Biomedical subjects

A Tsicopoulos

Publications and source records attributed to A Tsicopoulos.

At least 19 recordsLinked to original sources

PubMed1992

Preferential messenger RNA expression of Th1-type cells (IFN-gamma+, IL-2+) in classical delayed-type (tuberculin) hypersensitivity reactions in human skin.

We recently established that the allergen-induced late-phase cutaneous reaction in atopic subjects was associated with high mRNA expression for the cytokine gene cluster IL-3, IL-4, IL-5, and granulocyte/macrophage-CSF (GM-CSF), compared with IFN-gamma and IL-2, suggesting that allergic skin reactions contained the equivalent of murine Th2 cells. We now show that, in humans, classical delayed-type hypersensitivity is associated with cells preferentially expressing a Th1-type cytokine profile. Cryostat sections from skin biopsies from 24-h tuberculin reactions in 10 nonatopic subjects were hybridized with 35S-labeled RNA probes and processed by using in situ hybridization. On the whole, tuberculin biopsies showed preferential expression of mRNA encoding IFN-gamma and IL-2, although in some cases mRNA expression for IL-3, IL-4, IL-5, and GM-CSF was also observed. Biopsies from diluent control sites gave only occasional signals. The difference in the number of cells expressing mRNA in the diluent compared with tuberculin sites was statistically significant for IL-2 and IFN-gamma (p less than 0.01) but not for IL-3, IL-4, IL-5, and GM-CSF. These results suggest that cells infiltrating the site of the 24-h tuberculin reaction preferentially transcribe mRNA encoding IFN-gamma and IL-2, supporting the hypothesis that delayed-type hypersensitivity is associated with preferential activation of cells having a cytokine profile similar to the murine Th1 subset.

Adult↗

PubMed1992

Predominant TH2-like bronchoalveolar T-lymphocyte population in atopic asthma.

BACKGROUND: In atopic asthma, activated T helper lymphocytes are present in bronchial-biopsy specimens and bronchoalveolar-lavage (BAL) fluid, and their production of cytokines may be important in the pathogenesis of this disorder. Different patterns of cytokine release are characteristic of certain subgroups of T helper cells, termed TH1 and TH2, the former mediating delayed-type hypersensitivity and the latter mediating IgE synthesis and eosinophilia. The pattern of cytokine production in atopic asthma is unknown. METHODS: We assessed cells obtained by BAL in subjects with mild atopic asthma and in normal control subjects for the expression of messenger RNA (mRNA) for interleukin-2, 3, 4, and 5, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon gamma by in situ hybridization with 32P-labeled complementary RNA. Localization of mRNA to BAL T cells was assessed by simultaneous in situ hybridization and immunofluorescence and by in situ hybridization after immunomagnetic enrichment or depletion of T cells. RESULTS: As compared with the control subjects, the subjects with asthma had more BAL cells per 1000 cell that were positive for mRNA for interleukin-2 (P less than 0.05), 3 (P less than 0.01), 4 (P less than 0.001), and 5 (P less than 0.001) and GM-CSF (P less than 0.001). There was no significant difference between the two groups in the number of cells expressing mRNA for interferon gamma. In the subjects with asthma, mRNA for interleukin-4 and 5 was expressed predominantly by T lymphocytes. CONCLUSIONS: Atopic asthma is associated with activation in the bronchi of the interleukin-3, 4, and 5 and GM-CSF gene cluster, a pattern compatible with predominant activation of the TH2-like T-cell population.

Adult↗

PubMed1992

Specific activation of platelets from patients allergic to Dermatophagoides pteronyssinus by synthetic peptides derived from the allergen Der p I.

Previous studies have shown that Fc epsilon RII-bearing platelets from patients with allergic disorders could be stimulated either by anti-human IgE antibodies or the relevant allergens to generate cytotoxic mediators. In this report, the reactivity of platelets from Dermatophagoides pteronyssinus (D. pt)-sensitive patients to three Der p I-derived synthetic peptides (52-71, 117-133 and 188-199) was investigated. The platelet stimulation observed in D. pt-sensitive patients was demonstrated to be allergen-specific and to be mediated by IgE. These Der p I-derived peptides failed to stimulate platelets from healthy donors or platelets from non-D. pt-allergic patients. D. pt-sensitive patients responded more frequently to the peptides 52-71 and 117-133 than to the peptide 188-199. Thus, in this model, synthetic peptides selected for their assumed accessibility on the native antigen could be associated to an IgE-dependent biological activity.

