Dietmar Geissler

Priming of normal human neutrophils by recombinant human growth hormone

Summary Growth hormone (GH) plays an important role in the development, maintenance and function of the immune system. Previous data has demonstrated that GH is also a newly defined macrophage‐activating factor. Activation of polymorphonuclear neutrophils (PMN) by GH has not yet been examined. This paper presents studies demonstrating the effects of GH on the migratory behaviour and respiratory burst of PMN. In a modified Boyden chamber chemotaxis assay, GH did not stimulate PMN locomotion when added directly to the cells but potently inhibited formylpeptide‐stimulated chemotaxis with effective concentrations in the picomolar range. The migration inhibition observed is known from studies on PMN priming‐factors to be due to enhanced adhesiveness of PMN to artificial surfaces such as nitrocellulose, suggesting that GH stimulates PMN adhesiveness. Priming of PMN by GH was confirmed by direct demonstration of a stimulatory effect on reduction of nitroblue tetrazolium. These findings suggest that GH may be involved in the regulation of PMN functions.

Effects of clozapine on hematopoiesis and the cytokine system

Using a bioassay for hematopoietic progenitor cells we looked for mechanisms causing clozapine induced neutropenia and agranulocytosis. Micro-agar-cultures of normal peripheral blood mononuclear cells (MNC) of eight patients currently treated with clozapine and of eight probands not receiving any kind of pharmacological treatment were incubated with increasing concentrations of clozapine (0, 7.5, 15, 30 micrograms/ml). Erythropoiesis and megakaryopoiesis were totally unaffected by clozapine. A biologically relevant suppression of granulopoiesis (CFU-GM) could only be shown in cultures incubated with 30 micrograms/ml clozapine. Cytokine analysis presented a strictly dose-dependent suppression of GM-CSF and neopterin release in all cultures. There was no difference between patients and controls at any clozapine concentration. The data support a possible role for cytokines as one mediator of the agranulocytosis producing effects of clozapine.

Interferon-alpha-2C and LD ara-C for the treatment of patients with CML: Results of the austrian multicenter phase II study

Small pilot studies of patients with CML have reported on encouraging response rates after treatment with interferon-alpha (IFNalpha) in combination with low-dose cytosine arabinoside (LD ara-C). We therefore initiated a multi-center phase II trial in order to investigate the efficacy and tolerability of this combination in newly diagnosed patients with Ph-positive chronic myelogenous leukemia (CML). Eighty-four patients were treated with IFN-alpha-2c at daily subcutaneous doses of 3.5 MU and LD ara-C added subcutaneously for 10 days every month at a dose of 10 mg/m2, following an initial reduction of WBC to less than 20 x 10(9)/l with hydroxyurea (HU). Within a median observation period of 28 (5-59) months the patients received a median of 7 (1-35) IFNalpha and LD ara-C cycles. Treatment was stopped due to side effects in 16 cases (19%) and to primary or secondary treatment failure in 38 cases (45%). In 45 patients (54%) complete hematological response (CHR) was achieved; in 39 patients (46%) cytogenetic responses including 15 (18%) complete cytogenetic responses (CHR) were observed. Median duration of cytogenetic responses was 15 months. Relapses were seen in 8/15 patients (53%) with complete cytogenetic remission (CCR), in 3/6 patients (50%) with partial cytogenetic response and in 9/18 patients (50%) with minor cytogenetic response. In conclusion, the combination of IFNalpha and LD ara-C resulted in encouraging rates of hematological and cytogenetic responses in patients with CML with low to moderate toxicity.

Azacitidine in CMML: Matched-pair analyses of daily-life patients reveal modest effects on clinical course and survival

Recent data suggest that azacitidine may be beneficial in CMML. We report on 48 CMML-patients treated with azacitidine. Overall response rates were high (70% according to IWG-criteria, including 22% complete responses). Monocyte count and cytogenetics adversely affected survival, whereas age, WHO-type, FAB-type, and spleen size did not. Matched-pair analyses revealed a trend for higher two-year-survival for azacitidine as compared to best supportive care (62% vs. 41%, p=0.067) and longer OS for azacitidine first-line vs. hydroxyurea first-line (p=0.072, median OS 27.7 vs. 6.2 months). This report reinforces existing evidence that azacitidine is safe and efficacious in both myelodysplastic and myeloproliferative CMML.

Detection of soluble Il-2 receptor in the serum of patients with myelodysplastic syndromes : induction under therapy with GM-CSF

Sera of 15 healthy controls and 33 patients suffering from myelodysplastic syndromes (MDS) were investigated for soluble interleukin‐2 receptor (sIL‐2R) expression with a cell‐free enzyme‐linked immunosorbent assay (ELISA) system (T‐Cell Sciences; Cambridge, U. S. A.). The upper limit of the assay is indicated with 477 U/ml. According to the FAB classification eight refractory anaemia (RA). 15 refractory anaemia with excess of blasts (RAEB), five refractory anaemia with excess blasts in transformation (RAEBt) and five chronic myelomonocytic leukaemia (CMML) were examined. None of the patients had reported infectious episodes or been under treatment with cytotoxic agents and/or cytokines within the previous 3 months. Significant differences in sIL‐2R levels between RA (median 368 U/ml), RAEB (median 675 U/ml) and RAEBt (median 971 U/ml) and between RA and CMML (median 723 U/ml) were detected.

