Immune reconstitution following allogeneic peripheral blood progenitor cell transplantation: Comparison of recipients of positive CD34(+) selected grafts with recipients of unmanipulated grafts

We compared the kinetic recovery of lymphocytes and their subsets in two gr oups of patients submitted to allogeneic peripheral blood progenitor cell t ransplantation (allo-PBT): those receiving lymphocyte-depleted leukapherese s by positive selection of CD34(+) cells (group 1, n = 18) and those receiv ing unmanipulated leukaphereses (group 2, n = 15). Patients were conditione d with cyclophosphamide (120 mg/kg) and fractioned total body irradiation ( 13 Gy, group 1; 12 Gy, group 2). The mean number (x10(6)/kg) of CD34(+) and CD3(+) cells infused was 4.0 and 0.67, respectively, in group 1 patients, and 4.7 and 274, respectively, for group 2 patients. Graft-versus-host dise ase prophylaxis consisted of cyclosporin A + methylprednisolone for group I and cyclosporin A + methotrexate for group 2. Median follow-up was 7 month s (range 2-8 months) for both groups. During the first 6 months post-transp lant, CD4(+) cell counts were lower in group 1 as compared with group 2 (p = 0.014, 0.010, 0.011, 0.0003, and 0.052 at 0.5, 1, 2, 3, and 6 months, res pectively), whereas there was no difference at 8 months. The number of CD4( +)CD45RA(+) cells was very low throughout the study in both groups, being l ower in group 1 than in group 2, especially during the first 3 months postt ransplant (p = 0.007 and 0.0006 at 1 and 3 months). Normal levels of CD8(+) cells were reached by 1 month post-transplant in both groups. TCR gamma de lta(+) cell counts were lower in group 1 than in group 2 during the first 4 months post-transplant (p = 0.001, 0.004, and 0.04 at 1, 3, and 4 months). A normal number of natural killer cells (CD3(-)CD56(+)) was achieved 1 mon th posttransplant in both groups. B lymphocytes (CD19(+)) showed low or und etectable counts throughout the first 4 months in both groups, achieving th e normal range at 8 months. These results show that, during the first 6 mon ths-following allo-PBT with CD34(+) selected grafts, the number of CD4(+), CD4(+)CD45RA(+), and TCR gamma delta(+) cells is significantly lower than a fter unmanipulated allo-PBT; these differences disappeared at 8 months. In contrast, there are no differences between transplant groups in the recover y of CD8(+), CD19(+), and natural killer cells. (C) 1999 International Soci ety for Experimental Hematology. Published by Elsevier Science Inc.