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Natural Killer Cell (NK Cells)

Immune cells in the uterus are important in the early detection and elimination of foreign cells, such as infections or cancer. These immune cells are normally present in every person as part of their immune system.

Ongoing research into 'Natural Killer cells' (NK Cells) is needed to determine their role in implantation failure. Some women who have fertility problems, and specifically recurrent miscarriage or failed IVF, are more likely to have higher levels of activity of these NK cells than other women. What this means for treatment is still not clear, but a number of different treatments are being trialled.

What is natural killer cell testing?

Testing for Natural Killer Cell Activity at Melbourne IVF involves a simple blood test to measure the number and activation levels of the NK cells. The blood test can be performed as an alternative to, or in conjunction with, a traditional endometrial biopsy of the uterus.

An endometrial biopsy can be taken via a soft plastic catheter that is used to gently aspirate a tiny piece of the uterine lining as an awake procedure, or under general anaesthetic as part of a hysteroscopy. The biopsy is then sent off to the laboratory for testing. The biopsy has to be done at the luteal phase of the month (around Day 21 in a 28 Day cycle) while the blood test can be done at any stage of the month. Your fertility specialist will decide which combination is suitable for you.

NK Cell activity testing can be considered in the following situations:

  • recurrent miscarriage (defined as three successive miscarriages if aged less than 35 years, two successive miscarriages if aged over 35 years)
  • repeated IVF failure (defined as two or more unsuccessful fresh IVF cycles)

How do I get the natural killer cell test?

The NK Cell Activity blood test is available by appointment only at Melbourne IVF East Melbourne.

  1. Obtain a blood test request from your Melbourne IVF fertility specialist
  2. Your referring Melbourne IVF fertility specialist will make your appointment with our East Melbourne laboratory for your Natural Killer Cell blood test
  3. The test must be done only once your appointment time has been confirmed on a Monday or Wednesday between 11am to 2pm
  4. Attend the appointment. Patients need to bring their blood test request form with them and present it to reception. One of our phlebotomists will draw one small tube of blood collected into a specialised tube (Streck) for the NK Cell blood test. Any additional tests on the request form may be collected at the same appointment
  5. Results of the test should be available within 4 business days after collection and will be sent to your referring Melbourne IVF fertility specialist
  6. Make an appointment for a follow-up visit to your fertility specialist for discussion of your test results and any advice on treatment therapies [as deemed appropriate]

More about natural killer cells

Immune factors affecting pregnancy

The body's immune system includes among its functions the ability to recognise ‘foreign’ or threatening invasion by infection or cancer cells. In some instances (called autoimmune diseases) the immune system mistakenly recognises and attacks ‘self’, and this leads to inflammation, damage and disease.

Pregnancy is a unique situation in which the placenta invades the lining of the womb and is a potential threat to the wellbeing of the mother. The mother’s immune system must recognise that threat, but also respond in such a way that does not eliminate it. The mother’s immune system is critical in establishing the relationship between the mother and the fetus that allows both to flourish.

The immune system has two main mechanisms:
1.    cellular (type 1); and
2.    antibody (type 2)

In normal pregnancy, substances produced by the placenta (particularly progesterone) cause a shift in how the mother’s immune system behaves so that it becomes ‘type 2 dominant’. This is because type 1 responses are potentially more dangerous for the pregnancy. People with autoimmune diseases, such as Lupus, rheumatoid arthritis tend to have high levels of anti-nuclear antibodies, that can lead to inflammation of the uterus and placenta, implantation failure and recurrent miscarriages.

Costs and getting started

The cost of the Natural Killer Cell test at Melbourne IVF is $350.00

If you would like to know more about the NK Cell blood test and the Melbourne IVF Fertility Specialists with expertise in this area, please call our Public Liaison Administrators on 1800 111 483 or complete the form below.