Priming of normal human neutrophils by tachykinins: tuftsin-like inhibition of in vitro chemotaxis stimulated by formylpeptide or interleukin-8

Tachykinins have priming effects on polymorphonuclear neutrophils, since they may activate the neutrophils to exhibit an exaggerated inflammatory response to phlogistic mediators. In order to investigate mechanisms involved in this action, we determined the influence of substance P and neurokinin A on chemotaxis of human neutrophils towards gradients of formymethionyl-leucyl-phenylalanine or recombinant human interleukin-8. As seen with other neutrophil-priming agents such as tumor necrosis factor-alpha, exposure of neutrophils to substance P or neurokinin A had an inhibitory effect upon a stimulated migration, with effective concentrations being in the nanomolar range. Tuftsin, a known neutrophil activating peptide, similarly inhibited stimulated migration. Analysis of structure-activity relationships revealed that activity of tachykinins is located in amino-terminal, tuftsin-like sequences. The inhibition of stimulated migration was partly reversed by (Pro1)-tuftsin, a partial tuftsin receptor antagonist, which suggests that the effects of amino-terminal tachykinins involves activation of tuftsin receptors of neutrophils.

A regulatory role of activated T-lymphocytes on human megakaryocytopoiesis in vitro

Cellular interactions responsible for regulating in vitro megakaryocytopoiesis were studied using a microagar culture system which permits the simultaneous proliferation of human megakaryocytic progenitor cells (CFU‐M) and T‐lymphocytic colonies (CFU‐TL). The proliferation of these colony types depends mainly on two factors: phytohaemagglutinin (PHA) and erythropoietin (EP). The direct addition of increasing PHA concentrations to the liquid overlayer resulted in a parallel increase of CFU‐M and CFU‐TL. If the T‐lymphocytes were removed by an E‐rosetting technique a marked diminution of CFU‐M and CFU‐TL numbers was observed. However, monocyte depletion resulted in a marked augmentation of CFU‐M proliferation compared to unfractionated mononuclear cells. In order to confirm that the reduction of CFU‐M proliferation observed after T‐depletion was primarily mediated by the absence of T‐lymphocytes, we have co‐cultured different concentrations of previously removed autologous T‐lymphocytes with a constant number of T‐depleted bone marrow cells. A parallel increase of CFU‐TL and CFU‐M was found if 0.75‐7.5 × 104 T‐lymphocytes were added to the culture. In conclusion, our results indicate that activated T‐lymphocytes augment proliferation of human bone marrow CFU‐M and that monocytes are less important for the growth of megakaryocytic colonies.

A randomized study comparing interferon (IFNα) plus low-dose cytarabine and interferon plus hydroxyurea (HU) in early chronic-phase chronic myeloid leukemia (CML)

This multicenter randomized phase III study was designed to compare the efficacy and toxicity of IFN alpha-2c (3.5 MU/d) in combination with either araC (10 mg/m(2) d1-10) or hydroxyurea (HU: 25 mg/kg per day) in newly diagnosed CML patients. A total of 114 patients were randomized. Following a median observation period of 36 (range 1-73) months the major cytogenetic response rates were 25 and 27% and the 4-year survival probabilities 62.5 and 63% for the araC and HU group, respectively. While the overall toxicity profile was comparable between both groups, patients in the HU arm exhibited a slightly higher degree of WHO grades 3 and 4 non-hematological toxicities.

Iron metabolism and iron supplementation in cancer patients

SummaryIron deficiency and iron deficiency-associated anemia are common complications in cancer patients. Most iron deficient cancer patients present with functional iron deficiency (FID), a status with adequate storage iron, but insufficient iron supply for erythroblasts and other iron dependent tissues. FID is the consequence of the cancer-associated cytokine release, while in absolute iron deficiency iron stores are depleted resulting in similar but often more severe symptoms of insufficient iron supply. Here we present a short review on the epidemiology, pathophysiology, diagnosis, clinical symptoms, and treatment of iron deficiency in cancer patients. Special emphasis is given to intravenous iron supplementation and on the benefits and limitations of different formulations. Based on these considerations and recommendations from current international guidelines we developed recommendations for clinical practice and classified the level of evidence and grade of recommendation according to the principles of evidence-based medicine.

Abnormal megakaryopoiesis in patients with myelodysplastic syndromes: analysis of cellular and humoral defects.

Summary. In 13 patients with myelodysplastic syndrome (MDS) mature and immature erythropoietic (CFU‐E, BFU‐E), granulopoietic (CFU‐GM) and megakaryopoietic (CFU‐Meg) colony formation from human bone marrow mononuclear cells was evaluated in a microagar culture system. All but three patients exhibited abnormal CFU‐Meg. The defect of CFU‐Meg paralleled the reduction of BFU‐E, whereas CFU‐GM number declined to a lesser extent. Not only the CFU‐Meg number, but also the number of megakaryocytes (Mk) per colony was reduced suggesting an additional functional CFU‐Meg defect.