Adult↗

PubMed1992

Tumor necrosis factor alpha and interleukin-6 production by human mononuclear phagocytes from allergic asthmatics after IgE-dependent stimulation.

We have previously demonstrated the production of tumor necrosis factor alpha (TNF) and interleukin-6 (IL-6) by alveolar macrophages (AM) from allergic asthmatics developing a late asthmatic reaction after bronchial allergen challenge. In order to explain the modalities of this monokine synthesis, we tested in vitro the effect of an IgE-dependent stimulation on blood monocytes (BM) and AM from control and asthmatic subjects. TNF and IL-6 secretions were evaluated in 24-h supernatants by radioimmunoassay and by the 7TD1 cell proliferation test, respectively. AM from allergic asthmatics secreted spontaneously higher concentrations of TNF and IL-6 than did BM or AM from control subjects. BM from asthmatics also produced spontaneously increased levels of TNF, but at a lesser degree than did AM. The addition of anti-IgE induced a significant increase of TNF and IL-6 secretions by mononuclear phagocytes from control subjects only after previous sensitization with IgE-rich medium. In contrast, the direct stimulation by allergen or anti-IgE of AM and BM from asthmatics enhanced significantly the production of TNF and IL-6 when compared with cells cultured in medium alone. In these conditions, IgE-dependent activation of cells from allergic asthmatics compared with those from control subjects increased monokine production in a similar manner. Costimulation by recombinant human interferon gamma and IgE-dependent triggering had a synergistic effect on TNF production, but it had only an additive action on IL-6 synthesis (respective increase index: 9.8 compared with 2.9 and 9.8 compared with 2.1, respectively, for BM from control and asthmatic subjects).(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗

PubMed1991

Expression of mRNA and immunoreactivity for the granulocyte/macrophage colony-stimulating factor in activated human eosinophils.

Using in situ hybridization, we have shown that activated human peripheral blood eosinophils express mRNA for granulocyte/macrophage colony-stimulating factor (GM-CSF). Between 15 and 27% of eosinophils gave positive hybridization signals for GM-CSF mRNA after stimulation with the calcium ionophore A23187 or interferon gamma, and 4 and 6% after incubation with interleukin 3 (IL-3) or IL-5. Activated eosinophils also gave specific immunoreactivity with an anti-GM-CSF polyclonal antibody, suggesting translation of the mRNA. These data indicate that eosinophils may be an important source of GM-CSF at sites of allergic inflammation. Furthermore, the identification of GM-CSF production by human eosinophils suggests that the pro-inflammatory potential of this cell type may be substantially greater than hitherto recognized.

Calcimycin↗

PubMed1991

Release of granule proteins by eosinophils from allergic and nonallergic patients with eosinophilia on immunoglobulin-dependent activation.

The release of eosinophil peroxidase (EPO) and eosinophil cationic protein (ECP) was evaluated after incubation of eosinophils (EOSs) from allergic subjects with the specific allergen or with anti-IgE monoclonal antibodies (MAbs). High levels of EPO could be released after addition of the specific allergen (and not unrelated ones) or anti-IgE MAb. Moreover, EPO release with the two stimuli was significantly correlated both in allergic and in nonallergic patients. In the same supernatants, another granule protein, ECP, could not be detected, suggesting a lack of correlation between EPO and ECP release after IgE-dependent stimulation. However, when EOSs with surface-IgA antibodies were incubated with anti-IgA MAb, both EPO and ECP were released. In contrast, incubation of EOSs with anti-IgG MAb induced mainly the release of ECP and not EPO. These results indicate that pharmacologically active mediators can be released by EOSs from allergic and nonallergic patients on immunoglobulin-dependent activation. The results also confirm the hypothesis of a selective release of the various granule proteins and raise the question of transduction signals delivered by the three Fc receptors (Fc epsilon R, FC alpha R, and FC gamma R) present on human EOSs.

Allergens↗

PubMed1991

Increased secretion of tumor necrosis factor alpha and interleukin-6 by alveolar macrophages consecutive to the development of the late asthmatic reaction.

