Laura Masami Sumita

Human herpesvirus-8 infection and oral shedding in Amerindian and non-amerindian populations in the Brazilian Amazon region

BACKGROUND Human herpesvirus type 8 (HHV-8) is hyperendemic in Amerindian populations, but its modes of transmission are unknown. METHODS Antibodies against either HHV-8 lytic antigen or HHV-8 latency-associated nuclear antigen (LANA) were detected, by immunofluorescence assays, in 339 Amerindians and 181 non-Amerindians from the Brazilian Amazon. Serological markers of oro-fecal (hepatitis A), parenteral (hepatitis B and C), and sexual (herpes simplex virus type 2 and syphilis) transmission were measured by specific ELISAs. Salivary HHV-8 DNA was detected by use of a nested polymerase chain reaction assay and was sequenced. RESULTS Antibodies against either lytic antigen or LANA were detected in 79.1% of Amerindians and in 6.1% of non-Amerindians (adjusted seroprevalence ratio [SR], 12.63 [95% confidence interval {CI}, 7.1-22.4]; P<.0001). HHV-8 seroprevalence increased with age among Amerindians (P(Trend) < .001) and already had high prevalence in childhood but was not sex specific in either population. The 2 populations did not differ in seroprevalence of oro-fecal or parenteral markers, but seroprevalence of markers of sexual transmission was lower among Amerindians. HHV-8 DNA in saliva was detected in 47 (23.7%) of 198 HHV-8 seropositive Amerindians. Detection of HHV-8 DNA decreased with age (P(Trend) < .04) and was more common in men (SR, 2.14 [95% CI, 1.3-3.5]; P=.003). A total of 36 (76.6%) of the 47 saliva HHV-8 DNA samples were sequenced, and all clustered as subtype E. CONCLUSION The data support the hypothesis of early acquisition and horizontal transmission, via saliva, of HHV-8 subtype E in Amerindian populations.

Comparative Study of Kaposi's Sarcoma-Associated Herpesvirus Serological Assays Using Clinically and Serologically Defined Reference Standards and Latent Class Analysis

ABSTRACT Accurate determination of infection with Kaposis sarcoma-associated herpesvirus (KSHV) has been hindered by the lack of a “gold standard” for comparison of serological assays used to estimate KSHV prevalence in serosurveys conducted in different settings. We have evaluated the performance of five in-house (developed at University College London [UCL], United Kingdom, and at the virology laboratory of the Instituto de Medicine Tropical [IMT] in Sao Paulo, Brazil) and two commercial (ABI and DIAVIR) serological assays to detect antibodies to latency-associated nuclear antigen (LANA) and to lytic KSHV antigens. We used a variety of serum samples assembled to represent populations likely to be at high, intermediate, and low risk of KSHV infection in Brazil. Composite reference standard panels were prepared based on clinical and serological parameters, against which assay performances were assessed using conventional Bayesian statistics and latent class analysis (LCA). Against the clinical reference standard, in-house immunofluorescence assays to detect anti-LANA antibodies (IFA-LANA) produced at UCL and IMT had similar performances, with sensitivities of 61% (95% confidence interval [CI], 48% to 74%) and 72% (95% CI, 58% to 83%) and specificities of 99% (95% CI, 94% to 100%) and 100% (95% CI, 96% to 100%), respectively, and only the IMT IFA-LANA was included in LCA, together with the IMT IFA-lytic and four enzyme-linked immunosorbent assays (ELISAs). The LCA indicated that the IMT whole-virus ELISA performed best (sensitivity, 87% [95% CI, 81% to 91%]; and specificity, 100% [95% CI, 98% to 100%]), confirming the results obtained with the conventional statistical approach. Commercially available ELISA-based tests yielded the lowest specificities using a spectrum of serum samples. The evaluation of KSHV serological assays is warranted before planning serosurveys in various settings.

