Herpes simplex virus type 2 antibody detection performance in Kisumu, Kenya, using the Herpeselect ELISA, Kalon ELISA, Western blot and inhibition testing
- J S Smith1,
- R C Bailey2,
- D J Westreich1,
- I Maclean3,
- K Agot4,
- J O Ndinya-Achola5,
- W Hogrefe6,
- R A Morrow7,
- S Moses2
- 1University of North Carolina, Chapel Hill, North Carolina, USA
- 2University of Illinois at Chicago, Illinois, USA
- 3University of Manitoba, Manitoba, Canada, USA
- 4UNIM Project, Kisumu, Kenya
- 5University of Nairobi, Nairobi, Kenya
- 6Focus Diagnostics, Cypress, California, USA
- 7University of Washington, Seattle, Washington, USA
- Jennifer Smith, University of North Carolina at Chapel Hill, School of Public Health, McGavran-Greenberg, Campus Box 7435, Chapel Hill, North Carolina, 27599-7435, USA;
- Accepted 5 October 2008
- Published Online First 27 October 2008
Background: In certain parts of Africa, type-specific herpes simplex virus type 2 (HSV-2) ELISAs may have limited specificity. To date, no study has been conducted to validate HerpeSelect and Kalon type-specific HSV-2 ELISAs using both the Western blot and recombinant gG ELISA inhibition testing as reference standards.
Methods: A total of 120 men who were HIV seronegative (aged 18–24 years) provided blood samples. HSV-2 IgG serum antibodies were detected using four different methods: HerpeSelect HSV-2 ELISA (n = 120), Kalon HSV-2 ELISA (n = 120), University of Washington Western blot (n = 101) and a recombinant inhibition test (n = 93).
Results: HSV-2 seroprevalence differed significantly by HSV-2 detection method, ranging from 24.8% with the Western blot to 69.8% with the HerpeSelect ELISA. Using the Western blot as the reference standard, the HerpesSelect had the highest sensitivity for HSV-2 antibody detection (100%) yet lowest specificity (40%). Similar results were obtained using the inhibition test as the reference standard. The sensitivity and specificity of the Kalon test versus the Western blot were 92% and 79%, respectively, and 80% and 82% versus the inhibition test. Using the inhibition test as the reference standard, the sensitivity of the Western blot appeared low (49%).
Conclusions: In men in western Kenya who were HIV seronegative, the HerpeSelect and Kalon type-specific ELISAs had high sensitivities yet limited specificities using the Western blot as reference standard. Overall, the Kalon ELISA performed better than the HerpeSelect ELISA in these young men from Kisumu. Further understanding is needed for the interpretation of HSV-2 inhibition or ELISA test positive/ Western blot seronegative results. Before HSV-2 seropositivity may be reliably reported in selected areas of Africa, performance studies of HSV-2 serological assays in individual geographical areas are recommended.
Funding: This study was supported by a RO1 grant from the National Cancer Institute, National Institutes of Health (NIH) (CA114773-01); by grant number AI50440 from the Division of AIDS, National Institute of Allergies and Infectious Disease, NIH; and by grant number HCT 44180 from the Canadian Institutes of Health Research (CIHR). SM was the recipient of an Investigator Award from the CIHR. DW was supported by an unrestricted educational training grant from the University of North Carolina (NC-GSK) Center for Excellence in Pharmacoepidemiology and Public Health, University of North Carolina School of Public Health and NIH/NIAID 5 T32 AI 07001-31 Training in Sexually Transmitted Diseases and AIDS.
Competing interests: WH is a full-time employee of Focus Diagnostics. RAM has received research contracts during the last 5 years from Bio-Rad Laboratories, Focus Diagnostics and GlaxoSmithKline, and speaker honoraria or consulting fees from Biokit USA and Roche Diagnostics. JSS has received consulting fees from Focus Diagnostics within the past 4 years.
Ethics approval: All study protocols were reviewed and approved by the Institutional Review Boards of the University of Illinois at Chicago, University of Manitoba, University of Nairobi and the University of North Carolina, and by RTI International.
Contributors: RCB, SM, KA and NJO conceived the study protocol and supervised the fieldwork; DJW was responsible for statistical analyses; RAM was responsible for HSV Western blot serological testing; WH was responsible for the inhibition HSV serological testing; IM was responsible for HerpeSelect ELISA testing; JSS drafted the manuscript, which was critically revised by all authors.