What do these letters and numbers mean? The study of immunology is complex and confusing. I will try to simplify this, but it still may be hard to follow. Don't worry- most doctors don't get it either. Lymphocytes are the major white blood cells involved in the body's immune responses to infection- and other conditions, including cancer. They have been subdivided based on receptors located on their surface. The "expression" of these receptors is the basis for categorizing the various types of lymphocytes. The various types of lymphocytes have been shown to have specific functions. Lymphocytes express multiple receptors. The CD8 cells are generally referred to as killer T cells, not to be confused with natural killer T cells. The CD4 cells are referred to as helper T cells.
The initial response, the innate response, is directed by lymphocytes. The natural killer T cells, defined by receptors found on their surface, constitute a very tiny percentage of the T cell population. Nonetheless, they have an important role in fighting infection. Laboratory scientists have developed specialized technology which allows for the separation of these various subsets of lymphocytes.(Flow cytometry).
Most natural killer T cells (NKT cells) are associated with a surface receptor referred to as CD56. The CD57 marker is associated with a smaller subset of NKT cells. Interestingly, these surface receptors (CD57) have been found on both CD8 cells and CD4 cells. Normally, one would expect these markers to be found on CD8 cells- the population of killer T cells.
A powerful CD57 response is associated with Lyme infection and with other bacteria as well. Other spirochetes do not invoke this response because the structure of their cell wall is different. The unique thing about Lyme (Bb) is that it has lipo-polysacharides on its cell wall. This is antigenic(antibody producing) material, which is devoid of protein. CD57 cells respond to this type of antigen whereas other NKT cells do not.
The initial immune reaction- the innate response, involves the mobilization of CD57 cells and other T cells as well as cytokines and other chemicals. Normally, a secondary acquired immune response should follow the innate response. This is mediated by B cells aided by helper T cells. Ultimately, the acquired immune response fails. Lyme (Bb) is driven inside the cells as L-forms. B cell responses do not work here. It then falls on T cell responses to become the body's major immune response needed to keep Lyme and other intracellular germs at bay.
CD57 responses involve the same pro-inflammatory cytokines as seen in Th1 helper T cell responses.
If CD57 responses are low, it may mean that these cells are being consumed by the immune system in the fight against Lyme. If they are high, it may mean that the body is busy cranking out the T cells to assist in the fight against Lyme.
There is little published regarding the clinical usefulness of this test. Dr. Stricker has reported that this measurement "May" be helpful in assessing the degree of illness seen in chronic Lyme patients.
So I have been ordering this test for years. Thousands. Unfortunately, I am left with the conclusion that it has been of very little help to my patients. I have seen no correlation between CD57 and disease activity. Patients in clinical remission may have very low levels and patients with end stage tertiary Lyme disease may have very high levels. Individual immune responses are difficult to predict. Dr. Burrascano has suggested that the CD57 test might be an inexpensive way to screen for Lyme disease. I do not agree. Physicians may order CD57 levels because they are looking for evidence to support the diagnosis. I do not think this approach will not hold up to careful scrutiny. Many patients unfortunately are getting the awful 13 band test performed at "mill labs." Patients don't want to spend the money to get a decent Lyme test. I do throw out a wide net looking for a variety of markers associated with Lyme disease. I could argue that the vitamin D reversal pattern, a possible marker of the Th1 response, is a much better screen for patients with Lyme disease and other chronic intracellular infections.
I have seen recent published statements claiming that it is not known how CD57 and Lyme are associated. My research shows otherwise. (If you could follow any of what I said about it). However, in my opinion and experience, this marker has not been clinically useful.