IN-VITRO AND IN-VIVO DEPLETION OF T-CELLS

Transplant related mortality and relapse after bmt have a negative inf luence on the outcome of patients transplanted for acute leukaemia in first remission. Transplant related mortality includes graft-versus-ho st disease, infections and graft failure. To prevent gvhd and associat ed infections without increased graft rejection, a protocol of combine d in vivo/ex vivo T-cell depletion (Campath IgG 20 mg i.v. for 5 days and Campath IgM T-cell depleted graft) with no further immunosuppressi on was initiated. Up to now 22 adult patients (median age 39 years, ra nge 21 to 51) have been transplanted. One graft failure most probably due to persistent leukaemia, three acute gvhd (grade I) and no chronic gvhd occurred. Two patients relapsed after bmt and died. Two further patients died due to idiopathic interstitial pneumonitis and acute liv er failure, respectively. Eighteen patients are alive in complete remi ssion. With a median follow up of 13 months (1-30) the probability of survival is 78%, disease free survival is 80% and transplant related m ortality is 10%. We compared these results with 3 historical control g roups with different regimens of gvhd prophylaxis. 1. MTX group (n=15) : With a median follow up of 135 (115-147) months after bmt the probab ility of survival is 40%, disease free survival is 40% and transplant related mortality is 60% (mainly gvhd and infection). 2. Campath group (only ex vivo T-cell depletion n=25): With a median follow up of 86 ( 62-102) months probability of survival is 52%, disease free survival i s 43% and transplant related mortality is 36% (mainly rejection and in fection). 3. MTX/CSA group (n=33): with a median follow up of 48 month s (1-66) after bmt probability of survival is 66%, disease free surviv al is 58% and transplant related mortality is 21%. In comparison with the historical control groups combined T-cell depletion effectively pr events acute and chronic gvhd without an increase of graft rejection a nd transplant related mortality is reduced. Survival and disease free survival are at least comparable to the MTX/CSA group and a larger fol low up is needed for definite analysis.