Dominique Emilie

Blockade of B7-H1 improves myeloid dendritic cell–mediated antitumor immunity

Suppression of dendritic cell function in cancer patients is thought to contribute to the inhibition of immune responses and disease progression. Molecular mechanisms of this suppression remain elusive, however. Here, we show that a fraction of blood monocyte-derived myeloid dendritic cells (MDCs) express B7-H1, a member of the B7 family, on the cell surface. B7-H1 could be further upregulated by tumor environmental factors. Consistent with this finding, virtually all MDCs isolated from the tissues or draining lymph nodes of ovarian carcinomas express B7-H1. Blockade of B7-H1 enhanced MDC-mediated T-cell activation and was accompanied by downregulation of T-cell interleukin (IL)-10 and upregulation of IL-2 and interferon (IFN)-γ. T cells conditioned with the B7-H1–blocked MDCs had a more potent ability to inhibit autologous human ovarian carcinoma growth in non-obese diabetic–severe combined immunodeficient (NOD-SCID) mice. Therefore, upregulation of B7-H1 on MDCs in the tumor microenvironment downregulates T-cell immunity. Blockade of B7-H1 represents one approach for cancer immunotherapy.

Stromal-derived factor-1 in human tumors recruits and alters the function of plasmacytoid precursor dendritic cells

Dendritic-cell (DC) trafficking and function in tumors is poorly characterized, with studies confined to myeloid DCs (DC1s). Tumors inhibit DC1 migration and function, likely hindering specific immunity. The role of plasmacytoid DCs (DC2s) in tumor immunity is unknown. We show here that malignant human ovarian epithelial tumor cells express very high levels of stromal-derived factor-1, which induces DC2 precursor (preDC2) chemotaxis and adhesion/transmigration, upregulates preDC2 very late antigen (VLA)-5, and protects preDC2s from tumor macrophage interleukin-10–induced apoptosis, all through CXC chemokine receptor-4. The VLA-5 ligand vascular-cell adhesion molecule-1 mediated preDC2 adhesion/transmigration. Tumor preDC2s induced significant T-cell interleukin-10 unrelated to preDC2 differentiation or activation state, and this contributed to poor T-cell activation. Myeloid precursor DCs (preDC1s) were not detected. Tumors may weaken immunity by attracting preDC2s and protecting them from the harsh microenvironment, and by altering preDC1 distribution.

Clinical and biologic effects of anti–interleukin-10 monoclonal antibody administration in systemic lupus erythematosus

OBJECTIVE To evaluate the safety and clinical efficacy of administering an anti-interleukin-10 (anti-IL-10) monoclonal antibody (mAb) to systemic lupus erythematosus (SLE) patients with active and steroid-dependent disease. In addition, we sought to assess the effects of in vivo IL-10 neutralization on biologic markers of SLE. METHODS Treatment consisted of 20 mg/day intravenous administration of an anti-IL-10 murine mAb (B-N10) for 21 consecutive days, with a followup period of 6 months. Six patients were studied. RESULTS Treatment was safe and well tolerated. All patients developed antibodies against B-N10. Cutaneous lesions and joint symptoms improved in all patients beginning during B-N10 administration and continuing to month 6. The SLE Disease Activity Index decreased from a mean +/- SEM of 8.83+/-0.91 on day 1 to 3.67+/-0.67 on day 21 (P = 0.001), 1.50+/-0.84 at month 2, and 1.33+/-0.80 at month 6 (P<0.001). At the end of followup, the disease was clinically inactive in 5 of the 6 patients. Prednisone administration was decreased from a mean +/- SEM of 27.9+/-5.7 mg/day on day 1 to 9.6+/-2.0 mg/day at month 6 (P<0.005). Activity of immune and endothelial cells rapidly decreased, as assessed by the early evolution of several biologic markers. CONCLUSION This is the first report of IL-10 antagonist administration to humans. The study shows the involvement of IL-10 in the pathogenesis of SLE, and indicates that the use of IL-10 antagonists may be beneficial in the management of refractory SLE.

A double‐blind randomized controlled trial of infliximab associated with prednisolone in acute alcoholic hepatitis

Tumor necrosis factor‐α (TNF‐α) may contribute to the progression of acute alcoholic hepatitis (AAH). The aim of this study was to evaluate the efficacy of an association of infliximab and prednisolone at reducing the 2‐month mortality rate among patients with severe AAH. Patients with severe AAH (Maddrey score ≥32) were randomly assigned to group A receiving intravenous infusions of infliximab (10 mg/kg) in weeks 0, 2, and 4; or group B receiving a placebo at the same times. All patients received prednisolone (40 mg/day) for 28 days. Blood neutrophil functional capacities were monitored over 28 days. After randomization of 36 patients, seven patients from group A and three from group B died within 2 months. The probability of being dead at 2 months was higher (not significant [NS]) in group A (39% ± 11%) than in group B (18% ± 9%). The study was stopped by the follow‐up committee and the sponsor (Assistance Publique‐Hôpitaux de Paris). The frequency of severe infections within 2 months was higher in group A than in group B (P < .002). This difference was potentially related to a significantly lower ex vivo stimulation capacity of neutrophils. There were no differences between the two groups in terms of Maddrey scores at any time point. In conclusion, three infusions of 10 mg/kg of infliximab in association with prednisolone may be harmful in patients with severe AAH because of the high prevalence of severe infections. (HEPATOLOGY 2004;39:1390–1397.)

