Behavioral, Hormonal, Inflammatory, and Metabolic Effects Associated with FGF21-Pathway Activation in an ALS Mouse Model

In amyotrophic lateral sclerosis (ALS), motor neuron degeneration occurs simultaneously with systemic metabolic dysfunction and neuro-inflammation. The fibroblast growth factor 21 (FGF21) plays an important role in the regulation of both phenomena and is a major hormone of energetic homeostasis. In this study, we aimed to determine the relevance of FGF21 pathway stimulation in a male mouse model of ALS (mutated SOD1-G93A mice) by using a pharmacological agonist of FGF21, R1Mab1. Mice (SOD1-WT and mutant SOD1-G93A) were treated with R1Mab1 or vehicle. Longitudinal data about clinical status (motor function, body weight) and biological parameters (including hormonal, immunological, and metabolomics profiles) were collected from the first symptoms to euthanasia at week 20. Multivariate models were performed to identify the main parameters associated with R1Mab1 treatment and to link them with clinical status, and metabolic pathways involving the discriminant metabolites were also determined. A beneficial clinical effect of R1Mab1 was revealed on slow rotarod (p = 0.032), despite a significant decrease in body weight of ALS mice (p < 0.001). We observed a decrease in serum TNF-α, MCP-1, and insulin levels (p = 0.0059, p = 0.003, and p = 0.01, respectively). At 16 weeks, metabolomics analyses revealed a clear discrimination (CV-ANOVA = 0.0086) according to the treatment and the most discriminant pathways, including sphingolipid metabolism, butanoate metabolism, pantothenate and CoA biosynthesis, and the metabolism of amino acids like tyrosine, arginine, proline, glycine, serine, alanine, aspartate, and glutamate. Mice treated with R1Mab1 had mildly higher performance on slow rotarod despite a decrease on body weight and could be linked with the anti-inflammatory effect of R1Mab1. These results indicate that FGF21 pathway is an interesting target in ALS, with a slight improvement in motor function combined with metabolic and anti-inflammatory effects.

[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.

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.

[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.

Differential regulation of IL-13 and IL-4 production by human CD8+ and CD4+ Th0, Th1 and Th2 T cell clones and EBV-transformed B cells

In the present study, the requirements and characteristics for the production of IL-13 by human T cells, T cell clones and B cells were determined and compared with those of IL-4. IL-13 was produced by human CD4+ and CD8+ T lymphocyte subsets isolated from peripheral blood mononuclear cells and by CD4+ and CD8+ T cell clones. CD4+ T cell clones belonging to Th0, Th1-like and Th2-like subsets produced IL-13 following antigen-specific or polyclonal activation. In addition, EBV-transformed B cell lines expressed IL-13 mRNA and produced small amounts of IL-13 protein. Expression of IL-13 mRNA and production of IL-13 protein by peripheral blood T cells and T cell clones was induced rapidly and was relatively long lasting, whereas IL-4 production by these cells was transient. In addition, IL-13 mRNA expression was induced by modes of activation that failed to induce IL-4 mRNA expression. IL-13 shares many biological activities with IL-4 which is compatible with the notion that the IL-13 and IL-4 receptors share a common component required for signal transduction. However, IL-13 lacks the T cell-activating properties of IL-4. Here we have shown that this is related to the fact that T cells fail to bind radiolabeled IL-13 and do not express the IL-13-specific receptor component. Taken together, these results indicate that the differences in expression and biological activities of IL-4 and IL-13 on T cells may have consequences for the relative roles of these cytokines in the immune response.

