Patient with acute GVHD > grade 2 or extensive chronic GVHD at the time of CMV CTL infusion Patient receiving steroids (>0.5 mg/kg prednisone equivalent) at the time of CMV CTL infusion Patient treated with donor lymphocyte infusion (DLI) within 4 weeks prior to CMV CTL infusion Thymoglobulin (ATG), Alemtuzumab or T cell immunosuppressive monoclonal antibodies within 30 days Patient with poor performance status determined by Karnofsky (patients >16 years) or Lansky (patients ≤16 years) score ≤30% CMV retinitis Concomitant enrollment in another experimental clinical trial investigating the treatment of refractory CMV infection.