Objectives: APOE alleles have been associated with the severity of, or susceptibility to, infection by various microbes. We investigated the potential association between the APOE-∊4 allele and the rate of recurrence of genital herpes in HIV-positive patients.
Methods: One hundred consecutive HIV-positive patients known to be co-infected with HSV2 on baseline serological testing were recruited during their routine attendance to HIV outpatients. At study entry, we established the number of recurrences of genital ulceration experienced by each patient. Recurrent disease was defined as two or more clinical outbreaks of genital herpes in the preceding 12 months. Any history of genital ulceration prior to this time period was also recorded.
Results: The gender and ethnic mix of the study population was representative of our HIV clinic cohort. Of the 96 patients who provided complete data, 24 had 'recurrent' disease and 72 were in the 'non-recurrent' group. 79.2% of patients with recurrent disease were APOE-∊4 carriers, compared to 40.3% of those in the non-recurrent group (p=0.001). The APOE-∊4 allele was significantly associated with recurrent genital ulceration, independent of ethnicity, antiretroviral therapy and CD4 count (multivariate analysis: OR 8.3; 95% CI 2.4 - 28.5). APOE-∊4 was also more likely to be present in those reporting a history of genital ulceration at least once in their lifetime as opposed to asymptomatic HSV2 carriers (p=0.04).
Conclusion: To our knowledge, this is the first published study demonstrating this association. This pilot study suggests that APOE-∊4 may represent a future prognostic marker for symptomatic recurrence of genital herpes in HIV-positive individuals.