Detecting of the minimal residual disease contaminated in peripheral blood stem cell transplantation in the B-cell malignant lymphoma patients.

For sufficient collection of hemopoietic stem cells from peripheral blood for autologous peripheral blood stem cell transplantation (PBSCT), four patients with B-cell-type non-Hodgkin lymphoma (B-NHL) were examined for the appearance of circulating hemopoietic progenitors in blood (PSC) during the hemopoietic recovery phase following marrow ablative therapy in combination with or without administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF). Each patient received only chemotherapy in the first course, and rhG-CSF (1 microgram/kg/day) was administered for 14 consecutive days from the last day of the second chemotherapy. In the second chemotherapy course with rhG-CSF administration, white blood cell (WBC) counts demonstrated two peaks, and the appearance of granulocyte-macrophage precursor cells (CFU-GM) in blood at the maximum level was coincident with the second peak of WBC elevation. Erythroid precursor cells (BFU-E) were also detectable in blood after chemotherapy but the peak level was not enhanced by the use of rhG-CSF. To determine whether the minimal residual disease (MRD) cells were contaminated in PSC corrected from blood, kappa-lambda imaging (KLI) analysis was performed to detect the malignant B-cell population (mBp) before and after chemotherapy. No mBp was found in two of four patients in blood, although three of them were involved with mBp in bone marrow. The presence of mBp was detected in two patients both before and after chemotherapy, even though these cells were hardly detected morphologically, suggesting the necessity of judging for the incidence of contamination of MRD cells when collecting PSCs.