In vivo study on the healing of bone defects treated with bone marrow stromal cells, platelet-rich plasma, and freeze-dried bone allografts, alone and in combination.

The repair of confined trabecular bone defects in rabbits treated by autologous bone marrow stromal cells (BMSC), platelet-rich plasma (PRP), freeze-dried bone allografts (FDBA) alone and in combination (BMSC + PRP; FDBA + BMSC; FDBA + PRP; FDBA + PRP + BMSC) was compared. A critical size defect was created in the distal part of the femurs of 48 adult rabbits. Histology and histomorphometry were used in the evaluation of healing at 2, 4, and 12 weeks after surgery. The healing rate (%) was calculated by measuring the residual bone defect area. Architecture of the newly formed bone was compared with that of bone at the same distal femur area of healthy rabbits. The defect healing rate was higher in PRP + BMSC, FDBA + PRP, FDBA + BMSC, and FDBA + PRP + BMSC treatments, while lower values were achieved with PRP treatment at all experimental times. The highest bone-healing rate at 2 weeks was achieved with FDBA + PRP + BMSC treatment, which resulted significantly different from PRP (p < 0.05) and BMSC (p < 0.05) treatments. At 4 weeks, the bone-healing rate increased except for PRP treatment. Finally, the bone-healing rate of FDBA + PRP, FDBA + BMSC, and FDBA + PRP + BMSC was significantly higher than that of PRP at 12 weeks (p < 0.05). At 12 weeks, significant differences still existed between PRP, BMSC, and FDBA groups and normal bone (p < 0.05). These results showed that the combination of FDBA, BMSC and PRP permitted an acceleration in bone healing and bone remodeling processes.

Evaluation of bone healing enhancement by lyophilized bone grafts supplemented with platelet gel: a standardized methodology in patients with tibial osteotomy for genu varus.

Orthopedic practice may be adversely affected by an inadequate bone repair that might compromise the success of surgery. In recent years, new approaches have been sought to improve bone healing by accelerating the rate of new bone formation and the maturation of the matrix. There is currently great interest in procedures involving the use of platelet gel (PG) to improve tissue healing, with satisfactory results both in vitro and in maxillofacial surgery. Otherwise, to our knowledge, only a preliminary clinical study was undertaken in the orthopedic field [Kitoh et al., Bone 2004;35:892-898] and the efficacy of PG is still controversial. Our paper focuses on the effect on bone regeneration by adding PG to lyophilized bone chips used for orthopedic applications. The clinical model and the laboratory methodology were standardized. As a clinical model, we employed the first series of patients of a randomized case-control study undergoing high tibial osteotomy (HTO) for genu varus. Ten subjects were enrolled: in 5 patients lyophilized bone chips supplemented with PG were inserted during tibial osteotomy (group A); 5 patients were used as a control (group B) and lyophilized bone chips without gel were applied. Forty-five days after surgery, computed tomography scan guided biopsies of grafted areas were obtained and the bone maturation was evaluated by a standardized methodology: the osteogenic and angiogenic processes were semi-quantitatively characterized by using histomorphometry, and the mineral component of the lyophilized and host bone was analyzed by using X-ray diffraction technique with sample microfocusing and microradiography. Lyophilized bone with PG seems to accelerate the healing process, as shown by new vessel formation and deposition of newly formed bone, with no evidence of inflammatory cell infiltrate, when compared with lyophilized bone without gel. On the contrary, lyophilized bone undergo a resorption process, and a fibrous tissue often fills the spaces between chips. A histiocytic/giant-cell reaction is sometimes present. Otherwise, no differences have been found concerning microstructure. Our findings show the reliability of the methodology used to monitor early bone repair. The completion of the study and the evaluation of the ultimate clinical outcome are necessary in order to verify PG in vivo effects in orthopedic surgery.

Radiological assessment of the PRF/BMSC efficacy in the treatment of aseptic nonunions: A retrospective study on 90 subjects.

