and specificity paved the way for seroepidemiological studies to characterize the distribution of HHV8, the risk factors for infection, and the risk for KS after HHV8 infection. The geographic distribution of HHV8 seropositivity generally parallels that of KS [6, 7]. In sub-Saharan Africa, HHV8 seropositivity is higher (50%–80% in adults) in the eastern and central regions and lower (10%–40% in adults) in western and southern regions [7]. HHV8 infection seroprevalence increases with age in children [8] and is associated with having an HHV8-seropositive mother or family member [9]. HHV8 can be transmitted by transfusion, but the risk is relatively small (2%–3% per transfusion), compared with the risk of community-acquired HHV8 (3% per year) [10, 11]. HHV8 DNA is detected frequently and at high levels in saliva of asymptomatic individuals [12, 13], consistent with the theory that saliva is the dominant conduit of HHV8 spread [14]. Among adults, some studies [15], but not all [16], have shown a modest association of HHV8 seropositivity with age. The association of HHV8 seropositivity with sexual risk factors has been inconsistent [16–20]. The article by Butler et al [21] in this issue of the Journal is the largest population-based study to evaluate epidemiological risk factors of HHV8 infection among children and adults in a country where KS is a major public health problem. Thus far, our knowledge of HHV8 sero-epidemiology in Africa has been derived from studies that suffered from many limitations, including relatively small size and especially the reliance on selected populations, such as children attending hospital clinics [10], commercial sex workers[18, 20], patients attending sexually transmitted disease clinics, or selected occupational groups [17, 19]. These limitations may explain, in part, some of the conflicting associations and/or lingering doubts that even consistent findings can be generalized. Butler et al [21] avoided many of the limitations of prior studies. They studied 1383 children (age. 18 months–13 years) and 1477 adults enrolled from their homes in a rural parish in Uganda. They meticulously documented socioeconomic and behavioral risk factors, including saliva sharing practices, which have not been evaluated before, using questionnaires. In addition, they tested for serologic evidence of other infections (cytomegalovirus [CMV], herpes simplex virus-1 [HSV1], hepatitis B virus [HBV]), and HIV) that have established modes of transmission. They detected HHV8 antibodies using an in-house K8.1 immunoassay with which they have accumulated substantial experience in other studies conducted in Uganda [11]. Among the children, they found that HHV8 infection seroprevalence increased with age, doubling from 15.5% Received 21 October 2010; accepted 19 November 2010. The content is the responsibility of the authors alone and does not necessarily reflect the views or the policies of the United States Department of Health and Human Services or participating entities. Potential conflicts of interest: none reported. Reprints or correspondence: James J. Goedert, MD, 6120 Executive Blvd, Executive Plaza South, Rm 7068, MSC 7248, Rockville, MD 20852 (goedertj@mail.nih.gov). The Journal of Infectious Diseases 2011;203:575–577 Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2011. 1537-6613/2011/2035-0001$15.00 DOI: 10.1093/infdis/jiq094

Substantial regional differences in human herpesvirus 8 seroprevalence in sub‐Saharan Africa: Insights on the origin of the “Kaposi's sarcoma belt”

Equatorial Africa has among the highest incidences of Kaposi's sarcoma (KS) in the world, thus earning the name "KS Belt." This was the case even before the HIV epidemic. To date, there is no clear evidence that HHV-8 seroprevalence is higher in this region but interpretation of the available literature is tempered by differences in serologic assays used across studies. We examined representatively sampled ambulatory adults in Uganda, which is in the "KS Belt," and in Zimbabwe and South Africa which are outside the Belt, for HHV-8 antibodies. All serologic assays were uniformly performed in the same reference laboratory by the same personnel. In the base-case serologic algorithm, seropositivity was defined by reactivity in an immunofluorescence assay or in 2 enzyme immunoassays. A total of 2,375 participants were examined. In Uganda, HHV-8 seroprevalence was high early in adulthood (35.5% by age 21) without significant change thereafter. In contrast, HHV-8 seroprevalence early in adulthood was lower in Zimbabwe and South Africa (13.7 and 10.8%, respectively) but increased with age. After age adjustment, Ugandans had 3.24-fold greater odds of being HHV-8 infected than South Africans (p < 0.001) and 2.22-fold greater odds than Zimbabweans (p < 0.001). Inferences were unchanged using all other serologic algorithms evaluated. In conclusion, HHV-8 infection is substantially more common in Uganda than in Zimbabwe and South Africa. These findings help to explain the high KS incidence in the "KS Belt" and underscore the importance of a uniform approach to HHV-8 antibody testing.

