Rapid and sensitive detection of CpG-methylation using methyl-binding (MB)-PCR

Methylation of CpG islands is associated with transcriptional repression and, in cancer, leads to the abnormal silencing of tumor suppressor genes. We have developed a novel technique for detecting CpG-methylated DNA termed methyl-binding (MB)-PCR. This technique utilizes a recombinant protein with high affinity for CpG-methylated DNA that is coated onto the walls of a PCR vessel and selectively captures methylated DNA fragments from a mixture of genomic DNA. The retention and, hence, the degree of methylation of a specific DNA fragment (e.g. a CpG island promoter of a specific gene) is detected in the same tube by gene-specific PCR. MB-PCR does not require bisulfite treatment or methylation-sensitive restriction and provides a quick, simple and extremely sensitive technique allowing the detection of methylated DNA, in particular in tumor tissue or tumor cells from limited samples. Using this novel approach, we determined the methylation status of several established and candidate tumor suppressor genes and identified the ICSBP gene, encoding the myeloid and B-cell-specific transcription factor interferon consensus sequence-binding protein, as a target for aberrant hypermethylation in acute myeloid leukemia.

Pericarditis after high-dose chemotherapy: more frequent than expected?

BACKGROUND

Pericarditis is a rare side-effect of chemotherapy and has been reported following administration of cyclophosphamide, doxorubicin and other drugs but not treosulfan.

CASE REPORTS

We report on 2 patients with retrosternal chest pain and typical widespread upward concave ST-segment elevation in the 12-lead electrocardiogram prompting the diagnosis of acute pericarditis. The patients had received treatment for multiple myeloma or relapsed mantle cell lymphoma with high-dose treosulfan alone or in combination with etoposide and carboplatin followed by autologous stem cell transplantation 5 days before onset of the symptoms. In both patients, no serological evidence of viral infection was found. Serum creatine kinase and serum cardiac troponin I remained unchanged. Within 24 h of onset of the symptoms, C-reactive protein increased from normal values (< 5 mg/l) to 95 mg/l and 115 mg/l, respectively. In one of the patients, a paroxysmal supraventricular arrhythmia occurred that persisted for 2 days. After treatment with diclofenac, both patients recovered completely within 1 week.

CONCLUSION

The differential diagnosis of chest pain in the setting of high-dose chemotherapy with e.g. treosulfan should include pericarditis. The pathogenesis remains unclear. Alongside infections, direct toxic or immunological drug-related mechanisms are suggested.

Effect of anti-inflammatory therapy in patients with metastatic renal cell carcinoma on clinical response

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Background: Interaction among signalling networks from tumor and neighbouring stroma cells in complex disease traits is poorly understood. Methods: Two consecutive multi-centre phase II trials were designed (case calculation according response rate, T. Chen two stage design) to prove the hypothesis, whether the activation of presumably complementary receptor-triggered transcriptional cascades (via pioglitazone, and interferon alpha, IFNa) could result in synergistic clinical effects. Therapy in both trials consisted of low-dose capecitabine 1 g/m2 twice daily po for 14 days, every 3 weeks, day 1+, and rofecoxib 25 mg daily, day 1+ (from 11/04 etoricoxib 60 mg daily instead) plus pioglitazone 60 mg daily, day 1+. In study II low-dose IFNa 4.5 MU sc three times a week, week 1+, was added until disease progression. Results: Eighteen, and 33 patients (pts, 31 eligible for analysis), respectively, with clear cell carcinoma, progressive disease, and ECOG 0–2 were enrolled between 2/02 to 2/03 and 4/03 to 4/05, respectively. Mean Bradley score in both trials was not significantly different, 4.1(I)/4.9(II), however, the rate of previous systemic treatments 33%/19%. Objective response (48%) was exclusively observed in study II (PR 35%, CR 13%), and paralleled by a strong CRP response (after 4 weeks on treatment) in all 29 pts with elevated CRP levels (93%) (study I: no significant CRP response): CRP values decreased from mean 41.3 mg/l, range 8.1 to 221, to 5.1 mg/l, range 2.1 to 15.6, p = 0.005. Stable disease > 2 months (mos) occurred in 50%/48%. Median progression-free survival could be more than doubled from a median of 4.7 mos (95% CI, 1.0 to 10.4) to 11.5 mos (6.8 to 16.2) in study II, p = 0.0000. Median overall survival of population II has not been reached, yet. Toxicities > WHO grade II were reported (study I/II): Hand-foot syndrome (3/3), diarrhoea (2/2), depression (0/1), pneumonia (0/1). Conclusions: (1) Clinical results of anti-inflammatory/angiostatic therapy compare with available immuno-therapies. (2) Improved outcome with additive IFNa argues for a synergistic drug interaction. (3) Control of tumor-associated inflammation is an important therapeutic principle in metastatic clear cell carcinoma.

