Pregnancy Problems?
P.L.I. or L.I.T?
What is Paternal Lymphocyte Immunization? aka Lymphocyte Immunization Therapy?
Paternal Lymphocyte Immunization (PLI) or Lymphocyte immunization therapy (LIT) is a procedure wherein WBCs or White blood cells known as lymphocytes from the prospective father (hence paternal) are collected and separated from the other blood cells and injected into the prospective mother to prepare the maternal immune system for pregnancy. Because pregnancy is the product of both the mother's as well as the father's genes, PLI assists the mother's immune system in the development of immunologic tolerance to the genetically foreign pregnancy tissues.
Who should be treated with PLI or LIT?
PLI or LIT is recommended for couples experiencing various pregnancy problems such as difficulty in conception, recurrent miscarriages, multiple failed in vitro fertilization (IVFs) and/or intra uterine insemination (IUIs) from various conditions affecting the body’s immune system.
The decision to begin PLI or LIT will be based on several factors including:
· The identification of which category of immune problem is affecting the difficult pregnancy
· The pregnancy is spontaneous or assisted (IVF or IUI)
· The general health of the prospective mother (recipient)
· The general health of the prospective father (donor)
· The support of the OB/GYN specialist
Can “never been pregnant” prospective mothers receive PLI?
YES! PLI is a relatively non invasive procedure that may be given to prospective mothers. Prospective fathers also will have to undergo screening blood tests to determine their fitness to be a white blood cell donor.
How does PLI/LIT work?
During a healthy normal pregnancy, the mother’s immune system becomes tolerant to the fetus’ paternally-determined proteins (father’s trait of the baby) and this allows the pregnancy to continue to term. During immune problems however, the mother’s immune system does NOT become tolerant and prematurely terminates the pregnancy.
PLI/LIT changes the mother’s immune response by making it more tolerant to the soon to develop baby. PLI/LIT introduces the paternal (father’s) proteins, present in the father’s white blood cells to the mother. This changes the maternal (mother’s) immune system thru the following:
First, PLI/LIT promotes the development of protective antibodies to block the fetus’ paternally-determined proteins. These blocking antibodies allow the maternal immune system to recognize the fetus as friend rather than foe. The presence of these antibodies is used to predict the outcome of the subsequent pregnancy in women with previous consecutive miscarriages. These antibodies are also used to document if a mother has become immune or tolerant during or after PLI/LIT.
Second, PLI/LIT augments the development of tolerance by increasing the number and distribution of T regulatory cells (a specific WBC) that are part of the mother’s immune response. These T regulatory cells are the pregnancy-recognizing cells and act as guardians of pregnancy tissue, protecting it against attack from conventional immune cells.
What are the immune system dysfunctions that may cause pregnancy problems?
The body’s immune system defends against infection and plays an important role in cancer, autoimmune disease, aging, pregnancy, infertility and miscarriage.
An immune system problem may be suspected in cases of unexplained infertility, recurrent miscarriages or repeated implantation failure with IVF/IUI. Premature birth, intrauterine growth retardation, early rupture of membranes, or distress on delivery can all point to a possible immune cause to a difficult pregnancy.
There are 5 categories of immune problems in pregnancy, often occurring together in combination:
I. The couple’s tissue is too compatible; the woman’s body considers her placenta foreign with her own immune system activating against the baby
II. Blood clotting problems like anti phospholipid antibody syndrome or APAS
III. An immune reaction to the baby usually indicated by a positive ANA (anti nuclear antibody) test
IV. The couple produces antibodies to sperm which immobilize and destroy them on contact
V. Certain White blood cells are over active like the NKs or Natural killer cells
The doctor will determine the immune problem condition based on lab tests for the 5 categories indicated above. Treatments will also be based on the particular category.
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