Multivariate analyses of prognostic factors in acute myeloid leukemia: relevance of cytogenetic abnormalities and CD34 expression

Identification of additional prognostic factors besides karyotype is important for the improvement of the risk adapted treatment strategies in acute myeloid leukemia (AML). The aim of this study was to investigate whether other factors besides karyotype could be used as a prognostic tool in newly diagnosed AML. Biological and disease related established and potential prognostic factors were retrospectively analysed in 124 consecutive AML patients treated between 1993 and 2002 at the University hospital Rostock (Germany). One hundred patients received a potential curative intensive chemotherapy (81%), of whom 28 received an allogeneic HSCT at some point of their treatment course, 17 patients (14%) received palliative therapies and 7 patients (5%) received supportive care only. In patients that received potential curative therapies LDH >or=2000 U/l, WBC >50 GPT/l, CD34 surface expression on the AML blasts, secondary AML, unfavorable karyotype and no allogeneic HSCT at some point of treatment course were associated with unfavorable prognosis. However, in the multivariate risk factor analyses only unfavorable karyotype (p=0.012), CD34 positivity of AML blasts (p=0.046), no allogeneic HSCT (p=0.008) and first diagnosis after 1997 (p=0.025) were independent unfavourable prognostic factors. In conclusion, karyotype and CD34 expression are independent prognostic markers in newly diagnosed AML. Furthermore, receiving an allogeneic HSCT at some point of the treatment course seems to be of benefit for AML patients.

Treatment with campath-1H for relapsed chronic lymphocytic leukemia after allogeneic peripheral blood stem cell transplantation does not abrogate the development of chronic GVHD

The graft vs. leukemia (GVL) effect is one of the most important factors of anti-tumor activity after allogeneic hematopoetic stem cell transplants (alloSCT). Its effectiveness depends mainly on the tumor biology as well as the tumor burden. Patients with a high tumor burden may not respond to GVL-effect despite otherwise sensitive biology. Campath-1H is known as an effective treatment of chronic lymphocytic leukemia (CLL). Due to its ability to induce profound immunosuppression, it has also been used as part of conditioning regimens before alloSCT. We report a patient, who received campath-1H in combination with docetaxel for treatment of chemotherapy and donor lymphocyte infusion resistant CLL after alloSCT, who developed shortly after discontinuation of treatment with campath-1H severe eosinophilia of the peripheral blood and typical clinical as well as histological signs of cutaneous chronic graft vs. host disease followed by complete clearance of CLL. The clinical course demonstrates the impact of the tumor burden on the GVL-effect, as well as the effectiveness of campath-1H in the presence chemo-resistance in a patient with CLL. Furthermore, the GVL effect was not abrogated by the use of campath-1H.

Cytokine mRNA levels and lymphocyte infiltration in pancreatic tissue during experimental chronic pancreatitis induced by dibutyltin dichloride

There is little information available regarding the role of inflammatory cells in the pathogenesis of chronic pancreatitis. Therefore, we analyzed the local cytokine profile and infiltrating lymphocytes in a rat model of chronic pancreatitis. Experimental pancreatitis was induced by a single intravenous application of dibultyltin dichloride (DBTC). During a time course of two months we observed the mRNA expression of cytokines using competitive RT-PCR. Lymphocytes were characterized by immunohistochemistry, FACS analysis, and the lymphocyte proliferation test. IL-1beta, IL-6, IL-5, and IL-10 were immediately up-regulated in the acute phase of disease, while lymphocyte-restricted expression of IL-2, IL-2R, and IFN-y was only found in the chronic course. Among the infiltrating lymphocytes, CD4+ cells dominated, but during the chronic process there was an increase of CD8+ cells, resulting in a reduced CD4/CD8 ratio. Mitogen-induced activation of isolated mesenteric lymph node cells increased during the chronic inflammation. Our results suggest that in experimental pancreatitis acute inflammatory reactions are followed by a T-lymphocyte-mediated process.

