This report summarizes the Spanish experience of 62 cases of allogeneic transplantation of purified CD34+ cells from peripheral blood. HLA-identical sibling donors received G-CSF. After leukapheresis, peripheral blood progenitor cells were purified using one of two methods: Ceprate (n = 38), or Isolex 300 (n = 24). Sixty-two patients median age 42 years (range 17-60) diagnosed with hematological malignancies were conditioned with either cyclophosphamide and total body irradiation (n = 43) or busulphan and cyclophosphamide (n = 19). GVHD prophylaxis consisted of cyclosporin A (CsA) and prednisone (n = 48), CsA alone (n = 11), and CsA and methotrexate (n = 3). The median yield and purity of CD34+ cells after the procedure was 65% and 66% with Ceprate, and 48% and 86% with Isolex, respectively. The median number of CD34+ cells infused into the patients was 3.5 x 10(6)/kg (range 1-9.6). The median number of CD3+ cells administered was 0.4 x 10(6)/kg (range 0.01-2) using Ceprate and 0.14 x 10(6)/kg (range 0.03-2.5) using Isolex. Neutrophil recovery >500 and >1000/microl was achieved at a median of 13 days (range 8-22) and 14 days (range 9-31), respectively. Platelets recovered to >20,000 and >50,000/microl at a median of 13 days (range 0-128) and 18 days (range 0-180), respectively. The actuarial probability of acute GVHD II-IV was 10% (95% CI, 1-19%), and of extensive chronic GVHD 12% (95% CI, 11-13%).