Combined use of antifibrinolytics and activated prothrombin complex concentrate (aPCC) is not related to thromboembolic events in patients with acquired haemophilia A: data from FAIR Registry.

Antifibrinolytics combined with aPCC are not routinely administered to patients with acquired hemophilia A due to increased thrombotic risk. This association normalizes clot stability, and improves the efficacy of therapy, but can increase the risk of severe side effects. Due to these premises it has always raised doubts and perplexities in the clinics. We now report the data of the "FEIBA® on acquired haemophilia A Italian Registry (FAIR Registry)", a retrospective-prospective study that included 56 patients. This is the first study that assessed the clinical response of the combination of aPCC and antifibrinolytic agents in patients with acquired haemophilia A. A total of 101 acute bleeds were treated with aPCC. Antifibrinolytic agents were used in the treatment of 39.6% of total bleeds, based on both, a clinical assessment and an evaluation of bleeding. Twenty-five of the 30 patients (57.1%) treated with antifibrinolytic drugs showed serious co-morbidity. Among them, 40% presented severe cardiovascular diseases. All bleeds treated with combined therapy had a shorter duration of treatment (mean reduction 16.3%). All the treated patients presented a good tolerability and no arterial or venous thromboembolic events were reported. In our retrospective registry the combination of antifibrinolytics and aPCC appears safe and effective in the treatment of patients with AHA, especially in the case of severe and life-threatening bleeding, but this hypothesis needs to be confirmed in adequate, larger clinical trials.

Ex vivo pharmacological purging of leukapheresis collections with nitrogen mustard: amifostine pretreatment improves both early and late peripheral blood progenitor cell recovery.

Ex vivo pharmacological purging of bone marrow has been used to eliminate clonogenic tumor cells contaminating the autograft and potentially responsible of relapse. A considerable improvement of pharmacological purging would be achieved only if normal marrow progenitor cells could be selectively protected by the cytotoxicity of these agents. Amifostine (WR-2721; Ethyol), a phosphorylated aminothiol compound, has been shown to have this property both in vivo and in vitro. We describe here, an experimental model for ex vivo purging of peripheral blood progenitor cell (PBPC) collections based on the combination of 3 mg/ml of amifostine and the alkylating agent nitrogen mustard. Amifostine pretreatment resulted in a statistically significant protection of normal late and early progenitor cells. Under the same experimental conditions, we observed a 4-6 log reduction of contaminating leukemic cells (i.e., K-562 and CEM) and in contrast to the protection of normal peripheral blood progenitor cells, preincubation of contaminating K-562 or CEM with amifostine did not significantly alter the LD95 nitrogen mustard concentration. Moreover, when we tested fresh human leukemia progenitor cells, amifostine pretreatment sensitized the leukemic cells to the cytotoxic effects of NM.

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.

Expression of c-myb and B-myb oncogenes on myelofibrotic marrow fibroblasts.

The term IMF (Idiopathic Myelofibrosis) refers to a primary bone marrow disease in which the normal haematopoietic bone marrow cells are for unknown reasons replaced by connective tissue. The pathogenesis of the disease has not been clarified yet. We have speculated that the increment of proliferation of bone marrow fibroblasts in IMF may be the consequence of the over-expression of some oncogenes, leading or contributing to the fibrosis via a cell amplification. Thus, we investigated the possible role of the c-myb and B-myb genes in IMF and control bone marrow fibroblasts in different culture conditions to evaluate proliferation parameters in the absence or presence of serum. Using the reverse transcriptase polymerase chain reaction technique, we demonstrated that the kinetics of induction was similar for both c-myb and B-myb during the proliferation of normal bone marrow fibroblasts. When compared to normal controls, cultured IMF fibroblasts showed more elevated values of c-myb and B-myb RNA; furthermore, after a 72 hours stimulation with serum, c-myb and B-myb messages remained relatively high in myelofibrotic fibroblasts. Finally, after serum starvation, c-myb and to a lesser extent B-myb RNA levels remained unusually high in IMF fibroblasts, while under the same experimental conditions c-myb and B-myb messages became virtually undetectable in normal bone marrow fibroblasts. To our knowledge this work represents the first description of an abnormal behavior of these genes in IMF fibroblasts.

[Idiopathic myelofibrosis. Main pathogenetic, prognostic and therapeutic aspects]. / Mielofibrosi idiopatica. Principali aspetti patogenetici, prognostici e terapeutici.

Primary myelofibrosis is a complex disorder characterized by bone marrow fibrosis with no apparent cause. It is known in literature under a wide number of terms, reflecting the variety of clinical features and the different pathogenetic hypotheses. In most cases it is plain that marrow fibrosis is secondary to a clonal myeloproliferative disorder and, in particular, to the presence of abnormal megakaryocytes secreting (MKDGF/PDGF); but probably some other growth factors synthesized by megakaryocytes and contained in platelet alpha-granules are involved. The molecular event that determines the advantage of the clonal growth is, at present, unknown, and the pathogenetic importance of some chromosome anomalies is still under discussion. Over the last years, besides megakaryocyte dysplasia, several fibrogenetic mechanisms such as a bone marrow immune damage have been taken into consideration. Studies on prognostic factors regarding the main clinical, hematological and histological parameters have given conflicting results, because of low incidence of the disease, different criteria used for the diagnosis, and different terms of the clinic presentation of the pathology. Although a great deal of progress has been made in terms of pathogenetic mechanisms, a lot of questions must be still definitively settled, further in depth studies still have to go into many matters.