No significant financial relationships to disclose.

Genome-Wide Profiling of CpG Methylation Identifies Novel Targets of Aberrant Hypermethylation in Myeloid Leukemia

The methylation of CpG islands is associated with transcriptional repression and, in cancer, leads to the abnormal silencing of tumor suppressor genes. Because aberrant hypermethylation may be used as a marker for disease, a sensitive method for the global detection of DNA methylation events is of particular importance. We describe a novel and robust technique, called methyl-CpG immunoprecipitation, which allows the unbiased genome-wide profiling of CpG methylation in limited DNA samples. The approach is based on a recombinant, antibody-like protein that efficiently binds native CpG-methylated DNA. In combination with CpG island microarrays, the technique was used to identify >100 genes with aberrantly methylated CpG islands in three myeloid leukemia cell lines. Interestingly, within all hypermethylation targets, genes involved in transcriptional regulation were significantly overrepresented. More than half of the identified genes were absent in microarray expression studies in either leukemia or normal monocytes, indicating that hypermethylation in cancer may be largely independent of the transcriptional status of the affected gene. Most individually tested genes were also hypermethylated in primary blast cells from acute myeloid leukemia patients, suggesting that our approach can identify novel potential disease markers. The technique may prove useful for genome-wide comparative methylation analysis not only in malignancies.

Brave little world: spheroids as an in vitro model to study tumor-immune-cell interactions

Multicellular tumor spheroids (MCTS) are a well-established 3-D in vitro model system that reflects the pathophysiological in vivo situation in tumor microregions and of avascular micrometastatic sites. Because monocytes and other immune cells infiltrate into MCTS of different origin, such spheroid cocultures are a valuable, still underestimated tool to systematically study heterologous interactions between tumor and immune cells. The present article gives a brief overview on work that has been published on tumor-immune cell interactions in MCTS and also summarizes mechanisms of immune suppression in the tumor milieu focussing on myeloid cells. Using the coculture model, we recently demonstrated that tumor-derived lactic acid is a potent modulator of human monocyte as lactic acid inhibited the differentiation of monocytes (MO) into dendritic cells (DC) and also impaired antigen presentation. We show herein, that the capacity of various tumor cells in MCTS to secrete lactic acid differs up to tenfold, suggesting that this capacity is dependent on the tumor cell type. It is further demonstrated that lactic acid disturbs the migration of MO into MCTS as infiltration could be increased by blocking lactic acid production. We therefore discuss lactic acid which accumulates in many tumors and tumor microregions as a potent immune suppressor for MO/DC in the tumor milieu and conclude that these data are highly relevant for adoptive immunotherapy protocols with DC.

Isolation of CD4+CD25+ Regulatory T Cells for Clinical Trials

The adoptive transfer of donor CD4+CD25+ regulatory T cells has been shown to protect from lethal graft-versus-host disease after allogeneic bone marrow transplantation in murine disease models. Efficient isolation strategies that comply with good manufacturing practice (GMP) guidelines are prerequisites for the clinical application of human CD4+CD25+ regulatory T cells. Here we describe the isolation of CD4+CD25+ T cells with regulatory function from standard leukapheresis products by using a 2-step magnetic cell-separation protocol performed under GMP conditions. The generated cell products contained on average 49.5% CD4+CD25high T cells that phenotypically and functionally represented natural CD4+CD25+ regulatory T cells and showed a suppressive activity comparable to that of CD4+CD25+ regulatory T-cell preparations purified by non-GMP-approved fluorescence-activated cell sorting.

