[Value of systematic biological markers of inflammation for the prognosis at 12 months of patients undergoing programmed coronary angioplasty]

Value of systematic dosage of biological markers of inflammation for the prognosis at 12 months of patients undergoing programmed coronary angioplasty Systematic dosage of proteins of inflammation has been suggested for assessing the prognosis of athero-thrombotic diseases. The authors undertook a study of plasma C-reactive protein (CRP) and interleukin 6 (IL-6) for evaluating the prognosis of patients undergoing programmed coronary angioplasty. A prospective monocentric study of 117 patients (65 +/- 8 years) was divided into a control group of 28 patients undergoing coronary angiography (Group 1) and 89 patients undergoing programmed coronary angioplasty (Group 2). Serum IL-6 and CRP levels were measured before arterial puncture and at H12 and H24 after coronary catheterisation. The follow-up period was 12 months. The angioplasty did not significantly increase CRP and IL-6 concentrations compared with coronary angiography. Twenty patients (Group 2) (22%) suffered a cardiovascular event in the 12 months' follow-up. These patients had significantly higher CRP levels at H0, H12 and H24 after coronary angioplasty than those who had uncomplicated outcomes. This was not observed for IL-6 concentrations because of the wide dispersion of the results obtained. Increased CRP concentrations between H0 and H24 was also a good predictive factor independently of high basal CRP levels potentially due to other causes than atheroma. Coronary angioplasty is associated with increased CRP at H0, H12 and H24. These values are correlated with the risk of future events at 6 and 12 months. This information is easily obtained and should help management of these patients.

Role of interleukin-6 in cardiomyocyte/cardiac fibroblast interactions during myocyte hypertrophy and fibroblast proliferation

The process of cardiac hypertrophy is considered to involve two components: that of cardiac myocyte (CM) enlargement and cardiac fibroblast (CF) proliferation. The interleukin-6 (IL-6) family cytokines have been implicated in a variety of cellular and molecular interactions between myocytes and non-myocytes (NCMs), which in turn have important roles in the development of cardiac hypertrophy. In the study of these interactions, we previously detected very high levels of IL-6 in supernatants of a "dedifferentiated model" of adult ventricular CMs cultured with CFs. In the present study, we have used this in vitro coculture system to examine how IL-6 is involved in the interactions between CMs and CFs during CM hypertrophy and CF proliferation. IL-6 and its signal transducer, 130-kDa glycoprotein (gp130), were detected by immunostaining cultured CMs and CFs with anti-IL-6 or anti-gp130 antibodies. Addition of anti-IL-6 or anti-gp130 antagonist antibodies into CM/CF cocultures induced a significant decrease in expression of atrial natriuretic peptide (ANP) and beta-myosin heavy chain (beta-MHC) in CMs. The presence of IL-6 antagonist also resulted in a decrease in the surface area of 12-day-old CMs cultured with CFs or in the presence of fibroblast conditioned medium (FCM), and decreased fibroblast proliferation in CM/CF cocultures, particularly in the presence of a gp130 antagonist. The results also show that angiotensin II (AngII) is mainly secreted by CFs and induces IL-6 secretion in CMs cultured with CFs or with FCM. In addition, the effects of IL-6 on cardiomyocyte hypertrophy and fibroblast proliferation were inhibited by addition of the AT-1 receptor antagonist, losartan. These results suggest that IL-6 contributes significantly to CM hypertrophy by an autocrine pathway and to fibroblast proliferation by a paracrine pathway and that these effects could be mediated by AngII.

Cutting Edge: IL-21 Is a Switch Factor for the Production of IgG1 and IgG3 by Human B Cells

IL-21 is a cytokine that regulates the activation of T and NK cells and promotes the proliferation of B cells activated via CD40. In this study, we show that rIL-21 strongly induces the production of all IgG isotypes by purified CD19(+) human spleen or peripheral blood B cells stimulated with anti-CD40 mAb. Moreover, it was found to specifically induce the production of IgG(1) and IgG(3) by CD40-activated CD19(+)CD27(-) naive human B cells. Although stimulation of CD19(+) B cells via CD40 alone induced gamma 1 and gamma 3 germline transcripts, as well as the expression of activation-induced cytidine deaminase, only stimulation with both anti-CD40 mAb and rIL-21 resulted in the production of S gamma/S mu switch circular DNA. These results show that IL-21, in addition to promoting growth and differentiation of committed B cells, is a specific switch factor for the production of IgG(1) and IgG(3).

