Evidence of T cell-mediated anti-transgene cytotoxic T cell responses was documented in a phase 1/2 trial of intramuscular AAV-mediated gene transfer in Duchenne muscular dystrophy patients, where poor expression of dystrophin was associated with the detection of transgene-specific polyfunctional CD8 T cells (45). This evidence concerns the gene CD8A and Duchenne muscular dystrophy.