Presence Of Human Herpesvirus 6 In Endometrial Samples Of Women With Reproductive Failure

INTRODUCTION: Human herpesviruses 6A and 6B (HHV-6) are members of the Herpesviridae family that includes cytomegalovirus and herpes simplex virus. Like other human herpesviruses, HHV-6 can persist unknowingly in a latent state. Recent studies have identified the presence of HHV-6 within the endometrial cells in 43% of women with unexplained infertility, but has not been seen in known fertile women. This study evaluates the association between presence of HHV-6 and different infertility subgroups including repeated implantation failure (RIF), recurrent pregnancy loss (RPL), and unexplained infertility. METHODS: A prospective cohort evaluation was performed on 201 women undergoing examination for unexplained infertility, RPL, or RIF. Data was collected from five infertility clinics from October 2017 to October 2019. Endometrial biopsies were collected from each patient and immunohistochemistry was performed to identify a late viral protein of HHV-6. RESULTS: A total of 75 of the 201 women met the criteria for RIF. The other 126 women were diagnosed with unexplained infertility or RPL. Of the 201 women, 75 women (37.3%) were positive and 126 were negative for HHV-6 viral antigen. In the 75 patients with RIF, 38 biopsies (51%) were positive for HHV-6. In the 126 women without RIF, 37 biopsies (29.3%) were positive for HHV-6. CONCLUSION: While previous studies have shown an association between HHV-6 and unexplained infertility, this cohort demonstrates the infection is likely associated with multiple causes of reproductive failure. The presence of HHV-6 in the endometrial cells of these patients supports further study of the pathogenesis of the infection.