Searching for Human Herpesvirus 8 Antibodies in Serum Samples from Patients Infected with Human Immunodeficiency Virus Type 1 and Blood Donors from São Paulo, Brazil

Several articles published in the last few issues of Journal of Infectious Diseases have shown the seroprevalence of human herpesvirus 8 (HHV-8) antibodies in populations from different geographic areas and have shown a strong relationship between seropositive individuals and behavioral risk factors and region of birth [1–4]. In this respect, Blackbourn et al. [1] described a high prevalence of HHV-8 infection among young homosexual men from San Francisco who have multiple homosexual contacts with different partners. Zhang et al. [2] also provided data supporting preferential sexual transmission of HHV-8 in a study of persons from several epidemiologic groups of Brazil and Colorado, and they pointed out the high prevalence of HHV-8 in persons with Kaposi's sarcoma (KS) and in human immunodeficiency virus type 1 (HIV-1)—seropositive homosexual men without KS. A high seroprevalence of HHV-8 was also documented among women attending a sexually transmitted diseases clinic and an HIV clinic at a London hospital. Seropositivity varied according to the place of birth: 24.7% of women born in Africa were seropositive, as opposed to 11.5% of those born elsewhere [3]. In addition, 51.15% of HIV-1—infected and 47.35% of noninfected pregnant women in Zambia were seropositive for HHV-8 [4]. These and other data indicate that HHV-8 is endemic in Africa, and they explain the high incidence of KS among African women and children. In another Journal article, Angeloni et al. [5] presented data from a survey for HHV-8 antibodies conducted in Sardinia. The data showed a high prevalence of HHV-8 infection in relatives of patients with KS, suggesting intrafamilial person-to-person or vertical transmission of the virus. Indeed, LaDuca et al. [6] detected HHV-8 DNA sequences in several body fluids from patients with KS, suggesting that saliva could be more important than semen or stool in the transmission of HHV-8. Considering all of these data and knowing that the routes of transmission and groups at risk around the world are not completely defined, we conducted a pilot study to contribute data concerning this matter in São Paulo, the largest city in Brazil, which has a mixed-race population and the highest incidence of HIV-1 and AIDS cases. Using an immunofluorescence assay according to the method of Simpson et al. [7], we detected antibodies to latent nuclear antigens in BCP-1 cells (derived from an HIV-seronegative patient with body cavity-based lymphoma) infected with HHV-8, using a serum dilution of 1:200 instead of 1:150. In indeterminate cases, serum dilutions of 1:150 and 1:300 were also used. Two cross-sectional groups of serum samples randomly selected from a bank of the Immunology Department of Instituto Adolfo Lutz, São Paulo, were tested. The samples belonged to a cohort of 162 individuals: 81 patients infected with HIV-1 from Instituto de Infectologia Emílio Ribas and 81 blood donors from Fundação Pró-Sangue/Hemocentro Hospital das Clínicas, São Paulo, who tested seronegative for all blood bank markers. Of the patients infected with HIV-1, 51 were men (median age, 33 years; range, 16–54) and 30 were women (median age, 28 years; range, 16–47). The patients had the following risk factors for acquiring HIV-1 infection: 62 were at sexual risk (23 homosexual or bisexual men, 26 heterosexual women, and 13 heterosexual men), 10 were intravenous drug users (IVDUs; 8 men and 2 women), and 9 had unknown risk factors. Twenty-three of the 81 patients were asymptomatic, and the remaining 58 had AIDS. The overall frequency of HHV-8 antibodies was 16% but varied according to risk factor: the highest percentage of seropositivity was detected among homosexual or bisexual men (30.4% of cases), followed by heterosexual men (23.1%) and heterosexual women (7.8%). Only 1 case of HHV-8 seropositivity was detected among IVDUs. Table 1 presents the characteristics of HHV-8 seropositive cases according to age, gender, and HIV-1 stage, revealing a high incidence of HHV-8 antibodies among young homosexual men and patients with AIDS. Of note, although most patients infected with HHV-8 had AIDS, only 1 of them (patient 549) developed KS during a 3-year follow-up, and he was an asymptomatic patient infected with HIV-1. Characteristics of 13 human herpesvirus 8-seropositive and patients infected with human immunodeficiency virus type 1 (HIV-1). In the blood donor group (58 men and 23 women; median age, 31 years [range, 19–55]), 6 subjects (7.4%) were seropositive for HHV-8 antibodies. The patients who were seropositive for HHV-8 were men (median age, 37.5 years; range, 20–48). This percentage for a lower-risk population may represent an overestimate or an underestimate of the true prevalence of infection because of the small number of samples and the lack of a standard HHV-8 antibody assay, as mentioned by Rabkin et al. [8]. Although the end-point titers of antibodies were not determined, we observed strong reactivity among sera from patients infected with HIV-1 and weak reactivity of antibodies in sera from blood donors. Despite these considerations, this preliminary study supports the view that HHV-8 is easily transmitted by sexual routes, mostly among homosexual or bisexual men and patients with AIDS. It also emphasizes that HHV-8 circulates among healthy men in São Paulo. We are currently interested in expanding these data and searching for routes of HHV-8 transmission.