BACKGROUND: Nonunion is a major orthopaedic concern because of treatment difficulty, high costs and devastating effects on the patients' life quality. Therefore, there is interest in the use of bone substitutes and cell-based strategies to augment fracture repair. We aimed to verify if Platelet Rich Fibrin (PRF) added with bone marrow stromal cells (BMSC) was able to improve the reparative process in the aseptic nonunion, and to establish whether it was worthwhile with atrophic nonunion. The primary outcome was radiological union. As secondary endpoint, the healing time was assessed, and the radiological consolidation grade at each follow-up. METHODS: We identified 113 subjects with tibia or femur nonunion and retrospectively created two groups. Group A was constituted by 56 subjects who underwent the standard procedure, i.e. Judet decortication with/out internal fixation devices, and opposite cortical homoplastic stick. In 57 patients, the standard procedure was modified by adding PRF and BMSC carried by homologous lyophilised bone chips (group B). The same surgeon performed all the operations. To our knowledge, no data are reported in the literature about such application. Since a "gold standard" for healing quantification does not exist, a new scoring radiological system was applied, at 1.5, 3, 6, 12 and 24 months after treatment. RESULTS: At the final 24-month follow-up, the radiological union percentage was 94,12 in group B and 95,12% in group A. A decreased healing time was demonstrated in the presence of PRF/BMSC in comparison with the standard procedure. When we compared the radiological scores at each follow-up, we found that the PRF/BMSC combination significantly improved the consolidation grade at 1.5-, 3- and 6-month follow-up in femurs and at 1.5-month follow-up in tibiae. Furthermore, an improved consolidation grade was demonstrated in the atrophic subjects treated with adjuvants compared to atrophic patients treated with the standard procedure at 1.5-month follow-up. CONCLUSIONS: This study supports the concept that the use of PRF/BMSC, during the standard procedure, is effective in shortening nonunion healing time. It could allow an early mobilization of patients, minimizing suffering, and could be an effective tool to reduce the health-care costs resulting from this issue. LEVEL OF EVIDENCE: Therapeutic level III.

FLAG (fludarabine + high-dose cytarabine + G-CSF): an effective and tolerable protocol for the treatment of 'poor risk' acute myeloid leukemias.

Twenty-eight patients with poor prognosis acute myeloid leukemia (AML) received therapy with two courses of fludarabine 30 mg/m2/day + ara-C 2 g/m2/day (days 1-5) and G-CSF 5 mg/kg/day (FLAG) (from day 0 to polymorphonuclear recovery). Eighteen patients were considered 'refractory' (eight primarily resistant, five relapsing within 6 months of initial remission, or at a second relapse; five relapsing after an autologous bone marrow transplantation procedure. Ten cases were defined 'secondary' AML (diagnosis of AML made after a preexisting diagnosis of: myelodysplastic syndrome: five cases; myelodysplastic syndrome after therapy for breast cancer: one case; previously untreated, and concomitant, non-Hodgkin's lymphoma: two cases; Hodgkin's disease treated with chemoradiotherapy: one case). Overall, 15 patients (58%) achieved a complete remission (CR). Two patients died of infection during induction, and 11 had resistant disease. Analyzing the data in relation to selected host and disease characteristics, the response varied widely. The highest CR rates (89%) were obtained in secondary AML; in particular, two cases of 'second-primary' (concomitant with low-grade non-Hodgkin's lymphoma) AML obtained CR for both diseases. Refractory AML differed widely for response: high CR rate (75%), although with short mean CR duration for primary resistance AML, and very poor response (11% CR) for relapsed (early, second, after ABMT) cases. Interestingly, a slow kinetic of leukemic growth in vivo before FLAG administration was significantly related to the response and outcome (p = 0.0002). Hematological and nonhematological toxicities were acceptable. In conclusion, the FLAG regimen has significant antileukemic activity and acceptable toxicity especially in secondary AML, both with and without coexisting lymphoid malignancy.

Acute myeloid leukemia from diagnosis to bone marrow transplantation: experience from a single centre.

