Reduced-intensity conditioning allogeneic stem cell transplantation with donor T-cell depletion using alemtuzumab added to the graft ('Campath in the bag').

Allogeneicstemcelltransplantation(alloSCT)isapoten-tially curative treatment for patients with haematologicalmalignancies. Traditionally, myeloablative conditioningregimens have been used that induce considerabletoxicity, limiting the procedure to younger patients. InordertoprovidethecurativepotentialofalloSCTtoolderpatients or those with concomitant disease, non-myeloa-blativeorreduced-intensityconditioning(RIC)regimenshave been developed [1]. Although these regimens havebeen shown to permit engraftment with low toxicity,graft-versus-host disease (GvHD) is still an importantcomplication, with considerable morbidity and mortality.In particular, active chronic GvHD requiring prolongedimmunosuppressive therapy is associated with anincreased risk of death late after transplantation [2]. Byusing T-cell depletion of the graft, the incidence ofGvHD can be diminished; however, this may alsoadversely influence the outcome of the transplant byincreasing the incidence of infections through impairedimmune reconstitution and by inhibiting T-cell-mediated antitumour effects. In human leukocyte anti-gen (HLA)-identical myeloablative alloSCT we showedthatincubationofthegraftwithalemtuzumabjustbeforeinfusion (‘Campath in the bag’; Campath, Bayer Pharma-ceuticalsInc., Wayne,NewJersey, USA)resultsinbothalow incidence of GvHD and a low incidence of mortalityas a result of infectious complications [3]. In contrast, theadministration of alemtuzumab in vivo for T-celldepletion results in a similar decrease in GvHD inci-dence, but at the cost of impaired immune reconstitutionand increased infectious complications [3–5]. Therefore,wehaveaddedT-celldepletionbyincubationofthegraftwith alemtuzumab to a RIC regimen.