Comorbidity predicts survival in myelodysplastic syndromes or secondary acute myeloid leukaemia after allogeneic stem cell transplantation.

BACKGROUND: Recent data suggest that, among other factors, comorbidity may be an important prognostic variable in patients with myelodysplastic syndromes (MDS) who are eligible for haematopoietic stem cell transplantation (SCT). PATIENTS AND METHODS: We examined the overall survival (OS) and underlying risk factors in 45 adult patients with MDS (n = 38), chronic myelomonocytic leukaemia (n = 1), or secondary acute myeloid leukaemia (AML) arising from MDS (n = 6), who underwent allogeneic SCT at our Institution. RESULTS: With a median follow-up of 37 months, OS for all patients was 23%, post-transplant relapse occurred in 11 patients, and 10 patients died from treatment-related complications. The overall outcome and survival was independent of cytogenetic abnormalities and International Prognostic Scoring System (IPSS). However, we identified comorbidity as defined by the haematopoietic cell transplantation specific comorbidity index (HCT-CI), as a significant adverse prognostic variable in our MDS patients. CONCLUSIONS: Based on these data and similar published data we recommend selecting patients with MDS or secondary AML for SCT according to the presence of comorbidities.

Dasatinib inhibits progenitor cell proliferation from polycythaemia vera.

BACKGROUND: A mutation of Janus kinase 2 V617F is present in most patients with polycythaemia vera (PV). However, it is generally believed that JAK2(V617F) is not the sole molecular abnormality in PV. Since dasatinib is currently evaluated in patients with PV, it is of interest to study the effects of dasatinib on the growth of clonal progenitor cells in vitro. DESIGN AND METHODS: Peripheral blood mononuclear cells from patients with PV, chronic myeloid leukaemia (CML) and controls were exposed to dasatinib (0.1 to 500 nm mL(-1)). Colony growth was stimulated by interleukin-3, granulocyte-macrophage colony-stimulating factor and erythropoietin. Endogenous erythroid colony (EEC) growth was investigated without exogenous cytokines. Real-time PCR was performed to assess the percentage of JAK2(V617F) cells. RESULTS: 10 nm of dasatinib suppressed EEC growth from PV by 89% (P = 0.002). This inhibition was dose dependent and occurred at pharmacological concentrations. Erythroid and myeloid colony growth was also significantly suppressed in the presence of exogenous cytokines. When compared to PV the inhibition of stimulated colony growth was significantly less pronounced in controls but tended to be more vigorous in CML. Interestingly, despite the potent inhibition of PV cells real-time PCR revealed that the numbers of JAK2(V617F) transcripts did not decrease upon exposure to dasatinib. CONCLUSION: This study shows a marked inhibition of the proliferative capacity of progenitor cells from PV. Although JAK2(V617F) transcript levels did not decrease upon exposure to dasatinib, the drug might suppress PV progenitors through inhibition of a yet undefined molecular target.

In vivo effects of imatinib mesylate on human haematopoietic progenitor cells.

BACKGROUND: Imatinib mesylate has considerable antineoplastic activity in patients with chronic myeloid leukaemia (CML) and some solid tumours. Although originally regarded as nontoxic for normal haematopoiesis, mild to moderate myelosuppression is a commonly observed side-effect of this treatment. Recently, this molecule has been shown to suppress normal haematopoietic progenitor cells in vitro. This is the first study that has investigated the effect of imatinib on haematopoietic progenitor cells in vivo. MATERIALS AND METHODS: We investigated the number of circulating haematopoietic progenitor cells in 79 patients with CML and five patients with solid tumours who were treated with imatinib for at least 3 months. Bone marrow progenitor cells were assessed in a subgroup of 18 patients with CML after 12 months of imatinib treatment. Results were compared with haematopoietic progenitor cell numbers of normal controls. RESULTS: Circulating progenitors of all classes were significantly decreased in CML up to 24 months of imatinib therapy compared with healthy controls (median progenitor cells in CML after 12 months: CFU-GM 62, range 0-2543; BFU-E 216, range 0-3259; CFU-GEMM 0, range 0-139; versus controls: CFU-GM 208, range 50-936; BFU-E 690, range 120-1862; CFU-GEMM 20, range 4-77; P < 0.001). Similar reductions in the number of progenitor cells derived from bone marrow were found in a subgroup of 18 patients with CML. In patients with solid tumours the number of circulating progenitor cells was significantly lower under treatment with imatinib when compared with the controls. Withdrawal of imatinib in a patient with a malignant brain tumour resulted in a prompt normalization of circulating progenitors. CONCLUSIONS: This study suggests that imatinib exerts myelosuppressive effects through inhibition of haematopoietic progenitor cells.

Calcium ionophore: a single reagent for the differentiation of primary human acute myelogenous leukaemia cells towards dendritic cells.