Prevalence of herpes simplex type 2 antibodies and a clinical history of herpes in three different populations in Campinas City, Brazil

OBJECTIVES To determine the seroprevalence of herpes simplex virus type 2 (HSV-2) antibodies and the relation between the history of clinical herpes and the presence of type-specific HSV-2 antibodies in three different populations from the city of Campinas City, Brazil. POPULATION AND METHODS One hundred and one college students, 96 patients with sexually transmitted diseases (STD), and 102 women at delivery were interviewed and blood samples were collected. Total HSV (HSV-1 and HSV-2) antibodies were screened by enzyme-linked immunosorbent assay (ELISA) and type-specific HSV-2 antibodies were detected by Western blot assay. RESULTS Herpes simplex virus antibodies were detected in 66.3% of the students, 97.1% of the women at delivery, and 99.0% of the STD patients. Type-specific HSV-2 antibodies were detected in 6.9% of the students, 22.6% of the women at delivery, and in 53.1% of the STD patients. History of genital herpes was reported by none of the students, by one of the women at delivery, and by 11 of 51 (21.6%) STD patients who were HSV-2 seropositive. Four of the 45 (8.9%) seronegative STD patients reported a history of genital herpes. CONCLUSION The prevalence of HSV-2 infection in Campinas City can be significantly affected by the characteristics of the population studied, as was shown in previous studies. The sensitivity of the history of genital herpes was low in the present series, stressing that prophylactic measures for vertical and horizontal transmission of HSV-2 should not be based only on a positive history of genital ulcers.

Prevalence of antibodies to human herpesvirus-8 in populations with and without risk for infection in São Paulo State

Human herpesvirus 8 (HHV-8) is a newly described herpesvirus that is etiologically associated with all forms of Kaposis sarcoma (KS). Seroepidemiological studies have shown high prevalence rates of HHV-8 antibodies among men who have sex with men (MSM) and AIDS patients, African children, Brazilian Amerindians, and elderly individuals in certain regions of Europe. The aim of the present study was to determine the prevalence of HHV-8 antibodies in healthy children and young adults from different cities in São Paulo State, and in a population at high risk for HHV-8 infection: HIV-negative MSM, and AIDS patients with and without KS. Antibodies to HHV-8 latency-associated nuclear antigen and lytic-phase antigens were detected by immunofluorescence assays. In 643 healthy children and young adults from the general population attending a vaccination program for yellow fever in ten different cities in São Paulo State, the prevalence of HHV-8 antibodies detected by the presence of latent or lytic antigens ranged from 1.0 to 4.1% in the different age groups (mean=2.5%). In the MSM group, the prevalence was 31/95 (32.6%). In the group of patients with AIDS, the prevalence was 39.2% (51/130) for non-KS patients and 98.7% (77/78) for AIDS patients with the diagnosis of KS confirmed by histopathological examination. We conclude that HHV-8 has a restricted circulation among healthy children and young adults in the general population of São Paulo State and a high prevalence among MSM and AIDS patients.

Detection of human herpesvirus 8 DNA and antibodies to latent nuclear and lytic-phase antigens in serial samples from aids patients with Kaposi's sarcoma.

Abstract Background : human herpesvirus 8 (HHV-8) have recently implicated in the etiology of Kaposis sarcoma (KS), but the pathophysiologic and immunologic interactions between HHV-8 and the human host are incompletely understood. Objective : this paper intends to present partial results of a follow-up study of KS patients, designed to investigate HHV-8 viremia and antibody response. Methods : ninety-six paired serial samples (PBMCs and sera) were obtained from 12 aids patients with KS who received HAART prior or just after entry in the study. HHV-8 DNA was detected by nested-PCR and antibodies to HHV-8 latent nuclear antigen (LANA) and lytic antigen by immunofluorescence assay (IFA). Results : HHV-8 DNA was detected in 33.3% of the first PBMC samples. Among the eight PCR negative patients, four presented positive samples during the follow-up and four remained negative. Five patients had intermittent viremia. Fifteen of the 96 PBMC samples were PCR positive (15.6%). Four of 39 samples (10.2%) from patients classified as stadio II and 11 of the 53 samples (20.7%) from patients in stadio IV were PCR positive ( P =0.2). Six patients (50%) had anti-LANA antibodies at the entry in the study. Among the six seronegative patients, two seroconverted 2 months later and four patients remained seronegative during the 5–8 months of follow-up. All patients had anti-lytic antibodies since the first sample. Conclusion : the presence of HHV-8 viremia could be related to the severity of KS and could be intermittent even under HAART. A longer follow-up is needed to confirm these results.