Human cardiomyocyte hypertrophy induced in vitro by gp130 stimulation

OBJECTIVES

Recent in vivo and in vitro studies in animals have demonstrated that cytokines of the IL-6 family are involved in cardiac hypertrophy and in protection of cardiomyocytes against apoptosis. The present study aims to analyse the capacity of human atrial cardiac cells (i.e., cardiomyocytes and fibroblasts) to display the gp130 receptor subunit, and to evaluate its functionality.

METHODS

Twenty human atrial biopsies were used for immunohistochemistry, in situ hybridisation, and western blot analysis or dissociated for isolation and primary culture of cardiac cells.

RESULTS

Fibroblasts present in tissue or maintained in primary culture clearly express gp130 whereas the signal in cardiomyocytes is weaker. Culture of cardiac cells with a gp130 agonist antibody enhances atrial natriuretic peptide (ANP), beta myosin heavy chain (beta-MHC) expression in cardiomyocytes, and significantly increases the cell surface area microm(2)). This process could involve STAT3 (signal transducer and activator of transcription 3) phosphorylation.

CONCLUSIONS

These results demonstrate that gp130 activation in human cardiac cells leads to cardiomyocyte hypertrophy. We discuss several hypotheses on the role of IL-6-type cytokines on cardiomyocyte functions.

Immunoglobulin D enhances interleukin-6 release from the KU812 human prebasophil cell line

Despite the role of secreted immunoglobulin D (IgD) remains still largely unknown, previous studies have suggested that secreted IgD could induce basophils degranulation in some allergic asthma patients. In the present study we have searched direct evidence of the action of IgD on KU812 cells, generally classified as an immature basophilic cell line. We analyzed by flow cytometry the capacity of IgD, purified from IgD myeloma sera, to bind KU812 cells. Biotinylated monomeric IgD (mIgD) and biotinylated oligomeric IgD (oIgD) could bind KU812 cells. Blocking experiments with others immunoglobulin isotypes showed that KU812 cells expressed an unspecific receptor for IgD. However, oIgD but not mIgD enhances the release of interleukin-6 (IL-6) from KU812 cells. On the other hand, mIgD and oIgD failed to induce histamine release from KU812 cells or from cord blood derived basophils. Since IL-6 is known to induce basophil differentiation, we proposed that IgD could be implicated in allergic disorders by stimulating IL-6 release by prebasophil cells, then IL-6 could further induce an autocrine maturation of the cells.

IL-22, in contrast to IL-10, does not induce Ig production, due to absence of a functional IL-22 receptor on activated human B cells

IL-22 is an IL-10 homologue that binds to and signals via the class II cytokine receptor (R) heterodimer IL-22RA1/CFR2-4 (IL-10R2), the latter chain being part of the IL-10R complex. Here, we report that, despite its structural similarity with IL-10, as well as its use of the common IL-10R2 chain, IL-22, in contrast to IL-10, is unable to induce Ig production by activated human B cells. Whereas culture of anti-CD40 mAb-stimulated splenic or tonsillar B cells in the presence of rIL-10 resulted in the production of IgG, IgG1, IgG3 and IgA, rIL-22, at concentrations ranging from 4 to 100 ng/ml, did not induce the production of any of these isotypes. Moreover, unlike rIL-10 which enhanced rIL-4-induced IgG4 and IgE production, rIL-22 was ineffective. Although activated B cells expressed transcripts for a soluble IL-22-binding protein (IL-22RA2), no mRNA for a transmembrane IL-22R (IL-22RA1) could be detected. The latter result was confirmed by the demonstration that rIL-22 failed to induce activation of STAT-3 and -5 in resting or activated B cells. Together, these data show that IL-22, in contrast to its homologue IL-10, is not involved in the immunological activity of B cells, which is due to the absence of a functional IL-22R at the surface of these cells.

