We evaluated early and late hematopoietic reconstitution in 27 patients with advanced lymphoma, Hodgkin's disease, and breast or ovarian cancer after treatment using high-dose/myeloablative conditioning regimens and autologous peripheral blood stem cell PBSC) transplantation. Eighteen patients (67%) received G-CSF 5 micrograms/kg/day following chemotherapy and nine (33%) were mobilized using G-CSF alone. Each patient had 7 x 10(8) mononuclear cells (MNC) per kg collected. G-CSF was administered post-PBSC infusion. While all patients showed prompt granulocyte recovery by day 14, platelet recovery failed to occur in our (15%) heavily pretreated patients with non-Hodgkin's lymphoma. Retrospective analysis in 17 patients revealed that the infused number of CD34 surface antigen-positive cells correlated with time to granulocyte (r = 0.59, P = 0.012) and platelet (r = 0.58, P = 0.021) recovery. Patients receiving the higher numbers of CD34+ cells had consistently better hematologic parameters at 11 times examined. At 180 days post-transplant, the median Hb level was 124 g/l vs 88 g/l (P = 0.004); platelet count was 202 x 10(9)/l vs 25 x 10(9)/l (P = 0.004); and neutrophil count was 3100 x 10(6)/l vs 1400 x 10(6)/l (P = 0.15). Hemoglobin strongly correlated with the CD34+ cell dose at 360 days (r = 0.90, P = 0.01). We conclude that graft CD34+ cell content appears to be an indicator of the quality of late as well as early hematopoietic function.