Tolerance to the foeto-placental 'graft': ten ways to support a child for nine months.
Tolerance to the foetal 'allograft' has been extensively studied in the past few years, providing interesting new insights. In addition to a potential role for HLA-G, which has been widely discussed, there are hypotheses suggesting roles for several other molecules or cells: leukemia inhibitory factor and its receptor; indoleamine 2. 3-dioxygenase; the Th1/Th2 balance; suppressor macrophages; hormones such as progesterone or the placental growth hormone; CD95 and its ligand; and, as recently proposed, annexin II. Tolerance of the foetal allograft is probably the consequence of a wide panel of mechanisms that may or may not be pregnancy-specific, that are of major or secondary importance and that may be interconnected.
Thellin
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Institute of Human Histology, University of Liege, 20 Rue de Pitteurs, B-4020 Liege, Belgium.
Coumans
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B
Zorzi
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W
Igout
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A
Heinen
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E
D000818:Animals; D005260:Female; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D008431:Maternal-Fetal Exchange / Q000276:immunology*; D010920:Placenta / Q000276:immunology; D011247:Pregnancy / Q000276:immunology*