Human herpes virus 8 replication during disseminated tuberculosis in a man with human immunodeficiency virus: a case report

IntroductionHuman herpes virus 8 (HHV-8) is mainly responsible for the development of Kaposi's sarcoma and multicentric Castleman's disease in immunocompromised patients with untreated human immunodeficiency virus. Positive viral loads have been described in cases of Kaposi's sarcoma and multicentric Castleman's disease, with higher values found in the latter. We describe the case of a patient with HIV in whom a high level of HHV-8 replication was detected and who contracted an opportunistic disease other than multicentric Castleman's disease or Kaposi's sarcoma.Case presentationA 25-year-old man of West African origin with HIV complained of asthenia, weight loss, fever, and abdominal pain. Physical examination revealed that the patient had adenopathies and hepatosplenomegaly, but no skin or mucosal lesions were seen. Our first presumptive diagnosis was disseminated tuberculosis. However, since the cultures (sputum, bronchoalveolar lavage, blood, urine and lymph node biopsies) for mycobacteria were negative, the diagnosis was expanded to include multicentric Castleman's disease which was supported by high HHV-8 viral loads in the patient's blood: 196,000 copies/ml in whole blood, 39,400 copies/ml in plasma and 260 copies/10E5 in peripheral blood mononuclear cells. However, the histology and positive polymerase chain reaction assay for Mycobacterium tuberculosis complex of a second lymph node biopsy enabled us to conclude that the patient had disseminated tuberculosis and we started the patient on antituberculosis treatment.We analyzed the HHV-8 deoxyribonucleic acid in two other plasma samples (one from six months earlier and the other was 10 days after the positive test) and both yielded negative results. A search for latent and lytic HHV-8 antibodies confirmed that the patient was seropositive for HHV-8 before this episode.ConclusionWe describe the case of a patient with HIV who tested positive for asymptomatic HHV-8 replication during an opportunistic disease suggestive of multicentric Castleman's disease. The initial analysis was nullified by the diagnosis of a disease that was unrelated to HHV-8. This case report underlines the need to clarify the full clinical meaning and implication of a positive HHV-8 viral load in patients with AIDS. The diagnosis of multicentric Castleman's disease needs to be studied further to determine its sensitivity and specificity. Finally, when faced with the dilemma of urgently starting chemotherapy on a patient whose condition is deteriorating and whose clinical presentation suggests multicentric Castleman's disease, high HHV-8 viral loads should be interpreted with caution and histological analysis of lymph nodes or liver biopsies should be obtained first.

Human Herpesvirus 6 in Hematological Malignancies

Pathogenetic roles of human herpesvirus (HHV)-6 in lymphoproliferative diseases have been of continued interest. Many molecular studies have tried to establish a pathogenic role for HHV-6 in lymphoid malignancies. However, whether HHV-6 plays a role in these pathologies remains unclear, as positive polymerase chain reaction results for HHV-6 in those studies may reflect latent infection or reactivation rather than presence of HHV-6 in neoplastic cells. A small number of studies have investigated HHV-6 antigen expression in pathologic specimens. As a result, the lack of HHV-6 antigen expression on neoplastic cells argues against any major pathogenic role of HHV-6. The role of HHV-6 in childhood acute lymphoblastic leukemia (ALL) has also been of interest but remains controversial, with 2 studies documenting higher levels of HHV-6 antibody in ALL patients, and another 2 large-scale studies finding no significant differences in HHV-6 seroprevalences between ALL patients and controls. Alternatively, HHV-6 is increasingly recognized as an important opportunistic pathogen. HHV-6 reactivation is common among recipients of allogeneic stem cell transplantation (SCT), and is linked to various clinical manifestations. In particular, HHV-6 encephalitis appears to be significant, life-threatening complication. Most HHV-6 encephalitis develops in patients receiving transplant from an unrelated donor, particularly cord blood, typically around the time of engraftment. Symptoms are characterized by short-term memory loss and seizures. Magnetic resonance imaging typically shows limbic encephalitis. Prognosis for HHV-6 encephalitis is poor, but appropriate prophylactic measures have not been established. Establishment of preventive strategies against HHV-6 encephalitis represents an important challenge for physicians involved with SCT.

