Blood cell transplantation (BCT) is now common practice in the autologous setting. We performed a pilot study of allogeneic BCT, collected after the priming of an HLA-identical sibling with a glycosylated rhu-G-CSF (lenograstim) (10 microg/kg). Fifty-four patients were included (38 +/- 11; M/F = 33/21; CML (n = 17), AML (n = 14), ALL (n = 15); MDS (n = 8)). Transplant procedures were standard (TBI regimen = 47 (87%); MTX-CsA: n = 37; CsA-PDN: n = 17). No serious adverse events were reported in donors. A median of 11 (3.5-29.1) x 10(6)/kg CD34+ cells, 332 (33-820) x 10(6)/kg CD3+ cells were collected. Four patients did not engraft (early death: n = 2; graft failure: n = 2). Fifty-one patients initially recovered 0.5 x 10(9)/l ANC and 25 x 10(9)/l platelets at 15 (10-30) and 13 (9-188) days. 29/51 and 29/38 experienced grade > or =2 acute and chronic GVHD. With a median follow-up of 25 months (18-36), relapse rate is 16% +/- 8, survival and DFS probabilities are similar (50% +/- 13). A better outcome is documented for patients under 45 years and in the early phase of the disease (n = 28), with an identical survival and DFS of 71% +/- 13. In conclusion, lenograstim is a potent rhu-G-CSF for mobilisation of allogeneic hematopoietic progenitors. Two-year follow-up indicates good haematological recovery but some concerns about graft failure and chronic GVHD have arisen deserving prospective evaluation.