White blood cells circulate in the blood and can be divided into a number of different types that can be identified by conventional staining techniques that permit their identification under the microscope or by an automated blood counting instrument. One type of these cells is known as the lymphocyte and is the major cell of the immune system. There are a large variety of different types of lymphocytes each charged with a different role in immune function. While lymphocytes, in general can be distinguished from other white blood cells by conventional means, the wide variety of lymphocytes all appear the same. However, the different lymphocyte types each display different protein molecules on their surfaces. These molecules allow the identification of the lymphocyte types when they are identified by the use of laboratory-prepared antibodies directed against these molecules.
When identified on the surface of individual lymphocytes either singly or in combination with other surface protein markers, they allow the identification of individual lymphocytes. A specialized immunology laboratory instrument known as the flow cytometer is capable of detecting and identifying individual lymphocytes after they have been treated with antibodies selected to identify particular lymphocyte types. The instrument is able to provide information about the proportions of the individual lymphocytes within the entire pool circulating in the peripheral blood. Look at the section on immune pathology where a similar strategy is used to identify lymphocytes within biopsy specimens from the uterine lining.
Disturbances in the proportions of lymphocyte types may be an indicator that there is an immunologic problem that is found in patients suffering recurrent pregnancy loss or IVF failure. The findings may suggest to the physician that treatment is indicated to restore the proper proportions of lymphocytes in the peripheral blood.
The cells that are quantified in the assay each carry a specific cell marker that allows them to be identified. These include CD-3, CD-4, CD-8, CD-19, CD-5, CD56, CD16. As noted, they identify the major lymphocyte types either used singly or in combination.
CD-3 (Pan T-Cells)
T cells make up the majority of lymphocytes found in the blood. These cells are the most important in our immune system. They may be low when the immune system is weak (suppressed) and normal when the immune system is healthy. Experience has shown that women with high values may be found inInfertile patients and patients with recurrent pregnancy losses.
CD-4 (T-Helper Cells)
These cells are a type of CD-3 T lymphocytes. They are the directors of the immune response. They cannot function without the road map provided by the CD-4 T Helper cells. Some T-helper cells help mount a response against foreign agents such as viruses that inhabit the infected cell. These are the Th1 type lymphocyte. When active, they are capable of secreting hormone-like substances known as cytokines that turn on the immune response removing infected cells. Identification of these helper T cells requires another test, the intracellular cytokine assay.Other T-helper cells are adapted to releasing cytokines that help in eliminating foreign organisms outside of cells. These are the Th2 type lymphocyte. They are also identified in the intracellular cytokine assay.
CD8 T cells are the effectors of many of the immune responses. They efficiently eliminate infected and abnormal cells. They are infrequently abnormal in women with reproductive issues.
CD-19 (B Cells)
These lymphocytes mature into plasma cells that produce antibody. In our experience B cells are frequently high normal or elevated in women with an immune cause for their infertility or recurrent pregnancy losses. We often see values greater than 12% elevation.
CD 19+/5+ (B-1 Cells)
B cells may be of two subtypes known as B-1 and B-2 cells. When we examine a second surface-displayed marker on CD19 expressing cells known as CD5, the cells are classified at B-1 B cells. They represent a class of B cells that is involved in autoimmune disorders (conditions where the body mounts an immune response against a body tissue). Women with elevations of these cells may be at risk for thyroiditis and the premature menopause. We pay close attention to the numbers of these cells when attempting to identify patients with immune-related conditions.
CD 56+ Natural Killer Cells
Display of the CD56 protein on the cell surface identifies cells of the natural killer family. Natural killer cells are named such because, unlike T cells, they have an inherent capacity to identify foreign or abnormal self-self and effect their elimination. When their number reaches a certain level, in our experience, they are likely to be associated with reproductive failure. Interestingly, numbers that have been associated with failure may still remain within the range of healthy, non-pregnant women. To confirm suspicion that natural killer cells may be functioning too aggressively, a test, known as the NK Assay, is performed. In assay cells are actually tested for their ability to kill other cells. Natural killer cells are present both in the blood and in the uterine tissues of pregnancy. In the latter site, natural killer cells take on special functions unlike their brethren in the blood. There they assist in transforming the uterine blood vessels into vessels capable of the task of supporting the fetus and placenta over the nine months of pregnancy. Under normal, healthy circumstances, these NK cells serve a role that is unlike that of their blood borne brothers. That is until there is an infection. At that time natural killer cells assume their more recognized role in killing targeted cells. Often this response results in loss of the pregnancy. While these cells differ from those found in the blood, it is fortuitous that we can measure the natural killer activity of the cells in the blood and learn much about the activity of those within the uterus.
Natural Killer Cell Assay
The Natural Killer research test simply separates NK cells from the patient and asks them to perform their aggressive roles in the test tube. Varying concentrations of IVIg are added to the test tube to determine how much is necessary to prevent killing.
The information contained in this article is not intended to be a medical diagnosis, treatment or medical advice in any way, as it is general information and cannot be relied on without consultation with your physician. It is not intended nor is it implied to be a substitute for profession medical advice. As medical information can change rapidly, we strongly encourage you to discuss all health matters and concerns with your physician before embarking on new diagnostic or treatment strategies.