We evaluated the outcome of 29 patients (age 22-60 years), who received a CD34+selected related (n=16) or unrelated graft (n=13) with limited T-cell addback (TCAB) (median 5.9 x 10(4)/kg) following full-intensity conditioning for haematological malignancies. In all, 16 patients (55%) had either advanced disease or previous transplants. The cumulative incidences of grade 2-4 acute GVHD were 15.4 and 19.2% and that for chronic extensive GVHD were 35 and 37% in related and unrelated graft recipients, respectively. The strongest predictor of nonrelapse mortality and overall survival was the absolute lymphocyte count (ALC) at 30 days; patients with ALC<0.35 x 10(9)/l having an NRM and OS of 59.2 and 24.7%, compared to 10 and 90% in those with a higher ALC. Patients with acute leukaemia had poorer survival and this was associated with a lower ALC as well. Thus, TCAB with a CD34+ selected graft resulted in a comparable outcome in both older and younger patients, but the survival was strongly influenced by early lymphocyte recovery.