Evaluation of C-reactive protein, interleukin-6, and procalcitonin levels in allogeneic hematopoietic stem cell recipients

BACKGROUND

Prompt detection of transplant-related complications (TRC) as infections, acute graft-versus-host disease (aGVHD), microangiopathic hemolytic anemia, or veno-occlusive disease following allogeneic hematopoietic stem cell transplantation (HSCT) is essential.

PATIENTS AND METHODS

We conducted a prospective trial on clinical significance of C-reactive protein (CRP), interleukin-6 (IL-6) and procalcitonin (PCT) serum levels in TRC. A total of 350 stem cell recipients were admitted. CRP, IL-6 and PCT were analyzed prior to conditioning and weekly until 8 wk after HSCT. TRC were recorded weekly throughout the study.

RESULTS

CRP (4.4 mg/dL vs. 12.8 mg/dL; P < 0.001), IL-6 (93 ng/mL vs. 1.138 ng/mL; P < 0.001) and PCT (0.8 ng/dL vs. 5.7 ng/dL; P < 0.001) were increased in infectious complications. Only PCT differentiated between infection and other TRC. Exclusive aGVHD did not increase CRP (4.4 mg/dL vs. 5.7 mg/dL; n.s.), IL-6 (93 ng/mL vs. 153 ng/mL; n.s.) and PCT (0.8 ng/dL vs. 0.8 ng/dL; n.s.). CRP (6.1 mg/dL vs. 3.1 mg/dL; P < 0.001) and IL-6 (295 ng/mL vs. 122 ng/mL; P = 0.001) were decreased during steroid therapy, but not PCT (2.3 ng/dL vs. 2.0 ng/dL; n.s.).

CONCLUSION

Our study confirmed CRP, IL-6 and PCT serum levels as helpful markers for TRC. PCT can differentiate infection from GVHD despite steroid therapy. Further trials are needed focusing on the identification of patients who benefit from early risk stratification.

Prognostic significance of NOD2/CARD15 variants in HLA-identical sibling hematopoietic stem cell transplantation: effect on long-term outcome is confirmed in 2 independent cohorts and may be modulated by the type of gastrointestinal decontamination

To assess the role of NOD2/CARD15 variants on the long-term outcome of allogeneic stem cell transplantation in a genetically homogeneous group, we extended our previous study (cohort I, n = 78) and typed DNA for NOD2/CARD15 single nucleotide polymorphisms (SNPs) from an additional 225 recipients and their HLA-identical sibling donors (cohort II) treated at four other European centers. Results of genotyping were compared with clinical outcome. The strong association of NOD2/CARD15 variants with transplantation-related mortality (TRM) was confirmed in univariate and multivariate analysis; TRM increased from 20% in cohort I/22% in cohort II in recipient/donor pairs without any NOD2/CARD15 variants to 47% in cohort I/32% in cohort II in the presence of one variant in either donor or recipient and further to 57% in cohort I/74% in cohort II in the presence of 2 or more variants (P < .002 in both cohorts). NOD2/CARD15 SNPs were not associated with relapse rate but had a strong impact on overall survival. In an analysis of center effects, the type of gastrointestinal decontamination was the only factor interfering with the prognostic significance of NOD2/CARD15 SNPs. Our data further support an interaction between gastrointestinal defense mechanisms, activation of the innate immune system, and specific transplant-related complications.

SCF modulates organ distribution and hematopoietic engraftment of CB-derived pluripotent HPC transplanted in NOD/SCID mice

BACKGROUND

During the engraftment process of transplanted HPC, the beta 1 integrins play an important role. An increased expression and adhesive function of these integrins has been shown in hematopoietic cell lines and peripheral blood-derived HPC after stimulation with SCF. In this study, we investigated the influence of SCF on the engraftment capability and tissue distribution of cord blood (CB) cells transplanted into NOD/SCID mice.

METHODS

CB-derived mononuclear cells were injected i.v. into 40 sublethally irradiated NOD/SCID mice with or without the addition of 10 microg SCF/ mouse. Six weeks later, BM, liver, kidneys, brain and testicular tissue were analyzed for the prevalence of human cells.

