The discovery could potentially lead to new antiviral treatments to battle infertility.
According to the Centers for Disease Control and Prevention (CDC), infertility affects about 6 percent of women aged 15 to 44, which amounts to about 1.5 million women in the United States.
Unfortunately, about 25 percent of these infertility cases are unexplained, but a new study by researchers at the University of Ferrara in Italy may have exposed an unlikely culprit — a little-known member of the herpes virus family, called HHV-6A.
HHV-6A was first discovered back in 1986, according to the press release, and it’s one of nine human herpes viruses. However, its true prevalence is unknown since HHV-66A is typically undetectable in the blood or saliva.
The study, which looked at 66 women, found that HHV-6A infects the uterus lining of 43 percent of the women with unexplained infertility, but it was nowhere to be found in the uterine lining of the fertile women.
Further, the researchers found that the immune response to the herpes virus may contribute to making a uterus less hospitable to a fertilized egg.
Basically, the virus activates immune cells, called natural killer cells, in the uterus, and this leads to an increased production of proteins called cytokines. The immune system uses cytokines to attack foreign invaders (like viruses), but the researchers believe that the activated immune system cells and abnormal levels of certain cytokines may make it difficult for a fertilized egg to lodge in the uterus.
"This is a surprising and potentially important discovery," Anthony Komaroff, a professor at Harvard Medical School who has studied the herpes virus, said in a press release. "If confirmed, the finding may lead to treatments that improve the outcome for a large subset of infertile women."
Unfortunately, finding a proper treatment for HHV-6A may take some time, since there are currently no FDA-approved drugs for HHV-6A.
However, an HHV-6A infection in the uterine lining can be diagnosed using a standard biopsy procedure done by gynecologists, using a small suction device without a need for anesthesia.
If further research confirms HHV-6A’s role in infertility, perhaps researchers will have more incentive to work diligently towards an effective antiviral treatment.
“Overall, our study indicates that HHV-6A infection might be an important factor in female primary unexplained infertility,” the researchers conclude in the paper.
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