Evaluation of Parvovirus B19 and Herpesvirus-6 Serology in Brazilian Children with Common B Cell Precursor Acute Lymphoblastic Leukemia

Background. Indirect epidemiologic evidences have suggested that viral infections may represent an important risk factor in the etiological mechanisms of B cell precursor lymphoblastic leukemia (BpALL), specially common-ALL. Parvovirus B19 (PvB19) is associated with aplastic crisis, thrombocytopenia, and congenital anemia. Five studies have reported the concurrent PvB19 infection in pediatric ALL. In a view of the increasing contest about the direct or indirect role of viral infection in ALL, we evaluated the possible associations of PvB19 and herpes virus 6 (HHV-6) in samples from children suffering from hematological disorders in order to estimate the magnitude of risk of association with common-BpALL.Material and Methods. A total of 659 blood samples were randomly selected to perform the serological tests. They were part of diagnostic samples referred to CPq-INCA-Rio de Janeiro, Brazil, from 2002–2006, for diagnostic purpose. Blood samples were exclusively selected from patients in whom samples were taken at the time of the onset of sickness. The diagnosis of BpALL was based on immunophenotyping methods according to EGIL criteria. The presence of serum antibodies for PvB19 and HHV-6 were determinate by enzyme-linked immunosorbent assay. Statistical analyses were conducted using SPSS for Windows 11.0. All p values were two sided; p<0.05 was considered statistically significant.Results. Common-ALL (n=176) and non-leukemic samples (n=107) considered as control group were stratified according to age-groups at diagnosis. Age distribution was:less than 2 years (15.5%);2–6 years-old (46.0%), and7–12 years-old (17.7%).The estimation of associated risk PvB19 IgG+ antibodies with common-BpALL was OR 0.53 95% CI (0.52–0.54); whereas HHV-6 IgG was OR 2.36, 95% CI (1.08–5.17).Conclusions. We find out a higher prevalence of HHV-6 antibodies in patients with common-BpALL, suggesting an association between HHV-6 infection e common-BpALL in Brazilian children. There is a long history in developed countries regarding the role of infections in leukemogenesis process. Further tests are necessary to confirm these results.

Prevalence of Human Herpes Virus-8 and Hepatitis B Virus among HIV Seropositive Pregnant Women Enrolled in the Mother-to-child HIV Transmission Prevention Program at Saint Camille Medical Centre in Burkina Faso

The aims of this research are: i) to evaluate the prevalence of HHV-8, HBV and HIV among pregnant women, ii) to determine the percentage of these co-infections and iii) to estimate the frequency of the mother-to-child transmission of HIV among HBV and HHV-8 positive mothers. Thus, 379 pregnant women attending ante-natal consultation in Saint Camille Medical Centre were subject to HIV, HHV-8 antibodies and the viral marker Hepatitis B Surface Antigen (HBsAg) detection. We observed 48/379 (12.66%) HIV seropositive subjects. Among them, HIV-1 type infection was predominant (95.83%), only 2/48 (4.17%) subjects had a dual HIV-1 type and HIV-2 type infection, no single HIV-2 type infection was detected. 38/379 (10.02%) subjects were infected by HHV-8 and 30/379 (7.91%) were HBsAg positive. HHV-8 and HIV Co-infections rates were high within HBV positive patients and we had respectively 20.00 and 16.67%. 10.42% HIV positive women were coinfected by HBV while 12.50% were infected by HHV-8. Then, 15.79% subjects HHV-8 positive were co-infected by HBV or HIV. In spite of the PMTCT protocol application, five (10.42%) HIV positive women transmitted the virus to their children. Two HIV positive mothers were co-infected by HHV-8 and one by HBV. Among the 5 HIV infected, one mother (20.0%) was HBV positive and two (40.0%) HHV-8 positive. Although we did not have a large sample which would show large prélalences of the infections, we could put forward that the Co-infection of the HIV with one of these viruses (HBV or HHV-8) could favorite the mother-to-child transmission.

