Constitutively activating mutation in WASP causes X-linked severe congenital neutropenia.

The Wiskott-Aldrich syndrome protein (WASP; encoded by the gene WAS) and its homologs are important regulators of the actin cytoskeleton, mediating communication between Rho-family GTPases and the actin nucleation/crosslinking factor, the Arp2/3 complex. Many WAS mutations impair cytoskeletal control in hematopoietic tissues, resulting in functional and developmental defects that define the X-linked Wiskott-Aldrich syndrome (WAS) and the related X-linked thrombocytopenia (XLT). These diseases seem to result from reduced WASP signaling, often through decreased transcription or translation of the gene. Here we describe a new disease, X-linked severe congenital neutropenia (XLN), caused by a novel L270P mutation in the region of WAS encoding the conserved GTPase binding domain (GBD). In vitro, the mutant protein is constitutively activated through disruption of an autoinhibitory domain in the wild-type protein, indicating that loss of WASP autoinhibition is a key event in XLN. Our findings highlight the importance of precise regulation of WASP in hematopoietic development and function, as impairment versus enhancement of its activity give rise to distinct spectra of cellular defects and clinical phenotypes.

High-vs low-dose cytarabine combined with interferon alfa in patients with first chronic phase chronic myeloid leukemia. A prospective randomized phase III study.

A prospective randomized phase III study was performed to evaluate whether intensified cytarabine would induce a higher response rate and longer event-free interval as compared to low-dose cytarabine in chronic myeloid leukemia (CML). One hundred and eighteen patients with CML in early chronic phase entered the study. Twenty-eight out of 32 patients assigned to group A received two cycles of a combination of intensified cytarabine and idarubicin followed by interferon alfa (IFN-alpha) maintenance, 28 patients in group B received standard treatment by a combination of low-dose cytarabine and IFN-alpha. Forty-nine patients with a human leukocyte antigen-identical sibling donor proceeded to allogeneic stem cell transplantation (allo-SCT) and nine patients were excluded from the analysis. Hematological response was observed in 97% of the patients in group A vs 86% of the patients in group B during the first year of treatment. In group A, 16 patients (50%) achieved a major cytogenetic response, which compared to seven patients (25%) with a major cytogenetic response in group B. With a median follow-up of 58 months (range 34-76), event-free survival was not significantly different between arms A and B. The estimated 5-year survival rate was 56% in the intensified arm and 77% in the low-dose arm (P = 0.05). Recipients of allo-SCT showed a 5-year estimated survival rate of 55%. Although intensified cytarabine induced a higher initial percentage of major and complete cytogenetic responses, responses were not sustained by IFN-alpha maintenance therapy.

Value of different modalities of granulocyte-macrophage colony-stimulating factor applied during or after induction therapy of acute myeloid leukemia.

PURPOSE: The hematopoietic growth factors (HGFs) introduced into induction chemotherapy (CT) of acute myeloid leukemia (AML) might be of benefit to treatment outcome by at least two mechanisms. HGFs given on days simultaneously with CT might sensitize the leukemic cells and enhance their susceptibility to CT. HGFs applied after CT might hasten hematopoietic recovery and reduce morbidity or mortality. MATERIALS AND METHODS: We set out to evaluate the use of granulocyte-macrophage colony-stimulating factor (GM-CSF; 5 microg/kg) in a prospective randomized study of factorial design (yes or no GM-CSF during CT, and yes or no GM-CSF after CT) in patients aged 15 to 60 years (mean, 42) with newly diagnosed AML. GM-CSF was applied as follows: during CT only (+/-, n = 64 assessable patients), GM-CSF during and following CT (+/+, n = 66), no GM-CSF (-/-, n = 63), or GM-CSF after CT only (-/+, n = 60). RESULTS: The complete response (CR) rate was 77%. At a median follow-up time of 42 months, probabilities of overall survival (OS) and disease-free survival (DFS) at 3 years were 38% and 37% in all patients. CR rates, OS, and DFS did not differ between the treatment groups (intention-to-treat analysis). Neutrophil recovery (1.0 x 10(9)/L) and monocyte recovery were significantly faster in patients who received GM-CSF after CT (26 days v 30 days; neutrophils, P < .001; monocytes, P < .005). Platelet regeneration, transfusion requirements, use of antibiotics, frequency of infections, and duration of hospitalization did not vary as a function of any of the therapeutic GM-CSF modalities. More frequent side effects (eg, fever and fluid retention) were noted in GM-CSF-treated patients predominantly related to the use of GM-CSF during CT. CONCLUSION: Priming of AML cells to the cytotoxic effects of CT by the use of GM-CSF during CT or accelerating myeloid recovery by the use of GM-CSF after CT does not significantly improve treatment outcome of young and middle-aged adults with newly diagnosed AML.

