I see a lot of clients and have over the past few
years been increasingly aware of the area of reproductive immunology. Like most
the starting point for this was the book ‘ Is your body baby friendly’ by Dr
Alan. Dr Alan Beer is the man behind the whole area of reproductive immunology
and the originator of the ‘Chicago protocol’. He set up his clinic as a pioneer
and he was instrumental in the fertility world with regards to looking into the
immune system as a causative factor to multiple miscarriage and failed
implantation. As a result, many IVF clinics started looking at Cytokines, the
bodies ‘war’ machine and as I like to call them the ‘ Special forces’ or more
commonly know - Natural Killer Cells.
What are NK cells and how are they
relevant to pregnancy?
Natural killer cells are under normal circumstances
a natural and healthy part of the immune system. They are there to eliminate
anything harmful that could cause a threat to your body. They are a type of white blood cell that
provides a rapid response to infected cells and go to task particularly if they
are needed in the case of tumours that start to form but equally get in there with viruses, parasites and bacteria.
When we get pregnant, NK cells need to get the
signal to ‘ power down’ - after all although it is the most natural thing in the
world to be pregnant, it is essentially 50% foreign DNA. At the time of pregnancy (and normally the first
12 weeks) the brain needs to give the signal to lower the natural defences of
the body, a situation that can understandidly confuse things. It must be really hard for the body's immune system to
ignore what looks like a pathogen starting to develop, via the uterus, as
during this early time - implantation starts a whole chain reaction where it then
starts to establish its own blood supply!
What should happen before an
expensive blood test for NK cells
If you have had multiple miscarriages or grade A
eggs at IVF and your partners sperm has also been verified as good with no DNA
fragmentation, then the next step for me is always a hysteroscopy. This procedure
involves taking a biopsy of your uterine lining and the results will show if
there is unusually high NK cells. For me this is the most effective way to
establish if NK cells are invasive and could be causing miscarriage.
What normally happens…
If you are working with a progressive IVF centre,
they may after 3 or more failed IVFs or miscarriages, send off for a raft of
blood tests, which cost a pretty penny!
What you need to know before ordering or letting
your reproductive specialist lead on some very expensive tests is the
difference between blood NK cells and uterine NK cells. Another thing to keep in mind which takes it a
little deeper is you should know is that NK Cells are deemed Bright NK, Super
Bright and Dim NK cells http://www.jimmunol.org/content/181/3/1869.full.pdf
..’During implantation, CD56bright NK cells are reputed to play an
important role whereas CD56dim NK cells are mostly negatively associated with
reproduction'.
In a few studies they found
that the proportion of the uterine CD56dimCD16+ NK cells was significantly lower in IVF patients
as compared to the controls (6.9 and 13.7% ) The proportion of CD56bright NK cells was no different between IVF patients and
controls in the uterus (28.8 and 33.5%) This data indicated a shift in the ratio
towards the beneficial CD56bright NK cells and away from the harmful CD56dim NK cells…’
In peripheral blood there is no shift in the CD56dim/CD56bright ratio
Blood NK cells are very different to uterine NK cells leading some
experts to conclude that “measuring any parameter of NK cells in blood is not
useful in trying to understand the cause of reproductive failure” http://humrep.oxfordjournals.org/content/early/2015/12/05/humrep.dev290
The important thing to keep in mind when you
have had multiple miscarriages is that the you need to know a little more about
these new tests before proceeding to the next stage and what inevitably can
then involve more costs. It is my view that a biopsy is the only way to confirm
high NK cells which may be causing some issues with implantation and growth of
the baby.
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