NK cell counts and chimerism early after haploidentical HSCT and PT-Cy. (A) Outline of the haploidentical HSCT platforms used at OSR (left) and at JHU (right). (B) Absolute counts of NK cells (red circles) and T cells (blue squares) circulating in the PB of patients (n = 17) receiving haploidentical HSCT followed by PT-Cy (days of Cy administration are shaded in yellow). Data are displayed as mean values ± standard error of the mean (SEM). (C) Absolute counts of PB NK cells in patients treated in the 2 transplantation centers (OSR, red circles: n = 10; JHU, white circles: n = 7). Data are displayed as mean values with SEM. (D) Chimerism within T- and NK-cell compartment after HSCT. HLA-A*02 mismatches allowed to discriminate by multiparametric flow cytometry donor-derived cells (colored) and residual host lymphocytes (white). Pies depict NK cell (upper line) and T cell (bottom lines) chimerism measured at different time points after HSCT in 3 donor-recipient pairs. Numbers indicate mean values with standard deviation (SD). MMF, mycophenolate mofetil; PBSC, peripheral blood cell transplantation; TBI, total body irradiation.