Simultaneous cord blood transplantation of ex vivo expanded together with non-expanded cells for high risk leukemia

In the absence of a donor alternative a stem cell transplantation consistin g of two cord blood components originating from the haploidentical brother was performed in a 2-year-old girl with c-ALL, early CNS relapse and 7% of blast cells in the BM 14 days before transplantation. Because of various on going infectious complications at that time, 1/8 of the immunogenetically a cceptable sibling cord blood was ex vivo expanded 10 days before the transp lantation date. The total CB consisting of 1.17 x 10(9) NC was cryopreserve d in four separate bags. The one containing 1/8 of the total CB with 1.4 x 10(8) NC CliniMACS selected CD34(+) cells was expanded in the presence of 1 00 ng/ml G-CSF, 100 ng/ml TPO and 100 ng/ml flt3-L in 10% autologous CB pla sma and X-VIVO 10 medium at day -10 before transplantation. This expanded c ell population was sterile and consisted of about 60% granulocytic cells (C D13(+), CD15(+)), about 30% myelomonocytic cells (CD14, HLA-DR+), 5.2% mega karyocytes (CD61(+)) and 1.2% CD34(+) cells. The proportion of T (CD3(+)), NK cells (CD56(+)) as well as dendritic cells (CD83(+)) was below 0.2%. The unseparated CB infused at day 0 and +1 consisted of a total of thawed 4.4 x 10(7) NC/kg BW, 5.8 x 10(4) CFU-GM/kg BW, 1.54 x 10(5) CD34(+) cells/kg B W and 7.73 x 10(2) LTC-IC/kg BW. In addition, the 1 x 10(7) NC/kg BW ex viv o expanded cells representing 1.9 x 10(4) CFU-GM/kg BW, 1.13 x 10(5) CD34() cells/kg BW and 4.37 x 10(2) LTC-IC/kg BW, were infused at day +1. At day +2 after transplantation the patient revealed a focal pneumonia on X-ray w ith generalized sepsis and became catecholamine dependent. From day +4 the patient received 280 mu g/m(2) G-CSF. At day +5 she developed an erythroder ma, which could not be identified as acute GVHD by biopsy. Early engraftmen t with leukocyte counts at days 8 and 14 were 350 and 700/mu l, ANC 310 and 410/mu l, respectively. Donor cells determined by chimerism analysis were 97% and 98% in the periphery at this early time. Most importantly, the pneu monia as well as the septicemia subsided within a few days. Notably, as wel l is the clearly shortened aplastic phase observed after this simultaneous CB cell component transplantation. The patients T cell and NK cell reconsti tution could be detected at day +37 with 330 CD3(+) cells/mu l and 40 CD56( +) cells/mu l, respectively. The time to reach an absolute platelet count o f 20000 (50000)/mu l was 75 (103) days. The disease-free survival now excee ds 1 year in complete remission without chronic GVHD or any other health pr oblems. These data show that the applicability of ex vivo expanded committe d progenitors and LTC-IC, even in high risk leukemia at the time of transpl antation, is feasible and can provide sufficient myeloid progenitors result ing in rapid engraftment able to clear bacterial pneumonia and sepsis. In a ddition, accelerated hematopoietic reconstitution apparently served as a we ll functioning platform for definitive graft-versus-leukemia activity. This transplantation of defined ex vivo generated components presents a feasibl e and generally applicable approach and may open a promising new avenue for cell therapy in malignant diseases.