. Patient with acute GVHD > grade 2 or extensive chronic GVHD at the time of CTL infusion Patient receiving steroids (>0.5 mg/kg prednisone equivalent) at the time of CTL infusion Patient treated with donor lymphocyte infusion (DLI) within 4 weeks prior to CTL infusion Patient with poor performance status determined by Karnofsky (patients >16 years) or Lansky (patients ≤16 years) score ≤30% Concomitant enrollment in another experimental clinical trial investigating the treatment of refractory adenovirus infection(s) Any medical condition which could compromise participation in the study according to the investigator's assessment Known HIV infection Female patient of childbearing age who is pregnant or breast-feeding or not willing to use an effective method of birth control during study treatment.