Proliferative response of human CD4+ T lymphocytes stimulated by the lectin jacalin

The Gal beta(1-3)GalNAc-binding lectin jacalin is known to specifically induce the proliferation of human CD4+ T lymphocytes in the presence of autologous monocytes and to interact with the CD4 molecule and block HIV-1 infection of CD4+ cells. We further show that jacalin-induced proliferation is characterized by an unusual pattern of T cell activation and cytokine production by human peripheral blood mononuclear cells (PBMC). A cognate interaction between T cells and monocytes was critical for jacalin-induced proliferation, and human recombinant interleukin (IL)-1 and IL-6 did not replace the co-stimulatory activity of monocytes. Blocking studies using monoclonal antibodies (mAb) point out the possible importance of two molecular pathways of interaction, the CD2/LFA-3 and LFA-1/ICAM-1 pathways. One out of two anti-CD4 mAb abolished jacalin responsiveness. Jacalin induced interferon-gamma and high IL-6 secretion, mostly by monocytes, and no detectable IL-2 synthesis or secretion by PBMC. In contrast, jacalin-stimulated Jurkat T cells secreted IL-2. CD3- Jurkat cell variants failed to secrete IL-2, suggesting the involvement of the T cell receptor/CD3 complex pathway in jacalin signaling. IL-2 secretion by CD4- Jurkat variant cells was delayed and lowered. In addition to CD4, jacalin interacts with the CD5 molecule. Jacalin-CD4 interaction and the proliferation of PBMC, as well as IL-2 secretion by Jurkat cells were inhibited by specific jacalin-competitive sugars.

Characterization of binding sites for neuropeptide FF on T lymphocytes of the Jurkat cell line

Neuropeptide FF (NPFF) is a neuropeptide with antiopiate properties able to antagonize the action of both endogenous and exogenous opiates. Because we have recently shown that NPFF modulates the proliferation of human T lymphocytes, we have searched for binding sites for this peptide on T lymphocytes. Our study shows that T lymphocytes of the Jurkat cell line express binding sites for [125I]YLFQPQRFamide, an iodinated analogue of NPFF. This binding is time and dose dependent, reversible, saturable, and may be resolved in two distinct components of high and low affinity. The opiate receptor agonists mu, delta, and kappa, as well the antagonist naloxone, were unable to affect binding. Beside the effects of opiates on immune cells, our results suggest that an antiopiate peptide, such as NPFF, could play a role in the modulation of the immune system.

Proliferative response of B chronic lymphocytic leukemia lymphocytes stimulated with IL2 and soluble CD23

The in vitro proliferative response of purified B-chronic lymphocytic leukemia (B-CLL) lymphocytes cultured in the presence of soluble CD23 (sCD23) with or without IL2 was compared to the responses induced by phorbol 12-myristate 13-acetate (PMA), Staphylococcus aureus strain Cowan I (SAC), IL1, IL2, IL4, IL6 and the combination of IL2 and interferon (IFN) alpha or IFN gamma. As expected, B-CLL lymphocytes proliferated with PMA, SAC and IL2 with a clear enhancement of the IL2-induced response by IFN alpha or IFN gamma. They failed to proliferate in response to sCD23, IL1, IL4 or IL6 alone nor to the combinations of sCD23 and any of the 3 latter cytokines. However, sCD23 significantly increased the proliferation of B-CLL cells induced by IL2, suggesting a protective effect of sCD23 on apoptosis. Serum levels of sCD23 and CD23 membrane expression were high in every patient which is compatible with the hypothesis of an autocrine or paracrine activation loop. Detectable CD23 expression was lost in all cultures except for that stimulated by PMA. Only supernatants of PMA-stimulated cultures contained high sCD23 levels.

Effects of alpha-interferon on MHC unrestricted cytotoxicity in chronic myelogenous leukemia

The capacity of alpha-interferon (alpha-IFN) to induce lymphokine activated killer (LAK) cytotoxicity in the absence of interleukin-2 (IL2) has prompted us to test whether its ability to reduce dramatically the number of Ph1+ clones in chronic myelogenous leukemia (CML) patients is in part mediated through the generation of natural killer (NK) or LAK activity. The latter were tested using NK-sensitive (K562) and NK-resistant (Raji) cell lines in a target-cell colony-growth inhibition assay. Effector cells (E) were patient blood mononuclear cells (MC) without in vitro activation prior to their coculture with targets (T). Here we report that cytogenetic remission in alpha-IFN-treated patients is associated with significantly enhanced NK and LAK activities. Nevertheless, some patients under alpha-IFN therapy were found to develop lymphoid blast crisis despite high levels of NK and LAK activities, and partial or total cytogenetic remission. In contrast, most of the patients who developed nonlymphoid blast crisis presented 100% Ph1+ cells and displayed defective NK and/or LAK activity. These observations could favor the hypothesis that there is an indirect but complex effect of alpha-IFN on leukemic cells, mediated by cells involved in immune surveillance; and also that lymphoid blast cells may actually escape LAK cytotoxicity.