We analysed the use of allogeneic bone marrow transplantation (BMT) in the treatment of acute myelogenous leukemia (AML). We evaluated 271 adult patients with newly diagnosed AML treated here between 1983 and 1992; 113 patients (42%) were eligible for BMT because of their age (< 45 years until 1986 and < 50 years later). Of these, HLA typing was performed on 81 patients (72%); 32 patients were not typed (19 had no sibling, 8 had a primary refractory leukemia, 3 died during induction, 1 had important previous toxicity and for one patient there was no recorded reason). Of the 81 typed, 36 patients (44.4%) were found to have an HLA-matched sibling donor and 21 (25%) underwent BMT (8% of the total population); 15 patients did not undergo BMT (6 relapsed before transplantation and did not obtain a second remission, 3 declined the procedure, 1 died during induction, 1 had positive MLR, 1 had positive MLR and HCV hepatitis, 1 was a drug addict with HCV hepatitis, 1 had previous organ toxicity, 1 was psychotic). These data show that only a small fraction of unselected patients with AML can undergo BMT. Such findings make the comparison of BMT with other types of post-remission therapy more complex.

Pre-treatment with all-trans retinoic acid accelerates polymorphonuclear recovery after chemotherapy in patients with acute promyelocytic leukemia.

All-trans retinoic acid (ATRA) is currently being used as remission induction treatment for acute promyelocytic leukemia (APL). Conventional chemotherapy is added both during and after ATRA treatment, in order to avoid the occurrence of hyperleukocytosis, and to improve the duration of complete remission. In this study we analysed the hematopoietic recovery of 18 consecutive APL patients after standard Idarubicin or Daunorubicin +/- Cytosine-Arabinoside regimens. 9 of the patients were at the onset of the disease, (CHT group) while 9 had been pre-treated with ATRA 45 mg/sqm/day for at least 3 months (ATRA group). 500 PMN/mmc were reached after 20.8 day from the end of treatment in CHT group and after 12.0 days in ATRA group (p = 0.007). Platelets recovery was faster, even though not significantly in ATRA group. Interestingly, PMN recovery in ATRA group was even shorter (p = 0.004) than that obtained in CHT group, after the first course of chemotherapy (treatment in CR vs treatment in CR). If these results are confirmed in a larger study, a protective effect of ATRA on normal residual hemopoiesis should be postulated.

All-trans retinoic acid in the treatment of myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a group of hematopoietic disorders characterized by uni- or multilineage maturation defects of the bone marrow. Controversial therapeutic results have been obtained using growth factors or differentiating agents such as 13-cis retinoic acid. In this pilot study we evaluated the effects of all-trans retinoic acid (ATRA) in 10 MDS patients (5 male, 5 female). Six patients had refractory anemia (RA), 1 had refractory anemia with excess of blasts (RAEB), and 3 had refractory anemia with excess of blasts in transformation (RAEB-t). All patients received the same dose of ATRA (45 mg/sqm/day) orally for 6 weeks. A rise in hemoglobin concentration > 1g/dl was observed in 3/10 patients, while 5/10 patients showed an increase in granulocyte count > 0.5 x 10(9)/l without concomitant increase in the percentage of blast cells in the bone marrow. A rise in the platelet count > 50 x 10(9)/l was observed in 1/10 patients. All the effects were transient and maximal responses were obtained by the fourth week of treatment. Thereafter, the peripheral blood counts started to drop again, reaching pre-therapy values by the end of the treatment. This phenomenon could be attributed either to the exhaustion of an ATRA-responding cell pool, the development of cellular resistance to ATRA or to a reduction of plasma ATRA levels after prolonged treatment. According to our results, it seems that ATRA might have therapeutic efficacy in MDS, particularly if its effect could be improved by combinations with other differentiating agents or growth factors.

All-trans retinoic acid and induction of apoptosis in acute promyelocytic leukemia cells.

