ALLOGENEIC PERIPHERAL-BLOOD STEM-CELL TRANSPLANTATION FOR HEMATOLOGICAL MALIGNANCIES - AN ANALYSIS OF KINETICS OF ENGRAFTMENT AND GVHD RISK

We have carried out an analysis of 44 patients undergoing allogeneic P BSC transplants from fully HLA-matched related donors with particular emphasis on engraftment kinetics and the incidence and severity of GVH D, The recipients had a median age of 37 years (range 5-56 years), 16 patients had standard-risk disease and 28 had poor-risk disease, GVHD prophylaxis was with cyclosporin A and methotrexate (n = 41), cyclospo rin A alone (n = 2) or cyclosporin A and methylprednisolone (n = 1), S tem cells were mobilised using G-CSF, collecting a median of 5.75 x 10 (6) CD34(+) cells/kg recipient weight (range 0.94-35 x 10(6) CD34(+) c ells/kg), Engraftment times to a neutrophil count >0.5 x 10(9)/l and p latelets >20 x 10(9)/l were achieved at a median of day +14 (range 10- 25) and day + 14 (range 9-130) respectively, Patients receiving greate r than or equal to 4 x 10(6) CD34(+) cells/kg had significantly accele rated neutrophil and platelet engraftment and this number of CD34(+) c ells would appear to be a prerequisite for maximum engraftment using P BSC, Acute GVHD occurred in 25 of 43 evaluable patients although in on ly 12 was this clinically significant (grades II-IV), Chronic GVHD has occurred in 17 out of 36 evaluable patients, there was no significant difference between the standard- and poor-risk groups in incidence of either acute or chronic GVHD, In conclusion, these results confirm th e feasibility of using PBSC for allogeneic transplantation without evi dence for increased risk of either acute or chronic GVHD and provide f urther evidence supporting the potential of PBSC to replace bone marro w as the major source of haemopoietic cells for allogeneic transplanta tion.