Journal of Clinical Virology 30 (2004) 137–144 Human herpesvirus 8 seroconversion in Kenyan women by enzyme-linked immunosorbent assay and immunofluorescence assay Bhavna H. Chohan a,c,1 , Heather Taylor b,2 , Rosemary Obrigewitch b,2 , Ludo Lavreys c,3 , Barbra A. Richardson d,4 , Kishorchandra N. Mandaliya f,5 , Job J. Bwayo a,6 , Joan K. Kreiss c,e,7 , Rhoda Ashley Morrow b,∗ a Department of Medical Microbiology, University of Nairobi, P.O. 19676, Nairobi, Kenya b Department of Laboratory Medicine, University of Washington, Seattle, WA, USA c Department of Epidemiology, University of Washington, Seattle, WA, USA d Department of Biostatistics, University of Washington, Seattle, WA, USA e Department of Medicine, University of Washington, Seattle, WA, USA f Coast Provincial General Hospital, P.O. 91276, Mombasa, Kenya Received 30 April 2003; accepted 1 August 2003 Abstract Background: Human herpesvirus 8 (HHV-8) antibody tests vary in reported sensitivity and specificity, depending on the population tested and the assay. Objective: The purpose of this study was to compare the ability to detect seroconversion to HHV-8 in a cohort of HHV-8 seronegative female commercial sex workers in Kenya using three tests: HHV-8 viral lysate-based enzyme-linked immunosorbent assay (ELISA), an immunofluorescence assay for HHV-8 lytic antigens (IFA-lytic) and IFA for latent nuclear antigens (IFA-LANA). Study design: By ELISA, 16 women from a prospective cohort of commercial sex workers were identified as seroconverting to HHV-8. A total of 124 post-enrollment samples from these 16 women as well as the enrollment samples were tested for HHV-8 antibodies by all three assays to monitor seroconversion. Results: Of 16 women with apparent seroconversion by ELISA, 8 had a rise in IFA-lytic titers either concomitant with or prior to the first positive ELISA sample and no initial LANA by IFA. Five of the 16 women were IFA-LANA positive at entry, indicating prior infection with HHV-8. Three women had no evidence of seroconversion by either IFA-lytic or IFA-LANA and two of these three had increased ELISA reactivity concomitant with HIV-1 infection. Conclusions: Conversion from a negative to a positive ELISA result for HHV-8 antibody indicated seroconversion in only half of the study cohort of 16 women when IFA-lytic and IFA-LANA results were considered. The IFA-lytic assay was more sensitive than ELISA for early antibody responses. The IFA-LANA was positive in some women who had neither IFA-lytic nor ELISA antibodies suggesting it may be a marker for latent infections. Presumptive identification of incident HHV-8 infection by ELISA screening followed by IFA-lytic testing to confirm the positive test and IFA-LANA to rule out prior infection provides the most accurate documentation of HHV-8 seroconversion. © 2003 Elsevier B.V. All rights reserved. Keywords: Human herpesvirus 8; Human immunodeficiency virus; Kaposi’s sarcoma; Enzyme-linked immunosorbent assay; Immunofluorescence assay ∗ Corresponding author. Present address: Children’s Hospital & Regional Medical Center, Virology Office, G-815, 8G-3, 4800 Sand Point Way N.E., Seattle, WA 98105, USA. Tel.: +1-206-987-2117; fax: +1-206-987-3885. E-mail addresses: iartp@u.washington.edu (B.H. Chohan), hjt@u.washington.edu (H. Taylor), rm.obrigewitch@seattlechildrens.org (R. Obrigewitch), llavreys@africaOnline.co.ke (L. Lavreys), barbrar@u.washington.edu (B.A. Richardson), kishor@nyalimsa.com (K.N. Mandaliya), bwayo@africaonline.co.ke (J.J. Bwayo), jkreiss@u.washington.edu (J.K. Kreiss), rhoda.morrow@seattlechildrens.org (R.A. Morrow). 1 Present address: International AIDS Research and Training Program, Box 359909, 325 Ninth Ave., Seattle, WA 98104-2499, USA. Tel.: +1-206-731-2822; fax: +1-206-731-2427. 2 Present address: Children’s Hospital & Regional Medical Center, Clinical Virology Lab, G800A, 4800 Sand Point Way N.E., Seattle, WA 98105, USA. Tel.: +1-206-987-2088; fax: +1-206-987-2793. 3 Tel.: +254-11-474-055; fax +254-11-474-055. 4 Present address: 325 Ninth Ave., Box 359909, Seattle, WA 98104-2499, USA. Tel.: +1-206-731-2425; fax: +1-206-731-2427. 5 Tel.: +254-11-313-379/228-827; fax: +254-11-316-458. 6 Tel.: +254-2-724-194; fax: +254-2-712-007. 7 Present address: Box 359931, 325 Ninth Ave., Seattle, WA 98104-2499, USA. Tel.: +1-206-731-8496; fax: +1-206-731-6005. 1386-6532/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.jcv.2003.08.017