A 2016 study showed that 43% of women with unexplained infertility tested positive for HHV-6A while 0% of women in the fertile control group tested positive. HHV-6A was found present in endrometrial epithelial cells from women with unexplained infertility. [2]
A 2018 study reports the prevalence of HHV-6A in endometrial biopsies among women experiencing recurrent implantation failure after IVF/ET compared to control groups.[3]
A 2019 study confirmed the presence of HHV-6A infection in 40% of idiopathic infertile women. Identifying the effect of HHV-6A infection on endometrial immune status opens up a new perspectives on fertility care. Its possible to choose antiviral therapies and non-hormonal approaches for women with unexplained infertility characterized by HHV-6A to increase their pregnancy rate.[4]
Taxonomy
In 1992 the two variants were recognised within Human herpesvirus 6 on the basis of differing restriction endonuclease cleavages, monoclonal antibody reactions,[5] and growth patterns.[6] In 2012 these two variants were officially recognised as distinct species by the International Committee on Taxonomy of Viruses and named Human betaherpesvirus 6A and Human betaherpesvirus 6B.[7] Despite now being recognised as paraphyletic, the name Human herpesvirus 6 still sees usage in clinical contexts.
Human betaherpesvirus 6A affects humans and includes several adult-derived strains. Its disease spectrum is not well defined, although it is thought by some to be more neurovirulent than Human betaherpesvirus 6B.[8][9]
^Coulam CB, Bilal M, Salazar Garcia MD, Katukurundage D, Elazzamy H, Fernandez EF, et al. (July 2018). "Prevalence of HHV-6 in endometrium from women with recurrent implantation failure". American Journal of Reproductive Immunology. 80 (1): e12862. doi:10.1111/aji.12862. PMID29667291. S2CID4944870.
^Bortolotti D, Gentili V, Rotola A, Cultrera R, Marci R, Di Luca D, Rizzo R (October 2019). "HHV-6A infection of endometrial epithelial cells affects immune profile and trophoblast invasion". American Journal of Reproductive Immunology. 82 (4): e13174. doi:10.1111/aji.13174. hdl:11392/2406194. PMID31338899. S2CID198193327.