Genomic analysis of ERVWE2 locus in patients with multiple sclerosis: absence of genetic association but potential role of human endogenous retrovirus type W elements in molecular mimicry with myelin antigen

Human endogenous retroviruses (HERVs) arise from ancient infections of the host germline cells by exogenous retroviruses, constituting 8% of the human genome. Elevated level of envelope transcripts from HERVs-W has been detected in CSF, plasma and brain tissues from patients with Multiple Sclerosis (MS), most of them from Xq22.3, 15q21.3, and 6q21 chromosomes. However, since the locus Xq22.3 (ERVWE2) lack the 5′ LTR promoter and the putative protein should be truncated due to a stop codon, we investigated the ERVWE2 genomic loci from 84 individuals, including MS patients with active HERV-W expression detected in PBMC. In addition, an automated search for promoter sequences in 20 kb nearby region of ERVWE2 reference sequence was performed. Several putative binding sites for cellular cofactors and enhancers were found, suggesting that transcription may occur via alternative promoters. However, ERVWE2 DNA sequencing of MS and healthy individuals revealed that all of them harbor a stop codon at site 39, undermining the expression of a full-length protein. Finally, since plaque formation in central nervous system (CNS) of MS patients is attributed to immunological mechanisms triggered by autoimmune attack against myelin, we also investigated the level of similarity between envelope protein and myelin oligodendrocyte glycoprotein (MOG). Comparison of the MOG to the envelope identified five retroviral regions similar to the Ig-like domain of MOG. Interestingly, one of them includes T and B cell epitopes, capable to induce T effector functions and circulating Abs in rats. In sum, although no DNA substitutions that would link ERVWE2 to the MS pathogeny was found, the similarity between the envelope protein to MOG extends the idea that ERVEW2 may be involved on the immunopathogenesis of MS, maybe facilitating the MOG recognizing by the immune system. Although awaiting experimental evidences, the data presented here may expand the scope of the endogenous retroviruses involvement on MS pathogenesis.

Prevalence of, and Risk Factors for Kaposi's Sarcoma-Associated Herpesvirus Infection Among Blood Donors in Brazil: A Multi-Center Serosurvey

Kaposis sarcoma‐associated herpesvirus (KSHV) is endemic in the Amazon and rare in southern regions of Brazil. However, geographical distribution and epidemiological correlates of infection in this large country are still poorly defined. To estimate the seroprevalence of, and risk factors for, KSHV infection in Brazil, a multi‐center study was conducted among 3,493 first‐time voluntary unpaid blood donors from Salvador, Sao Paulo and Manaus. Antibodies against KSHV were detected using a whole‐virus ELISA validated prior to the serosurvey. Antibodies against the latency‐associated nuclear antigen (LANA) were detected by immuno‐fluorescence assay (IFA) among ELISA‐positive sera and a random sample of ELISA‐negative sera. Overall, seroprevalence of KSHV by whole‐virus ELISA was 21.7% (95% confidence interval (CI): 20–23.4%) in men and 31.7% (95% CI: 29–34.3%) in women (P < 0.0001). KSHV antibodies were detected by IFA‐LANA in 3% (95% CI: 2–4.3%) of 867 ELISA‐positive samples and in none of 365 randomly selected ELISA‐negative samples. In multivariate analysis, KSHV seroprevalence by whole‐virus ELISA was independently associated with female sex (odds ratio [OR] = 1.6, 95% CI: 1.4–1.9); residence in the Amazon (OR = 1.4, 95% CI: 1.2–1.8; compared to Salvador); Caucasian ethnicity (OR = 1.3, 95% CI: 1.1–1.6) and herpes simplex virus type 2 (HSV‐2) infection (OR = 1.3, 95% CI: 1.1–1.6). KSHV seroprevalence did not significantly increase with age, nor was it associated with self‐reported sexual behavior. KSHV seroprevalence is high among Brazilian blood donors, particularly from the Amazon region. This study supports the co‐existence of sexual and non‐sexual routes of KSHV transmission in this population. J. Med. Virol. 80: 1202–1210, 2008.

