The CD56 Test
What is the CD56 Test?
Natural Killer Cells, which are part of the immune system, have been found to adversely affect pregnancy formation when elevated levels are present in the uterus. The CD56 test is used to determine the density of “killer cells” within the uterus, which adversely affect the formation of pregnancy. The CD56 test is a test that allows us to understand the amount of killer cells in the uterus called the endometrium. It has been recommended for in vitro fertilization patients who have not been pregnant despite very good quality embryo transfer. Numerous molecular mechanisms are involved in the implantation of embryos to the uterus, both in spontaneous pregnancies and pregnancies resulting from IVF treatments. Within these mechanisms, it is of great importance that the immune system be appropriate for pregnancy.
In recent scientific studies, natural killer cells (NK cells) have been shown to play a very important role in the uterine implantation process. Whether the density of NK cells is above or below average in the inner layer of the uterus may adversely affect the implantation of embryos onto the uterus. One of the causes of pregnancy losses is a high density of NK cells in the inner layer of the uterus.
Who is the CD56 test recommended for?
The CD56 test can be performed on patients who want to have children, and who have had two or more miscarriages. In addition, it can be performed on patients who have not achieved pregnancy despite the transfer of three or more healthy embryos.
How is the CD56 Test Performed?
The CD56 test determines the ratio of natural killer cells (killer cells). It can be performed through blood sampling or uterine tissue sampling. However, since blood sampling may give inaccurate results, the preferred approach is to perform the test on uterine tissue.
After the ovulation period, an immunohistochemical assessment will be performed under anaesthesia by expert pathologists on the tissue sampled from the inner layer of the uterus between days 21 and 24.
Patients with high CD56 levels are administered immune system stabilizing treatments (such as intralipid injections) at appropriate intervals after the preparation for embryo transfer, and after appropriate conditions are provided.