Inflammatory alterations in mesenteric adipose tissue in Crohn's disease

BACKGROUND & AIMS Abnormalities of fat in the mesentery including adipose tissue hypertrophy and fat wrapping have been long recognized on surgical specimens as characteristic features of Crohns disease. However, the importance, origin, and significance of the mesenteric fat hypertrophy in this chronic inflammatory disease are unknown. Peroxisome proliferator-activated receptor gamma (PPARgamma) is a crucial factor involved in the homeostasis of adipose tissue, a major source of biologically active mediators. METHODS Intra-abdominal fat accumulation was quantified using a magnetic resonance imaging method in patients with Crohns disease and controls. PPARgamma and inflammatory cytokines synthesized by mesenteric adipose tissues were assessed by quantitative polymerase chain reaction, in situ hybridization, and immunohistochemistry. RESULTS In vivo, patients with Crohns disease have an important accumulation of intra-abdominal fat. This mesenteric obesity, present from the onset of the disease, is associated with overexpression of PPARgamma and tumor necrosis factor (TNF)-alpha, synthesized, at least in part, by adipocytes. CONCLUSIONS These results suggest that confined increased PPARgamma mesenteric concentrations could lead to the mesenteric fat hypertrophy, which could actively participate through the synthesis of TNF-alpha in the inflammatory response.

Stress-induced disruption of colonic epithelial barrier: role of interferon-γ and myosin light chain kinase in mice

BACKGROUND & AIMS Stressful life events are supposed to be involved in various diseases such as inflammatory bowel diseases and irritable bowel syndrome. Impairment of the intestinal epithelial barrier function is a suspected consequence of stress, but the underlying mechanisms remain unclear. This study aimed to determine the mechanisms through which stress modulates the colonic epithelial barrier. METHODS Cytokine messenger RNA (mRNA) expression was evaluated in murine colon, liver, and spleen by competitive reverse-transcription polymerase chain reaction after 1-4 days of daily 2-hour stress sessions. Colonic paracellular permeability was measured as the in vivo lumen-to-blood ratio of (51)Cr-ethylenediaminetetraacetic acid. The effect of a myosin light chain (MLC) kinase inhibitor (ML-7) was assessed on stress-induced interferon (IFN)-gamma mRNA expression and colonic epithelial barrier impairment, and MLC phosphorylation was determined by immunoblot. Finally, the incidence of repeated stress sessions on bacterial translocation was determined. RESULTS Repeated stress induced an overexpression of colonic IFN-gamma. In the liver, higher levels of IFN-gamma, interleukin (IL)-4, and IL-10 mRNAs were detected and were associated with bacterial translocation, inflammation, and apoptosis. Stress increased colonic permeability of control mice, but not of SCID and IFN-gamma-deficient mice. ML-7 inhibited the stress-induced increased permeability, bacterial translocation, and cytokine overexpression in the liver and restored a normal histology. Larger amounts of phosphorylated MLC were detected in stressed animals. CONCLUSIONS Repeated stress sessions drive organ-specific cytokine expression patterns and alter colonic mucosal barrier functions associated with bacterial translocation. This effect depends on the presence of CD4(+) T cells and requires IFN-gamma production and MLC phosphorylation.

Pro- and anti-inflammatory cytokines during acute severe pancreatitis: An early and sustained response, although unpredictable of death