Blood monocytes and CD34(+) haemopoietic progenitor cells, as well as certain leukaemic cell lines, acquire characteristics of mature dendritic cells (DC) after stimulation with calcium ionophore (CI). We studied whether the in vitro treatment of primary human acute myelogenous leukaemia (AML) cells with CI leads to differentiation towards DC. Blast cells derived from nine AML patients were cultured in the presence of either CI or an established differentiation cocktail consisting of granulocyte-macrophage colony-stimulating factor plus interleukin 4 and tumour necrosis factor-alpha for 5-7 d. Microscopic examination revealed that under both conditions, AML cells were shifted along the DC pathway. In seven out of nine cases, CI-cultivation led to a higher proportion of cells with dendritic morphology. The percentage of CD40 and CD86 expressing cells was significantly increased upon CI treatment compared with cytokine-cultured cells. DC molecules as CD80 and CD83 were up-regulated upon calcium mobilization of AML cells in four out of nine samples. In four cases, CI-treated stimulator cells induced an enhanced proliferative allogeneic T-cell response compared with cytokine-treated stimulator cells. In conclusion, these data demonstrate that CI treatment is an alternative in vitro strategy to differentiate human AML cells into DC.

Generation of dendritic cells from human chronic myelomonocytic leukemia cells in fetal calf serum-free medium.

It is generally believed that the immune system plays a role not only in the acquisition of malignant diseases but also in the rejection of microscopic as well as established tumor cells. Failure of the immune system to eliminate tumor cells may be, among other factors, due to an insufficient presentation of tumor antigens. Dendritic cells (DCs), as professional antigen-presenting cells, therefore, may be therapeutically used to initiate or enhance immune responses in patients with malignancies. In this study we demonstrate that peripheral blood cells of patients with chronic myelomonocytic leukemia (CMML) can be induced to acquire DC characteristics. Upon culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) plus interleukin-4 (IL-4) plus tumor necrosis factor alpha (TNFalpha), CMML cells develop DC morphology and acquire the phenotypic characteristics of DCs. When a CD14+ cell population is used for DC generation, a homogeneous differentiation towards the DC lineage occurs similar to that, observed in normal peripheral blood monocytes. CMML-derived DCs are potent stimulators of the allogeneic mixed lymphocyte reaction (MLR) when compared with uncultivated cells. The demonstration of a deletion of the long arm of chromosome 7, del(7)(q22), in 86% of highly enriched CD1a+ cells by fluorescence in situ hybridization (FISH) indicates the leukemic origin of generated DCs. In addition, we present data that generation of CMML-derived DCs is also possible under fetal calf serum-free conditions for a potential clinical use. These DCs may be used as a cellular vaccine to induce anti-tumor immunity in patients with CMML.

Culture requirements for induction of dendritic cell differentiation in acute myeloid leukemia.

Peripheral blood mononuclear cells (PBMCs) from 15 newly diagnosed acute myeloid leukemia (AML) patients were cultured in fetal calf serum-free media supplemented with either granulocyte/macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-4 and tumor necrosis factor alpha (TNFalpha), or GM-CSF, stem cell factor (SCF), TNFalpha and transforming growth factor beta (TGFbeta) in order to generate leukemia-derived dendritic cells (DCs). Cultured cells were analyzed by flow cytometry with respect to DC-associated surface molecules (CD1a, CD83, CD40, CD80, CD86, HLA-DR) when they showed significant DC morphology in culture (14 cases). After cultivation, neo-expression or upregulation of CD1a antigen was found in 8 samples, CD83 in 2, CD40 in 14, CD80 in 7, and CD86 in 9. Twelve of 14 AMLs, in which DC morphology could be induced upon cultivation, showed upregulation of at least 2 DC-associated molecules. For induction of DC differentiation. GM-CSF, IL-4 plus TNFalpha was superior in 11 cases, and better results were obtained with GM-CSF, SCF, TNFalpha plus TGFbeta in 3 cases. In 7 of 14 samples tested, a marked increase of the T-cell stimulatory capacity could be demonstrated in the allogeneic mixed lymphocyte reaction. The leukemic origin of in vitro-generated DCs was demonstrated by fluorescence in situ hybridization in a patient with translocation t(15;17). Our results suggest that the use of different culture conditions may extend the number of AML patients in which a differentiation towards the DC lineage can be induced in vitro.

1,25-Dihydroxyvitamin D(3) inhibits dendritic cell differentiation and maturation in vitro.