Cytokine mRNA levels and lymphocyte infiltration in pancreatic tissue during experimental chronic pancreatitis induced by dibutyltin dichloride

There is little information available regarding the role of inflammatory cells in the pathogenesis of chronic pancreatitis. Therefore, we analyzed the local cytokine profile and infiltrating lymphocytes in a rat model of chronic pancreatitis. Experimental pancreatitis was induced by a single intravenous application of dibultyltin dichloride (DBTC). During a time course of two months we observed the mRNA expression of cytokines using competitive RT-PCR. Lymphocytes were characterized by immunohistochemistry, FACS analysis, and the lymphocyte proliferation test. IL-1beta, IL-6, IL-5, and IL-10 were immediately up-regulated in the acute phase of disease, while lymphocyte-restricted expression of IL-2, IL-2R, and IFN-y was only found in the chronic course. Among the infiltrating lymphocytes, CD4+ cells dominated, but during the chronic process there was an increase of CD8+ cells, resulting in a reduced CD4/CD8 ratio. Mitogen-induced activation of isolated mesenteric lymph node cells increased during the chronic inflammation. Our results suggest that in experimental pancreatitis acute inflammatory reactions are followed by a T-lymphocyte-mediated process.

High-dose etoposide phosphate and G-CSF mobilizes peripheral blood stem cells in patients that previously failed to mobilize

Ten consecutive patients in our unit who had failed to mobilize a sufficient stem cell yield after either an initial or several mobilization regimens received high-dose etoposide phosphate (1500-2000 mg/m2) followed by granulocyte colony-stimulating factor (G-CSF; 10 micrograms/kg per day) to stimulate mobilization. Eight of the ten patients were apheresed. A median of 2.1 x 10(6) CD34+/kg (range 0-5.2) was collected. The number of CD34+ cells/microliter peripheral blood (pB) was significantly increased compared to the first-line mobilization [median 13.0 (range 2.68-29) versus median 4.76 (range 1.36-12); P < 0.05]. Besides hematotoxicity and four cases of infection (WHO grade 3), no major side effects were seen. The median duration of neutropenia was short (5 days, range 0-10), which is important in heavily pretreated patients. These results indicate that high-dose etoposide phosphate with G-CSF is safe, well tolerated, and may be effective in peripheral blood stem cell (PBSC) mobilization in patients who had previously failed to mobilize.

Oxidative burst measurement in patients treated with cytostatics: influence of G-CSF and role as a prognostic factor

The ability to generate reactive oxygen species, the so-called oxidative burst, is essential for neutrophils to kill infectious micro-organisms. Flow cytometry was used to study oxidative burst prior to, during, and after cytostatic therapy. Seven patients were treated according to the DexaBEAM regimen with 12 cycles monitored. Four patients were treated according to the B-NHL regimen in which nine cycles were monitored. Ten healthy volunteers were chosen as a control group without any treatment. Neutrophils were collected from heparinized peripheral blood and were stimulated by phorbol-12-myristate-13-acetate (PMA), N-formyl-methionyl-leucyl-phenylalanine (FMLP), and Escherichia coli. The oxidative burst was estimated by the amount of nonfluorescent dihydrorhodamine 123 converted to green fluorescent rhodamine 123. Measurements were done daily. The FMLP-induced burst was enhanced in patients before therapy as compared with the control group, whereas PMA-induced burst was decreased slightly. E. coli-, FMLP-, and PMA-induced oxidative burst decreased in both groups during cytostatic therapy. E. coli-induced burst increased again within 2 days of G-CSF treatment in vivo. FMLP-induced burst increased in the B-NHL group but decreased in the DexaBEAM group. In patients who have recovered from leukopenia the oxidative burst is still partly suppressed. PMA-induced oxidative burst measured at the start of therapy correlates with infectious complications. Thus, PMA-induced burst may be used as a simple method for evaluating the individual risk of infections during therapy. The results demonstrate the modulating effect of cytostatic drugs on the oxidative burst and may explain why some patients suffer from severe bacterial infections although the total number of granulocytes is normal.

Cytokine expression of T cells in chronic myeloid leukemia

OBJECTIVE

To evaluate the function of T cells in chronic myeloid leukemia (CML).

