DHAP regimen plus G-CSF as salvage therapy and priming for blood progenitor cell collection in patients with poor prognosis lymphoma.

We studied 14 patients affected by lymphoma to assess the toxicity, efficacy and mobilization capability of salvage DHAP regimen followed by G-CSF 5 micrograms/kg/day. Ten patients were affected by intermediate-grade NHL and 4 by HD; all of them were in relapse or in PR. We administered a total of 34 courses of DHAP plus G-CSF (median 2 per patient; range 1-5) and did not observe either life-threatening extrahematologic toxicity or severe infections during the short neutropenic period. A significant tumor burden reduction was observed in 86% of patients (50% CR, 36% PR). A total of 35 aphereses were performed (median 3 per patient; range 1-5). The hemopoietic progenitors showed a very rapid increase from day +11 with a synchronous and impressive peak on day +13. We collected a median of 2.6 x 10(6)/kg CD34+ cells, 10 x 10(4)/kg CFU-GM, 5 x 10(4)/kg BFU-E and 0.5 x 10(4)/kg CFU-GEMM per apheresis. All patients transplanted with PBPC had a rapid and sustained hematological recovery. The DHAP regimen followed by G-CSF proved to be a very effective and well-tolerated schedule for debulking disease before transplantation and for enhancing progenitor cell mobilization.

Addition of erythropoietin to granulocyte colony-stimulating factor after priming chemotherapy enhances hemopoietic progenitor mobilization.

Hemopoietic progenitor cell mobilization intended for autotransplantation is now feasible in many patients, following the administration of single cytokines (G-CSF, GM-CSF, IL-3) or their combination. Erythropoietin (EPO) is a cytokine which showed an interesting activity also on non-erythroid progenitors, however the clinical relevance of this activity has not been sufficiently investigated yet. This retrospective study has attempted to assess the effectiveness of the combination of EPO plus G-CSF after priming chemotherapy to increase the number of blood progenitor cells, as compared to the results obtained by G-CSF alone. Thirty-four patients underwent priming chemotherapy followed by cytokine administration: 18 patients received G-CSF 5 micrograms/kg/day and 16 patients G-CSF plus EPO 50 U/kg/day. The two groups were homogeneous as regards the main clinical characteristics which are thought to affect BPC mobilization. As for hemopoietic progenitor cell mobilization, we observed that the combination of EPO and G-CSF was more effective in comparison with G-CSF alone, with a median of 1.9-fold for circulating MNC, 4.0-fold for CFU-GM, 4.7-fold for BFU-E and 2.8-fold increase for CD34+ cells. The results of apheresis collections revealed that the same group of patients showed better results for total blood progenitor cells/kg. The difference was statistically significant both for BPC mobilization and collection. Our findings suggest that EPO has a synergistic activity with G-CSF in mobilizing hemopoietic progenitors; the good results obtained, despite our pretreated patients, suggest that this cytokine combination has both biologic and clinical relevance.

Direct demonstration of cytokeratin filaments by electron microscopy in K562 cell lines in liquid culture.

Our previous study suggested the presence of cytokeratins in the supernatant of human K562 erythroleukemic cell line. In this study we confirm, by using an electron microscopy technique, that K562 cells contain typical intermediate tonofilaments with the characteristics of cytokeratins. After variable intervals of liquid culture, K562 cells have been examined for their clonogenic ability by immunostaining and ultrastructural study. K562 cells showed variable amounts of medium-sized filaments (intermediate filaments) of 10 nm mean size, having the submicroscopic pattern consistent with tonofilaments, arranged as electron-dense curve-shaped bundles, in perinuclear position independently from the different growth phases. A pool of monoclonal antibodies against cytokeratins confirmed the presence of cytokeratins in immunostaining, while the cytofluorimetric analysis showed an unexpected positivity of the CD34 antigen, associated with the typical adhesion molecule VLA5. In conclusion, the immunostaining with monoclonal antibodies and the ultrastructural findings suggest the expression of epithelial features in human K562 leukemic cells.

Factors affecting hemopoietic recovery after high-dose therapy and autologous peripheral blood progenitor cell transplantation: a single center experience.

BACKGROUND AND OBJECTIVE: While the minimum number of CD34+ cells required for complete and long-lasting engraftment is quite well established, there is not general agreement about the optimal number of CD34+ per kg needed in order to obtain engraftment as rapidly as possible. In the present study we assess factors affecting hemopoietic recovery and the optimal peripheral blood progenitor cell (PBPC) number for rapid engraftment in patients treated with high-dose therapy. DESIGN AND METHODS: We enrolled 80 consecutive patients affected by hematologic and non-hematologic malignancies treated with a median of 10 chemotherapy courses (range 3-38). PBPC collection was performed after mobilization with high-dose chemotherapy and G-CSF 5 micrograms/kg/day. The circulating and harvested CD34+ cells were recognized in the cytofluorimetric CD45+/CD14- lymphocyte gate. After myeloablative therapy, PBPC infusion was followed by G-CSF 5 micrograms/kg/day from day +5 until WBC > or = 5.0 x 10(9)/L. Univariate and multivariate Cox analyses were performed to investigate factors affecting hemopoietic recovery. The Kaplan-Meier probabilities of hemopoietic reconstitution were compared by log-rank test to assess the optimal CD34+ cell number for rapid engraftment. RESULTS: We performed a median of two apheresis (range 1-4) per patient and we infused a median of 6.1 x 10(6) CD34+ cells/kg (range 0.5-30.5). Absolute neutrophil count (ANC) > 0.5 x 10(9)/L was reached after 11 days (range 8-15). The only factor affecting granulocyte recovery proved to be the CD34+ cell number; 5.0 to 7.8 x 10(6) CD34+ cells/kg allowed a significantly faster granulocyte recovery than < 2.5 x 10(6) CD34+ cells/kg (p = 0.0312). Platelet transfusion independence (> 20 x 10(9)/L) and 50 x 10(9)/L platelets were reached after 12 (range 8-24) and 15 days (range 9-40), respectively. The CD34+ cell number was also the only factor affecting platelet recovery; the number of 5.0 to 7.8 CD34+ cells/kg allowed a significantly faster platelet recovery than the lower dose, whereas a higher number did not. No late graft failures were observed. Patients receiving 5.0 to 7.8 x 10(9) CD34+ cells/kg had a significantly shorter duration of neutropenia, fewer platelet transfusions and less time spent in hospital than those receiving lower number did, whereas patients transplanted with a higher number had no advantage. INTERPRETATION AND CONCLUSIONS: When G-CSF is employed both for PBPC mobilization and after PBPC transplantation, the CD34+ cell number is the only factor that affects hemopoietic recovery. Moreover, > 5.0 x 10(6) CD34+ cells/kg is the optimal number for obtaining rapid platelet recovery and reducing the costs of HDT but there is no advantage exceeding the threshold of 7.8 x 10(6) CD34+ cells/kg.