article_snippet: T-cells are a type of white blood cell, which fight infections or threats .
article_snippet: An infusion of donor stem cells – which can transform into T-cells – may also be used to boost the immune system .
article_snippet: ’ treatment involves taking bone marrow from a donor and splitting bone marrow into stem cells and T-cells.
article_snippet: the T-cells are then given to the patient in a series of injections over several months.
article_snippet: One patient has already received an infusion containing genetically engineered’ T-cells and there are others whose cells are being prepared.
article_snippet: DNA is transferred into the T-cells using a ‘dummy’ virus that does not cause an infection.