RESULTS

The mean proportion of human CD45+ CD71+ cells within the BM of all engrafted mice receiving SCF in addition to the cells was 1.7-fold higher than in the respective controls. By immunohistochemical staining, human cells were found in liver and kidneys of the engrafted animals, but not in neural tissues or testicles. In the kidneys, the proportion of human cells rose significantly from 0.07 +/- 0.3% to 0.24 +/- 0.05% with treatment with SCF, compared with untreated controls. Single human cells in the liver additionally stained positive for human albumin, indicating organ-specific differentiation of the transplanted cells.

DISCUSSION

Our results indicate that stimulation with SCF modulates the tissue distribution of the progeny of the transplanted cells and improves the hematopoietic engraftment potential of transplanted CB cells.

C-reactive Protein in Patients with Metastatic Clear Cell Renal Carcinoma: An Important Biomarker for Tumor-associated Inflammation

Two consecutive multi-center phase II trials were designed to prove the hypothesis, whether therapeutic modeling of tumor-associated inflammatory processes could result in improved tumor response.

Therapy in both trials consisted of low-dose capecitabine 1g/m2 twice daily p.o. for 14 days, every 3 weeks, day 1+, and rofecoxib 25 mg daily p.o., day 1+ (from 11/04 etoricoxib 60 mg daily instead) plus pioglitazone 60 mg daily p.o., day 1+. In study II low-dose IFN-α 4.5 MU sc. three times a week, week 1+, was added until disease progression.

Eighteen, and 33 patients, respectively, with clear cell renal carcinoma and progressive disease were enrolled. Objective response (48%) was exclusively observed in study II (PR 35%, CR 13%), and paralleled by a strong CRP response after 4 weeks on treatment, p = 0.0005, in all 29 pts (100%) with elevated CRP levels. Median progression-free survival could be more than doubled from a median of 4.7 months (95% CI, 1.0 to 10.4) to 11.5 months (6.8 to 16.2) in study II, p = 0.00001. Median overall survival of population II was 26 months.

Efficacious negative regulation of tumor-associated inflammation by transcription modulators may result in a steep increase of tumor response and survival.

Peripheral dendritic cell chimerism in allogeneic hematopoietic stem cell recipients

BACKGROUND

Relapse and graft-versus-host disease (GVHD) represent major causes of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (HSCT). Although leukocyte and T-cell chimerism analyses are performed routinely suggesting a predictive value on the patients outcome, little is known about chimerism of dendritic cells (DC) representing strong initiators of immune responses.

METHODS

In this prospective study, peripheral DC1 (CD11c+) and DC2 (CD123+) chimerism was determined in hematopoetic stem cell recipients. DCs were isolated from peripheral blood by fluorescence activated cell sorting. Chimerism analyses were performed by fluorescent in situ hybridization or by polymerase chain reaction-based typing of short tandem repeats.

RESULTS

At time of engraftment, DC chimerism analyses showed complete chimerism in 76.3% (DC1)/79.5% (DC2), mixed chimerism (MC) in 21.0% (DC1)/17.9% (DC2) and no chimerism in 2.7% (DC1)/2.6% (DC2) of the patients. Peripheral DC chimerism had no significant effect on relapse-free or overall survival. Although acute GVHD was observed more often in patients with MC for DC1/DC2 and chronic GVHD occurred more often in patients with MC for DC2, there was no statistically significant correlation.

CONCLUSIONS

Although DCs as antigen presenting cells are supposed to have an impact on the induction of GVHD, there was no significant correlation between incidence of GVHD and DC chimerism after HSCT.

An open-label randomized trial comparing itraconazole oral solution with fluconazole oral solution for primary prophylaxis of fungal infections in patients with haematological malignancy and profound neutropenia

OBJECTIVES

This trial studied the efficacy and safety of itraconazole and fluconazole in the prevention of invasive fungal infections in neutropenic patients with haematological malignancies.

