New York: The US researchers have discovered a class of immune cells that plays a role in miscarriage, which affects about a quarter of pregnancies. Researchers at University of California-San Francisco found that the recently discovered subset of cells known as extrathymic Aire-expressing cells in the immune system may prevent the mother's immune system from attacking the placenta and foetus.
The researchers showed that pregnant mice who did not have this subset of cells were twice as likely to miscarry, and in many of these pregnancies foetal growth was severely restricted. "When you're pregnant, the immune system is seeing the placenta for the first time in decades — not since the mother made a placenta when she herself was a foetus," said Eva Gillis-Buck, from UCSF.
"Our research suggests that this subset of immune cells is carrying out a sort of 'secondary education' — sometimes many years after the better-known population of the educator cells have carried out the primary education in the thymus — teaching T cells not to attack the foetus, the placenta and other tissues involved in pregnancy," she added. The findings are published in the journal Science Immunology.
The immune system has to be educated not to attack one's own tissues and organs to prevent autoimmune disease. But pregnancy presents a unique challenge, since the foetus expresses proteins found in the placenta as well as proteins whose genetics are distinct from the mother.