Multiple sclerosis and herpesvirus interaction

Multiple sclerosis is the most common autoimmune inflammatory demyelinating disease of the central nervous system, and its etiology is believed to have both genetic and environmental components. Several viruses have already been implicated as triggers and there are several studies that implicate members of the Herpesviridae family in the pathogenesis of MS. The most important characteristic of these viruses is that they have periods of latency and exacerbations within their biological sanctuary, the central nervous system. The Epstein-Barr, cytomegalovirus, human herpesvirus 6 and human herpesvirus 7 viruses are the members that are most studied as being possible triggers of multiple sclerosis. According to evidence in the literature, the herpesvirus family is strongly involved in the pathogenesis of this disease, but it is unlikely that they are the only component responsible for its development. There are probably multiple triggers and more studies are necessary to investigate and define these interactions.

Non-detection of human herpesvirus 8 (HHV-8) DNA in HHV-8-seropositive blood donors from three Brazilian regions.

Human herpesvirus 8 (HHV-8), also known as Kaposis sarcoma-associated herpesvirus (KSHV), is the etiologic agent of all forms of Kaposis sarcoma, primary effusion lymphoma and the plasmablastic cell variant of multicentric Castleman disease. In endemic areas of sub-Saharan Africa, blood transfusions have been associated with a substantial risk of HHV-8 transmission. By contrast, several studies among healthy blood donors from North America have failed to detect HHV-8 DNA in samples of seropositive individuals. In this study, using a real-time PCR assay, we investigated the presence of HHV-8 DNA in whole-blood samples of 803 HHV-8 blood donors from three Brazilian states (São Paulo, Amazon, Bahia) who tested positive for HHV-8 antibodies, in a previous multicenter study. HHV-8 DNA was not detected in any sample. Our findings do not support the introduction of routine HHV-8 screening among healthy blood donors in Brazil. (WC = 140).

Prevalence of rubella antibodies in a non-immunized urban population, São Paulo, Brazil

A prevalencia de anticorpos contra o virus da rubeola foi avaliada atraves de inquerito soroepidemiologico, em 1400 amostras de sangue de criancas com idade entre 2 e 14 anos e 329 amostras de soro de cordao umbilical. Anticorpos para o virus da rubeola foram detectados pela tecnica de ELISA e as amostras foram colhidas em 1987, 5 anos antes da campanha de vacinacao em massa com a vacina triplice viral realizada na cidade de Sao Paulo em 1992. Um aumento significativo na prevalencia foi observado apos 6 anos de idade, e 77% dos individuos entre 15 e 19 anos apresentaram anticorpos anti-rubeola. Entretanto, a soroprevalencia elevou-se para 90,5% (171/189) em soros de cordao de criancas cujas maes apresentavam idade entre 20 e 29 anos, alcancando 95,6% no grupo etario de 30 a 34 anos., indicando que um grande numero de mulheres sao infectadas durante a idade fertil. Este estudo confirma que a infeccao pelo virus da rubeola representa um importante problema de saude publica na cidade de Sao Paulo. Os dados de prevalencia de anticorpos contra o virus da rubeola antes da campanha de vacinacao em massa reflete o estado imunologico desta populacao antes de qualquer intervencao e pode ser usado para desenvolver estrategias adequadas de vacinacao e avaliar o impacto soroepidemiologico dessa intervencao.The prevalence of rubella antibodies was evaluated through a random seroepidemiological survey in 1400 blood samples of 2-14 year old children and in 329 samples of umbilical cord serum. Rubella IgG antibodies were detected by ELISA, and the sera were collected in 1987, five years before the mass vaccination campaign with measles-mumps-rubella vaccine carried out in the city of São Paulo in 1992. A significant increase in prevalence of rubella infection was observed after 6 years of age, and 77% of the individuals aged from 15 to 19 years had detectable rubella antibodies. However, the seroprevalence rose to 90.5% (171/189) in cord serum samples from children whose mothers were 20 to 29 years old, and reached 95.6% in newborns of mothers who were 30 to 34 years old, indicating that a large number of women are infected during childbearing years. This study confirms that rubella infection represents an important Public Health problem in São Paulo city. The data on the seroprevalence of rubella antibodies before the mass vaccination campaign reflects the baseline immunological status of this population before any intervention and should be used to design an adequate vaccination strategy and to assess the seroepidemiological impact of this intervention.