METHODS

Interleukin-1 beta (IL-1 beta), interleukin-2 (IL-2), interleukin-3 (IL-3), interleukin-4 (IL-4), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF alpha), and granulocyte macrophage-colony stimulating factor (GM-CSF) gene expressions were investigated by reverse transcription polymerase chain reaction (RT-PCR) assay in fluorescence active cell sorter (FACS) sorted peripheral blood CD2+/CD56-T cells from 12 CML patients, 10 meylodysplastic syndrome (MDS) patients and 7 normal individuals.

RESULTS

TNF alpha mRNA was transcribed in T cells from all of the CML, MDS and normal individuals. IL-1 beta mRNA was transcribed in T cells from 10 CML, 9 MDS and 6 normal individuals. Low levels of IL-2 and IL-4 mRNA were detected in 5 CML patients. IL-3, IL-6 and GM-CSF mRNA were undetectable in all samples.

CONCLUSION

IL-4 and IL-2 were expressed abnormally in T cells of CML.

Detection of residual aneuploid leukemic cells by "continuous gating"

BACKGROUND

A new method for the detection of residual aneuploid leukemic cells in bone marrow by flow cytometry is described. This method is based on the analysis of FCM derived list-mode-datasets with a new software called "Continuous Gating". The program is able to decrease the detection level of aneuploid tumor cells by analyzing groups of cells with comparable antigen density and scatter properties.

METHODS

Aneuploid acute lymphocytic leukemia cells with a known CD34 expression were diluted with diploid bone marrow cells to a concentration of 10, 1, 0.1, 0.05, and 0.01%. Each sample was measured in a FACScan flow cytometer, after staining with CD34 Moab and propidium iodide. Listmode-data were analyzed with the new "Windows"-based "Continuous Gating" software. A gate was set in the DNA parameter, defining the channels in which the aneuploid G0/G1-peak of possible residual tumor-cells should be found. Ten thousand overlapping gates of size 200 x 200 channels (out of 1,023 x 1,023 channels) were set automatically by the program into the side-scatter (SSC)/CD34 dot-plot, calculating the percentage of aneuploid G0/G1-phase cells for every specific gate.

RESULTS

The results are plotted in a contour-plot. In dot-plot gates with less than 20 cells, the calculation of the percentage of aneuploid cells was declared invalid and the area in the contour-plot was marked. Detection of residual aneuploid cells, based on a defined expression of CD34 and granularity (SSC), was possible down to a contamination of 0.1%.

CONCLUSIONS

The new "Continuous Gating" software can be used for the automated detection of aneuploid leukemic cells, if the density of a certain surface-marker is slightly different from normal cells.

Differential induction of apoptosis by fludarabine monophosphate in leukemic B and normal T cells in chronic lymphocytic leukemia

Fludarabine (F-ara-A), an adenine nucleoside analog with efficacy in B-cell chronic lymphocytic leukemia (B-CLL), has also been shown to have a long-lasting suppressive effect on T lymphocytes. In heterogeneous clinical samples, apoptosis cannot be detected by standard methods in small cellular subsets. We developed, therefore, a combined assay of in situ end-labeling of nicked DNA by terminal deoxynucleotide transferase, with measurements of cellular DNA content and surface antigens (CD3, CD4, CD8, and CD19) by multiparametric flow cytometry. This assay was used to determine F-ara-A-induced apoptosis in different lymphocyte subsets from CLL patients and normal controls treated with F-ara-A in vitro. Apoptosis was also correlated to bcl-2 protein levels. We observed a direct effect of F-ara-A on both B-CLL and T lymphocytes. The response to F-ara-A in B-CLL lymphocytes in vitro was Rai stage-dependent, the early-stages being more responsive (P = .01). Higher levels of spontaneous apoptosis were observed in B-CLL lymphocytes from early stage patients (P = .02). No difference was observed in spontaneous apoptosis of normal T cells in B-CLL, although T lymphocytes in late-stage disease were more sensitive to F-ara-A-induced apoptosis. Incubation with cyclosporin A did not affect B-CLL and T-lymphocyte survival compared with control cultures. Results suggested a direct apoptotic effect of F-ara-A on B-CLL lymphocytes that decreases with increasing clinical stage. No correlation was found between bcl-2 and spontaneous or F-ara-A-induced apoptosis. Apoptosis occurred at all cell-cycle stages and was not restricted to cells in S phase. The mechanisms of this stage-dependent apoptosis in CLL remain to be elucidated.