Oral Kaposi's sarcoma in Tanzania: Presentation, immunopathology and human herpesvirus-8 association

Oral Kaposi's sarcoma (OKS) from Tanzanian patients (78) at Muhimbili National Hospital/Muhimbili University College of Health Sciences corresponding to approximately 10% of KS registered during 1990-2005, were diagnosed (ELISA) as HIV-infected (OAKS) (74/78) and endemic KS (4/78). Females were 69.2% (54/78) with median age 31 and males 30.8% (24/78) with median age 38. More males (50%) had systemic KS than females (37%) and 4-times more multicentric OKS. All tested (34) oral KS patients sera had HHV-8 antibodies. Available (31/78) blood showed very low CD4+ T-lymphocyte counts. Most OKS (61.5%) had nodular histology. Immunostaining showed adult male nodular OAKS to have a significantly higher frequency of viral LANA+, endothelial CD34+ tumour spindle-cells (SC) and more Ki-67+ (median =24.1%) proliferating cells compared to females (17.2%). Juvenile nodular OAKS had more LANA+ and Ki-67+ cells than corresponding adult cases. Significantly more LANA+ and Ki-67+ cells were found in nodular OAKS compared to cutaneous HIV/AIDS Kaposi's sarcoma (CAKS). A positive correlation (60%) was found between the proliferation index (Ki-67+ cell frequency) and LANA+/CD34+ SC. OKS in Tanzania is since 1990, mostly seen in females, associated with HIV/AIDS and advanced (nodular) histopathology. Males have more systemic tumour burden while more females develop primary OAKS. HHV-8+ cells were more frequent in nodular male than female and in juvenile than adult nodular OAKS than cAKS. Higher tumoral HHV-8 content appeared to be correlated to proliferation index.

Reactivation of human herpesvirus (HHV) family members other than HHV-6 in drug-induced hypersensitivity syndrome

Drug-induced hypersensitivity syndrome (DIHS) is characterized by a severe multiorgan hypersensitivity reaction that usually appears after a 3-6-week exposure to certain drugs, including anticonvulsants. There are some reports showing that serum IgG levels often decrease at the early stage of DIHS. Reactivation of human herpesvirus (HHV)-6 has been reported in patients with DIHS, and some other DIHS patients showed reactivation of cytomegalovirus (CMV) or Epstein-Barr virus (EBV). To determine whether reactivation of HHV-6, HHV-7, CMV and/or EBV occurs in patients with DIHS. Titres of IgG and IgM antibodies to HHV-6 and HHV-7 were determined using an indirect immunofluorescence antibody assay on admission and at various times after admission. Anti-CMV IgG and IgM antibody titres and anti-EBV capsid antigen IgG, IgA, IgM, and EBV nuclear antigen and EBV early antigen IgG titres were determined by enzyme immunoassay. Polymerase chain reaction (PCR) procedures for HHV-6, HHV-7, CMV and EBV DNAs were performed using serum samples. IgG antibody titres to HHV-6, HHV-7, CMV and EBV were increased after the onset in seven, six, seven and two of seven patients, respectively. IgG antibody titres to HHV-6 and HHV-7 were elevated simultaneously 21-38 days after the onset. IgG antibody titres to CMV and EBV were elevated 10-21 days after the elevation of HHV-6 and HHV-7 antibody titres. PCR showed that HHV-6, HHV-7, CMV and EBV DNAs became positive in six, five, seven and two of seven patients, respectively. HHV-6 and HHV-7 DNAs were detected 21-35 days after the onset, and CMV DNA was detected 10-21 days after detection of HHV-6 and HHV-7 DNAs. The present study suggests that in addition to HHV-6 reactivation, reactivation of HHV-7, CMV and/or EBV may also occur following drug eruption in some patients with DIHS.