PATIENTS AND METHODS

An 8 week, open-label, randomized, parallel-group, multicentre trial comparing itraconazole oral solution (2.5 mg/kg twice daily; N=248) with fluconazole oral solution or capsules (400 mg daily; N=246) in 494 patients with anticipated profound neutropenia (i.e. neutrophil count expected to be <500 cells/mm3 for at least 10 days) from tertiary care centres.

RESULTS

Invasive fungal infections were reported for 4 out of 248 patients (1.6%) in the itraconazole group and 5 out of 246 patients (2.0%) in the fluconazole group. Invasive Aspergillus infections were proven for 2 out of 248 patients (0.8%) in the itraconazole group and 3 out of 246 patients (1.2%) in the fluconazole group. For both the ITT and profoundly neutropenic populations, no differences were detected between treatment groups in proven or suspected invasive fungal infections or other endpoints. The mortality rates owing to proven invasive fungal infections were 2 out of 248 patients (0.8%) for the itraconazole group and 3 out of 246 patients (1.2%) for the fluconazole group. There was also no difference between treatment groups in the number of patients who recovered from neutropenia or in the duration of neutropenia. More discontinuation of drug intake owing to nausea and more hypokalaemia occurred in the itraconazole group, other adverse events and the total number of adverse events were similar in both groups.

CONCLUSIONS

In this study there were no differences in the efficacy and safety of itraconazole and fluconazole prophylaxis in neutropenic patients with haematological malignancies.

Diagnosis of Hepatic Veno-occlusive Disease by Plasminogen Activator Inhibitor-1 Plasma Antigen Levels: A Prospective Analysis in 350 Allogeneic Hematopoietic Stem Cell Recipients

BACKGROUND

Veno-occlusive disease (VOD) is one of the most serious complications following allogeneic hematopoietic stem cell transplantation (HSCT) and is associated with a high mortality. We conducted a large trial in order to investigate the value of plasminogen activator inhibitor-1 (PAI-1) plasma antigen levels in VOD patients as PAI-1 has been described as a possible diagnostic marker of VOD.

METHODS

In all, 350 stem cell recipients were included in our study. PAI-1 levels were analyzed prior to conditioning therapy and then weekly until eight weeks after HSCT. Transplantation-related complications (TRC) including VOD, microangiopathic hemolytic anemia (MAHA), and graft-versus-host disease (GVHD) were recorded weekly throughout the study.

RESULTS

Maximum PAI-1 antigen levels were increased in all patients with VOD (n=15; mean 248 ng/ml; 95% CI 183-314 ng/ml). Maximum PAI-1 levels above 120 ng/ml showed a sensitivity of 100% and a specificity of 30.6% for VOD after HSCT.

CONCLUSION

Our study underlines that maximum PAI-1 plasma antigen levels not exceeding 120 ng/ml have a strong negative predictive value in the diagnosis of VOD and thus represent a helpful non-invasive tool for exclusion of VOD after HSCT.

Tumor-derived lactic acid modulates dendritic cell activation and antigen expression

The tumor milieu can influence dendritic cell (DC) differentiation. We analyzed DC differentiation in a 3-dimensional tumor model and propose a new mechanism of DC modulation by the tumor environment. Monocytes were cultured in the presence of IL-4 and GM-CSF within multicellular tumor spheroids (MCTSs) generated from different tumor cell lines. Monocytes invaded the MCTSs and differentiated into tumor-associated dendritic cells (TADCs). The antigen expression was altered on TADCs independent of the culture conditions (immature/mature DCs, Langerhans cells) and IL-12 secretion was reduced. Supernatants of MCTSs could partially transfer the suppressive effect. Conditioned media from urothelial carcinoma cell lines contained high levels of M-CSF and IL-6, both cytokines known to modulate DC differentiation. In contrast, melanoma and prostate carcinoma MCTS cocultures produced little M-CSF and IL-6, but high levels of lactic acid. Indeed, addition of lactic acid during DC differentiation in vitro induced a phenotype comparable with TADCs generated within melanoma and prostate carcinoma MCTSs. Blocking of lactic acid production in melanoma MCTS cocultures reverted the TADC phenotype to normal. We therefore conclude that tumor-derived lactic acid is an important factor modulating the DC phenotype in the tumor environment, which may critically contribute to tumor escape mechanisms.

