Monday, April 17, 2017

Natural Killer Cells / “alloimmune implantation dysfunction” / “autoimmune Implantation Dysfunction"

Here’s post 2 of 2 on some of the more “pseudo-science” infertility issues: natural killer cells / “alloimmune implantation dysfunction” / “autoimmune implantation dysfunction”.

I’ve read about “NK” (natural killer) cells (it sounds like something made-up, doesn’t it?), and I found an article that gives some background on them:

“Natural killer cells acquired their name as a result of the initial test used to identify them in vitro…. Regrettably, this is a misleading name in reproduction, and the powerful image of maternal cells attacking the fetus is emotive and easily exploited.”

The article concludes that, at least as it relate to NK cells, there is no evidence to support use of steroids (such as prednisone):

“Infertile women and those with recurrent miscarriages are being given treatments such as steroids, intravenous immunoglobulin, and tumour necrosis factor-α blocking drugs with the questionable aim of suppressing NK cells. Recent high profile radio and press reports have featured a UK trial of steroids in recurrent miscarriage that has not been published but claims a success rate of about 85% (Woman's Hour, 29 Jan 2004).14 How this study was controlled is uncertain, but it is important to bear in mind the placebo effect and the well documented success achieved with such patients simply using care and reassurance.15 Neither steroids nor the other treatments being offered to women with “raised” levels of NK cells in blood are licensed for use in reproductive medicine, and all these treatments are associated with known risks to mother and fetus. The treatments are offered despite recent guidelines from the Royal College of Obstetricians and Gynaecologists, a Cochrane review, and a meta-analysis all concluding that there is no evidence to show they are beneficial.”

Here’s another study talking about: “peripheral blood NK cells of women with [repeated spontaneous abortion] and infertility of unknown aetiology have higher proportions of activated NK cells in vivo.”

Multiple studies have shown an association between high density of uterine natural killer cells and recurrent miscarriage. We have shown that prednisolone reduces the number of uNK cells in the endometrium. The question remains as to whether reducing the number of uNK cells improves pregnancy outcome.

“Embryo implantation and early pregnancy development occur in a relatively hypoxic environment (2-3% O2) [12]. Inappropriate blood flow to the intervillous space has been associated with oxidative stress damage to the developing placenta and thus miscarriage [13]. UNK cell density in women with recurrent miscarriage was found to be positively correlated with endometrial angiogenesis and uterine artery blood flow [14]. A similar positive correlation was also found in women with unexplained recurrent failure of in-vitro fertilisation (IVF) [15]. Thus, we have proposed that increased uNK cell density is associated with increased number of spiral arteries which may lead to inappropriate blood flow to the developing foetal-placental unit causing oxidative stress and consequent miscarriage [14].”

This study wants to do a trial on prednisolone use.

Here’s another article that suggests that 20mg prednisolone reduces UNK cells:

Here are some other links:


  1. I find this whole area very interesting. When I was diagnosed as having elevated natural killer cells by my immune doctor, I started doing my own research and ended up feeling more confused than ever! In the end I decided I would go with the treatment (prednisolon and Intralipid infusions) in case it helped as of course you will do anything if you think it might work! I also found the book "is your body baby friendly?" by Dr Beer interesting as he talks about the whole immune area. According to him if the infertility/miscarriages are related to immune issues then he has seen success in 80% of women within 3 natural or IVF cycles after getting treated and there were loads of success stories in the book. I don't agree with the article quoted about which talks about the placebo effect and 'care and reassurance'. I don't see how the placebo effect can prevent a woman miscarrying since that implies it's all in our heads.

    1. Yea, it seems like when it comes to unexplained recurrent losses, there are no accepted answers. (I guess that's what makes them unexplained!) A friend is seeing a doctor specializing in recurrent loss, and it doesn't seem like this stuff is well accepted. (Her doc specifically says the IVIG stuff has not evidence on her bio:

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