OBJECTIVE: Because of its potent immunosuppressive properties in vitro as well as in vivo, we studied the effect of 1,25-dihydroxyvitamin D(3) (calcitriol) on differentiation, maturation, and function of dendritic cells (DC). MATERIALS AND METHODS: Monocyte-derived DCs were generated with GM-CSF plus IL-4, and maturation was induced by a 2-day exposure to TNFalpha. DCs were derived from CD34(+) progenitors using SCF plus GM-CSF plus TNFalpha. For differentiation studies, cells were exposed to calcitriol at concentrations of 10(-)(9)- 10(-7) M at days 0, 6, and 8, respectively. The obtained cell populations were evaluated by morphology, phenotype, and function. RESULTS: When added at day 0, calcitriol blocked DC differentiation from monocytes and inhibited the generation of CD1a(+) cells from progenitor cells while increasing CD14(+) cells. Exposure of immature DCs to calcitriol at day 6 resulted in a loss of the DC-characteristic surface molecule CD1a, downregulation of the costimulatory molecules CD40 and CD80, and MHC class II expression, whereas the monocyte/macrophage marker CD14 was clearly reinduced. In addition, calcitriol hindered TNFalpha-induced DC maturation, which is usually accompanied with induction of CD83 expression and upregulation of costimulatory molecules. In contrast, the mature CD83(+) DCs remained CD1a(+)CD14(-) when exposed to calcitriol. The capacity of cytokine-treated cells to stimulate allogeneic and autologous T cells and to take up soluble antigen was inhibited by calcitriol. CONCLUSION: The potent suppression of DC differentiation, the reversal of DC phenotype, and function in immature DCs, as well as the inhibition of DC maturation by calcitriol, may explain some of its immunosuppressive properties.

Interleukin-10 inhibits burst-forming unit-erythroid growth by suppression of endogenous granulocyte-macrophage colony-stimulating factor production from T cells.

Numerous cytokines released from accessory cells have been shown to exert either stimulatory or inhibitory growth signals on burst-forming unit-erythroid (BFU-E) growth. Because of its cytokine synthesis-inhibiting effects on T cells and monocytes, interleukin-10 (IL-10) may be a potential candidate for indirectly affecting erythropoiesis. We investigated the effects of IL-10 on BFU-E growth from normal human peripheral blood mononuclear cells (PBMC) using a clonogenic progenitor cell assay. The addition of recombinant human IL-10 to cultures containing recombinant human erythropoietin suppressed BFU-E growth in a dose-dependent manner (by 55.2%, range 47.3-63.3%, p < 0.01, at 10 ng/mL). In contrast, no inhibitory effect of IL-10 was seen when cultivating highly enriched CD34+ cells. BFU-E growth from PBMC also was markedly suppressed in the presence of a neutralizing anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody (by 48.7%, range 32.9-61.2% inhibition,p < 0.01), but not by neutralizing antibodies against granulocyte colony-stimulating factor and interleukin-3. This suggests a stimulatory role of endogenously released GM-CSF on BFU-E formation. Also, the addition of exogenous GM-CSF completely restored IL-10-induced suppression of BFU-E growth. To determine the cellular source of GM-CSF production, we analyzed GM-CSF levels in suspension cultures containing PBMC that were either depleted of monocytes or T cells. Monocyte-depleted PBMC showed spontaneous production of increasing amounts of GM-CSF on days 3, 5, and 7, respectively, which could be suppressed by IL-10, whereas GM-CSF levels did not increase in cultures containing T-cell-depleted PBMC. Our data indicate that IL-10 inhibits the growth of erythroid progenitor cells in vitro, most likely by suppression of endogenous GM-CSF production from T cells.

Neutrophil granulocyte-committed cells can be driven to acquire dendritic cell characteristics.

Polymorphonuclear granulocytes (PMNs) are thought to fulfill their role in host defense primarily via phagocytosis and release of cytotoxic compounds and to be inefficient in antigen presentation and stimulation of specific T cells. Dendritic cells (DCs), in contrast, are potent antigen-presenting cells with the unique capacity to initiate primary immune responses. We demonstrate here that highly purified lactoferrin-positive immediate precursors of end-stage neutrophilic PMN (PMNp) can be reverted in their functional maturation program and driven to acquire characteristic DC features. Upon culture with the cytokine combination granulocyte/macrophage colony-stimulating factor plus interleukin 4 plus tumor necrosis factor alpha, they develop DC morphology and acquire molecular features characteristic for DCs. These molecular changes include neo-expression of the DC-associated surface molecules cluster of differentiation (CD)1a, CD1b, CD1c, human leukocyte antigen (HLA)-DR, HLA-DQ, CD80, CD86, CD40, CD54, and CD5, and downregulation of CD15 and CD65s. Additional stimulation with CD40 ligand induces also expression of CD83 and upregulates CD80, CD86, and HLA-DR. The neutrophil-derived DCs are potent T cell stimulators in allogeneic, as well as autologous, mixed lymphocyte reactions (MLRs), whereas freshly isolated neutrophils are completely unable to do so. In addition, neutrophil-derived DCs are at least 10,000 times more efficient in presenting soluble antigen to autologous T cells when compared to freshly isolated monocytes. Also, in functional terms, these neutrophil-derived DCs thus closely resemble "classical" DC populations.