The enlarging clinical, genetic, and population spectrum of tumor necrosis factor receptor-associated periodic syndrome

OBJECTIVE

To characterize the frequency, clinical signs, and genotypic features of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) in a series of 394 patients of various ethnic origins who have recurrent inflammatory syndromes.

METHODS

Sequencing of the coding region of the TNFRSF1A gene was performed in 128 patients in whom there was a high suspicion of TRAPS, and denatured high-performance liquid chromatography was used to systematically screen for TNFRSF1A in 266 patients with recurrent inflammatory syndrome and no or only 1 Mediterranean fever gene (MEFV) mutation.

RESULTS

TNFRSF1A mutations were found in 28 (7.1%) of 394 unrelated patients. Nine (32%) of the 28 patients had a family history of recurrent inflammatory syndromes. In 13 patients, the length of the attack of inflammation was fewer than 5 days. Three of the mutations (Y20H, L67P, and C96Y) were novel. Two mutations, R92Q and (mainly) P46L, found in 12 and 10 patients, respectively, had lower penetrance compared with other mutations. TNFRSF1A mutations were found in patients of various ethnic origins, including those at risk for familial Mediterranean fever (FMF): Armenians, Sephardic Jews, and especially Arabs from Maghreb. Only 3 (10.7%) of the 28 patients had amyloidosis.

CONCLUSION

TRAPS is an underdiagnosed cause of recurrent inflammatory syndrome. Its presence in the population of persons of Mediterranean ancestry and the short duration of the attacks of inflammation can lead to a fallacious diagnosis of FMF. Because an accurate diagnosis in patients with recurrent inflammatory syndromes is crucial for proper clinical management and treatment, genetic screening for TNFRSF1A is warranted.

Secretion of IL-6, IL-11 and LIF by human cardiomyocytes in primary culture

Interleukin (IL)-6-type cytokines are multifunctional proteins involved in cardiac hypertrophy and myocardial protection. Recent studies, performed on animal models, report the production of these cytokines by heart. The aim of this study was to analyse the capacity of myocytes and fibroblasts isolated from human atrium to secrete IL-6, leukaemia inhibitory factor (LIF), cardiotrophin-1 (CT-1), IL-11, oncostatin M (OSM), ciliary neurotrophic factor (CNTF) and the soluble receptor subunits sIL-6R and sgp130 during primary culture. We detected LIF, IL-11, sgp130 and a large amount of IL-6, but not OSM, CT-1, CNTF nor IL-6R in these culture supernatants. Both cardiomyocytes and fibroblasts are able to spontaneously produce IL-6. The increase of IL-6 production all along the culture period appears to be the consequence of fibroblast proliferation and gp130 stimulation. This is the first demonstration that human cardiac cells are able to secrete IL-6, but also LIF and IL-11 in vitro. These cytokines could be involved in an autocrine and/or a paracrine networks regulating myocardial cyto-protection, hypertrophy and fibrosis.

Cyclosporin A inhibition of macrophage colony-stimulating factor (M-CSF) production by activated human T lymphocytes

M-CSF is a pleiotropic cytokine involved in the survival, proliferation, and differentiation of cells of the monocyte/macrophage lineage. M-CSF is produced by numerous cells including CD3-activated T cells. M-CSF serum levels are increased during acute graft rejection. We tested the in vitro production of M-CSF, GM-CSF, IL-2, and IL-4 by T-cell clones costimulated by CD3 and accessory activation pathways and the effects of cyclosporin A and methylprednisolone. The nine clones studied and CD4+ cells purified from peripheral blood mononuclear cells (PBMC) spontaneously produced low levels of M-CSF, which PMA and CD3 mAb strongly enhanced. In contrast to IL-2, CD28 mAb did not further enhance this production. CsA inhibited M-CSF production by clones and purified CD4 T cells. Addition of IL-2, anti IL-2, or anti CD25 mAb to the cultures demonstrated that CsA down-regulated M-CSF synthesis by activated T cells through its inhibition of IL-2 synthesis. These results could help to better understand the complex mechanisms of acute graft rejection and immunosuppression.