All-trans retinoic acid (ATRA) represents a highly effective treatment for acute promyelocytic leukemia (M3-ANLL). This compound induces the leukemic promyelocytes to differentiate into morphologically and phenotypically mature myeloid cells. The mechanism of action of ATRA is far from fully understood. It has recently been reported that, along with its differentiation activity, ATRA causes apoptosis in the acute promyelocytic leukemia cell line HL-60. In this study we attempted to test whether ATRA is also able to induce apoptosis in fresh leukemic cells from M3-ANLL patients. Our results indicated that although morphological differentiation was detectable in 9/9 M3-ANLL samples after in vitro exposure to ATRA 10(-6) M, the percentage of apoptotic cells in the treated samples did not significantly differ from that obtained in controls (13.1% vs 9.4% respectively, after 8 days exposure). These data suggest that apoptosis does not seem to be the key mechanism by which ATRA exerts its action in M3-ANLL, at least at the blast cell level.

MEC (mitoxantrone, etoposide and intermediate dose cytarabine): an effective induction regimen for previously untreated acute non-lymphocytic leukemia.

Twenty-three patients with acute non lymphocytic leukemia (ANLL), were treated with a single-6 day course of Mitoxantrone 6mg/m2/day, Etoposide 80mg/m2/day and intermediate dose Cytarabine (ara-C) 1g/m2/day (MEC). Patients who achieved complete remission (CR) were submitted to a 4-day-course of MEC as consolidation. Seventeen patients (73.9%) obtained CR, five patients (22.7%) were resistant to the treatment and one patient died during induction. Median remission duration was 11 months; overall median survival was 16 months. Relapses occurred in 11 patients; eight patients are still alive: 6 in 1st, 2 in 2nd CR (mean survival 20.1 months, range 17-26). All patients experienced severe myelosuppression comparable to that observed after classical induction cycles including ara-C in continuous intravenous infusion; none, however, died of infection. Non-hematologic toxicity was minimal; in particular, neurotoxicity was not observed. According to our results, the MEC regimen, which was previously demonstrated to be active in refractory patients, represents an effective induction treatment in ANLL, with an acceptable toxicity.

Contemporaneous acute myeloid leukaemia and sarcoidosis. Report of three cases.

Three cases of contemporaneous acute myeloid leukaemia (AML) and sarcoidosis are described. The possible pathogenic mechanisms concerning their concurrent appearance are discussed: if sarcoidosis impaired T-cell response, it could perhaps predispose the development of AML; alternatively, the development of sarcoidosis during AML may be due to a reaction linked to a diffuse release of tumour antigens with a subsequent formation of a non-caseating granulomata.

Enhanced tibial osteotomy healing with use of bone grafts supplemented with platelet gel or platelet gel and bone marrow stromal cells.

BACKGROUND: There is great interest in the use of bone substitutes to improve bone repair. We compared the osteogenic potential of lyophilized bone chips combined with platelet gel, or with platelet gel and bone marrow stromal cells, with that of lyophilized bone chips alone in the healing of a high tibial osteotomy. METHODS: A prospective, randomized, controlled study was performed, and a standardized clinical model was applied. Thirty-three patients undergoing high tibial osteotomy to treat genu varum were enrolled and assigned to three groups. During the osteotomy, lyophilized bone chips with platelet gel were implanted into eleven patients (Group A), lyophilized bone chips with platelet gel and bone marrow stromal cells were implanted in twelve patients (Group B), and lyophilized bone chips without gel were placed in ten patients as controls (Group C). Six weeks after surgery, computed tomography-guided biopsies of the grafted areas were performed and the specimens were analyzed by histomorphometry. Clinical and radiographic evaluation was performed at six weeks, twelve weeks, six months, and one year after surgery. RESULTS: Histomorphometry at six weeks showed significantly increased osteoblasts and osteoid areas in both Group A (p = 0.006 and p = 0.03, respectively) and Group B (p = 0.009 and p = 0.001) in comparison with controls, as well as increased bone apposition on the chips (p = 0.007 and p = 0.001, respectively), which was greater in Group B than in Group A (p < 0.05). Group B showed significantly higher revascularization than the controls (p = 0.004). Radiographs revealed a significantly higher rate of osseointegration in Groups A and B than in the controls at six weeks (p < 0.005 and p < 0.0001, respectively). At the final evaluation at one year, the osseointegration was still better in Groups A and B than in Group C; however, all patients had complete clinical and functional evidence of healing. CONCLUSIONS: Adding a platelet gel or a platelet gel combined with bone marrow stromal cells to lyophilized bone chips increases the osteogenetic potential of the lyophilized bone chips and may be a useful tool in the treatment of patients with massive bone loss.