Interleukin-10 inhibits spontaneous colony-forming unit-granulocyte-macrophage growth from human peripheral blood mononuclear cells by suppression of endogenous granulocyte-macrophage colony-stimulating factor release.

Spontaneous growth of myeloid colonies (colony-forming unit-granulocyte-macrophage [CFU-GM]) can be observed in methylcellulose cultures containing peripheral blood mononuclear cells (PB-MNCs) and is supposedly caused by the release of colony-stimulating factors (CSF) by accessory cells. Because of its cytokine synthesis-inhibiting effects on T lymphocytes and monocytes, interleukin-10 (IL-10) may be a potential candidate for indirect modulation of hematopoiesis. We studied the effect of recombinant human IL-10 (rhIL-10) on spontaneous growth of myeloid colonies derived from human PB-MNCs. A total of 10 ng/mL of IL-10 almost completely inhibited spontaneous CFU-GM proliferation (by 95.1%; P < .001, n = 7) in unseparated PB-MNCs. This effect was dose-dependent and specific, because a neutralizing anti-IL-10 antibody was able to prevent IL-10-induced suppression of CFU-GM growth. Spontaneous CFU-GM growth, which required the presence of both monocytes (CD14+ cells) and T lymphocytes (CD3+ cells), was also greatly suppressed by a neutralizing anti-granulocyte-macrophage CSF (GM-CSF) antibody but was only slightly or not at all inhibited by antibodies against G-CSF or IL-3. Moreover, IL-10-suppressed colony growth could be completely restored by the addition of exogenous GM-CSF. Using semiquantitative polymerase chain reaction, we were able to show that GM-CSF transcripts that spontaneously increased in PB-MNCs within 48 hours of culture were markedly reduced by the addition of IL-10. Inhibiton of GM-CSF production in PB-MNCs by IL-10 was also confirmed at the protein level by measuring GM-CSF levels in suspension cultures. Our findings suggest that autonomous CFU-GM growth, resulting from an interaction of monocytes and T lymphocytes, is mainly caused by endogenous GM-CSF release and can be profoundly suppressed by the addition of exogenous IL-10. Considering the strong inhibitory action of IL-10 on GM-CSF production and spontaneous cell growth in vitro, this cytokine may be useful in myeloid malignancies in which autocrine and/or paracrine mechanisms involving GM-CSF are likely to play a pathogenetic role.

Effective stimulation of neutropoiesis with rh G-CSF in dyskeratosis congenita: a case report.

Dyskeratosis congenita (DC) is a rare congenital X-linked disorder. The major clinical manifestations are abnormal skin pigmentation, nail dystrophy, and leukoplakia of mucosal membranes. About 50% of the patients develop bone marrow failure, which is partly responsible for the poor prognosis. Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) has been administered to some neutropenic patients with DC, but only a moderate stimulation of neutropoiesis has been observed. We report on a patient with DC treated with recombinant human granulocyte-colony-stimulating factor (rhG-CSF). This treatment resulted in a substantial dose-dependent increase in the neutrophil count.

Rapid achievement of PML-RAR alpha polymerase chain reaction (PCR)-negativity by combined treatment with all-trans-retinoic acid and chemotherapy in acute promyelocytic leukemia: a pilot study.

The reverse transcriptase-polymerase chain reaction (RT-PCR) for the fusion transcript of PML-RAR alpha can be used to detect minimal residual disease (MRD) in acute promyelocytic leukemia (APL). We have applied a semi-quantitative two-step PCR assay (sensitivity: step 1 = 1 in 10(3) cells; step 2 = 1 in 10(6) cells) to monitor the dynamics of MRD after combined therapy with all-trans-retinoic acid (ATRA) and chemotherapy (CT) in 5 patients in whom complete clinical remission (CR) was achieved. The patients received an induction treatment with ATRA for 47, 40, 38, 14 or 10 days. In three patients ATRA was followed by CT. Two patients with hyperleukocytosis at diagnosis or after ATRA received an overlapping CT starting from day 3 or 7. Four of the five patients became two-step PCR-negative in their bone marrow within 43 to 82 days after onset of therapy. Two-step PCR-negatively was achieved with ATRA plus one course of CT in these four patients who are still in continuous complete remission after 19, 18, 7 and 5 months. One of these patients did not even receive consolidation CT because of congestive heart failure. The fifth patient remained second-step PCR-positive and relapsed after 5 months. Our results indicate that the combined regimen can rapidly reduce MRD below a detection limit of 1 in 10(6) cells within 1-3 months and that these results can even by achieved by a short course of ATRA together with only one cycle of CT.