Selection and immunomagnetic purging of peripheral blood CD34+ cells for autologous transplantation in B-cell non-Hodgkin's lymphomas

Background: Clonogenic tumor cells in the hematopoietic progenitor cell harvest may contribute to relapse after high dose therapy for B-cell malignancies. Purging of the HPC harvest requires large amounts of anti-B-cell antibodies, whereas CD34-selection enriches self renewing HPC's but malignant cells are still detectable in many CD34+ fractions.Patients and methods: We examined the feasability and safety of a CD34-selection followed by purging with anti-B-cell antibodies in 11 patients with B-cell non-Hodgkin's lymphomas undergoing high-dose therapy with cyclophosphamide, BCNU and etoposide with retransfusion of autologous HPC's.Results: A mean number of 340 × 10⁸ mononuclear cells was used for CD34-selection and immunomagnetic purging. CD34+ cells were enriched from a mean of 1.7% (range 0.2%–4.5%) to a mean of 68% (range 49%–87%) with a mean recovery of 27% (range 15%–43%). The mean number of retransfused CD34+ cells was 1.2 × 10⁶/kg (range 0.6–2.2 × 10⁶/kg) body weight with a median of 11 days (range 10–13 days) to neutrophil recovery of 0.5 × 10⁹/l and 17 days (range 13–25 days) to platelet recovery of 50 × 10⁹/l. Mean number of intravenous antibiotics and inpatient days were 8 (range 0–14) and 22 (range 19–26) respectively. Major toxicity consisted in four septicemias.Conclusions: CD34-selected and purged HPC's are safe and mediate rapid hematological recovery after high dose therapy for B-cell non-Hodgkin's lymphomas.