Relationship between femoral neck fractures and osteoporosis in the elderly: densitometric analysis.

The authors report the findings of densitometric analysis performed on 25 patients from of 70 to 90 years of age with fractures of the proximal femur. Although bone density decreased progressively with age, there was not a close correlation between bone density and fracture, as the latter occurred even when the densitometric values were relatively high for the patient's sex and age.

Sweet's syndrome and chronic lymphocytic leukemia associated with scirrhous breast cancer. A case report.

A 55-year-old woman developed Sweet's syndrome (acute febrile neutrophilic dermatosis, AFND) 5 years after a diagnosis of chronic lymphocytic leukemia (CLL). Two months later she developed a scirrhous carcinoma of the breast. The patient died 7 months later from sepsis. To our knowledge, this is the first case of an association among a cancer of the breast, CLL and Sweet's syndrome.

Synergistic cytotoxicity of AZT plus alpha and gamma interferon in chronic myeloid leukemia cell line K562.

We have previously reported that the antineoplastic activity of 3'-azido 3' deoxythymidine (AZT) can be increased by drugs that inhibit "de novo" thymidylate synthesis, such as 5-fluorouracil, methotrexate and hydroxyurea. In the present study we tested the combinations AZT+alpha interferon (IFN) and AZT+gamma IFN on in vitro growth of the human acute-phase chronic myeloid leukemia (CML) cell line K562. After 72 hours incubation, not only AZT+alpha-IFN but also AZT+gamma-IFN were synergistic in inhibiting K562 growth, as demonstrated by isobologram analysis of the data. This enhanced cytotoxicity was confirmed by the evaluation of [3H]AZT incorporation into cellular DNA, that was increased by 50% and 222% in the presence of alpha- and gamma-IFN, respectively. The addition of 50 mumol/l thymidine to the culture medium was able to reduce the cytotoxicity of the drug combinations to the degree observed with each compound alone; furthermore, the increased incorporation of AZT into DNA was completely reversed. These data indicate the existence of a biochemical interaction between AZT and IFNs that results in an increased cytotoxic effect. While the combination AZT+alpha-IFN is currently being tested in HIV-related malignancies, AZT+gamma-IFN is new and deserves further study in human CML acute and chronic phase models, in view of possible clinical applications.

Thromboembolic complications and pharmacological prophylaxis in orthopaedic surgery.

Two thousand, three hundred and three patients who had undergone major orthopaedic surgery were statistically analysed for the incidence of complications comparing three regimens of prophylaxis and coexisting diseases; 2090 patients did not present postoperative complications. PTE occurred in 0.65% (one fatal). The mortality rate was 0.34% and the incidence of haemorrhage (haematoma and one gastric haemorrhage) was 3.8%. Patients treated with indobufen had a shorter hospital stay and the need for homologous blood transfusions was lower than for patients treated with calcium heparin. The rate of PTE was notably different in the three groups, being lower in the group treated with enoxaparin, although this result was not found to be statistically significant.

Comparative effects of racemic verapamil vs R-verapamil on normal and leukemic progenitors.