[Systemic markers of inflammation after coronary angioplasty]

THE RISK OF RESTENOSIS: Coronary angioplasty is an effective treatment of stable and instable coronary disease and its principle limitation, despite technical progress, remains restenosis. In instable angina, the physiopathologic and prognostic role of inflammation proteins is well documented. THE ROLE OF THE C-REACTIVE PROTEIN (CRP): Is a validated risk factor for patients presenting with heart failure, whether instable or stable angina and in the general population. This risk factor is distinct from tobacco abuse, hypercholesterolemia or diabetes. In all the series studied to date, the frequency of restenosis following coronary angioplasty increases when CRP values are high prior to surgery and continue to rise up to the 48th or 72nd hour.

PERSPECTIVES

New therapeutic measures widen the possibilities of mechanical strategies (angioplasty with or without stent) and treatment of inflammatory mechanisms in the atheromatous plaques (statines, brachytherapy or "covered" stents).

Familial Mediterranean Fever: association of elevated IgD plasma levels with specific MEFV mutations

Familial Mediterranean Fever (FMF) is a recessively inherited disorder, characterized by episodic fever, abdominal and arthritic pain, as well as other forms of inflammation. Some FMF patients present higher IgD serum levels, and it is not yet known whether such an elevation is related to specific genotypes or correlated with a specific phenotype. In order to evaluate the association between known FMF-related mutations and IgD levels in confirmed patients, as well as the correlation between those levels and the presence of specific clinical signs, genotypic analysis and IgD plasma measurements were performed for 148 Lebanese and Jordanian FMF patients. Most common mutational patterns were M694V heterozygotes (19%) and homozygotes (17%), and V726A heterozygotes (18%) and homozygotes (5%), with an additional 11% combining both mutations. Twenty-one patients had higher IgD levels (superior to 100 microg/ml). The risk for higher IgD levels was significantly associated with M694V homozygote status (OR = 6.25) but not with heterozygotic one (OR = 1). Similarly, the risk for higher IgD was also found with V726A homozygotes (OR = 2.2) but not with heterozygotes (OR = 1.05). The use of colchicine was not statistically associated with IgD levels. Clinically, hyper IgD was also found significantly associated with arthritis (OR = 18). Thus, homozygotic status for M694V, and to a lesser extent V726A, is associated with increased risk for higher IgD plasma levels, regardless of colchicine use. Elevated IgD plasma levels are also correlated with the severity of FMF manifestations, and especially with arthritis.

Interleukine-6 (IL-6) synthesis and gp130 expression by human pericardium

Growing evidence shows that cytokines of the IL-6 family play an important regulatory role in heart physiology such as inducing cardiomyocyte hypertrophy. The purpose of this study was to see if IL-6 and its soluble receptors (sIL-6R and sgp130) could be detected in pericardial fluids, and to see if they are produced by the pericardium. We report that human pericardial fluid from patients with coronary pathologies contained IL-6, sIL-6R, and sgp130. However, the levels present in sera and pericardial fluid did not correlate, which suggests local production. This observation was confirmed by in vitro studies demonstrating massive IL-6 production by cultured pericardial samples, which could be strongly inhibited by methylprednisolone. RT-PCR studies revealed that IL-6 was weakly expressed in fresh tissues and strongly induced after culture. In situ hybridisation and immunohistochemical analysis showed that IL-6 and gp130 were mainly present in mesothelial cells. sIL-6R and sgp130 were also produced by pericardium in vitro, and their synthesis was upregulated by methylprednisolone. Taken together, these results demonstrate that IL-6 is present in pericardial fluid and that its presence could be due to synthesis by pericardial tissue. In vitro studies suggest that IL-6 production by this tissue could be strongly induced and regulated. A potential paracrine role of these factors in cardiomyocyte functions in normal or pathological conditions is discussed.

Survival prognostic value of serum interleukin-6 level in very old people

OBJECTIVE

To determine the survival prognostic value of serum interleukin-6 level in very old people.

DESIGN

Prospective 12-month clinical survey in a long term ward and in a day care hospital.

SETTING

A long-term ward and a day care hospital for very old and dependent people, located in Poitiers (France).