CHOP compared with CHOP plus granulocyte colony-stimulating factor in elderly patients with aggressive non-Hodgkin's lymphoma.

PURPOSE: To investigate whether the relative dose-intensity of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy could be improved by prophylactic administration of granulocyte colony-stimulating factor (G-CSF) in elderly patients with aggressive non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Patients aged 65 to 90 years (median, 72 years) with stage II to IV aggressive NHL were randomly assigned to receive standard CHOP every 3 weeks or CHOP plus G-CSF every 3 weeks on days 2 to 11 of each cycle. RESULTS: In 389 eligible patients, the relative dose intensities (RDIs) of cyclophosphamide (median, 96.3% v 93.9%; P =.01) and doxorubicin (median, 95.4% v 93.3%; P =.04) were higher in patients treated with CHOP plus G-CSF. The complete response rates were 55% and 52% for CHOP and CHOP plus G-CSF, respectively (P =.63). The actuarial overall survival at 5 years was 22% with CHOP alone, compared with 24% with CHOP plus G-CSF (P =.76), with a median follow-up of 33 months. Patients treated with CHOP plus G-CSF had an identical incidence of infections, with World Health Organization grade 3 to 4 (34 of 1,191 cycles v 36 of 1,195 cycles). Only the cumulative days with antibiotics were fewer with CHOP plus G-CSF (median, 0 v 6 days; P =.006) than with CHOP alone. The number of hospital admissions and the number of days in hospital were not different. CONCLUSION: In elderly patients, G-CSF improved the RDI of CHOP, but this did not lead to a higher complete response rate or better overall survival. G-CSF did not prevent serious infections.

Measurement of serum cytokine levels in patients with myelodysplastic syndromes.

Sera of 25 healthy controls and 75 patients suffering from myelodysplastic syndromes (MDS) were investigated for serum concentration of interleukin-1 alpha (IL-1 alpha), IL-3, IL-6, granulocyte-colony-stimulating factor (G-CSF), granulocyte-macrophage-CSF (GM-CSF), erythropoietin (Epo), and tumor necrosis factor-alpha (TNF-alpha). According to French-American-British (FAB) classification, 21 refractory anemia (RA), seven refractory anemia with ring sideroblasts (RARS), 15 chronic myelomonocytic leukemia (CMML), 12 refractory anemia with excess of blasts (RAEB), and 20 RAEB in transformation (RAEBt) were examined. TNF-alpha levels were inversely correlated with lower levels of hemoglobin concentration (r = -0.31, p = 0.005), irrespective of the requirements for transfusion in anemic MDS patients. Significant differences in TNF-alpha levels between CMML (26.2 +/- 5.9 pg/ml) and the FAB subgroups (16.1 +/- 1.6 pg/ml) were detected. There was an overall inverse relationship between the level of erythropoietin and the degree of anemia, but a wide range of Epo response between patients with similar hemoglobin concentrations. Serum levels of IL-1 alpha and GM-CSF were undetected in most of the patients. In 57% of the samples there were detectable levels of G-CSF, without a correlation of the serum levels with blood cell counts, nor with any of the FAB subcategories. Overall, 29% and 25% of the patient sera exhibited elevated IL-3 and IL-6 levels, respectively. There was no correlation of the serum levels with any of the blood counts, other cytokines, nor FAB subcategories. In conclusion, simple negative feedback mechanism between a specific cytokine and the production of blood cells seems not to be the case in MDS, except for red cell production and erythropoietin concentration. Our data may suggest the involvement of TNF-alpha in the pathogenesis of anemia in MDS.

A single course of remission reinduction chemotherapy for acute myelogenous leukemia relapsing after allogeneic bone marrow transplantation is complicated by graft-versus-host disease and followed by sustained complete remission.