Studies of Human Herpes Virus-8 in Thailand

Thailand has experienced a major epidemic of HIV/AIDS since 1988. Currently over 650,000 persons are HIVinfected and 400,000 have died of AIDS in Thailand. However, Kaposi's Sarcoma (KS) is very rare. Among the 101,945 adults AIDS cases reported between 1994 and 1998 only 0.2% had KS. We have ruled out the possibility that HHV-8 infections are rare; in a study of 992 persons at risk or positive for HIV we found an HHV-8 antibody prevalence of 24.2%. Another hypothesis to explain the rarity of KS is that endothelial cells in Thai's are relatively resistant to HHV-8 infection. We obtained umbilical cord endothelial cell cultures from 10 Thai women who were HIV negative and analyzed their DNA for novel single nucleotide polymorphisms (SNPs) in the coding region for the promoter and 3' UTR region of the DC-SIGN gene. These results were compared to other Asian (11), Caucasian (n = 120), and African (n = 206) samples. No novel SNPs were found in the Thai samples, however some haplotypes that differed from the Caucasian samples were found. Three Thai samples were homozygous for a complete absence of SNPs in the UTR and reduced diversity in the promoter. This was not seen in the Caucasian samples. Additional analysis of linkage disequilibrium and HHV-8 infectivity analysis of these cell cultures are in progress. It is possible that genetic differences in the endothelial cell receptors for HHV-8 or resistance of cells to HHV-8 among Thai's could partially explain the rarity of AIDSrelated KS among Asians. from 2005 International Meeting of The Institute of Human Virology Baltimore, USA, 29 August – 2 September 2005

Human herpesvirus‐8: what (not) to do?

Human herpesvirus‐8: what (not) to do?

Low socioeconomic status and risk for infection with Human Herpesvirus 8 among HIV-1 negative, South African black cancer patients

Between January 1994 and October 1997, we interviewed 2576 black in-patients with newly diagnosed cancer in Johannesburg and Soweto, South Africa. Blood was tested for HIV-1 and HHV-8 antibodies and the study was restricted to 2191 HIV-1 antibody-negative patients. We examined the relationship between infection with HHV-8 and sociodemographic and behavioural factors using unconditional logistic regression models. Of the 2191 HIV-1 negative patients who did not have Kaposi's sarcoma, 854 (39.1%) were positive for antibodies against the latent nuclear antigen of HHV-8 encoded by orf73 in a immunofluorescence assay. Infection with HHV-8 was independently associated with increasing age (P trend = 0.02). For females, independent risk factors also included working in a paid domestic capacity (OR 1.63, 95% CI 1.09-2.44, P = 0.02), defining occupational status as economically non-active unemployed (OR 1.70, 95% CI 1.06-2.72, P = 0.03), having a state pension or being on a disability grant (OR 1.49, 95% CI 1.05-2.11, P = 0.02), using oral contraceptives (OR 1.43, 95% CI 1.03-1.99, P = 0.03) and having a delayed age at menarche (P trend = 0.04). The relationship between these variables and HHV-8 antibody status requires further, prospective study.

Anti-HHV-8/KSHV antibodies in infected individuals inhibit infection in vitro.

To detect human herpesvirus (HHV)-8/Kaposi's sarcoma-associated herpesvirus (KSHV) neutralizing antibodies (nAb). Antibodies capable of inhibiting HHV-8 infection were measured by infecting transformed dermal microvascular endothelial cells (tDMVEC) with HHV-8 that had been pre-incubated with serum from HHV-8-seropositive or -seronegative subjects. The level of infection was quantified 48 h later. HHV-8 was prepared from JSC-1 primary effusion lymphoma cells; the titre of enveloped virions was determined by electron microscopy. Virus was incubated with serum samples for 60 min before inoculating tDMVEC. The level of infection was quantified by indirect immunofluorescence assay, staining for HHV-8 latency-associated nuclear antigen (LANA)-1. Inhibition of infection was determined by comparing the level of infection obtained with HHV-8-seropositive subject serum with the level obtained by incubation with seronegative serum. Up to 61% of cells were infected with HHV-8 in the absence of human serum; this level was not affected by pre-incubating the virus with HHV-8-seronegative serum. At dilutions of 1:10 and 1:50, HHV-8-seropositive sera significantly inhibited infection compared to seronegative controls (P = 0.036 for both serum dilutions, Mann-Whitney). The endpoint of inhibition was 1:100, when the serum of one of five subjects inhibited virus infection. At 1:500 dilution, there was no difference in the level of infection after virus incubation with seropositive or seronegative sera (P = 0.578). Depletion of antibody from serum with protein A reversed the inhibitory effect, confirming it was antibody-mediated. This study is the first to identify HHV-8 antibodies in infected subjects that reduce in vitro infectivity of the virus.