[Effect of remifentanil on respiratory burst of human neutrophilic granulocytes in vitro]

Recovery chances for severely ill patients have been significantly improved by the progress of intensive care medicine. The success of any therapy, however, is still jeopardized by postoperative infections and septic complications. In the early stage of bacterial infections polymorphonuclear leukocytes (PMNL) play a decisive role. After PMNL activation, the production of oxygen radicals during the respiratory burst (RB) denature the phagocytosed micro-organisms. Remifentanil is a new opioid which has been safely administered to various patient groups and shows pharmacokinetic advantages in comparison to the already established opioids. As some intravenous anaesthetics can influence PMNL functions, we analysed, by flow cytometry, the in vitro influence of clinically relevant remifentanil concentrations on the respiratory burst. In our study remifentanil had no influence on the respiratory burst of human PMNL in vitro, regardless of the RB triggering agents chosen.

Cellular uptake and localization of liposomal-methylphosphonate oligodeoxynucleotides

Nuclease digestion and intracellular delivery are major factors limiting the potential use of oligodeoxynucleotides as antisense molecules. Structural analogues of phosphodiester oligodeoxynucleotides, such as phosphorothioates and methylphosphonates, are resistant to nuclease degradation and can still bind to their mRNA targets. However, their limited ability to escape from the endosomal/lysosomal compartments and reach the intracellular sites of action have dampened their potential clinical application. To circumvent this problem we have incorporated methylphosphonate oligodeoxynucleotides into liposomes. We found that the level of uptake of liposome-incorporated methylphosphonate oligodeoxynucleotides is time and concentration dependent. Maximal up take occurred at 8 h when 4-8 microM liposome-incorporated methylphosphonate oligodeoxynucleotides was added. Approximately 50% of liposome-incorporated methylphosphonate oligodeoxynucleotides were retained in cells after 24 h of incubation. Using fluorescent microscopy, intracellular fluorescence could be seen within 2.5 h of incubation. Diffused fluorescence was found throughout the cytoplasm, suggesting that the liposome-incorporated methylphosphonate oligodeoxynucleotides were not confined within the endosomal/lysosomal structures. We conclude that liposomes can effectively deliver methylphosphonate oligodeoxynucleotides to the cytoplasm, which is the major intracellular site of action for translational arrest.

[Therapy of chronic myeloid leukemia with interferon-alpha. A decade of experiences]

PATIENTS AND RESULTS

One hundred and fifty-nine patients with chronic myelogenous leukemia have been treated in six studies during 10 years at Hannover Medical School University Center. The prognosis of 111 patients without pretreatment has been improved compared to conventional therapy with a median survival of 5.7 years. Cytogenetic remissions have been induced in all studies followed for a longer time. The most pronounced improvement of prognosis has been observed in these patients.

CONCLUSIONS

Several conclusions can be drawn on the basis of the results on the different treatment concepts: 1. Patients with pretreatment have an unfavourable response to interferon. 2. There is a likely effect of the dose of Interferon alpha on the frequency of cytogenetic remissions. 3. The combination of Interferon alpha and interferon gamma has been toxic and ineffective in a pilot study. 4. The combination of interferon and cytosine arabinoside has a positive impact on the frequency of cytogenetic remissions. A continuous parallel application of both drugs seems to be most effective in this respect. An ongoing trial has been initiated to compare a fixed combination of Interferon alpha and cytosine arabinoside and with hydroxyurea respectively. Additionally the feasibility of autologous peripheral blood stem cell transplantation will be studied in patients with insufficient response to the interferon treatment.

