The immune system has become known to play a part in the potential success rate of planned pregnancies through IVF. A women’s immune system has within it, natural killer cells and these cells have been the subject of much ongoing study to know exactly the amount of correlation the presence of natural killer cells has in the successful outcome of pregnancy and child birth through IVF. Pregnancy has the ability to bring about changes in a women’s immune system and is believed to make a woman more prone to certain infections and complications with the child.

The kind of changes to the immune system that we are talking about are:

  • increased production of cells that destroy bacteria – improving antibody response

  • decreased activity of natural killer cells, which kill cells that have become infected

  • decreased activity of T cells, which help to control infections caused by viruses

  • decreased production of cytokines to recruit other cells to help fight infection

During pregnancy, your immune system changes so that it can protect both you and your baby from disease. Your body sees the baby as part self and part foreign. Some infections that occur during pregnancy pose a risk primarily to the mother and others can be transmitted to the foetus. Some infections during pregnancy can even lead to miscarriage.

Some known causes of miscarriage, though there are more, include:

  • Infection

  • Exposure to environmental and workplace hazards such as high levels of radiation or toxic agents

  • Hormonal irregularities

  • Lifestyle factors such as smoking, drinking alcohol, or using illegal drugs

  • Disorders of the immune system including lupus, an autoimmune disease

  • Radiation

  • Severe malnutrition

Immune System – Lupus

Lupus is an autoimmune disease where the body’s immune system becomes hyperactive and attacks normal, healthy tissue. Symptoms may include:

  • inflammation

  • swelling and damage to joints, skin, kidneys, blood, heart and lungs

Neonatal lupus occurs when a mother passes autoantibodies to a fetus. The unborn and newborn child can have skin rashes and other complications with the heart and blood. Lupus can increase risk of miscarriage.

Natural Killer Cells in study

On the Melbourne IVF blog page we can find a report from Assoc. Prof. Gavin Sacks who comments on research around this topic –

“Investigating an approach known as the Bondi Protocol, this research offers experimental immune therapy for women who test positive to high levels of natural killer (NK) cells in the blood or uterus. High NK cell activity has been associated with miscarriage and embryo implantation failure. Further randomised trials are clearly needed to prove that treatment leads to better pregnancy outcomes. However, the results of the research to date are promising, and there are exciting possibilities for the future.”

“…As the main immune cell-type found in the uterus in pregnancy, the concept of testing natural killer cells in a new group of patients – those suffering unexplained infertility, repeated miscarriages or IVF failure – was spawned by doctors in the United States. Their theory was that high levels of natural killer cells prevented pregnancy from occurring, and thousands of women across the globe latched onto this news in the hope that this was the answer and solution they had been searching for, but evidence has been lacking.”

“…When I moved to Australia 7 years ago, skepticism was rife amongst Australian specialists and not surprisingly. At this time I set out to find more evidence, and create a reliable test. It was important to identify the fundamental features of the test, such as what was a normal level of natural killer cells. This was of vital importance, as some American clinics claimed, unrealistically, that extremely high numbers of women apparently have abnormal immune function. What was found was that 15% of women with recurrent miscarriage had high levels of natural killer cells by our definition.”

“…A treatment protocol was then developed to study the effects of using an immunosuppressant to reduce the number and activation levels of natural killer cells. Known as the Bondi Protocol, it involves the use of Clexane and Prednisolone, both previously used in this area of study.”

“…In the seven years the study has been running, over 2000 women have been tested, and over 100 babies have been born. In a recently presented analysis, 87 women with high blood NK cell levels were treated with the Bondi Protocol and followed up closely (58 women had repeated IVF failure, and 29 had repeated miscarriage). This group of patients had particularly poor prognoses, with average age 38 and a history of 6 miscarriages or 6 failed IVF cycles. The overall cumulative live birth rate over several cycles was 52%. This success rate rose to 59% in those who had high levels of activated NK cells (using a marker called CD69), and 86% in those women aged less than 38. 80% of the miscarriage patients had a successful pregnancy within a year of the NK cell test, most occurring in the very first pregnancy treated. And 70% of the IVF patients had a successful pregnancy in the first 3 IVF cycles with the Bondi Protocol. It was also interesting to observe that the best outcomes occurred in couples with no other infertility factor (ie. ‘unexplained’), supporting the hypothesis that high NK cell levels may be itself an infertility factor.”

“…What was interesting about this study is that it has shown higher than expected live birth rates in patients with an otherwise poor prognosis. Many of these patients carried a successful pregnancy after many many miscarriages or failed IVF cycles.”

If you would like to talk further with a medical professional in regards to a woman’s immune system and the impact of natural killer cells on a pregnancy, contact the Dr Gary Swift Fertility Clinic here.