Searching for antibodies to HHV-8 in children born to HIV-1 infected mothers from São Paulo, Brazil: relationship to maternal infection.

With the spread of AIDS, many HIV-1 infected women and children have been diagnosed with Kaposi's sarcoma (KS), mostly in Africa. Since the discovery of the causative agent of KS (human herpesvirus 8, HHV-8) several seroepidemiological studies have been conducted to identify groups at risk of KS. The present study was conducted in order to add some information from São Paulo, Brazil. We searched for HHV-8 antibodies in plasma samples obtained from a cohort of 108 children born to HIV-1 infected mothers, and from 15 mother-child pairs enrolled in a longitudinal study of HIV-1 vertical transmission. An in house immunofluorescence assay was used to detect anti-latent and anti-lytic HHV-8 antibodies based on the BCBL-1 cell line. No case of anti-latent antibodies and a 7.4 per cent frequency of anti-lytic antibodies were detected among children. Interestingly, the detection of HHV-8 antibodies varied according to the children's HIV-1 status; no antibodies were detected in HIV-1 non-infected children and 10.9 per cent and 8.3 per cent frequencies of antilytic antibodies in truly HIV-1 infected children and in children in whom the HIV-1 status could not be defined. Since concordant results were obtained by the analysis of plasma samples obtained from mother-child pairs and considering the children's age, the antibodies detected in the present study probably reflect maternal antibodies. Unfortunately, we were not able to determine if any case of KS occurred among mothers, but because of the risk of HHV-8 horizontal transmission, the results obtained prompt us to continue investigating groups at risk to acquire HHV-8 and to search for preventive measures to avoid virus transmission.

Prevalence and clinical significance of human herpesviruses 6 and 7 active infection in pediatric liver transplant patients.

Recent studies in adult liver transplant patients have suggested that both human herpesvirus (HHV)-6 and HHV-7 infection are important causes of morbidity following liver transplantation. However, the impact of HHV-6 and -7 infection in pediatric liver transplant patients remains largely unknown. The aims were to determine the prevalence of HHV-6 and -7 infection in pediatric liver transplant patients and to determine whether there is an association between HHV-6 and -7 infection with episodes of graft rejection and cytomegalovirus (CMV) infection. A total of 46 pediatric liver transplant patients transplanted at Mayo Clinic between January 1994 and January 2000 were evaluated. Quantitative polymerase chain reaction (PCR) assays for CMV, HHV-6 and HHV-7 were performed on stored sera obtained prior to transplant, weekly for 8 wk and at 4 months and 1 yr post-transplant. Pretransplant sera were tested for HHV-6 antibodies by indirect immunofluorescence assay. A total of 215 blood samples were tested (mean 6.5 +/- 3.1, range 3-18). CMV infection occurred in 11 of 33 (33.3%) patients, while CMV disease occurred in 4 of 33 (12%) patients. Infection with HHV-6 (variant B) was detected in three of 33 (9.1%) patients. HHV-7 infection was not detected. Case 1 and 2 were infants (10- and 11-month old, respectively). Both were seronegative for HHV-6 pretransplant. In both cases, HHV-6 infection was associated with concurrent episodes of moderate to severe acute graft rejection. Case 3 was a 16-yr-old girl who was seropositive for HHV-6 pretransplant. No clinical events were recorded and a liver biopsy performed per protocol showed no evidence of rejection. None of the three patients had concomitant CMV infection or disease. In this study, HHV-6 infection occurred in 9% of pediatric liver transplant patients while HHV-7 was not detected. A potential association between primary HHV-6 infection and allograft rejection warrants further investigation.