A new fibroblast growth stimulating activity from the human megakaryoblastic leukaemia cell line ELF-153: in vitro and in vivo findings

Although the exact mechanism for the progression of myelofibrosis in acute megakaryoblastic leukaemia is unclear, certain humoral factors released from the proliferating megakaryoblasts that are unable to store these factors in their defective alpha-granules, including platelet derived growth factor (PDGF), fibroblast growth factors (FGF), platelet factor-4 (PF-4), transforming growth factor-beta (TGF-beta) and beta-thromboglobulin, could result in increased collagen synthesis by bone marrow fibroblasts. Recently, the human megakaryoblastic leukaemia cell line MEG-01 has been shown to produce both TGF-beta and PF-4 which have enhanced the growth of bone marrow fibroblasts. Therefore, we have examined the presence of a fibroblast growth stimulating activity and the humoral factors that might be responsible for it in the supernatant of the human megakaryoblastic leukaemia cell line ELF-153 recently established in our laboratory from a patient with acute myelofibrosis. A new fibroblast growth stimulating activity has been identified in the supernatant of the ELF-153 human megakaryoblastic leukaemia cell line that is independent of the percentage of fetal calf serum in NRK-49F fibroblast agar clonogenic assays and is not due to any of the known fibroblast growth stimulating humoral factors including PDGF, epithelial growth factor, TGF-alpha or beta, tumour necrosis factor-alpha, interleukin-1, 2, 4 or 6, FGF, fibronectin, PF-4 and factor VIII AG. Also, in vivo, subcutaneous injection of ELF-153 megakaryoblastic leukaemia cells into nude mice formed, in three out of the five mice after 6 weeks, subcutaneous tumours with a very rigid texture whose histological examination revealed dense infiltration by blast cells and pronounced reticular fibrosis. Immunohistochemistry demonstrated exclusive deposition of collagen III in the extracellular matrix whereas laminin and collagen IV were absent.(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased expression of the deleted in colorectal carcinoma gene in non-Hodgkin's lymphoma

The putative tumor suppressor gene deleted in colorectal carcinoma (DCC), located on human chromosome band 18q21, is deleted or inactivated in many solid tumors. Its role in the pathogenesis of non-Hodgkin's lymphoma (NHL) has not been studied. Recently, inactivation of this gene was reported in cases of leukemia with monosomy 18. As monosomy 18 is frequently observed in low-grade NHL, we investigated the incidence of altered DCC gene expression in patients with NHL, and correlated it with the number of copies of chromosome 18. Fifteen unselected cases of NHL were studied for evidence of DCC gene expression by reverse transcriptase-polymerase chain reaction. The results were correlated with Southern blot analysis of the DCC gene and with the number of copies of chromosome 18 determined by fluorescent in situ hybridization (FISH). The controls were tissues from normal colon mucosa and normal tonsils. Eight of 15 (53%) NHL cases lacked DCC mRNA, and one expressed substantially less than normal. Southern blot analysis showed normal configuration of the DCC gene in all samples. Two copies of chromosome 18 were found in 9 of 11 samples studied by FISH: one case had a subpopulation of cells with monosomy 18 and one had trisomy 18. All controls expressed DCC. We conclude that DCC gene expression is frequently absent or decreased in NHL and may be involved in the pathogenesis of NHL. Monosomy 18 was not required for DCC inactivation.

Cell cycle-related shifts in subcellular localization of BCR: association with mitotic chromosomes and with heterochromatin

The disruption of the BCR gene and its juxtaposition to and consequent activation of the ABL gene has been implicated as the critical molecular defect in Philadelphia chromosome-positive leukemias. The normal BCR protein is a multifunctional molecule with domains that suggest its participation in phosphokinase and GTP-binding pathways. Taken together with its localization to the cytoplasm of uncycled cells, it is therefore presumed to be involved in cytoplasmic signaling. By performing a double aphidicolin block for cell cycle synchronization, we currently demonstrate that the subcellular localization of BCR shifts from being largely cytoplasmic in interphase cells to being predominantly perichromosomal in mitosis. Furthermore, with the use of immunogold labeling and electron microscopy, association of BCR with DNA, in particular heterochromatin, can be demonstrated even in quiescent cells. Results were similar in cell lines of lymphoid or myeloid origin. These observations suggest a role for BCR in the phosphokinase interactions linked to condensed chromatin, a network previously implicated in cell cycle regulation.

