Introduction HSV type specific antibodies (IgG1 and IgG2) are produced and persist after HSV-1 and –2 infections. Therefore, IgG2 HSV serologic tests are used as an indicator for genital herpes history (e.g. in pregnant women), to counsel partners of genital herpes patients, and as a proxy marker of high-risk sexual behaviour. We tested this paradigm by retrospectively measuring IgG1 or IgG2 HSV antibodies in sequential serum samples from visitors with symptomatic PCR proven recurring genital herpes episodes.
Methods We selected individuals with two episodes of PCR proven HSV-1 or HSV-2 genital herpes, which were at least 3 months apart. Serum samples collected during the second (recurring) episode were tested with a HSV type specific ELISA and Immunoblot (both Focus HerpeSelect®) for anti-gG1 or anti-gG2 antibodies. The immunoblot was used as a reference test.
Results From May 2006 to December 2010 we selected 18 and 35 individuals with recurrent HSV-1 or HSV-2 genital herpes, respectively. In the HSV-1 cohort, serum sample testing showed that 13 out of 18 (72%) samples were tested positive in both tests, 2 out of 18 (11%) samples were positive in the gG1 ELISA but negative in the immunoblot, and 3 out of 18 (17%) samples were negative/equivocal in both tests. In the HSV-2 cohort, serum sample testing showed that 29 out of 35 (83%) samples were positive in both tests, 1 out of 35 (3%) was positive in the gG2 ELISA but negative in the immunoblot, and 5 out of 35 (14%) samples were negative in both tests.
Discussion Our data show that HSV IgG1 and IgG2 antibodies are false negative in respectively 28% and 17% of recurrent genital infections. This should be taken in consideration when these tests are used in a clinical setting or as proxy for risk behaviour in epidemiologic studies.
- genital herpes