R-Verapamil (R-VPM), an enantiomer of racemic verapamil (VPM), has been recently reported to possess an activity equivalent to VPM in reverting drug resistance in vitro, without showing remarkable cardiovascular toxicity in animal models, even in doses three times higher than VPM. In this study, we assessed the effects of R-VPM in vitro, on clonogenic leukemia cells (CFU-L) from 15 patients with acute nonlymphoid leukemia (ANLL) at diagnosis, and on bone marrow erythroid (BFU-E) and myeloid (CFU-GM) progenitors from 15 healthy volunteers. On CFU-L, continuous exposure to VPM or R-VPM alone showed a slight inhibitory activity; in combination with daunorubicin (DNR), R-VPM proved more effective (mean IC50 of DNR: alone = 24.53 ng/ml +/- 6.2 SE, + VPM = 18.8 ng/ml +/- 4.6 SE, +R-VPM = 17.9 ng/ml +/- 4.8 SE). On CFU-GM, both VPM and R-VPM were minimally toxic at the lowest concentration used, but 30 microM VPM were significantly more toxic than R-VPM at the same dose (residual growth = 39.2% +/- 6.5% vs. 71.8% +/- 9.3% with R-VPM, p = 0.005). On BFU-E, both VPM and R-VPM caused more consistent growth inhibition; at high doses, VPM was again more toxic than R-VPM (33.4% +/- 12.8% vs 53.4% +/- 10.4% residual growth at 30 microM, p = 0.03). DNR toxicity on bone marrow was more greatly enhanced by VPM than R-VPM, and this difference was statistically significant on erythroid progenitor colony growth (p = 0.04). In conclusion, in comparison to VPM, R-VPM appeared to be at least equally effective on leukemic clonogenic cells and less toxic on normal bone marrow precursors, thus suggesting a possible safe use in vivo, even in concentrations that cannot be achieved with VPM, owing to its toxic effects.

In vitro effects of bisantrene on fresh clonogenic leukemia cells: a preliminary study on 15 cases.

In vitro clonogenic assays may be useful for determining the sensitivity of leukemic cells to chemotherapeutic agents. We evaluated the antileukemic effect of Bisantrene (an anthracene derivative now undergoing phase II clinical trials in relapsed/resistant acute non lymphoid leukemias-ANLL) using the ANLL cell clonogenic assay. Fifteen cases were studied (9 newly diagnosed, 5 relapsed and 1 refractory ANLL). Normal CFU-GM sensitivity was tested in a subset of 10 normal controls. A wide range of concentrations (from 0.01 to 10 micrograms/ml) at 3 durations of exposure (30 min, 120 min, continuous) was employed. Bisantrene proved effective in 12 out of 15 ANLL cases, inhibiting blast colony growth (50% at 1 micrograms/ml; nearly 100% at 10 micrograms/ml) in a dose-dependent, time-independent way. Three cases were unresponsive both in vitro and in vivo. Normal CFU-GM were inhibited at lower doses (50% at 0.5 micrograms/ml; 100% at 5 micrograms/ml). We conclude that: 1) Bisantrene is active in vitro on leukemic clonogenic cells at doses corresponding to plasmatic levels achievable in patients, with a parallel activity in vivo in 3 relapsed cases. It should be tested in vitro before therapeutic use in order to avoid, if possible, improper use in resistant patients. 2) Normal CFU-GM are more sensitive than clonogenic leukemic cells. This must be taken into account, in view of possible prolonged neutropenias after therapy. 3) The time-independent effect of the drug should be evaluated in the design of new therapeutic schedules.

Effect of in vivo treatment with rh GM-CSF on in vitro growth of haematopoietic progenitors in patients with myelodysplastic syndromes.

