either fulminant mononucleosis or EBV lymphoproliferation (21). In addition 
patients with acquired defects in T lymphocyte function such as transplant 
recipients or patients with AIDS have an increased risk of EBV 
lymphoproliferation. 
3.6 Immune Reconstitution Post MUD or Mismatched Family Donor BMT 
Conditioning regimens for BMT destroy the recipient's own immune and 
hemopoietic systems. Recovery is dependent on the establishment of a graft 
and the development of donor-derived hemopoietic and immune systems. 
After T cell-depleted matched sibling allograft or autograft there is rapid 
recovery of activated CD3 + CD16- and CD16 + CD3- activated killer cells 
which are cytotoxic towards EBV infected targets and spontaneously secrete 
cytotoxic cytokines (22,23). The generation of these endogenously activated 
cells may help explain the low incidence of EBV after MHC identical sibling 
grafts. Immune recovery post MUD transplant is less well characterized. In 
preliminary studies at the Royal Free Hospital in patients receiving T cell 
depleted MUD BMT, activated killer cells were not found in the early post 
transplant period (H Heslop, D Gottlieb unpublished observations). In 
addition recovery of CD3+ cells was delayed. Studies in patients receiving 
MUD or mismatched family BMT at St Jude confirm that recovery of CD3 + 
T cells is slower than in patients receiving matched sibling BMT. Although 
CD3 numbers are low studies of repertoire usage do not show any specific 
defects (24). 
3.7 Possibility of Generating Immune System Effector CePs iu nnV 
One approach which may improve immune defenses against viruses following 
matched unrelated or mismatched BMT is to adoptively transfer donor 
derived virus specific cytotoxic T lymphocytes. This strategy is successful in 
animal models and is currently being explored in human BMT recipients at 
the Fred Hutchinson Cancer Center in Seattle using CMV as a model (25). 
These investigators had previously documented that the of CMV disease 
correlated with the generation of spontaneous CMV specific cytotoxic T 
lymphocytes post transplant. To extend this observation they generated CMV 
specific cytotoxic T lymphocytes from BMT donors in vitro and in a dose 
escalation study adoptively transferred these virus specific cells to recipients. 
Administration of such cells to 5 patients resulted in no clinical adverse events 
and detection of CMV specific responses. 
In this study we wish to generate cytotoxic T cells specific for EBV and 
adoptively transfer these cells to recipients at high risk for EBV reactivation 
and lymphoproliferation. Our aim is to track the infused cells by means of a 
marker gene, analyze their activity after infusion, and determine a safe and 
efficacious cell dose for subsequent analysis as prophylaxis for EBV disease. 
We have already generated EBV specific cytotoxic T cells from one donor 
Recombinant DNA Research, Volume 17 
