But this study, Triche and co-authors at the University of Iowa wrote, "provides to our knowledge the first examination of the effects of maternal-fetal HLA sharing in the context of history of exposure to seminal fluid."
(Co-author Audrey Saftlas led another study, online Aug. 22 in the journal, showing that increasing degrees of vaginal, but not oral, semen exposure significantly reduced preeclampsia risk among women in the SOPHIA population.)
Different means compatible?
The underlying biology, Triche said, appears to relate to how the mother's immune system comes to view these foreign genes, first as introduced by the father's sperm and then in the fetus.
"At the maternal-fetal interface it appears that for a successful pregnancy to occur it's likely the mother has to recognize it as foreign and develop a tolerance," Triche said.
In other words, unlike a transplanted organ that is most readily accepted if HLA genes are very similar, a fetus will be welcome if it appears genetically distinct. Greater exposure to the father's semen perhaps better primes the mother's immune system to recognize and tolerate that difference.
That said, the study yielded a nuanced secondary finding, which is that similarity between mother and fetus for the Class II gene HLA-DQB1 was associated with a smaller but still significant increase in preeclampsia odds among women who had higher degrees of exposure to semen.
"That is something that has to be looked at in further studies," Triche said. It could be, she said, that those results simply confirm a unique role in preeclampsia for sharing of that particular gene.
Potential for planning
If the higher odds from these particular combina
|Contact: David Orenstein|