Allogeneic blood stem cell transplantation for refractory leukemia and lymphoma: potential advantage of blood over marrow allografts

Peripheral blood stem cells (PBSCs) have been used rarely for allogeneic transplantation because of concerns regarding graft failure and graft-versus-host disease (GVHD). We evaluated the results of allogeneic PBSC transplantation (allo-PBSCT) in 9 patients with refractory leukemia or lymphoma receiving myeloablative therapy followed by allo-PBSCT from an HLA-identical sibling donor. Three patients had relapsed 11 to 21 months after allogeneic bone marrow transplantation (allo-BMT) and underwent allo-PBSCT using the same donor. Six patients received PBSCs as their initial allogeneic transplant. Filgrastim-mobilized PBSCs were collected from the donors in 3 to 4 aphereses and cryopreserved. The apheresis collections contained a median nucleated cell count of 16.5 x 10(8)/kg (range, 10.8 to 28.7 x 10(8), 10.7 x 10(6) CD34+ cells/kg (range, 7.5 to 22.5 x 10(6)), and 300.0 x 10(6) CD3+ cells/kg (range, 127.8 to 1,523.2 x 10(6)). The median recovery of CD34+ progenitor cells after freezing, thawing, and washing was 106.4% (range, 36.7% to 132.0%). All patients received filgrastim posttransplant through engraftment, and cyclosporine and methylprednisolone were used for GVHD prophylaxis. Neutrophil recovery to greater than 0.5 x 10(9)/L and greater than 1.0 x 10(9)/L occurred at a median of 9 (range, 8 to 10) and 9 days (range, 8 to 11) posttransplant, respectively, which was similar to historical controls after allo-BMT and granulocyte colony-stimulating factor therapy. Platelets recovered to greater than 20 x 10(9)/L and greater than 50 x 10(9)/L at a median of 12 (range, 8 to 25) and 15 days (range, 11 to 59), respectively, which was significantly more rapid than for the controls (P < .01). Donor cell engraftment was documented by cytogenetics, fluorescence in situ hybridization, and/or restriction fragment length polymorphisms with longest follow-up of 283 + days. Three patients developed grade 2 acute GVHD involving only the skin. Three of five evaluable patients show limited chronic GVHD. Cryopreserved, filgrastim-stimulated allogeneic PBSCs may be a suitable alternative to allogeneic marrow for transplantation with the advantage of more rapid platelet recovery. Acute GVHD was minimal despite the infusion of 1 log more CD3 cells than with marrow allografts. Further studies are required to assess long-term risks of chronic GVHD.

Large-scale preparation of highly purified, frozen/thawed CD34+, HLA-DR- hematopoietic progenitor cells by sequential immunoadsorption (CEPRATE SC) and fluorescence-activated cell sorting: implications for gene transduction and/or transplantation

The purification of early hematopoietic progenitor cells for autologous transplantation is based on two rationales: (1) elimination of clonogenic tumor cells, and/or (2) gene transfer into indefinitely self-replicating hematopoietic stem cells. Primitive CD34+ stem cells can be separated from more mature stem cells, or probably from clonogenic tumor cells, by differences in HLA-DR surface antigen expression. The objective of this study was to establish a large-scale technique for purification of CD34+, DR- progenitor cells from a large volume marrow harvest. In five different experiments, CD34+ cells were purified to between 76% and 91% by avidin-biotin immunoadsorption (CEPRATE SC) as a first step. This was followed by fluorescence-activated cell sorting to separate DR+ and DR- cells, which resulted in the generation of between 1.75 and 11.3 x 10(5) CD34+, DR- cells. The purity of DR- cells increased from between 0.5% and 4.3% in the immuno-adsorbed fraction up to 99% in the DR- sorted fraction. As shown in a single experiment, the purity of CD34+, DR- cells immediately after thawing increased from 0.01% to 94.3% while losing 99% of those early progenitor cells during the multistep purification procedure. We were able to physically separate one CD34+, DR- cell from up to 8000 nucleated cells in the prepurified cell suspension. One million highly purified CD34+, DR- progenitor cells is potentially an adequate cell dose for autologous transplantation equivalent to what is contained in an unselected and functioning marrow autograft.