The late asthmatic reaction (LAR), consecutive to bronchial allergen challenge, is characterized both by the influx of various cells in proximal and distal airways and by the enhancement of bronchial hyperresponsiveness. However, the exact conditions for the development of the inflammatory reaction during the LAR remain to be specified. Since monokines play a key role in inflammatory processes, particularly in the lung, the production of tumor necrosis factor-alpha (TNF-alpha), interleukin; 1-beta (IL-1-beta) and interleukin-6 (IL-6) by alveolar macrophages (AM), collected 18 to 20 hours after exposure to allergen, was evaluated in 15 allergic subjects with asthma submitted to a challenge test with Dermatophagoides pteronyssinus (N = 6) or with wheat flour (N = 9) and in three healthy subjects. After bronchial provocation test, four patients presented no bronchial response (group 1), and six patients, a single early reaction (group 2). In contrast, five patients developed successively an immediate plus a late response (group 3). The monokine production was compared to that from nine allergic subjects with asthma studied at baseline (group 0) and from 11 unchallenged healthy subjects (control subjects). Measurements of cytokines were evaluated for TNF-alpha and IL-1-beta by a specific immunoradiometric assay, whereas IL-6 levels were appreciated by the proliferation of 7TD1 cells. No detectable amounts of TNF-alpha, IL-1-beta, and IL-6 were in bronchial alveolar lavage fluid, even after a tenfold concentration. In contrast, a significant increase of TNF-alpha (10,642 +/- 3127 U/ml) and IL-6 (1250 +/- 427 U/ml) concentrations was noted in AM supernatants from patients exhibiting an LAR (group 3) compared to cells recovered from groups 2, 1, and 0 and to challenged or unchallenged control subjects (805 +/- 244, 995 +/- 521, 1269 +/- 524, 688 +/- 85, and 445 +/- 74 pg of TNF-alpha per milliliter, respectively; 190 +/- 64, 114 +/- 91, 242 +/- 95, 80 +/- 9, and 54 +/- 19 U/ml of IL-6 per milliliter, respectively). No modification of IL-1-beta contents could be detected between the different groups. A significant correlation was detected between concentrations of TNF and IL-6 (r = 0.92; p less than 0.001). These results demonstrate TNF-alpha and IL-6 secretion by AM consecutively to the development of LAR in allergic subjects with asthma, confirming that AMs are activated after allergen challenge.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1991

TNF alpha mRNA expression in allergic inflammation.

Using the technique of in situ hybridization, we have attempted to identify messenger RNA for tumour necrosis factor-alpha (TNF alpha) in cells infiltrating allergen-induced late phase reaction (LPR) of the skin and the nose of atopic subjects. We have also compared the number of TNF alpha mRNA positive cells in bronchoalveolar lavage (BAL) from atopic asthmatics and normal controls. Twenty-four hours after local allergen challenge, 12/14 skin biopsies and 9/10 nasal biopsies had positive hybridization signals for TNF alpha mRNA whereas only 4/14 and 2/10 biopsies were positive in the relevant diluent controls. Compared with diluent sites significantly increased numbers of cells expressing mRNA for TNF alpha were observed in the LPR of skin (P less than 0.004) and nose (P less than 0.006). All BAL from asthmatics (n = 10) and from normal volunteers (n = 10) had cells showing positive hybridization signals for TNF alpha mRNA but these were at increased frequency in asthmatics (P less than 0.001). These results suggest that TNF alpha may be an important cytokine in atopic allergic inflammation.

Adolescent↗

PubMed1990

Lymphocyte-mediated inhibition of platelet cytotoxic functions during Hymenoptera venom desensitization: characterization of a suppressive lymphokine.

Recently, it has been shown that platelets, through a receptor for the Fc fragment of IgE, could be specially triggered by venom allergens in hypersensitivity to hymenoptera, generating cytocidal mediators toward Schistosoma mansoni larvae, and oxygen metabolites measured by chemiluminescence. After rush immunotherapy, a depressed platelet response was demonstrated to be associated with the production of lymphokine(s). Here we report the characterization of a factor present in supernatants of antigen-stimulated T cells from patients after hymenoptera venom desensitization which is able to inhibit platelet cytotoxic functions in a dose-dependent manner. The optimal inhibition was observed with supernatants obtained after T lymphocyte stimulated with 10(-5) micrograms venom allergen/ml. Once specifically produced the platelet-suppressive effect of lymphocyte supernatants was not antigen specific. The producing T cell subpopulation was identified as CD8+. This lymphokine had an approximate molecular mass of 25 kDa and a pI of 4.8. It was heat and acid stable and sensitive to trypsin and proteinase K but not to neuraminidase. This platelet inhibitory activity was absorbed by platelet membrane suggesting its binding to a receptor. These properties were very similar to a previously described platelet activity suppressive lymphokine, suggesting the participation of this lymphokine in the mechanisms of rush desensitization.

Animals↗

PubMed1990

The abnormal in vitro response to aspirin of platelets from aspirin-sensitive asthmatics is inhibited after inhalation of nedocromil sodium but not of sodium cromoglycate.