Effect of different tumor necrosis factor (TNF) reactive agents on reverse signaling of membrane integrated TNF in monocytes

Reverse signaling of transmembrane TNF (mTNF) contributes to the versatility of this cytokine superfamily. Previously, we could demonstrate that mTNF acting as receptor confers resistance to bacterial lipopolysaccharide in monocytes and macrophages (MO/MPhi). Reverse signaling can be induced by incubation with the monoclonal anti-TNF antibody 195F and other TNF antagonists, such as the humanized monoclonal antibody infliximab and the humanized soluble TNF receptor construct etanercept, respectively, all in former or present clinical use. Here, we addressed the question whether there are differences in modulating the LPS response in MO/MPhi among these three antagonists. Whereas 195F and infliximab suppress both, the release of an LPS-induced endothelial cell apoptotic factor and proinflammatory cytokines, etanercept only protected against the LPS-triggered apoptosis activity, but left the LPS-induced cytokine release unchanged. These data could have clinical impact with regard to TNF neutralization strategies.

Reverse signalling of membrane-integrated tumour necrosis factor differentially regulates alloresponses of CD4+ and CD8+ T cells against human microvascular endothelial cells

Reverse signalling of membrane-integrated ligands is a common phenomenon in the tumour necrosis factor (TNF) family and contributes to the pleiotropy of this pro-inflammatory cytokine and to the plasticity of the immune system in general. Transmembrane TNF (mTNF) itself can induce resistance to bacterial endotoxin in monocytes and can stimulate the immune activity of mitogen-activated, as well as of virus-infected, T cells. The aim of the present study was to investigate the influence of reverse signalling of mTNF on the allogeneic activity of CD4+ and CD8+ T cells against human microvascular endothelial cells (HMEC), as targets of various inflammatory responses. The proliferative potential of CD4+ T cells towards HMEC was attenuated by mTNF signalling, whereas stimulation of mTNF on CD8+ T cells increased their cytotoxic potential against HMEC. These effects were specific for reverse signalling of mTNF, as a blockade of the classical TNF-TNF receptor interaction by a neutralizing TNF receptor antibody had no effect. Cytokine profiling of the effector cells revealed that the anti-endothelial CD4+ T cells were of a T helper 2 (Th2) phenotype, whereas CD8+ T cells mainly produced cytotox. T cell 1 (Tc1) cytokines. From the results obtained in this study, we conclude that reverse signalling of mTNF differentially modulates CD4+ and CD8+ T-cell activity against allogeneic endothelial cells, which should be taken into account in settings of therapeutic cytokine antagonisms.

Oligotide, a defibrotide derivative, protects human microvascular endothelial cells against fludarabine-induced activation, damage and allogenicity

Fludarabine is a nonmyeloablative immunosuppressant increasingly used as a component of alternative reduced-intensity conditioning regimens prior to allogeneic stem cell transplantation (SCT). However, we have previously shown that 2-fluoroadenine 9-beta-D-arabinofuranoside (F-Ara) as the active metabolized form of fludarabine induces damage, activation and allogenicity in human microvascular endothelial cells (HMEC). We had also identified the pharmaceutic compound Defibrotide (DF), originally used in the treatment of veno-occlusive disease and thrombotic microangiopathy, as being protective against F-Ara-induced dysfunction of HMEC, importantly, without affecting the antileukemic effect of F-Ara. In the present report, we show that a recently developed derivative of DF, Oligotide, similarly downregulates F-Ara-induced activation and damage of HMEC as well as their antigenicity for allogeneic CD8+ T cells. In addition, Oligotide could also block F-Ara-mediated transendothelial migration of peripheral blood cells across the HMEC barrier. Taken together, these observations argue for a potential clinical use of both DF and Oligotide in pre transplant conditioning.