Graft-versus-host disease (GVHD) remains a major immunological complication after allogeneic bone marrow transplantation (allo-BMT), but also favors development of the beneficial graft-versus-leukemia (GVL) effect. A patient with AML-M4 (inv (16)) is described, who was given non-myeloablative remission reinduction therapy for leukemic relapse (inv (16), trisomy 8) diagnosed on day 184 after HLA-compatible sibling BMT. On day 236, ie about 6 weeks after completion of this course, a clinical syndrome suggestive of acute GVHD grade 3 had developed. Skin biopsy confirmed the clinical diagnosis of GVHD, with a compatible liver biopsy. Transfusion-associated GVHD was ruled out by analysis of short tandem repeat (STR) alleles in the skin biopsy, revealing alleles from donor and recipient but not from third party origin. Cyclosporin A (CsA) therapy, which had been tapered between days 150 and 175, was resumed, resulting in a favorable response and gradual transition to limited chronic GVHD. The patient has since remained in complete remission with an excellent performance status for more than 40 months, without further chemotherapy. Thus this biopsy proven case of GVHD was induced by marrow donor lymphocytes more than 200 days after transplantation and apparently triggered by remission reinduction chemotherapy. The case indicates that intensive non-myeloablative chemotherapy can cure AML relapsing after allo-BMT. The therapeutic effect in this case probably involved a direct pharmacological suppression of the leukemic clone followed by a GVL effect initiated by donor-derived alloreactive T lymphocytes.

A randomized study of granulocyte colony-stimulating factor applied during and after chemotherapy in patients with poor risk myelodysplastic syndromes: a report from the HOVON Cooperative Group. Dutch-Belgian Hemato-Oncology Cooperative Group.

The purpose of this study was to determine the safety and efficacy of filgrastim as an adjunct to induction and consolidation chemotherapy in poor risk patients with myelodysplastic syndrome (MDS). Filgrastim was given both during and after chemotherapy with the objective to accelerate hematopoietic repopulation and enhance the efficacy of chemotherapy. In a prospective randomized multicentre phase II trial, a total of 64 patients with poor risk primary MDS were randomized to receive either granulocyte colony-stimulating factor (G-CSF, filgrastim, AMGEN, Breda, The Netherlands) 5 microg/kg/day subcutaneously or no G-CSF in addition to daunomycin (30 mg/m2/days 1, 2 and 3 intravenous bolus) and cytarabine (200 mg/m2 days 1-7, continuous infusion). The overall complete response rate was 63%: 73% for patients receiving filgrastim as compared to 52% in the standard arm (P = 0.08). Overall survival at 2 years was estimated at 29% for patients assigned to the filgrastim arm and 16% for control patients (P = 0.22). The median time for recovery of granulocytes towards 1.0 x 10(9)/l post-chemotherapy was 23 days in the filgrastim-treated patients vs 35 days in the standard arm (P = 0.015). There were no differences in time of platelet recovery, length of hospital stay, duration of antibiotic use or infectious complications between the two treatment groups. However the earlier recovery of neutrophils in the filgrastim group was associated with a reduced interval of 9 days between the induction and consolidation cycle. In patients with poor risk MDS the use of filgrastim during and after induction therapy results in a significantly reduced neutrophil recovery time. Further study may be warranted to see if the apparent trend of the improved response to chemotherapy in combination with filgrastim can be confirmed in greater number of patients and to assess the effect of the addition of filgrastim on survival.

P-glycoprotein and multidrug resistance protein activities in relation to treatment outcome in acute myeloid leukemia.

Despite treatment with intensive chemotherapy, a considerable number of patients with acute myeloid leukemia (AML) die from their disease due to the occurrence of resistance. Overexpression of the transporter proteins P-glycoprotein (P-gp) and multidrug resistance protein (MRP) 1 has been identified as a major cause of cross-resistance to functionally and structurally unrelated drugs. In the present study, the functional activity of P-gp and MRP was determined in 104 de novo AML patients with a flow cytometric assay using rhodamine 123 (Rh123) in combination with PSC833 and carboxyfluorescein (CF) in combination with MK-571. The results were compared with clinical outcome and with known prognostic factors. The functional activity of P-gp and MRP, expressed as Rh123 efflux blocking by PSC833 and CF efflux blocking by MK-571, demonstrated a great variability in the AML patients. A strong negative correlation was observed between Rh123 efflux blocking by PSC833 and Rh123 accumulation (r(s) = -0.69, P < 0.001) and between CF efflux blocking by MK-571 and CF accumulation (r(s) = -0.59, P < 0.001). A low Rh123 accumulation and a high Rh123 efflux blocking by PSC833 were associated with a low complete remission (CR) rate after the first cycle of chemotherapy (P = 0.008 and P = 0.01, respectively). Patients with both low Rh123 and CF accumulation (n = 16) had the lowest CR rate (6%), whereas patients with both high Rh123 and CF accumulation (n = 11) had a CR rate of 73%. AML patients with French-American-British classification M1 or M2 showed a lower Rh123 accumulation than patients with French-American-British classification M4 or M5 (P = 0.02). No association was observed between the multidrug resistance parameters and overall survival of the AML patients. Risk group was the only predictive parameter for overall survival (P = 0.003).

