An "overreaction" of the immune system in the early stages of pregnancy can have various causes. Thus, in women with repeated unsuccessful implantations or increased miscarriages, an increased concentration of NK cells could be detected both in the blood and in the uterine lining. In other cases, chronic inflammation of the uterine lining (endometritis) is responsible for the embryo rejection: studies suggest that endometritis is present in 10–20% of women who have suffered repeated failed implantations or multiple miscarriages.
Natural killer cells (NK cells) are a type of lymphocyte. As a subgroup of leukocytes (white blood cells), they are considered the "guardians" of the human immune system: they detect infected or abnormally altered cells (cancer cells) and kill them. Since an embryo always contains foreign genetic material, it can also be attacked in the case of an incorrect reaction on the part of the NK cells.
Plasma cells are formed from B lymphocytes as soon as the immune system signals the invasion of foreign cells. Plasma cells produce antibodies that fight pathogens and other invaders. Infections and chronic diseases – including chronic inflammation of the lining of the uterus (endometritis) – can be detected by an increased concentration of plasma cells in the blood.
If a patient has already undergone several unsuccessful attempts at implantation, or has suffered repeated miscarriages, without there being any other obvious causes, our doctors in the Fertility Clinic recommend the woman undergo immunological testing. This involves a piece of the uterine lining being biopsied between the 19th and 21st days of the cycle and then tested with respect to its concentration of NK cells and plasma cells in a specialist laboratory. Based on the result, our doctors will then recommend an individual course of therapy in order to best support you in your desire to have children.