Chromosomal analysis of purified B-chronic lymphocytic leukemia lymphocyte cultures: comparison with whole blood cultures and in situ hybridization

Chromosomal analysis of stimulated whole blood cells and purified B lymphocytes was performed in 13 stage A(0) and 1 stage C(IV) chronic lymphocytic leukemia (B-CLL) patients. Abnormal clones were found in 6 cases in purified B lymphocytes cultures and in a single one in whole blood cultures. In situ hybridization with a chromosome 12 probe was in accordance with the chromosomal analysis of purified B-CLL lymphocytes and not with the results obtained using whole blood culture. Cytogenetic analysis of isolated B cells is simple and sensitive. It enhances the detection of abnormal clones in B-CLL and applied to larger series of patients, it should allow a precise evaluation of the incidence of chromosomal abnormalities in CLL and of their clinical (prognostic) significance.

Effects of sCD23 on proliferation of leukemic cells from a patient with chronic myelogenous leukemia during blast crisis

The present study has attempted to further delineate the growth factor requirements of peripheral blasts of a patient with CML in acute phase. Phenotypic analysis of leukemic blasts from this patient before culture has shown a homogenous population of CD34+ cells at the onset of blast crisis. In the second and third samples the percentage of CD34+ DR+ blast cells decreased slightly and up to 32% of cells in the third sample expressed the CD19 antigen. Optimal proliferation of cells derived from the first sample required the presence of exogenous sCD23 and to a lesser extent IL7. The stimulatory effects of sCD23 and IL7 were clearly reduced 4 months later and no longer detected after 6 months. This variability in growth factor response along with disease progression may be related to phenotypic differentiation. There was no evidence for lymphoid or myeloid maturation after 4 days of liquid culture. Our results in conjunction with previous studies are in agreement with sCD23-involvement in the complex control of proliferative processes at both normal and leukemic stages, demonstrating that cytokines are critical in determining CML cell proliferation.

High circulating leukaemia inhibitory factor (LIF) in patients with giant cell arteritis: independent regulation of LIF and IL-6 under corticosteroid therapy

Leukaemia inhibitory factor (LIF) is a cytokine which possesses a wide range of biological activities including, like IL-6, the capacity to stimulate acute phase protein (APP) synthesis. We have developed a sensitive and specific ELISA for human LIF, and tested the circulating cytokine levels in various disease states, some of which are associated with inflammation. LIF was detected in 11/20 sera from patients with giant cell arteritis (GCA), a vasculitis syndrome affecting particularly the temporal artery, characterized by panarteritis with inflammatory cell infiltration. LIF levels were considerably elevated in some patients who also displayed elevated levels of IL-6 and C-reactive protein (CRP); however, no correlation was observed between the levels of circulating LIF and levels of IL-6 or CRP. Furthermore, LIF levels were not affected by corticosteroid therapy, whereas IL-6 and CRP decreased rapidly, as clinical symptoms resolved. A putative role for LIF in the persistence of histological lesions is discussed. This is the first report of the presence of circulating LIF in sera. These results are in agreement with the complexity of induced inflammatory cytokines and corticoid regulation of APP synthesis observed in vitro and in vivo.

Endogenous lymphokine activated killer cell activity and cytogenetic response in chronic myelogenous leukaemia treated with alpha-interferon

The capacity of alpha-interferon (alpha-IFN) to induce lymphokine activated killer (LAK) cytotoxicity in the absence of interleukin-2 (IL2) has prompted us to test whether or not its ability to reduce dramatically the number of Ph1+ clones in chronic myelogenous leukaemia (CML) patients is in part mediated through the generation of natural killer (NK) or LAK activity. The latter were tested using NK-sensitive (K562) and NK-resistant (Raji) cell lines in a target-cell colony-growth inhibition assay. Effector cells (E) were patient blood mononuclear cells (MC) without in vitro activation prior to their coculture with targets (T). Out of 16 patients tested so far, three failed to undergo cytogenetic remission under alpha-IFN therapy. No NK nor LAK cells could be detected in the MC from two of them while the other displayed NK activity within upper normal limits. 13 patients underwent complete (eight) or partial (five) cytogenetic remission together with significantly high NK and/or LAK activity as compared to normal controls. These observations could favour the hypothesis of an indirect effect of alpha-IFN on leukaemic cells, mediated by cells involved in immune surveillance.