Phase II study of lomustine, cytarabine, mitoxantrone, and prednisone (CAMP) combination chemotherapy for doxorubicin-resistant intermediate- and high-grade malignant non-Hodgkin's lymphoma.

A phase II study was conducted to evaluate the efficacy and toxicity of lomustine, cytarabine, mitoxantrone and prednisone (CAMP) chemotherapy in doxorubicin-resistant intermediate- and high-grade malignant non-Hodgkin's lymphomas (NHL). Among 30 patients, the complete remission rate was 27% (duration: 10, 16, 22, 35, 35+, 42+, 51+, 55+ months) and the partial remission rate was 20%. Median survival for complete responders was more than 4 years. The best responses were seen in patients with relapsed NHL compared to those with primary refractory NHL. Toxicity was mainly related to myelosuppression. The results suggest that the CAMP schedule can be applied on an outpatient basis with satisfactory efficacy in patients with relapsing intermediate- and high-grade malignant NHL.

Peripheral blood lymphocyte subset shifts in patients with untreated hematological tumors: evidence for systemic activation of the T cell compartment.

Flow cytometry immunophenotyping of peripheral blood lymphocyte subsets and multivariate data-analytical techniques revealed that among untreated hemato-oncological patients (n = 48) with lymphomas, acute and chronic myeloid and lymphocytic leukemias, monoclonal gammopathy of undetermined significance, and multiple myeloma, 42% had (nonmalignant) lymphocyte profiles clearly distinct from healthy donors. Notably, a similar pattern of increased CD3+ CD57+, CD3+ HLA-DR+, CD3+ CD(16 + 56)+, CD4- CD8+, CD8+ CD57+, CD8+ CD28-, and CD8+ CD62L- subsets was detected. More extensive three-color immunophenotyping on an additional group of 49 untreated patients revealed that both CD4+ and CD8+ T cells displayed significant increases of activation markers: CD69, CD(16 + 56), HLA-DR, CD71, and CD57, and a loss of CD62L and CD28, which is also interpreted as a sign of activation. Consistent with the phenotypical signs of in vivo immune activation, polyclonal cytolytic activity, measured ex vivo in an anti-CD3-redirected assay, was detected within immunomagnetically purified CD4+ T cells of three out of six B-CLL patients investigated, but not within purified CD4+ T cells of five healthy donors. The purified CD8+ T cells of patients (n = 28) and donors (n = 5) on the other hand displayed similar polyclonal cytotoxic activities at the various effector:target ratios investigated. Tumor-directed cytotoxic activity of purified CD4+ (n = 6) and/or CD8+ T cells (n = 15) against freshly isolated autologous tumor cells was not detected in any of the experiments. Collectively, our results demonstrate systemic T cell activation as a common feature in hematological neoplasia, and a markedly enhanced cytolytic activity of the CD4- subset in CLL patients. The reason(s) for this expansion of activated T cells and its pathophysiologic significance, however, remain unclear.

Mucormycosis in allogeneic bone marrow transplant recipients: report of five cases and review of the role of iron overload in the pathogenesis.

In a 10-year consecutive series of 263 allogeneic bone marrow transplant recipients, we identified five cases (1.9%) of invasive mucormycosis. Only one infection occurred within the first 100 days after transplantation, while the remainder complicated the late post-transplant course (median day of diagnosis: 343). Sites of infection were considered 'non-classical' and included pulmonary, cutaneous and gastric involvement. No case of fungal dissemination was observed. Mucormycosis was the primary cause of death in three of the five patients. Corticosteroid-treated graft-versus-host disease, either acute or chronic, or severe neutropenia were present in all cases. However, compared with a matched control population, the most striking finding was the demonstration of severe iron overload in each of the mucormycosis patients. The mean level of serum ferritin, transferrin saturation and number of transfused units of red cells (2029 microg/l, 92% and 52 units, respectively) in the study group is significantly higher compared with the control group (P < 0.05). The difference with other risk groups for mucormycosis, including deferoxamine-treated dialysis patients and acidotic diabetics, was analyzed in view of the possible pathogenic role of iron. Although these infections are often fatal, limited disease may have a better prognosis if diagnosed early and treated aggressively.