Transcription factor Tfec contributes to the IL-4-inducible expression of a small group of genes in mouse macrophages including the granulocyte colony-stimulating factor receptor

Expression of the mouse transcription factor EC (Tfec) is restricted to the myeloid compartment, suggesting a function for Tfec in the development or function of these cells. However, mice lacking Tfec develop normally, indicating a redundant role for Tfec in myeloid cell development. We now report that Tfec is specifically induced in bone marrow-derived macrophages upon stimulation with the Th2 cytokines, IL-4 and IL-13, or LPS. LPS induced a rapid and transient up-regulation of Tfec mRNA expression and promoter activity, which was dependent on a functional NF-kappaB site. IL-4, however, induced a rapid, but long-lasting, increase in Tfec mRNA, which, in contrast to LPS stimulation, also resulted in detectable levels of Tfec protein. IL-4-induced transcription of Tfec was absent in macrophages lacking Stat6, and its promoter depended on two functional Stat6-binding sites. A global comparison of IL-4-induced genes in both wild-type and Tfec mutant macrophages revealed a surprisingly mild phenotype with only a few genes affected by Tfec deficiency. These included the G-CSFR (Csf3r) gene that was strongly up-regulated by IL-4 in wild-type macrophages and, to a lesser extent, in Tfec mutant macrophages. Our study also provides a general definition of the transcriptome in alternatively activated mouse macrophages and identifies a large number of novel genes characterizing this cell type.

Protein C and procollagen III peptide levels in patients with hepatic dysfunction after allogeneic hematopoietic stem cell transplantation

Veno-occlusive disease (VOD) is one of the most serious complications following hematopoietic stem cell transplantation (HSCT) and is associated with a high mortality. We conducted a large trial on the clinical significance of protein C (PC) and procollagen III peptide (PNPIII) levels, which have been described as possible diagnostic markers of VOD. In total, 350 patients undergoing allogeneic HSCT were included. PC and PNPIII levels were analyzed prior to conditioning and weekly until 8 weeks after the HSCT. Signs of VOD and other transplantation-related complications (graft-versus-host disease (GVHD), toxicity, microangiopathic hemolytic anemia, infection) were recorded weekly throughout the trial. Patients showed a significant drop of the PC levels in VOD (70.3 vs 96.3%, P<0.001) and with increasing severity of aGVHD. Steroids increased the PC levels (69.4% vs 109.4%, P<0.001). The highest PNPIII levels were registered in patients with VOD (mean 6.3 IU/ml). Patients with aGVHD showed an elevation of PNPIII, especially patients with hepatic aGVHD. PC levels during conditioning do not predict VOD (98.5 vs 76.5%, NS). Although PC and PNPIII may play a role in the pathogenesis of VOD they cannot discriminate between complications with jaundice and are only of limited help in the differential diagnosis of VOD.

Interferon (IFN)-gamma is a main mediator of keratinocyte (HaCaT) apoptosis and contributes to autocrine IFN-gamma and tumour necrosis factor-alpha production

BACKGROUND

Apoptosis of keratinocytes or intestinal epithelial cells is an important pathophysiological mechanism of organ damage during acute graft-versus-host disease.

OBJECTIVES

To analyse in detail the mediators and their mutual interaction leading to keratinocyte apoptosis.

METHODS

Experiments were performed using a keratinocyte cell line (HaCaT) and human skin explant cultures.

RESULTS

Supernatants (SN) of major histocompatibility complex nonmatched mixed lymphocyte cultures (MLCs) induced apoptosis in HaCaT cells and also in keratinocytes from skin biopsies. Although both interferon (IFN)-gamma and Fas ligand (FasL) were detected in MLC-SN by enzyme-linked immunosorbent assay, the apoptosis-inducing capacity could be fully abrogated by neutralization of IFN-gamma, but not by neutralization of FasL. Recombinant (r) IFN-gamma induced HaCaT keratinocyte apoptosis in a dose- and time-dependent manner. Induction of HaCaT apoptosis by rFasL alone was induced only at higher doses than present in MLC-SN, but apoptosis was dramatically enhanced in the presence of rIFN-gamma. Further synergistic effects with IFN-gamma in the induction of apoptosis were also observed with agonistic antitumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) receptor 2 antibody, soluble TRAIL and TNF-alpha. However, in contrast to FasL and TRAIL, TNF-alpha alone did not induce HaCaT apoptosis. Interleukin-1beta and lipopolysaccharide did not enhance the apoptosis-inducing effect of IFN-gamma. Beside its apoptosis-inducing capacity in HaCaT cells, rIFN-gamma also induced autocrine IFN-gamma production, and combined treatment with IFN-gamma and TNF-alpha induced autocrine TNF-alpha production. Neutralization of autocrine IFN-gamma protected HaCaT cells from apoptosis.

