Preventing stillbirth: the role of the immune system in rejecting the placenta

Tommy’s scientists are studying chronic histiocytic intervillositis – a condition in which the mother’s immune system rejects the placenta, leading to stillbirth or miscarriage.
  • Author's list

    Dr Ian Crocker, Chloe Brady, Dr Clare Tower, Professor Alexander Heazell

    Start: September 2018
    End: September 2021

  • Research centre

  • Research status

    Ongoing projects

Why do we need this research?

Chronic histiocytic intervillositis (CHI) is a rare condition in which the mother’s immune system does not accept the placenta in the womb. If a woman has suffered from CHI in a previous pregnancy then there is a high chance that it will happen again in subsequent pregnancies, putting her at risk of multiple stillbirths or miscarriages.

Unfortunately, CHI has no symptoms and can only be diagnosed by looking at the placenta after pregnancy. There are also no treatments that have been proven to cure it. We want to know more about the causes of CHI so that we can better identify, manage and prevent the condition.

What’s happening in this project?

Antibodies are molecules that recognise substances or organisms in the body as ‘alien’ and tell the immune system to attack them. In CHI, we think that some antibodies mistake the placenta for an alien object, causing it to be rejected by the mother’s immune system.

A similar situation can occur when people receive organ transplants. Sometimes the recipient’s immune system rejects the organ because it has come from a different person’s body. Over time, however, transplant doctors have managed to reduce the chances of organs being rejected and have developed treatments to dampen the immune system if necessary. Our researchers believe that similar techniques could be used to test for and manage CHI.

Our scientists are finding out more about the antibodies that are present in CHI, in order to understand how they are produced by the immune system, and why they recognise the placenta as alien. So far, they have found that 1 in 5 mothers with CHI have antibodies in their blood that are usually linked to rejection of an organ transplant. They have also found that placentas from mothers with CHI look similar under a microscope to a rejected organ. The team now want to find out whether these unusual antibodies cause CHI, and if it is possible to use them to predict earlier in pregnancy which women are at high risk of developing it.

What difference will this project make?

Our researchers hope to create a screening tool for CHI that would help us predict which women are at risk of stillbirth, either during their pregnancy or even before they conceive. These women could then receive medicines that dampen the immune system to help prevent the loss of their baby. In the future, it may even be possible to develop new therapies to treat CHI and so prevent stillbirths and miscarriages associated with the condition.

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