PARTICIPANTS

A cohort of 115 old people [Range 64-101], either in a long-term ward (n=71) or in day care hospital (n=44).

MEASUREMENTS

Patients were checked for different nutritional parameters and the Interleukin-6 level in the serum at baseline and patients were followed up for one year.

RESULTS

A high level of interleukin-6 (Il-6) is associated with increased Prognostic Inflammatory and Nutritional Index (PINI) value, serum CRP thereby demonstrating the inflammatory role of this molecule. It is also associated with an increased risk of death. Using a survival regression model, a high Il-6 serum level observed at the beginning of the study is a bad prognostic indicator, with other biological or nutritional parameters having no significant influence.

CONCLUSION

A high level of Interleukin-6 may be a better marker of prognosis than an increased PINI score.

Structural and functional properties of membrane and secreted IgD

More than 35 years ago, study of an unknown immunoglobulin (Ig) in the serum from a myeloma patient led to the discovery of IgD. Subsequently, the finding that it also exists as a membrane-bound Ig stimulated a large number of studies during the 70s. Then, the interest on IgD shrank, largely because of the lack of known function of secretory IgD (secIgD) and of a stagnating knowledge of the functions of surface IgD. In the recent years, very significant advances followed the tremendous accumulation of data on the physiology of the B cell receptor, of which IgD is the major component, on the role of secIgD in normal and diseased individuals. This review, which is focused on human IgD but integrates data in the mouse and other species when needed, summarizes present data on the structure, synthesis and functions of both membrane and secIgD, IgD receptors and the involvement of IgD in various diseases, especially the hyperIgD syndrome.

Circulating soluble gp130, soluble IL-6R, and IL-6 in patients undergoing cardiac surgery, with or without extracorporeal circulation

OBJECTIVE

Soluble forms of interleukin-6 (IL-6) receptors are known to modulate biological activities of IL-6. The purpose of the study was to measure circulating levels of IL-6, sIL-6R and sgp130 in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (CPB group) or without CPB (non-CPB group).

METHODS

The CPB group included 19 patients and the non-CPB group 12 patients. Sera levels of IL-6, sIL-6R and sgp130 were measured by specific ELISA at the beginning of the operation (T0, 15 min before skin incision) and 6 h later (T1).

RESULTS

IL-6 sera levels were respectively 9+/-20 pg/ml (mean+/-SD) and 13+/-19 pg/ml at T0 and reached 340+/-250 pg/ml and 965+/-1060 pg/ml at T1 in CPB and non-CPB groups, indicating a significant increase from T0 to T1, but no differences between the two groups. When compared to T0 values, sgp130 levels decreased in both groups (respectively 105+/-37 and 115+/-35 ng/ml at T0 for CPB and non-CPB groups, and 72+/-25 and 84+/-29 ng/ml at T1) while we are not able to detect differences between the groups. Whatever the group or the time, sIL-6R concentrations remained unchanged.

CONCLUSIONS

We showed that the increase of IL-6 after artery bypass grafting was similar between patients operated with CPB or without CPB. We conclude that the main inductor of IL-6 release is linked to surgical trauma rather than a reaction to CPB. Since it is known that gp130 inhibits IL-6-biological activities, we suggest that the decrease of sgp130 sera levels could further enhance the inflammatory effects of IL-6 in cardiac surgery.

Correlation between IL-8 induction, cagA status and vacA genotypes in 153 French Helicobacter pylori isolates

The polymorphism of clinical presentations associated with Helicobacter pylori infection is potentially due to differences in the virulence of individual strains. H. pylori virulence has been associated with the ability to induce secretion of interleukin-8 (IL-8), the vacA genotypes, and the cagA status. The aim of this study was to determine the virulence profiles of 153 French H. pylori isolates on the basis of vacA genotypes, cagA status, and IL-8 induction ability. A total of 153 H. pylori isolates from patients with chronic gastritis (n = 74) or gastro-duodenal ulcers (n = 79) was examined for vacA genotypes and cagA status by polymerase chain reaction (PCR) and dot blot, and for their ability to induce IL-8 secretion by HEp-2 cells. The prevalence of vacA genotypes was: s1/m1 44.3%, s1/m2 24.9%, and s2/m2 23.5%. The cagA gene was present in 64% of the strains. IL-8 secretion was induced by 58.7% of the isolates. The presence of the cagA gene was significantly correlated with the s1/m1 vacA genotype and with the induction of IL-8. Thirty-four strains were atypical (cagA-positive/IL-8 noninducer or cagA-negative/IL-8 inducer). vacA genotypes, cagA status, and IL-8 induction ability are not correlated with the presence or absence of ulcer. The cagA status is not sufficient to predict the proinflammatory ability of H. pylori.

