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Leukocyte antibodies (LA) identify non-self leukocytes, and leukocytes are types of white blood cells that circulate in the blood, bone marrow, and lymph systems. These white blood cells are an essential part of the immune system and include the Natural Killer (NK) cells.

The LA role is primarily to remove bacteria (or other foreign invaders) and any abnormal cells in the body. People typically have relatively high leukocyte antibody levels when they’re exposed to “foreign” material, including blood or organ transplants, and in pregnancy.

During pregnancy, the mother’s immune state changes as it makes adjustments to accept the presence of the foetus. The foetus isn’t 100% “self’” as half the genetic material comes from the father, and if the mother’s immune response is unbalanced, the foetal cells and placenta can be attacked in an overactive aggressive Th1 state. This is something that happens when Natural Killer (NK) cells are elevated.

Immune Balance

In a healthy pregnancy, the woman’s restraining and suppressive Th2 side of the immune system need to create antibodies that “cloak” the pregnancy from the normal immune response to “non-self” cells. Without both the aggressive and suppressive sides of the immune system becoming activated, pregnancies fail because:

  • The autoimmune Th1 aggressive state needs to recognise the pregnancy so changes to the womb, blood supply etc., are essential for pregnancy to occur
  • The foetus needs to be protected from an extreme Th1 immune response that would terminate the pregnancy, which is the function of the suppressive Th2 side
  • It’s a balancing act between altering the womb to accommodate a pregnancy without an aggressive immune response targeting the foetus

In leukocyte antibody dysfunction, there’s a lack of a reaction from the woman’s Th2 suppressive and restraining side of the immune system. The outcome is that although the pregnancy hasn’t triggered an overly aggressive Th1 response, it’s still terminated by the Th1 side.

LA imbalance

In normal pregnancies, a woman’s blood tests positive for a certain level of Th2 leukocyte antibodies, which appears to protect the pregnancy. However, when leukocyte antibodies on T white blood cells are below 30%, the Th2 “cloaking” response is too weak. In these cases, what’s essentially a normal aggressive Th1 immune response removes the cells of the placenta, and the pregnancy ends.

Although the outcome is similar to the better-known elevated NK-cells scenario that causes implantation failure and early miscarriage, the cause is different. Rather than an overly aggressive Th1 immune system, the problem here is the underperformance of the suppressive Th2 side to pregnancy.

Testing and Treatment

Standard testing uses blood samples from the male and female partners in a ‘leukocyte antibody detection assay’ (LAD) or “cross-match test”. LAD measures the woman’s level of blocking antibodies and her ability to produce the cloaking immune response:

  • Levels below 30% are an abnormally low response
  • 30-50% is borderline
  • Above 50% is seen as normal

The standard treatment for LA is Leukocyte Immunisation Therapy (LIT) which involves immunizing the woman with lymphocytes from the male partner or a donor. Research indicates an increased immune response with LIT, but that women who have repeated unexplained pregnancy losses produce a low immune response. i

Immune balance relies on many factors, including diet, stress and lifestyle. To identify ways to improve personal immune health, we recommend the morefertile PFPs, and herbal medicine also offers a relatively successful treatment option for leukocyte antibodies (88% of 59 patients). ii