Autoreactive T lymphocytes are pivotal in organ-specific autoimmune diseases and contribute substantially to tissue damage in diseases such as diabetes and rheumatoid arthritis. Immunotherapy can eliminate pathological cells but directing effective therapeutic T lymphocytes against autoreactive T cells has proved difficult. In November 11 Nature Biotechnology, Divya Jyothi and colleagues at St. Jude Children's Research Hospital, Memphis, USA, show that receptor-modified T cells (RMTC) can be directed against autoreactive T lymphocytes and can be uses to treat a model autoimmune disease (Nature Biotechnology, doi:10.1038/nbt758, November 11, 2002).