Leukocyte Antibody Detection (LAD) Test
The Leukocyte Antibody Detection or LAD test measures the amount of antibody that reacts with proteins of non-self (usually paternal) blood cells. These antibodies are of particular interest in part, because they appear to be protective in pregnancy. In women with a history of implantation failures and/or miscarriages LAD levels may be unusually low (IgG B cell levels<30%). The reason these antibodies are protective in pregnancy is still under investigation. However, some scientists believe that they act by preventing or “blocking” the damaging immune responses to fetal tissues that contain these similar foreign (paternal) proteins.
Regardless of which way they function, it has been noted that women with low levels of LAD antibodies have an increased risk of loss. To this end, physicians have sought means to increase “recognition” of paternal proteins detected in the LAD. This means of antibody increase is often done through a procedure called Lymphocyte Immunization Therapy or LIT. (See: Lymphocyte Immunization Therapy (LIT).
Which way the immune response functions, either with an aggressive immune response or one that is protective, is also, is determined, at least in part, by cells known as “T regulatory cells” (See: T regulatory cells). Low numbers of T regulatory cells have been found to fail to prevent an aggressive immune response. Chinese researchers have found that found that LIT actually increases these T regulatory cells in the blood. Because of this and other published data, we believe that patients contemplating LIT should be have both their LAD levels and T regulatory cell levels tested.