CHEMOPURGING OF PERIPHERAL BLOOD-DERIVED PROGENITOR CELLS BY ALKYL-LYSOPHOSPHOLIPID AND ITS EFFECT ON HEMATOPOIETIC RESCUE AFTER HIGH-DOSE THERAPY

One reason for relapse after high-dose tumor therapy with subsequent a utologous stem cell transplantation is tumor cell contamination of the graft. Removal of tumor cells from bone marrow grafts by chemopurging with the ether lipid edelfosine has been established as an effective and simple method. When compared with bone marrow derived grafts, prog enitor cells from peripheral blood have considerably reduced the haema tological recovery times. However, this advantage is put at risk by th e nonspecific haematotoxic activity of the purging agent, We therefore compared the lit vitro recovery of peripheral blood derived progenito r cells (PBPC) from either non-purged (n = 41) or purged (75 mu g/ml o f ether lipid for 4 h at 37 degrees C, n = 48) leukapheresis products, The recovery of CFU-GM after cryopreservation was 63 +/- 4% without a nd 48 +/- 3% with purging (P = 0.007). After high-dose therapy, patien ts (n = 37) received similar amounts of either non-purged (it = 17) or purged (ii = 20) autologous PBPC. The median haematological recovery times (non-purged vs purged) to >500 WBC/mu l were 9.0 vs 8.5 days aft er transplantation, to >2000 PMN/mu l 10.5 vs 10.0 days, and to >50000 PLT/mu l 15.5 vs 14.0 days. All differences were statistically not si gnificant, We conclude that ether lipid purging of PBPC leads to a sig nificant, however tolerable loss of progenitor cells in vitro, and tha t haematological recovery times after high-dose therapy are identicall y short, provided similar amounts of PBPC are reinfused.