ALLOGENEIC TRANSPLANTATION OF SELECTED CD34(-BLOOD - EXPERIENCE OF 62CASES USING IMMUNOADSORPTION OR IMMUNOMAGNETIC TECHNIQUE() CELLS FROMPERIPHERAL)

The objective of this study was to analyze CD34(+) cell recovery and T cell depletion (TCD) achieved in CD34+ cell grafts using either immun oadsorption or immunomagnetic methods applied to leukapheresis product s from healthy donors. We also wanted to determine the kinetics of eng raftment and incidence and severity of graft-versus-host disease (GVHD ) after allogeneic transplantation of selected CD34(+) cells. HLA-iden tical sibling donors received G-CSF. After leukapheresis, peripheral b lood progenitor cells were selected using immunoadsorption (Ceprate SC ) (n = 38) or immunomagnetic (Isolex 300) (a = 24) methods. Sixty-two patients, with a median age of 42 years (range 17-60) diagnosed with h ematological malignancies were conditioned with either cyclophosphamid e and total body irradiation (n = 43) or busulphan and cyclophosphamid e (n = 19). GVHD prophylaxis consisted of cyclosporin A (CsA) and pred nisone (n = 48), CsA alone (n = 11) and CsA and methotrexate (n = 3). The median yield and purity of CD34(+) cells after the procedure was 6 5 and 66% with immunoadsorption, and 48 and 86% with immunomagnetic me thod, respectively. The median number (range) of CD34(+) cells infused into the patients was 3.5 x 10(6)/kg (1-9.6). The median number (rang e) of CD3(+) cells administered was 0.4 x 10(6)/kg (0.01-2) using immu noadsorption and 0.14 x 10(6)/kg (0.03-2.5) using immunomagnetic metho ds. Neutrophil recovery >500 and >1000/mu l was achieved at a median ( range) of 13 days (8-22) and 14 days (9-31), respectively. Platelets r ecovered to >20 000 and >50 000/mu l at a median (range) of 13 days (0 -128) and 18 days (0-180), respectively. Two patients developed graft failure. Acute GVHD in patients at risk was clinical grade 0 (It = 43) , I (n = 8), LI (n = 4) and III (n = 1). No patient developed acute GV HD grade IV. Chronic GVHD was limited in two cases and extensive in fo ur cases. The actuarial probability of acute GVHD II-IV was 10% (95% C I, 1-19%), and of extensive chronic GVHD was 12% (95% CI, 11-13%). The cumulative incidence of transplant-related mortality was 12.6%, and t his figure was 9% at 6 months. In conclusion, with the immunomagnetic procedure, a lower recovery and higher purity of CD34(+) cells, and st ronger TCD is obtained as compared to immunoadsorption (P = 0.008, P < 0.0001 and P = 0.0002, respectively). Our results also indicate that allogeneic transplantation of selected CD34(+) cells is associated wit h a very rapid engraftment and with a low incidence of severe GVHD.