Treatment of patients with myelodysplastic syndromes with allogeneic bone marrow transplantation from genotypically HLA-identical sibling and alternative donors.

Between December 1981 and March 1994, 24 patients with a myelodysplastic syndrome (MDS) underwent allogeneic bone marrow transplantation (BMT) for RA with trilineage dysplasia (n = 4), CMML (n = 1), RAEB (n = 4), RAEBt (n = 9) and AML following MDS (n = 6). Fifteen patients (two RAEB, seven RAEBt and six sAML) received chemotherapy before BMT resulting in complete remission in 10 patients (six RAEBt and four sAML) at the time of BMT. Sixteen marrow donors were genotypically HLA-identical siblings. Remaining donors were other family members (five) or unrelated donors (three). The status of the underlying disease at the time of conditioning was the major factor determining long-term survival. The disease-freed survival of RA patients and patients presenting with RAEB, RAEBt and AML but transplanted in complete remission, was respectively 50 and 60%. On the contrary, none of the nine high-risk MDS patients transplanted with persistent disease, survived. Outcome after transplantation with alternative donors was inferior with one long-term survivor, mainly related to the high incidence of severe acute GVHD and its accompanying infectious complications. Six patients relapsed resulting in an actuarial probability of relapse of 28%. Twelve patients died of transplant-related complications leading to a non-relapse mortality at 5 years of 50%. At present eight patients are alive and disease-free 20 to 132 months post-transplantation resulting in an actuarial 5-year disease-free survival of 40.7%. Our results suggest that allogeneic bone marrow transplantation is a feasible treatment option for patients with MDS. However, improvement in GVHD prophylaxis and supportive care to reduce transplant-treated mortality and improved relapse prevention are imperative.

Mobilisation of haemopoietic progenitors in CML: a second course of intensive chemotherapy does not improve Ph-negativity in stem cell harvests.

We collected peripheral blood stem cells (PBSC) in 19 early chronic phase CML patients following each of two consecutive cycles of intensive chemotherapy (CT) to evaluate whether an additional cycle of CT would increase Philadelphia (Ph)-negativity of the PBSC harvest. Autologous SCT (autoSCT) was performed if a major cytogenetic response (MCR) of the PBSC harvest was obtained. CT consisted of cytarabine 200 mg/ m2/day (days 1-7)/idarubicin 12 mg/m2/day (days 1-2) (cycle one) and cytarabine 2000 mg/m2/day (days 1-6)/amsacrine 120 mg/m2/day (days 1-3) (cycle two). One patient died of fungal pneumonia after the first cycle. Stem cells were harvested in 18 patients after cycle one and in 16 patients after cycle two. After the first cycle, all patients showed a cytogenetic response of their graft (MCR in eight patients: three complete, five partial), after cycle two, seven patients obtained an MCR (one complete, six partial). Seven patients became eligible for autoSCT. All patients proceeded with IFNalpha maintenance. Currently, 16 patients are alive. At the latest cytogenetic examination of bone marrow, four patients showed an MCR and four a minor response. In conclusion, although a second cycle of CT may contribute to elimination of leukemia residing in the patient, it appeared to be ineffective in improving the Ph-negativity of the PBSC graft.

Peripheral blood stem cell transplantation as an alternative to autologous marrow transplantation in the treatment of acute myeloid leukemia?

The clinical use of autologous marrow transplantation in acute myeloid leukemia (AML) has been hampered by the inability to collect adequate numbers of cells after remission induction chemotherapy and the notably delayed hematopoietic regeneration following autograft reinfusion. Here we present a study in which the feasibility of mobilizing stem cells was investigated in newly diagnosed AML. Among 96 AML patients, 76 patients (79%) entered complete remission. Mobilization was undertaken with low dose and high dose schedules of G-CSF in 63 patients, and 54 patients (87%) were leukapheresed. A median of 2.0 x 10(6) CD34+ cells/kg (range 0.1-72.0) was obtained in a median of three leukaphereses following a low dose G-CSF schedule (150 microg/m2) during an average of 20 days. Higher dose regimens of G-CSF (450 microg/m2 and 600 microg/m2) given during an average of 11 days resulted in 28 patients in a yield of 3.6 x 10(6) CD34+ cells/kg (range 0-60.3) also obtained following three leukaphereses. The low dose and high dose schedules of G-CSF permitted the collection of 2 x 10(6) CD34-positive cells in 46% and 79% of cases respectively (P = 0.01). Twenty-eight patients were transplanted with a peripheral blood stem cell (PBSC) graft and hemopoietic repopulation was compared with the results of a previous study with autologous bone marrow. Recovery of granulocytes (>0.5 x 10(9)/l, 17 vs 37 days) and platelets (>20 x 10(9)/l; 26 vs 96 days) was significantly faster after peripheral stem cell transplantation compared to autologous bone marrow transplantation. These results demonstrate the feasibility of PBSCT in the majority of cases with AML and the potential advantage of this approach with respect to hemopoietic recovery.