T(h)2 cytokine dependence of IgD production by normal human B cells

IgD is a minor component of serum Ig and the control of IgD secretion is virtually unknown. We measured concentrations of IgD (and IgE and IgM as controls) in culture supernatants of peripheral blood mononuclear cells (PBMC) from 60 normal donors as well as mononuclear cells from 10 tonsils following culture in the absence or presence of CD40 mAb and cytokines. Low levels of IgD were measured in cultures of PBMC, either unstimulated or stimulated by anti-CD40 antibodies. IL-4 and IL-10 significantly increased IgD production by CD40 mAb-stimulated cells in the majority of normal subjects studied, whereas in a limited number of individuals, spontaneous IgD production was either low or high, but with no increase upon stimulation. Spontaneous IgD production by tonsil-derived mononuclear cells was higher than by PBMC and increased after CD40 stimulation and even more in the presence of IL-10, but not IL-4. IL-2 and IFN-gamma exerted a dose-dependent inhibition on spontaneous as well as CD40- and cytokine-induced IgD production by PBMC, but not by tonsil mononuclear cells. Activation by IL-4 of CD40-stimulated purified B cells from tonsil and PBMC, and by IL-10 of tonsil B cells increased IgD production, whereas IL-2 and IFN-gamma had no detectable inhibitory effect. This suggests that accessory cells indirectly regulate IgD synthesis. IgD production induced in PBMC by IL-4 or IL-10 appeared to result from an active synthesis, and correlated with an increase in the number of IgD-containing plasma cells as demonstrated by immunofluorescence and increased expression of secreted IgD transcripts. These findings suggest that IgD production by normal peripheral blood human B cells is regulated positively by T(h)2 cytokines and negatively by T(h)1 cytokines.

Preincubation of human resting T cell clones with interleukin 10 strongly enhances their ability to produce cytokines after stimulation

Interleukin 10 (IL-10) has been described as a cytokine inhibitory factor downregulating IL-2 secretion and inducing T cell anergy. The data reported in this study show that preincubation of resting T cells from the human CD4+ clone SP-B21 (and clone TA-23.6) with IL-10 strongly enhances their capacity to further produce IL-2, interferon gamma (IFN-gamma), IL-4 and tumour necrosis factor alpha (TNF-alpha) after subsequent activation. In contrast, when IL-10 was added during the activation step, the previously reported specific inhibition of IL-2 synthesis was observed. Flow cytometric analysis of intracellular IL-2- and IL-4-producing cells revealed that preincubation with IL-10 increased the number of cytokine-producing cells, but did not affect their individual ability to produce these cytokines. We further show that IL-10 plays a dose-dependent role of viability maintenance factor. This effect relates to a direct anti-apoptotic effect of IL-10, which is likely independent of the expression of bcl-2, bcl-x and fas. Such paradoxal properties of IL-10 on T cells should be considered when aiming at using IL-10 as an immunosuppressive molecule in the treatment of diseases.

Cytokines released in vitro by stromal cells from autologous bone marrow transplant patients with lymphoid malignancy