Granulocyte colony-stimulating factor enhances the expression of CD62 on platelets in vivo

The expression of CD41, CD42 and CD62 on platelets was determined in ten patients with and without G-CSF treatment. CD41 and CD42 is expressed in nearly 100% of the platelets without change after G-CSF treatment. The expression of CD62 on the platelets' surface is significantly enhanced by G-CSF indicating a depletion of the alpha-granules. No platelet aggregation was observed. The enhanced secretion of thrombocyte-specific proteins does not induce aggregation but may promote ADP-induced aggregation. Furthermore, the surface-bound and soluble CD62 binds specifically to macrophages and endothelial cells and is involved in the regulation of inflammatory processes. Thus indirect mechanisms may supplement direct effects of G-CSF after chemotherapy.

A constant flux system using the 'magnetic cell separator' (MACS) for highly efficient T-cell depletion

A method for highly efficient T-cell depletion using a 'Magnetic Cell Separator' (MACS) is described. T-lymphocytes were depleted from peripheral blood samples of 37 patients with chronic lymphocytic leukemia (CLL). The flow speed in the MACS column was adjusted by a syringe-driver allowing a constant flow speed of about 100 microliters/min. The mean content of T-cells after depletion was 0.17% (S.D. +/- 0.27). The effectiveness of depletion was calculated to a mean 93.7%. There was no correlation between the proportion of CD3-positive cells before and after depletion.

Optimizing follicular dendritic cell isolation by discontinuous gradient centrifugation and use of the magnetic cell sorter (MACS)

Follicular dendritic cells (FDC) contribute minimally to the total cell population of lymphatic tissue. In order to obtain higher numbers of viable FDC with only a small fraction of contaminating cells the following procedure was developed. Subsequent to the usual mechanical and enzymatical digestion of human tonsils, single cells were layered on top of a discontinuous bovine albumin gradient and centrifuged at 8500 x g. The suspension collected from the 1.052-1.030 interphase contained an average of 10.5% FDC. Next, the preparation was subjected to a new step involving separation of FDC previously treated with biotin-labelled KiM4 monoclonal antibody, raised against FDC, and attached via biotin-streptavidin bonding to streptavidin-conjugated paramagnetic beads. Purification on a magnetic cell sorter (MACS) yielded 3.3-10.1 x 10(6) cells with an average FDC content of 78.4%. The viability and morphology of the resulting FDC population was examined using trypan blue staining or electron microscopy. This technique will permit in vitro studies and long term cultures with FDC isolated from human lymphatic tissue.

Detection of cytomegalovirus-infected cells by flow cytometry and fluorescence in suspension hybridisation (FLASH) using DNA probes labeled with biotin by polymerase chain reaction

A biotin-labeled DNA probe specific for the immediate early gene of the cytomegalovirus (CMV) strain AD 169 was generated with the polymerase chain reaction. Nucleic acid hybridisation was carried out with CMV-infected T-lymphoblastoid cells (MOLT-4) after 4 hr to 6 days of culture. Biotin molecules were made visible with streptavidin coupled with fluorescein. The fluorescence signal of the hybridised probe was measured by flow cytometry in the cell suspension. The number of CMV-positive cells was 7% at 4 hr, 8% after 28 hr, 18% after 2 days, 26% after 3 days, 91% after 4 days, 97% after 5 days, and 98% after 6 days. The first detection of CMV antigen (pp65) was possible with immunoenzymatic labeling by day 4, whereas CMV-DNA was detected by PCR after 4 hr. CMV-specific RNA could be detected in a similar way. The analysis of mononuclear peripheral blood leukocytes in a patient with active CMV infection showed 14.7% CMV DNA-positive cells at day 1 and 7% at day 8, as compared to 0.9% and 0.0% cells which were positive for CMV antigen (pp65) by immunoenzymatic labeling at day 1 and day 8, respectively. We conclude that flow cytometry and fluorescence in suspension hybridisation (FLASH) offers a new tool for analysing exactly and quantifying large numbers of cells for specific DNA or RNA and may be useful for other laboratory and clinical applications.