BACKGROUND: Recombinant (r) human (h) granulocyte/macrophage colony stimulating factor (rh GM-CSF) has been shown to increase the number of peripheral blood (PB) neutrophils, eosinophils and monocytes in myelodysplastic syndromes (MDS). The aims of this study were: 1) to evaluate the effect of rh GM-CSF therapy on the in vitro growth of granulocyte-erythroid-macrophage-megakaryocyte colonies (CFU-GEMM), erythroid colonies (BFU-E), and granulocyte-macrophage colonies (CFU-GM) in patients with MDS; 2) to assess in these patients, while they are being treated in vivo with rh GM-CSF, the possible additive effect of rh IL-3 and rh G-CSF on the in vitro growth of haematopoietic progenitors. METHODS: The in vitro growth of CFU-GEMM, BFU-E and CFU-GM was studies in 10 myelodysplastic (MDS) patients, before and after in vivo administration of rh GM-CSF. RESULTS: After rh GM-CSF administration, the number of CFU-GM increased in all standard risk MDS patients. In 2 out of 5 cases, this effect was more pronounced and persisted up to 30 days after the end of rh GM-CSF treatment. On the other hand, the number of CFU-GEMM and BFU-E was substantially unchanged. When rh GM-CSF, rh G-CSF and rh IL-3 were added in vitro alone or in combination as the source of colony stimulating activity, no significant increase of the CFU-GM colony number was noticed. CONCLUSIONS: Rh GM-CSF therapy appears useful for increasing the number of peripheral blood granulocytes and of marrow CFU-GM in standard-risk MDS patients. High-risk MDS patients are far less responsive to rh GM-CSF treatment, probably reflecting a more aggressive and/or advanced disease.

Sensitivity of chronic myeloid leukemia hemopoietic progenitors to PTT-119 in combination with human recombinant interferon alpha and gamma.

PTT-119, a new synthetic alkylating compound, has shown a marked "in vitro" inhibitory effect on chronic myeloid leukemia (CML) granulo-monocytic precursors (CFU-GM) at doses greater than 5 micrograms/ml. Based on previous experiences of synergistic associations between alkylating drugs and biological modifiers, we tested the effects of low doses of PTT-119 (from 0.1 to 1 microgram/ml) in concert with alpha, gamma, or alpha + gamma interferons and compared to IFNs alone, in order to investigate an alternative choice for treatment of CML patients in chronic phase. Our results showed a significantly higher CFU-GM cloning inhibition after addition of 100 or 1,000 U/ml of alpha IFN to 0.1 microgram/ml PTT-119 (from 39.6% +/- 26.6 SD to 80.7% +/- 10 SD and 91.5% +/- 8 SD, respectively), while gamma IFN resulted in only a slight increase in colony growth inhibition when compared to the drug used alone. The association of alpha plus gamma IFN coupled with PTT-119 treatment did not significantly improve the results observed after exposure of leukemic progenitors to PTT-119 and alpha IFN alone. We conclude that a combined treatment with PTT-119 and IFN is probably worth testing both for purging methods before autologous bone marrow transplantation and for in vivo administration in chronic myeloid leukemia.

Impairment of GM-CSF production in myelodysplastic syndromes.

In this study we evaluated the production of granulocyte/macrophage-colony stimulating factor (GM-CSF), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) by enriched bone marrow (BM) macrophages in 15 patients affected by myelodysplasia and 20 normal BM donors. The presence of GM-CSF, IL-6 and TNF-alpha in the culture supernatants of BM macrophages was detectable only after stimulation with lipopolysaccharide (LPS), whereas no differences were present in the amount of IL-6 and TNF-alpha between myelodysplastic patients and normal controls, GM-CSF production appeared eight-fold reduced in BM macrophage culture supernatants from myelodysplastic patients with respect to normal controls. After further experiments, we concluded that the impaired release of GM-CSF by BM macrophages could not be due to a different production kinetic in myelodysplastic patients. Moreover, the number of multipotent (CFU-GEMM), granulocyte/macrophage (CFU-GM) and erythroid (BFU-E) progenitors was significantly impaired in myelodysplastic patients. In conclusion, we demonstrated that the production of GM-CSF by purified adherent cells from MDS patients is markedly impaired in spite of the peripheral blood cytopenia. This selective defect in GM-CSF production, along with an intrinsic defect of haematopoietic progenitor cells, might contribute to the impairment of haematopoiesis always observed in myelodysplastic patients.