CONCLUSIONS

Taken together, our data suggest a central role for IFN-gamma in HaCaT keratinocyte apoptosis but also show the importance of co-acting mediators such as TNF-alpha, TRAIL and FasL, which potentiate the effect of paracrine and autocrine IFN-gamma and TNF-alpha release.

A role for CD54 (intercellular adhesion molecule-1) in leukocyte recruitment to the lung during the development of experimental idiopathic pneumonia syndrome

BACKGROUND

Idiopathic pneumonia syndrome (IPS) is a frequently fatal complication of allogeneic bone marrow transplantation (BMT). IPS is associated with elevated bronchoalveolar lavage (BAL) fluid levels of tumor necrosis factor-alpha and lipopolysaccharide, both of which are potent activators of endothelial cells (ECs). EC expression of the adhesion molecule CD54 (intercellular adhesion molecule [ICAM]-1) has been shown to be a major regulator of pulmonary inflammation in various experimental models.

METHODS

Using a well-established murine BMT system in which lung injury and graft-versus-host disease (GvHD) are induced by minor histocompatibility antigenic differences between donor and host, the RNase Protection Assay, mice deficient in ICAM-1 expression, and a monoclonal blocking antibody to ICAM, we evaluated the role of the pulmonary vascular expression of CD54 in the development of IPS.

RESULTS

Enhanced pulmonary vascular expression of ICAM-1 coincided with the development of IPS. When ICAM-1 -/- mice were used as allogeneic BMT recipients, IPS severity (measured by lung histopathology, BAL cellularity, and cytokine expression) was significantly reduced compared with wild-type controls. Similar results were also observed when wild-type recipients were treated with a monoclonal blocking antibody to ICAM-1. Surprisingly, ICAM-1 had differential effects on leukocyte infiltration into GvHD target organs; ICAM-1 deficiency had no impact on intestinal histopathology, whereas ICAM-1-/- BMT recipients had significantly enhanced hepatic injury.

CONCLUSIONS

These data demonstrate that although the expression of ICAM-1 is critical for the development of IPS, different mechanisms of leukocyte recruitment are operative in other GvHD target organs.

Expression and function of homing-essential molecules and enhanced in vivo homing ability of human peripheral blood-derived hematopoietic progenitor cells after stimulation with stem cell factor

Hematopoietic stem cell (HSC) homing from blood to bone marrow is a multistep process involving rolling, extravasation, migration, and finally adhesion in the correct microenvironment. With view to the hematopoietic recovery after clinical stem cell transplantation, we investigated the effect of stem cell factor (SCF) on the expression and the adhesive function of the alpha4beta1 and alpha5beta1 integrins very-late antigen (VLA)-4 and VLA-5 on peripheral blood-derived hematopoietic progenitor cells. After SCF stimulation, the expression of VLA-4 and VLA-5 on CD34+/c-kit+ cells obtained from healthy donors increased from 54% to 90% and from 3% to 82%, respectively. For patient-derived cells, the increase was 67% to 90% and 12% to 46%. The proportion of mononuclear cells adhering to the fibronectin fragment CH296 increased by stimulation with SCF from 14% to 23%. Accordingly, functional studies showed an approximate 30% increase of adherent long-term culture-initiating cell. The improvement of the homing abilities of SCF-stimulated HSC was confirmed by transplantation into sublethally irradiated nonobese diabetic-scid/scid mice. Six weeks after the transplantation, in eight of eight animals receiving human HSC with the addition of SCF, a profound multilineage hematopoietic engraftment was detected, whereas in the control group receiving only HSC, none of eight animals engrafted. Our data provide the first in vivo evidence that stimulation with cytokines improves the homing ability of transplanted human hematopoietic progenitor cells.