The role of GM-CSF in infection

GM-CSF is a hemopoietic growth factor with substantial effects on the proliferation of neutrophils, eosinophils and monocytes/macrophages. Its physiologic role in infection is still poorly understood. The gene for GM-CSF is constitutively transcribed in cells substantial for antiinfectious response. Various cells are activated and induced by TNF and IL-1 to synthesize GM-CSF. No systemic GM-CSF levels can be detected in patients with infection. It is likely that GM-CSF plays its physiological role in the immediate vicinity of the cells by which it is secreted. GM-CSF functionally activates neutrophils, monocytes/macrophages and eosinophils. It may augment T-cell proliferation and function. GM-CSF is effective in mice infected with Staphylococcus aureus or Salmonella typhimurium. Its effect in infectious disease in man should be explored.

Effects of tumour necrosis factor alpha on bone marrow aspirates of patients with acute myelogenous leukemia determined by flow-cytometric cell-cycle analysis

Tumour necrosis factor alpha (TNF alpha) exerts cytotoxic and antiproliferative effects on neoplastic cells. It has been used as a therapeutic agent for solid tumours and haematological malignancies. We report on the ex vivo determination of the effect of recombinant human rhuTNF alpha on bone marrow aspirates by a bromodeoxyuridine/propidium iodide method. Cell samples were drawn after 0.5, 2, 4, 6, 8, 10, 22, and 25 h from short-term suspension bone marrow cultures from patients with acute myelogenous leukemia (AML). Flow-cytometric cell-cycle analysis was performed after double DNA staining with propidium iodide and anti-BrdU antibodies. By this method the effect of rhuTNF alpha on cell proliferation can be evaluated after only 35 h. In about two-thirds of the bone marrow aspirates of AML an inhibiting effect on rhuTNF alpha can be demonstrated, developing to its full extent after 10 h.

Labeling of the centromeric region on human chromosome 8 by in situ hybridization

Probe DNA that binds preferentially to the centromeric region of human chromosomes 8 was synthesized. Alpha satellite probe DNA molecules were selectively amplified from sorter-purified human chromosomes 8 by in vitro DNA amplification using the polymerase chain reaction (PCR). Probe labeling was performed during PCR by incorporation of biotinylated deoxyuridine. In situ hybridization of unpurified probe DNA comprised of alpha satellite monomer and higher molecular weight DNA fragments with metaphase chromosome spreads showed binding to the centromeric regions of numerous chromosomes. However, blocking with unlabeled total human alphoid DNA dramatically reduced crosshybridization to chromosomes other than 8. Under these conditions, the degenerate probe DNA allowed unambiguous visualization of domains occupied by centromeric DNA of chromosome 8 in metaphase spreads and interphase cell nuclei, thus greatly facilitating the detection of numerical chromosome aberrations in tumor cells. In situ hybridization of size-fractionated alpha satellite DNA identified the monomeric fraction as the major cause of crosshybridization. Alpha satellite dimers and higher molecular weight DNA fragments showed relatively high specificity for human chromosomes 8.

Results and prognosis of acute non-lymphocytic leukemia in adults. A retrospective study of 319 patients between 1977-1987

Between 1977-87, 319 patients with AML were admitted to Hannover Medical School. At all 41 of these patients were not treated (median duration of survival 0.6 months). Among the 278 treated patients, there was a CR rate of 53.6%, the median duration of remission was 10.1 months and the median duration of survival 7.0 months. The patients with FAB-classification M4-M5 had a worse prognosis than those with M1-M3. Patients under 50 years of age had a significant higher remission rate and survival time than those over 50 years. In the last 10 years, the remission rate rose from 37.3% to 61.0% (p = 0.1776). There was a rise in median duration of survival from 5.9 months (1977-79) to 8.0 months (1984-85) (p less than 0.001). The median remission time decreased from 15.8 months (1977-79) to 12.0 months (1984-85) (p less than 0.001). After the first reinduction therapy, the remission rate (46.6%), duration of remission (5.3 months), and duration of survival (4.1 months) was lower than after primary therapy. After the second reinduction therapy the CR rate was 69.2%, and the remission time 2.9 months. The CR rate after the third reinduction therapy was 22.2%.