Human Herpesvirus-8 (HHV-8), also known as Kaposi sarcoma-associated herpesvirus (KSHV), is a large (165 kB) double-stranded DNA virus belonging to the gamma herpesvirus family [1,2]. It was first detected in Kaposi sarcoma (KS) tissue from a patient with acquired immunodeficiency syndrome (AIDS) in 1994 [1]. HHV-8 is categorized as a group 1 biological carcinogenic agent, defined as having sufficient evidence to establish a link to carcinogenicity in humans, by the International Agency for Research on Cancer (IARC) [2]. While HHV-8-associated tumors are most common in people living with HIV (PLWH), they have also been reported in other immunosuppressed and older individuals, and occasionally in patients with congenital immunodeficiencies. HHV-8-associated tumors are estimated to account for just under 1 percent of all cancers occurring worldwide. Although HHV-8 infection is necessary to cause the associated tumors, the tumors require other cofactors (eg, untreated HIV infection, immunosuppression) to develop. In contrast, as many as one-half of patients with HIV and HHV-8 coinfection will develop KS in the absence of effective antiretroviral treatment [2,3] HHV-8 infection is considered to be the causative agent of all forms of KS, including classic (Mediterranean), endemic (African), iatrogenic (transplant-related) and epidemic (HIV/AIDS-associated) forms, but has distinct epidemiological and clinical presentations. It is also associated with other malignancies, including primary effusion lymphoma, multicentric Castleman disease, HHV-8 positive diffuse large B-cell lymphoma, and germinotropic lymphoproliferative disorder [[4], [5], [6]]. These cancers usually occur in immunodeficient patients but may also affect immunocompetent individuals [5]. HHV-8, which is transmitted via saliva and multiplies in the oropharynx, remains latent in lymphoid cells. HHV-8 DNA is detected in saliva, semen and peripheral blood mononuclear cells of patients with HIV/AIDS [1]. HHV-8 is mainly spread through saliva, particularly in endemic areas where close interpersonal contact is common. Primary infection in childhood occurs via saliva-mediated routes, whereas in adults, especially in non-endemic areas, sexual transmission is the predominant pathway [7,8].

Globally, the seroprevalence of HHV-8 is very heterogeneous according to regions of the world and populations [3]. Currently, the virus has a prevalence of 40 % in sub-Saharan Africa; 10 % in Mediterranean countries; 2-4 % in Northwest Europe, Southeast Asia and the Caribbean; and 5-20 % in the United States. However, these data are likely underestimated, as the number of publications regarding HHV-8 epidemiology is scarce and incomplete [9].

Various tests with varying sensitivity and specificity have been developed for the serological diagnosis and determination of seroprevalence of HHV-8. These include ELISA, indirect fluorescent antibody test (IFA), immunoblot and neutralization tests. ELISA is technically easier to apply and is a preferred method in seroprevalence studies. ELISA tests use recombinant antigens, synthetic peptides, or viral lysates. ELISA tests using HHV-8 recombinant antigens are useful in the diagnosis of HHV-8 infection because they detect specific antibody responses to capsid proteins [1,6].

In our previous bibliometric analysis, we reported that only a minimal number of publications on HIV-associated HHV-8 have been produced in Türkiye [10]. As a result of the literature review, it was observed that the number of studies investigating the seroprevalence of HHV-8 in PLWH in our country is quite limited. In 2002, Yilmaz et al. investigated HHV-8 IgG antibody positivity in 49 blood donors and 50 PLWH using an IFA-based method and determined seropositivity rates of 4 % and 21 %, respectively [11]. In 2013, Karlı et al. found the HHV-8 IgG positivity rate as 28.2 % in 85 HIV-1 positive patients using an ELISA-based method [6]. In 2016, Altuğlu et al. found the HHV-8 IgG positivity rate in 551 blood donors and 173 PLWH to be 5.3 % and 25.4 %, respectively, using an ELISA-based assay [1]. These studies are old and have outdated information. To address the lack of data, our study aimed to determine the seroprevalence of HHV-8 infection by investigating HHV-8 antigen-specific IgG antibodies in PLWH using the ELISA method.