OBJECTIVES To define the pro- and anti-inflammatory cytokine response during acute severe pancreatitis and to evaluate its predictive value on hospital mortality. DESIGN Prospective, multicenter study. SETTING Nine multidisciplinary intensive care units (ICUs). PATIENTS Fifty patients with a diagnosis of acute pancreatitis who were admitted to the ICUs during a 14-month period were prospectively enrolled. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Plasma concentrations of tumor necrosis factor (TNF)-alpha interleukin (IL)-1beta, IL-6, IL-10, IL-1 receptor antagonist (IL-1ra) were determined at the inclusion and during the ICU stay at Days 1, 3, 8, and 15. The patient population was analyzed by age, gender, previous health status, preexisting organ dysfunction, and type of acute pancreatitis. Physiologic variables were measured at inclusion and during ICU stay to calculate the new Simplified Acute Physiology Score II, the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and the number of organ system failures. Prognostic factors were determined by univariate methods and stepwise logistic regression analysis. Fifty patients were included, among whom 34 at the time of the ICU admission. Preinclusion symptom history was < or = 48 hrs in 78% of the patients. Eleven patients (22%) died during their hospital stay. At inclusion, 46 of 50 patients had elevated IL-6 serum levels (1512 +/- 635 pg/mL; normal value < 10 pg/mL), 36% of the patients had raised TNF-alpha concentrations, and all patients had an anti-inflammatory response (IL-10, 92 +/- 15 pg/mL [normal value < 10 pg/mL]; and/or IL-1ra, 7271 +/- 2530 pg/mL [normal value < 200 mg/mL]). During the follow-up period, pro- and anti-inflammatory cytokines remained elevated in at least 75% of the population. Positive correlations were found between inclusion pro- (IL-6) and anti-inflammatory cytokine concentrations at Day 1 (IL-10, IL-1ra; p < .0001) and between cytokines levels and the Simplified Acute Physiology Score II. While hospital mortality was linked to six factors in univariate analysis (age, cirrhosis, delay between hospitalization and ICU admission, severity of illness, and IL-10 and IL-6 plasma levels) when using stepwise logistic regression, only severity scoring indexes were predictive of death. CONCLUSIONS During acute severe pancreatitis, the pro- and anti-inflammatory cytokine response occurred early and persisted in the systemic circulation for several days. Although associated with the patients severity at inclusion and outcome, cytokine plasma concentrations were unable to predict death accurately in individual patients. If confirmed, these results should be taken into consideration when selecting patients who are apt to benefit from new therapies aimed at modifying the immune inflammatory response.

Fractalkine-induced smooth muscle cell proliferation in pulmonary hypertension.

Pulmonary hypertension is characterised by a progressive increase in pulmonary arterial resistance due to endothelial and smooth muscle cell proliferation resulting in chronic obstruction of small pulmonary arteries. There is evidence that inflammatory mechanisms may contribute to the pathogenesis of human and experimental pulmonary hypertension. The aim of the study was to address the role of fractalkine (CX3CL1) in the inflammatory responses and pulmonary vascular remodelling of a monocrotaline-induced pulmonary hypertension model. The expression of CX3CL1 and its receptor CX3CR1 was studied in monocrotaline-induced pulmonary hypertension by means of immunohistochemistry and quantitative reverse-transcription PCR on laser-captured microdissected pulmonary arteries. It was demonstrated that CX3CL1 was expressed by inflammatory cells surrounding pulmonary arterial lesions and that smooth muscle cells from these vessels had increased CX3CR1 expression. It was then shown that cultured rat pulmonary artery smooth muscle cells expressed CX3CR1 and that CX3CL1 induced proliferation but not migration of these cells. In conclusion, the current authors proposed that fractalkine may act as a growth factor for pulmonary artery smooth muscle cells. Chemokines may thus play a role in pulmonary artery remodelling.

Fractalkine receptor expression by T lymphocyte subpopulations and in vivo production of fractalkine in human

Expression and function of the fractalkine receptor CX3CR1 by T lymphocyte subpopulations was evaluated in healthy individuals. In CD8+ T lymphocytes, CX3CR1 was expressed by and functional in both CD45RO– and CD45RO+ cells. In CD4+ T lymphocytes, CX3CR1 was expressed mainly by CD45RO+ cells, and almost exclusively by activated HLA‐DR+ T lymphocytes. This receptor was functional in CD45RO+ cells, but not in CD45RO– cells. Expression of fractalkine was detected by in situ hybridization and immunohistochemistry in endothelial cells of normal lung and thymus. In hyperplastic lymph nodes, fractalkine was expressed by endothelial cells of high endothelial venules and of subcapsular vessels, by follicular dendritic cells (FDC) and by some follicle lymphocytes. Fractalkine mRNA was constitutively present in the HK FDC‐like cell line, and it was induced in vitro in B lymphocytes stimulated by an anti‐μ or by a CD40 mAb. These findings indicate that fractalkine may contribute to the recruitment of effector T helper lymphocytes, either in peripheral tissues or in lymphoid organs. In these tissues, fractalkine and its receptor may favor contact within follicles between activated T helper lymphocytes, activated B lymphocytes and FDC, thus contributing to the maturation of the B lymphocyte response.

Amniotic fluid concentrations of Interleukin‐1β, Interleukin‐6 and TNF‐α in chorioamnionitis before 32 weeks of gestation: histological associations and neonatal outcome

Objectives To test the association between cytokine levels in the amniotic fluid and (i) the vascular invasion phase of intrauterine infection, (ii) the occurrence of periventricular leukomalacia; to assess the correlation between C‐reactive protein levels, a recognised biological marker of inflammation in maternal serum and cytokine levels in the amniotic fluid.