Leading science, pioneering therapies



ThymiStem is an EU-funded research consortium coordinated by Prof Clare Blackburn at CRM. The project is working towards stem cell therapies that can boost the immune system by repairing the thymus, an essential organ of the immune system.

The thymus is the site in the body where T cells are made. T cells are crucial cells in the immune system, needed to mount effective immune responses. They are also important for coordinating our immune responses, so we make appropriate responses for different types of disease and infection. Nine research teams from seven countries have joined forces in ThymiStem.


Our members are based in the UK, Spain, Croatia, Ukraine, Turkey, the Czech Republic and the USA. We are a mix of stem cell biologists, immunologists, genetic engineers, tissue engineers and cell banking experts. Together, we have the skills to make progress towards new medical treatments. Our project began on 1 October 2013 and will run for four years.

We will test whether thymus stem cells can be grown in the lab and used to make a fully working thymus for transplantation. We will then investigate how to produce these cells in sufficient quantities and at high enough quality that they could, in the future, be transferred into patients. Why do we need new treatments for the thymus? New ways to repair or regenerate the thymus could benefit many older people and those who have received a bone marrow transplant.

The thymus is the first organ to degenerate in normal healthy ageing. This means we make fewer new T cells as we age, which is why older people are often more susceptible to infections such as flu. Damage to the thymus is also one of the major risks to life for patients who have undergone a bone marrow transplant, for example to treat blood cancer.

Our work

Our nine research teams are collaborating to advance understanding of the cells within the thymus, one of the central organs in the immune system. Our goal is to develop and test novel approaches for thymus replacement or regeneration, in order to pave the way for new stem cell based therapies to repair the thymus. Previous clinical research has shown that transplanting a thymus into patients can be an effective way to repair and restore the immune system. The thymus tissue used for these transplants came from patients undergoing heart surgery and would normally have been discarded, since the thymus is removed routinely during some heart operations. However, an alternative, more sustainable and large-scale source of thymus tissue must be found before this type of treatment can become routine.

What we will do

We plan to:

  • Establish methods for growing human thymus stem cells in the lab, or for making human thymus cells from other types of cell that we can already grow easily in the lab, such as embryonic stem cells or induced pluripotent stem (iPS) cells;
  • Test whether transplantation of these lab-grown cells can improve immune system function;
  • Use tissue engineering to develop a fully functional artificial thymus suitable for transplantation;
  • Develop procedures for long-term storage of human thymus cells using a technique called cryopreservation (storage at very low temperatures) and for ensuring strict quality control of lab-grown thymus cells;
  • Produce information and educational tools to share our research with members of the public across Europe.

Communicating our research

Thymistem is active in communicating with the members of the public and others about its research. We support the EU public engagement project EuroStemCell to bring up to date stem cell and regenerative medicine information to non-specialists.