1. Blood platelets from patients with aspirin-sensitive asthma (ASA) generated cytotoxic mediators in the presence of aspirin. This abnormal in vitro response to aspirin was abolished within 1 h after nedocromil sodium inhalation but not after sodium cromoglycate inhalation. 2. Platelets recovered this reactivity to aspirin by 12 hours after nedocromil sodium treatment of ASA-patients. 3. The in vitro reactivity to aspirin of ASA platelets isolated before inhalation was inhibited in the presence of serum isolated 15 and 60 min after nedocromil sodium inhalation.

Administration, Inhalation↗

PubMed1990

Short-term decrease of skin-test sensitivity after rush desensitization in Hymenoptera venom hypersensitivity.

Thirty-seven patients with a history of systemic anaphylactic stings were desensitized by the rush method. Patients were evaluated by skin testing twice, before and 6 weeks after desensitization. An additional control group of 10 patients, not yet desensitized, were tested for skin test technique reproducibility at 6-week intervals. Results were compared with IgE and IgG antibody levels, and with platelet reactivity towards specific Hymenoptera venom. Before desensitization, the maximum skin-test sensitivity was observed at 10(-5) micrograms venom/ml in 56% of patients and decreased to 10(-1) micrograms venom/ml after desensitization (48.6% of patients). Decrease of cutaneous tests was observed in 28/37 patients (75%) (P less than 0.001) and was not associated with significant variations of specific IgE or IgG antibody levels, but was correlated with the decrease of platelet reactivity (P less than 0.05). Conversely, variations of skin-test sensitivity in the control group was not significant.

Adolescent↗

PubMed1989

A circulating suppressive factor of platelet cytotoxic functions after rush immunotherapy in Hymenoptera venom hypersensitivity.

A receptor for the Fc fragment of IgE has been described on human blood platelets. This receptor mediated the IgE-dependent stimulation of platelets by the specific allergen in Hymenoptera venom (HV) hypersensitivity. This platelet reactivity was abolished after rush desensitization. To understand the mechanism of such a down-regulation, we studied the effects of sera recovered from patients treated by HV rush desensitization on platelets of untreated HV sensitive patients. The present data describe the presence of a circulating factor able to suppress, in a dose-dependent manner, platelet stimulation by the specific allergen. This circulating factor was not allergen specific, not depleted by IgE or IgG antibody immunoadsorption, and was found at higher concentrations in the sera of patients receiving monthly high dosages of HV (200 micrograms maintenance dose). The physicochemical characterization showed that this circulating factor had a m.w. of 20,000 to 25,000, an isoelectric point of 4.2, was heat and acid stable, and sensitive to trypsin, but not to neuraminidase. These characteristics were similar to a newly described lymphokine, platelet activity suppressive lymphokine, suggesting the intervention of such a lymphokine in HV rush desensitization.

Bee Venoms↗

PubMed1989

Nedocromil sodium inhibition of IgE-mediated activation of human mononuclear phagocytes and platelets from asthmatics.

The demonstration of a specific receptor for IgE on non-mast cell or basophil leucocytes, such as mononuclear phagocytes, eosinophils and platelets, suggests that these cells may participate directly in immunological disorders of allergy. In this study, inhibition by nedocromil sodium of IgE-dependent activation of human alveolar macrophages, blood monocytes and platelets was investigated. Nedocromil sodium produced an inhibition of IgE-mediated generation of cytotoxic molecules from monocytes and platelets together with a concomitant inhibition of their oxidative metabolism, measured by chemiluminescence. In addition, nedocromil sodium reduced the ability of alveolar macrophages to synthesise and release mediators, estimated by beta-glucuronidase activity. Furthermore, nedocromil sodium inhibited the abnormal response to aspirin of platelets from aspirin-sensitive asthmatics at therapeutic concentrations. These studies confirm that nedocromil sodium acts on a cell compartment other than the classical mast cell population in IgE-dependent allergy and asthma.

Animals↗

PubMed1989

Concomitant augmentation of CD4+ CD45R+ suppressor/inducer subset and diminution of CD4+ CDw29+ helper/inducer subset during rush hyposensitization in hymenoptera venom allergy.