[Biologic aspects and clinical use of granulocyte growth factor]. / Aspetti biologici e impiego clinico del fattore di crescita granulocitario.

Granulocyte colony stimulating factors (G-CSF) has a wide spectrum of action: it stimulates proliferation and differentiation of granulocyte-macrophage progenitors, it promotes the chemotactic activity of monocytes and granulocytes and it develops the antibody-dependent cytotoxicity of neutrophils. In vivo G-CSF induces leucocytosis and it hastens the granulocyte recovery after chemio-radiotherapy. So it has been used in many pathologies: aplastic anaemia, AIDS in treatment with antiviral drugs, myelodysplastic syndromes, acute leukemias and solid tumors. If G-CSF is administered after chemotherapy, both in acute leukemias and in solid tumors, it reduces the duration of neutropenia and the number of febrile episodes so that it is possible to give the whole therapy at the planned dosage with no delay. However G-CSF does not modify the incidence of complete remissions and the overall survival. G-CSF allowed the increase of dose-intensity in chemoresistent neoplasms even if this therapy is always complicated by a heavy extrahaematological toxicity. Moreover G-CSF shortens the total duration of neutropenia after autologous or allogenic bone marrow and peripheral stem cell transplantation even if the appearance of the first neutrophil is not accelerated.

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.

Pharmacologic bone marrow purging: is there any place for etoposide? In vitro comparison with mafosfamide.

Residual leukemic cells in a bone marrow graft may increase the risk of relapse after autotransplantation. We have compared the efficacy of etoposide with that of mafosfamide, which has been used mainly for purging in acute leukemias. First, we examined the effects of VP-16 and ASTA-Z on the normal hematopoietic progenitors and on the erythroleukemic cell K562. Subsequently, we evaluated purging activity in cocultures using two different ratios of leukemic contamination. The most effective drug concentrations in inhibiting 100% of K562 growth were 50 micrograms/ml of ASTA-Z and 70 micrograms of VP-16. Residual growth of normal colony-forming units-granulocyte-macrophage (CFU-GM) was 4.8% with VP-16 and 32.5% with ASTA-Z. In treated cocultures, ASTA-Z produced a higher inhibition of the K562 line than VP-16 at both levels of leukemic cell contamination. At 0.5% contamination, VP-16 showed higher toxicity toward normal hematopoietic progenitors than ASTA-Z. At the 5% contamination level, VP-16 completely inhibited colony formation, whereas ASTA-Z spared some normal progenitor cells (21.2%). In conclusion, in our experimental model, VP-16 did not show improved efficacy over ASTA-Z in killing leukemic cells and in sparing normal progenitors.

Selection and transplantation of autologous CD34+ B-lineage negative cells in advanced-phase multiple myeloma patients: a pilot study.

The feasibility of sequential positive and negative selection of mobilized CD34+ B-lineage negative cells to achieve tumour-free autografts in multiple myeloma (MM) patients was evaluated. Peripheral blood stem cells (PBSC) of 14 patients with advanced disease were mobilized. CD34+ cells were enriched in 12 of the patients by the avidin-biotin immunoabsorption technique. Subsequently, CD10+, CD19+, CD20+ and CD56+ cells (B-lin cells) were removed by immunomagnetic depletion. Minimal residual disease (MRD) was detected by flow cytometry and PCR-based molecular analysis of the patient specific IgH complementary-determining region III (CDRIII). Positive selection of stem cells produced a median recovery of 54.7% of the initial content of CD34+ cells (median purity 71.9%). Negative depletion of B-lineage cells reduced the number of CD34+ cells to 33.3% of the baseline value (median purity 72.7%). However, long-term culture assays showed the recovery of >60% of primitive haemopoietic progenitor cells after depletion of the B-lineage-positive cells. All evaluable patients had detectable disease in PBSC collections. The first step of positive selection of CD34+ cells resulted in >2 logs of tumour cell purging. However, molecular assessment showed the persistence of the disease in 6/7 cases. Immunofluorescence analysis demonstrated 1 additional log of B-cell purging by negative depletion. More importantly, molecular evaluation of IgH CDRIII region showed the disappearance of myeloma cells in 6/7 patients. 12 patients received a median of 3.9 x 106 CD34+ B-lin- cells/kg after conditioning with high-dose melphalan and showed a rapid reconstitution of haemopoiesis. These results were similar to two similar cohorts of patients who received either unmanipulated PBSC or positively selected CD34+ cells after the same conditioning regimen. Severe extrahaematological toxicity was limited to mucositis; no late infections were observed. We concluded that autotransplantation of purified CD34+ B-lin- cells was associated with a rapid and sustained recovery of haemopoiesis and low peritransplant morbidity. Sequential positive and negative enrichment of stem cells reduced tumour cell contamination in B-cell malignancies below the lower limit of detection of molecular analysis.