Marrow stromal cells of patients treated by autologous bone marrow transplantation (ABMT) for malignancies have been assessed for their ability to secrete granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), stem cell factor (SCF), leukemia inhibitory factor (LIF), interleukin-6 (IL-6), transforming growth factor beta1 (TGFbeta1) and macrophage inflammatory protein-1alpha. (MIP-1alpha). Long-term marrow cultures were established from 10 patients prior to and 3 months after ABMT, from 7 patients 1 yr after ABMT and from 11 controls. Cytokines in culture supernatants of stromal layers (SL) were evaluated by enzyme-linked immunosorbent assay (ELISA). Significant differences between patient groups and controls were apparent in baseline production of GM-CSF, SCF, MIP-1alpha and TGFbeta1. After IL-1beta addition in cultures, G-CSF production was reduced in pretransplant and post-transplant patients compared to controls. The production of TGFbeta1, LIF, IL-6 and more particularly SCF were reduced in post-transplant patients, while elevated levels of GM-CSF and MIP-1alpha were observed in these patients only when the values were corrected for the number of cells growing in the SL. These results indicate a prolonged stromal defect in growth factor production following ABMT for the early-stage acting cytokines IL-6, LIF and SCF as well as for G-CSF, but not for GM-CSF, while the production of the 2 inhibitors shows different pathways.

An antagonistic monoclonal antibody (B-N6) specific for the human neurotensin receptor-1

The neuropeptide neurotensin (NT) interacts with two types of human receptors (hNTR) termed hNTR-1 and hNTR-2. This study describes a monoclonal antibody (MAb) specific for hNTR-1, B-N6. This MAb binds specifically to hNTR-1, but not to hNTR-2 transfected CHO cells. B-N6 and NT display a reciprocal competition and react in a similar way to trypsin, suggesting that the B-N6 epitope is at or close to the NT binding site on the third extracellular loop. Unlike B-N6, NT induces hNTR-1 internalization. Although neither NT-FITC nor B-N6 binding was detected by flow cytometry on different human cells, specific mRNA expression for hNTR-1 was detected in these cells. In CHO cells expressing hNTR-1 and a luciferase gene coupled to the krox24 reporter, B-N6 and the antagonist SR 48692 inhibited NT-induced intracellular activation of krox24 in a dose-dependent manner. From these results it is concluded that B-N6 is an antagonistic anti-hNTR-1 MAb.

IL-6 and soluble IL-6 receptors (sIL-6R and sgp130) in human pleural effusions: massive IL-6 production independently of underlying diseases

IL-6, soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130) levels were measured in sera and pleural effusions from 42 patients with metastatic carcinoma, non-Hodgkin's lymphoma, tuberculosis, cardiac failure and miscellaneous diseases. Pleural IL-6 levels measured by ELISA were very high in all patient groups (mean 34.8 +/- 15.3 ng/ml) without significant difference according to diseases. IL-6 was shown to be biologically active in a proliferative assay. Serum IL-6 levels were low (0.049 +/- 0.014 ng/ml) and did not correlate with pleural fluid levels. Pleural IL-6 levels correlated with the number of polymorphonuclear cells in pleural fluid (P < 0.03). Pleural sIL-6R levels (76 +/- 8 ng/ml) were always lower than serum levels (196 +/- 12 ng/ml; P < 0.0001) but correlated with them (P < 0.01). Pleural sIL-6R and albumin levels correlated (P < 0.01), suggesting a transudation of sIL-6R from the serum. Pleural sgp130 levels (10.9 +/- 1.0 ng/ml) were lower than serum levels (24.6 +/- 2.8 ng/ml; P < 0.002). After gel filtration of pleural fluid, the bulk of IL-6 (> 90%) was recovered in a 15,000-30,000 fraction, corresponding to the expected mol. wt of free IL-6. These results suggest a production and a sequestration of IL-6 in the pleural cavity in all studied conditions.

Serum soluble CD23 levels in giant cell arteritis

Lymphocytes and monocytes express various levels of membrane-bound CD23, the low affinity receptor for IgE (Fc epsilon RII), and in some cases release it as a soluble form. Soluble CD23 (sCD23) has been implicated in the regulation of many immunological functions of T and B lymphocytes, macrophages and myeloid cells in humans. To study serum sCD23 levels in inflammatory conditions, we selected a systemic disease sensitive to corticotherapy, the giant cell arteritis, which is characterized by an inflammation of the temporal artery. Serum sCD23 levels, as measured by a radioimmunoassay, were increased in these patients, and returned to normal values within the 24 h following initiation of corticotherapy. The data suggest that the increase in sCD23 levels in giant cell arteritis results from an overproduction.