Evaluation of the specificity and sensitivity of indirect immunofluorescence tests for IgG to human herpesviruses-6 and -7

Sera from 118 children aged up to 4 years were tested by indirect immunofluorescence for human herpesvirus-6 and -7 (HHV-6 and HHV-7) antibodies. Antibody results were confirmed as true positives if the relevant viral DNA was detected in saliva or, in some cases of primary infection, by the finding of the relevant DNA in cerebrospinal fluid or serum. Results from samples taken from the 15 children less than 6 months old showed that HHV-6 and/or HHV-7 antibody was either absent or present at low titre suggesting persistent maternal antibody rather than true infection. The sensitivity, specificity, positive and negative predictive values of the HHV-6 IgG test were therefore based on the data from the 103 children older than 6 months and the results were 95, 84, 91 and 90%, respectively. Likewise, the sensitivity, specificity, positive and negative predictive values of the HHV-7 IgG test were 95, 76, 84 and 93%, respectively. There was limited cross-reactivity between HHV-6 and HHV-7 antibodies; where both HHV-6 and HHV-7 antibodies are detected, titres above 32 may be accepted as true positives but lower titres require confirmation by detection of the relevant viral DNA or, in the case of primary infection, by a rising antibody titre.

Reactivation of human herpesvirus 6 and 7 in pregnant women.

To elucidate the roles of human herpesvirus (HHV)-6 and -7 in pregnant women, peripheral blood samples and genital tract secretions were collected serially from pregnant women, and both serological testing and polymerase chain reaction (PCR) were carried out to detect viral DNA in the secretions. HHV-6 or HHV-7 Immunoglobulin(Ig)M antibodies were not detected in 432 plasma samples collected from pregnant women and cord blood, but IgG antibodies against both viruses were detected in all plasma samples. Significant increases in HHV-6 and HHV-7 IgG antibodies were observed in two (1.6%) and three (2.4%) pregnant women respectively of a total of 123 cases. HHV-6 DNA was detected in the genital tract in three (3.7%) of 82 pregnant women at the first trimester, and in 10 (12.2%) of the same women in the third trimester. The detection rate in the third trimester was significantly higher than that in the first trimester (P = 0.043). Although HHV-7 DNA was detected in the genital tract of two (2.7%) and seven (9.6%) pregnant women of a total of 73 during the first and third trimesters respectively, there was no statistical difference in the detection rate of the viral DNA between the trimesters. Because a significant increase in HHV-6 IgG antibodies was detected in only two pregnant women, it was not possible to carry out statistical analysis to determine the relationship between HHV-6 infection and associated clinical features. Although there was a significant increase in HHV-7 antibody titers in three pregnant women, a positive correlation between the virus infection and the clinical features was not demonstrated. There was no statistical association between virus shedding in the genital tract and the clinical features examined in this study.

Prevalence trend and correlates of HHV-8 infection in HIV-infected patients.

To assess the circulation of human herpesvirus (HHV)-8 infection over the years, two seroprevalence surveys were conducted, which tested sera from HIV-infected individuals recruited 10 years apart (206 individuals from 1986 to 1988 and 177 individuals from 1997 to 1998). For all patients, antibodies to hepatitis C virus (HCV), hepatitis B virus (HBV), and HHV-8 lytic and latent antigens were evaluated.HHV-8 seroprevalence was higher among individuals recruited in the 1990s (31.6% for anti-lytic, 8.5% for anti-latent antibodies) compared with similar findings in those seen in the late 1980s (14.6% and 3.4% for anti-lytic and anti-latent antibodies, respectively), with a twofold increase of the risk of HHV-8 infection. However, the increase was observed only among injecting drug users, whereas seroprevalence tended to slightly increase among those infected by sexual contact. At univariate analysis, time of recruitment and being homosexual men were factors associated with HHV-8 infection, an association that remained after adjusting for age. HBV infection was significantly associated with HHV-8 infection (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.3-3.6), whereas those infected with HCV had a lower probability of having HHV-8 antibodies (OR, 0.3; 95% CI, 0.20-0.6). After controlling for age and gender, time of recruitment remained independently associated with HHV-8 infection among injecting drug users. In conclusion, HHV-8 seroprevalence appears to be increased during 10 years among HIV-infected injection drug users but not among homosexual men, who remain those at the highest risk of infection.