Congenital hypomagnesemia: alternatives to tissue biopsies for monitoring body magnesium status

We have been monitoring a 12-year-old boy (his present age) suffering from selective magnesium (Mg) malabsorption. After ascertaining his Mg status, we attempted to maintain Mg balance through the use of oral supplements. Plasma and erythrocyte Mg concentrations were monitored at bimonthly intervals. However these measurements did not accurately reflect Mg status and we subsequently measured Mg in the following tissues: lymphocyte, tooth, and hair. Levels of Mg in stable tissues such as temporary teeth and lymphocytes, unfailingly revealed a marked deficit in Mg that was only two-thirds of the normal levels found in the control group. The use of these readily-accessible stable tissues can thus obviate the need for muscle or bone biopsy. Unfortunately the level in hair is higher than in healthy subjects, and thus does not constitute an adequate measure of Mg status.

Identification of the B cell derived T cell colony promoting activity to soluble CD23

We previously reported that supernatants of phytohemagglutinin (PHA)-stimulated normal human B cells (NBCsup) contain a T cell colony promoting activity. NBCsup were able to (a) increase the number of secondary colonies generated under PHA and interleukin-2 (IL-2) stimulation by peripheral blood-derived primary T colony cells, (b) enhance the ability of CD4+ but not CD8+ peripheral blood T cells to form agar colonies in the presence of PHA and IL-2 and (c) support in vitro differentiation of CD2-3-4-8- prothymocytes into CD2+3+4+ T cells. This activity was therefore refered to as Prothymocyte Differentiating Activity (PTDA). Subsequent studies pointed to striking biochemical and cell source homologies between this B cell derived factor and the 25-kDa soluble CD23 (sCD23). sCD23 has been recently found to display prothymocyte differentiating activity.

Modulation of human lymphocyte proliferation by FLFQPQRFamide, a FMRFamide-like peptide with anti-opiate properties

The octapeptide Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2 (F8Fa), originally detected in mammalian brain by antisera raised against the invertebrate peptide Phe-Met-Arg-Phe-NH2 (FMRFamide) is a neuropeptide able to antagonize the actions of both endogenous and exogenous opiates. Since it is well accepted that lymphocytes are targets for opiates, we have tested the effect of F8Fa on T cell proliferation from normal human peripheral blood lymphocytes. Our study shows that F8Fa exerts a concentration-dependent diphasic modulation of human T lymphocyte proliferation. Thus, despite a great variability between individuals, 10(-13) M F8Fa was found to enhance the proliferation of T cells induced by phytohemagglutinin or anti-CD2 monoclonal antibodies, while 10(-7) M F8Fa inhibited T cell proliferation, without affecting cell viability. When F8Fa was tested on monocyte-depleted cell preparations, only the inhibitory effect was observed. These results indicate that F8Fa may stimulate T cells via monocytes, but may also directly inhibit T lymphocyte proliferation. Given the presence of F8Fa-like peptide in human plasma, we suggest that F8Fa may act as a neurohormone in the control of the immune system.

Soluble CD23 displays T-cell growth enhancing activity

Soluble CD23 (sCD23) enhances, in a dose-dependent manner, the number of secondary T-cell colonies generated by peripheral blood-derived agar T-colony cells in the presence of phytohaemagglutinin (PHA) and interleukin-2 (IL-2). This effect is not affected by IL-1 or IL-4 but is abolished by an anti-CD23 monoclonal antibody (mAb) or by IgE. No colonies were observed when sCD23 was added to PHA- or IL-2-free cultures. sCD23 also enhanced the cloning frequency of primary T-colony cells in a limiting dilution assay. These data provide the first direct evidence that sCD23 recruits T-cell clones in peripheral blood-born T cells and may be involved indirectly in the regulation of IgE response.