A longitudinal study of patients undergoing rush hyposensitization by honey-bee or yellow jacket venom revealed significant changes of the immunophenotypes until the optimal dose was reached, and a progressive reversion to pre-treatment values in the following months. The activation markers CD23 on B cells and CD25 (IL-2 receptor) on T and B lymphocytes decreased. Although there was little variation of the major CD4 and CD8 lymphocyte populations, CD45R+ cells increased whilst CDw29+ lymphocytes diminished. This inverse variation was associated with a peak of CD4+ CD45R+ cells with concomitant decrease in CD4+ CDw29+ cells showing an inverse effect of the treatment on the reciprocal subsets of CD4 lymphocytes. This indicates a shift in the suppressor/inducer to helper/inducer cell ratio early during rush hyposensitization which may also suggest reversion into a less mature stage of CD4+ cells, associated with the transition from a highly allergen-reactive state to progressive unresponsiveness.

Adolescent↗

PubMed1989

[Pheochromocytoma revealed by pulmonary edema].

We report the case of a young patient of 37 presenting with two attacks of pulmonary oedema which revealed an underlying pheochromocytoma. The diagnosis was suggested by the raised level of vanyl-mandelic acid in the urine and the abdominal CT scan. After an adrenalectomy the outcome was satisfactory. Pheochromocytoma should be considered in the differential diagnosis of the acute respiratory distress syndrome in the adult linked to the action of the circulating catecholamines on the pulmonary capillaries.

Adrenal Gland Neoplasms↗

PubMed1989

[Pulmonary hemorrhagic syndromes. Clinical and diagnostic approach].

The diagnosis of pulmonary hemorrhage syndromes (PHS) rests on a body of clinical and paraclinical evidence found in all etiologic forms. Usually, the combination of hemoptysis, iron deficiency anemia, and roentgenologic infiltrates is easy to recognize; in more atypical cases, alveolar bleeding can be demonstrated by determination of the Golde score on bronchoalveolar lavage specimens. Whereas clinical features are nearly invariable, etiologies cover a broad spectrum including some glomerular diseases, idiopathic pulmonary hemosiderosis, connective tissue disorders, pulmonary conditions related to compromised immunity, airborne pulmonary aggressions, and some apparently primary vascular disorders. Regardless of the severity of clinical features at presentation, pulmonary hemorrhage syndromes are always a diagnostic and therapeutic emergency.

Bronchoalveolar Lavage Fluid↗

PubMed1988

Effect of disodium cromoglycate on inflammatory cells bearing the Fc epsilon receptor type II (Fc epsilon RII).

Disodium cromoglycate (DSCG) has well-established stabilizing properties on mast cells and basophils. However, the potential inhibitory effect of DSCG has been little demonstrated on the IgE stimulation of cell populations expressing epsilon receptors type II, (Fc epsilon RII), such as mononuclear phagocytes, eosinophils or platelets. Therefore, using various parameters of IgE-mediated triggering, we demonstrated the inhibitory role of DSCG on: (i) the release of neutrophil chemotactic factor by human alveolar macrophages, (ii) the oxygen metabolite-dependent chemiluminescence of human alveolar macrophages, rat peritonal macrophages, human eosinophils, human and rat platelets, and (iii) the beta-glucuronidase release and synthesis by human alveolar macrophages. The inhibition of IgE-dependent stimulation ranged from 60% to 80%, according to the cells and to the measured parameter. It could therefore be considered that the action of DSCG was not restricted to its effects on mast cells and basophils, but also on other cells expressing Fc epsilon R leading to a potential reduction of the physiopathological consequences of allergic asthma and, possibly, of the late phase reaction sometimes associated with the disease, insofar as these cells are involved.

Animals↗

PubMed1988

Inhibition by nedocromil sodium of IgE-mediated activation of human mononuclear phagocytes and platelets in allergy.

The demonstration of a specific receptor for IgE on nonmast cell or basophil leukocytes, such as mononuclear phagocytes, eosinophils, and platelets, suggests that these cells may participate directly in immunological disorders of allergy. Thus, a full understanding of the mode of action of antiallergic or antiasthma drugs must take into account their activity on these nonmast cell leukocytes. Consequently, inhibition by nedocromil sodium of IgE-dependent activation of human alveolar macrophages, blood monocytes and platelets, was investigated. This compound induced an inhibition of the IgE-mediated generation of cytotoxic molecules from monocytes and platelets, together with a concomitant inhibition of their oxidative metabolism, measured by chemiluminescence, and a reduction of the potential ability of alveolar macrophages to synthesize and release mediators, estimated by lysosomal beta-glucuronidase activity. These observations confirm the hypothesis that nedocromil sodium acts on a cell compartment other than the classical mast cell population, in IgE-dependent allergy and, more particularly, in asthma.

Airway Obstruction↗