Prevalence and distribution of HHV-8 in different subpopulations, with and without HIV infection, in Spain.

To estimate the seroprevalence of HHV-8 in several Spanish subpopulations with different risk levels of acquiring HIV-1 infection and from different geographical regions. Cross-sectional seroprevalence study. A total of 1699 serum samples from blood donors (613), children under the age of 12 years (100), injecting drug users (IDU) (382), heterosexuals attending a sexually transmitted disease (STD) clinic (273) and homosexual men attending a STD clinic or a HIV-based hospital unit (331) were analysed for anti-HHV-8 antibodies. The presence of antibodies against HHV-8 was tested with an indirect immunofluorescence assay (IFA). A subsample of HHV-8-positive samples was also tested for antibody titre against HHV-8. The overall seroprevalence of antibodies against HHV-8 for the blood donor population was 6.5% (7.0% in Andalusia, 8.0% in Catalonia and 4.5% in the Basque Country). None of the children tested positive for HHV-8. The HHV-8 prevalence was 86.7% in HIV-positive homosexual men and 28.0% in HIV-negative homosexual men (P < 0.001). Of heterosexual men attending STD clinics, 17.2% tested positive for HHV-8; 11.5% of IDU tested positive for HHV-8. HHV-8 antibody titres by groups parallel the distribution of HHV-8 prevalence. No association between HHV-8 antibody titres and CD4 cell count or HIV viral load was identified. The HHV-8 prevalence among blood donors in Spain is higher than in Northern Europe and the USA, but is similar to that in Northern Italy. The distribution of HHV-8 is compatible with a sexually transmitted agent. The distribution of HHV-8 correlates with that of Kaposi's sarcoma but factors other than HHV-8 seem to explain the Kaposi sarcoma distribution.

Social Support Mediates Loneliness and Human Herpesvirus Type 6 (HHV‐6) Antibody Titers

The current study investigated the impact of a severe environmental stressor and the role that declining social integration played in mediating its effect on loneliness and immune status. Increased loneliness and decreased social support in the months following the stressor (storm) were significantly associated with increased HHV-6 antibody titers, reflecting poorer control over the virus. Poorer social integration mediated the relationship between loneliness and HHV-6, even after controlling for nonspecific polyclonal B-cell activation, disease status (CD3+CD4+ cell counts), living arrangements, acute social losses (bereavement), and potential disruptions in social-support resources. These findings suggest that specific elements of social support may explain the oft-noted negative effects of loneliness on the immune system, and generalized to a medically vulnerable population.

Epidemiological study of human herpesvirus-6 and human herpesvirus-7 in pityriasis rosea.

Pityriasis rosea (PR) is a common papulosquamous skin disorder that is suspected to have an infectious aetiology. We aimed to study the role of human herpesvirus (HHV)-7 and HHV-6 in the pathogenesis of PR. We performed seroepidemiological studies (indirect immunofluorescence test) and polymerase chain reaction (PCR) analysis for HHV-6 and HHV-7 in patients with PR. Seventy-two serum samples and 37 samples of peripheral blood mononuclear cells (PBMC) from 44 patients with PR were obtained. Twenty-five patients with other skin disorders such as drug eruption, urticaria or herpes zoster were studied as controls in the PCR analysis. HHV-7 DNA was detected in 13 of 30 (43%) samples of PBMC of the patients with PR and 14 of 25 (56%) samples of PBMC of controls. HHV-6 DNA was detected in six of 29 (21%) patients with PR and nine of 23 (39%) controls. Thus there was no difference in the prevalence of HHV-6 or HHV-7 in PBMC between patients with PR and those with other skin disorders. In the seroepidemiological study, two cases of at least a fourfold rise in titre and five cases of a fourfold decrease in titre to HHV-7 antibody, and two cases of a fourfold rise in titre and two cases of a fourfold decrease in titre to HHV-6 antibody, were observed in 24 patients with PR. This seroepidemiological study revealed antibody responses consistent with active infection in several PR patients, but the greater proportion of the patients had no definite increase in the antibody titres. We conclude that HHV-7 and HHV-6 may play a part in some patients with PR, but that other causative agents may exist. Further analyses are needed to determine the causative agents of PR.