In vitro differentiation and proliferation of purified human thymic and bone marrow CD7+CD2- T-cell precursors

It is well established that CD7, gp40 antigen is one of the first antigens detected on the surfaces of cells of the human T-cell lineage. Using complement-dependent cytotoxicity and immunoadherence to anti-CD7-coated surfaces, we were able to purify CD7+2-3-4-8-TcR- cells with greater than 90% purity from both human thymus and bone marrow. Limiting dilution analysis showed that these cells displayed high ability to generate mature T-cell clones when they were cultured in the appropriate conditions. These precursors needed phytohemagglutinin-stimulated leukocyte-conditioned medium (PHA-LCM) as a differentiation signal before being able to respond to PHA and recombinant interleukin 2 (rIL2). CD7+CD2- precursors differed from more mature CD7+CD2+ thymocytes because they were not sensitive to PHA, IL2, or CD2 triggering. Bone marrow-derived clones were mostly CD4+, whereas thymic cells generated more CD8+ than CD4+ clones. Together, this study indicates that the CD7+CD2- precursor is one of the earliest prothymocytes able to differentiate and proliferate in vitro.

Soluble CD23 (Fc epsilon RII) and interleukin 1 synergistically induce early human thymocyte maturation

The ability of human thymus-derived CD7+CD2-CD3- cells to acquire mature T cell antigens was assessed. Purified CD7+ thymocytes were incubated with rIL-1, rIL-2, and/or recombinant soluble CD23 (rsCD23). Short-term incubation of these cells with only rsCD23 + rIL-1 induced mature T cell antigen expression on at least half of the cells. The induction of CD2 was functionally significant, as these cells became able to respond to CD2 triggering and could proliferate in response to IL-2. Possible sources of CD23 in the thymus are under investigation.

The role of monocytes in IL-3 enhancement of human T cell proliferation

We have assessed the role of recombinant human interleukin 3 (rIL-3) in the activation and proliferation of peripheral blood lymphocytes (PBL) and their various subsets. rIL-3 significantly enhanced the CD2-responsiveness of unfractionated PBL. Proliferating cells were mainly T lymphocytes and most of them expressed CD4. This effect was absent following adherent cell depletion from PBL. rIL-3 also failed to directly activate purified lymphocytes, nor did it increase T cell responsiveness to mitogens and/or IL-2. By contrast, rIL-3 induced monocyte functions as enhancement of IL-1 production was observed following treatment of these cells by rIL-3. This effect was removed by anti IL-3 mAb addition to these cultures. In addition, anti IL-1 antibody partially inhibits IL-3-derived responses. Together, these data strongly suggest that IL-3 stimulation of T lymphocytes is related mainly to its ability to enhance monocyte functions.

Signal requirements for the generation of T-lymphocytes from T-depleted bone marrow cells: a sequential study

We have investigated the sequence of signals provided by a B- and null-cell-derived prothymocyte-differentiating activity (PTDA), phytohemagglutinin (PHA), and interleukin 2 (IL2) to the generation of mature T-lymphocytes by T-depleted bone marrow (BM) cells. Sequential studies show that preincubation of CD2-, CD3-, CD4-, CD6-, and CD8- BM cells with PTDA, but not with recombinant (r) IL2 or PHA increased their capacity to proliferate in liquid culture and to form agar T-cell colonies provided both PHA and rIL2 were added to the cultures. In contrast, the growth of T-cell-containing BM was significantly enhanced in both liquid and agar culture following its preincubation with rIL2 as well as with PTDA. The selective effect of PTDA on CD2-, CD3-, CD4-, CD6-, CD8- BM cells was abolished by adding a CD7 monoclonal antibody to the T-cell-purging coctail. Cell marker studies performed on T-cell-depleted BM-derived liquid or agar cultures have shown that they contain up to 70%-85% CD2+, CD3+, CD4+, CD8- cells. No IL1 or IL2 could substitute for PTDA, nor have these activities, as well as interferon (IFN), IL3, IL4, or granulocyte-macrophage colony-stimulating activity (GM-CSA) been detected so far in PTDA-containing preparations. These results indicate that PTDA can trigger marrow T-cell precursors into PHA-responsive T cells, which, following activation by PHA, require IL2 for growth. It is suggested that this may represent a thymus-independent alternative pathway for T-cell differentiation and activation.