Philadelphia chromosome-positive chronic myelogenous leukemia in treated Hodgkin's disease.

A patient who developed Philadelphia (Ph) chromosome-positive chronic myelogenous leukemia (CML) 8 years after successful treatment for Hodgkin's disease (HD) is reported. The Ph chromosome with a typical 9(22) translocation was identified by banding techniques in 80% of bone marrow (BM) cells. Southern blot analysis showed breakpoint cluster region (BCR) rearrangement as observed in classical CML. Until now, only three cases of Ph + CML have been reported after treatment for HD. At present, it is not clear whether development of CML after HD represents a therapy-induced complication, an increased susceptibility to secondary malignancies owing to the malignant process itself, a consequence of the immunological deficiencies in HD, or possibly a genetic susceptibility to malignancy.

Therapy-related acute myeloid leukemia with t(8;16)(p11;p13) following anthracycline-based therapy for nonmetastatic osteosarcoma.

A case of therapy-related AML with t(8;16)(p11;p13) 14 months following the end of anthracycline-containing chemotherapy for a nonmetastatic osteosarcoma of the left tibia is presented. The patient was successfully treated with intensive remission-induction chemotherapy. Subsequently, he underwent an uncomplicated allogeneic bone marrow transplantation from his HLA-identical brother and is at present alive and disease-free 10 months after diagnosis of the secondary AML.

[A man with plasma cell dyscrasia and polyneuropathy due to POEMS syndrome]. / Een man met plasmaceldyscrasie en polyneuropathie door het POEMS-syndroom.

In a 52-year-old man with general malaise, muscle stiffness and weakness, POEMS-syndrome was diagnosed based on polyneuropathy, splenomegaly, lymphadenopathy, subclinical hypothyroidism and the presence of a monoclonal paraprotein with osteosclerotic lesions and an indurated skin (POEMS is an acronym for Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, Skin changes). This is a rare systemic disease from the clinical spectrum of plasma cell dyscrasias with polyneuropathy. The clinical picture is broader and more pleomorphic than the acronym suggests. The possibility of a POEMS syndrome should be considered in the differential diagnosis of polyneuropathy in association with monoclonal gammopathy. Quite often it is associated with osteosclerotic myeloma or mixed osteoscleroticlytic lesions. The patient described was treated with high dose corticosteroids which were gradually decreased over the next three months, upon which a marked improvement could be seen. The general malaise subsided, as did the splenomegaly, and the skin became supple again.

Cytogenetics and its prognostic value in myelodysplastic syndromes.

In this review we describe the cytogenetics of primary and secondary myelodysplastic syndromes, discuss their relationship with other hemopoietic malignancies, and also attempt to put the described chromosome abnormalities into a clinically more useful perspective by emphasizing the prognostic impact they carry. In addition, we discuss their use as clonal markers in determining the mode of action and efficiency of different therapeutic approaches.

Treatment and prognostic factors in myelodysplastic syndromes.

While MDS remains an enigmatic disease, substantial progress has been made in the elucidation of its origin and the better understanding of its natural course. The advent of newer molecular and cytogenetic techniques has tremendously improved the 'older' morphological and histopathological prognostic criteria. More refined scoring systems may ultimately allow for individualized treatment programmes which will better preserve quality of life, while at the same time offer improved chances for survival and cure. Much can be expected from newer cytokines, such as thrombopoietin, stem cell factor, interleukin-11 or of the combination of different cytokines and growth factors, to alleviate MDS-symptoms and to possibly alter the course of the disease. After the initial disappointment with differentiation inducers, the availability of newer agents and/of combinations may offer better perspectives for the future. Much interest will also be generated on the use of mdr-reversal agents in the attempts to improve on chemotherapeutic efficacy. Finally, while allogeneic transplantation still remains the only option for definite cure of the disease, the spectacular advances made in the use and manipulation of autologous peripheral blood haemopoietic stem cells probably constitute the best hope for brightening the grim outlook most MDS patients still have.