Tolerance induction of donor cells following haploidentical transplantation combining megadose TCD HSCT and high-dose PTCY. Analysis of CTL-p against donor and third-party target cells by IFN-γ ELISpot assay, which measures the frequency of IFN-γ–secreting cells following specific activation at the single-cell level, in PBMCs of patients 1 and 3 at 144 and 117 days following transplantation, respectively (for details, see Materials and methods).