Although the use of peripheral blood stem cells instead of bone marrow is still a matter of debate in transplantation from HLA-identical sibling donors, allogeneic peripheral blood stem cell transplantation (PBSCT), with a stronger graft-versus-leukemia (GVL) effect, may be preferable as a source of stem cells, especially in the case of advanced hematologic diseases. As such, the current paper reports on the outcomes of 27 consecutive patients with high-risk hematologic diseases treated with allogeneic PBSCT. The median dose of CD34+, CD3+ cells, and MNC infused was 8.18 x 10(6)/kg (range: 2.78-14.93), 1.50 x 10(8)/kg (range: 0.06-4.25), and 7.17 x 10(8)/kg (range: 0.95-15.85), respectively. The median time taken for the ANC and platelets to reach 500 and 20,000 x 10(6)/microL was 15 (range: 9-25) and 16 d (range: 10-56), respectively. Three patients (11.1%) experienced transplant-related mortality within 90 d of transplantation, and 15 (62.5%) of 24 evaluated patients developed chronic graft-versus-host disease (GVHD; six limited, nine extensive). There was a significant difference in overall survival (OS) between the group with chronic GVHD and the group without chronic GVHD (P = 0.0253). The causes of death included relapse (six cases) and non-relapse mortality (infection: four cases, chronic GVHD-related death: three cases). The 4-yr OS rate and disease-free survival rate was 43.3 +/- 10.9% and 35.8 +/- 10.2%, respectively. Accordingly, chronic GVHD was found to have a positive role in patients with high-risk hematologic diseases that received allogeneic PBSCT.