Characterization of prothymocytes with cloning capacity in human bone marrow

The identity of human bone marrow (BM)-derived T cell precursors with colony forming capacity has led to controversy because of contamination with mature clonogenic T cells. We achieved 2 Log elimination of mature T cells from BM using a cocktail of monoclonal antibodies: CD2, CD3, CD4, CD6, and CD8 followed by two successive baby rabbit C' treatment. T cell depleted BM can generate colonies of CD2+, CD3+, Ti+, mostly CD4+, in the presence of PHA, rIL2, and a prothymocyte differentiating activity derived from phytohemagglutinin (PHA) induced mononuclear cells. These precursors could be enriched three- to sixfold by percoll gradient centrifugation and then significantly bypass the number of contaminant mature T cells as shown by limiting dilution analysis. Colony generation by marrow precursors was inhibited by the addition of autologous T cells. This inhibition was mostly caused by the T8+ subset. CFU-TL growth was dramatically inhibited by eliminating CD7+ cells suggesting their positivity for this surface marker. These precursors needed major histocompatibility complex (MHC) II-positive cells for optimal growth but lack DR themselves.

Relationship between IL-2 and human T cell colony formation

We have tested the reliability of a standard IL-2 microassay (3H-thymidine uptake by IL-2-dependent T cell lines) as a measure of the colony promoting activity (CPA) required for PHA-induced T cell colony growth in semi-solid cultures. Colonies were obtained from freshly isolated mononuclear cells (PBL) (primary colonies) or pooled cells of primary colony (secondary colonies). PHA-stimulated PBL generated primary colonies in the absence of exogenous CPA which, however, when added to the cultures enhanced colony growth. In contrast, primary colonies failed to form PHA-induced secondary colonies in the absence of exogenously supplied CPA. There was a close correlation between the colony forming capacity of PBL and primary colonies from the same donors plated in the presence of added CPA (r = 0.98). When CPA was measured in the secondary colony growth assay and the data compared to IL-2 measurement in the standard IL-2 microassay, CPA and IL-2 levels did not correlate, suggesting that IL-2 and CPA may represent distinct factors. The usefulness of primary colonies as target cells for the measurement of CPA levels in a variety of conditioned media is discussed.

Endogenous production of prothymocyte differentiating activity by phytohemagglutinin-stimulated T-cell-depleted human marrow

The PHA responsiveness of marrow T-cell precursors remains a matter of controversy. We have investigated the capacity of human marrow to proliferate under phytohemagglutinin (PHA) stimulation following extensive removal of mature T cells by complement-dependent cytotoxicity with MBG6 and RFT8 monoclonal antibodies. PHA-induced thymidine uptake by marrow cells occurred with a peak on Days 6-8 of incubation instead of Day 3 for PBL. This peak was observed 48 hr earlier in the presence of PHA-stimulated T-depleted marrow cell supernatants. These supernatants can also promote the growth of mature T-cell colonies from MBG6-, RFT8-, T11-, T3- marrow. However, full colony development requires exogenous interleukin 2 (IL-2). IL-2 could be detected in marrow supernatants but only at very low levels and beyond Days 3 and 4. In contrast Days 1-6 marrow supernatants were equally effective in promoting MBG6-RFT8- marrow cell responsiveness to PHA. We conclude that marrow T-cell precursors are not PHA responsive and that PHA induces the production by marrow non-T cells of a prothymocyte-differentiating activity (PTDA); PTDA can differentiate marrow T-cell progenitors into PHA-responsive T cells; following activation by PHA, these cells undergo limited proliferation induced by IL-2 endogenously released from de novo differentiated T cells. It is suggested that this mechanism may account for extrathymic differentiation of the T-cell lineage in heavily irradiated marrow transplantation recipients.