Multiple infusions of GMCs enhance the extent of the transgene-specific immune response. Samples 1 to 5 were collected from patient 2 at different times after HSCT. PBMCs containing 10⁶ CD3⁺ lymphocytes from each sample were stimulated with allogeneic and autologous SFCMM2-transduced T cells and tested 10 days later for their lytic activity against the stimulators. Results are plotted as ratio of anti-TN lytic units/10⁶ cells to anti-allo lytic units/10⁶ cells (TN/allo ratio). The numbers of infused cells at the various time points are reported on the right ordinate axis.