11 results on '"Mertens AV"'
Search Results
2. Evolution of lymphocyte transformation to wasp venom antigen during immunotherapy for wasp venom anaphylaxis
- Author
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Stevens, Wj, Didier EBO, Clerck, Ls, Bridts, Ch, Gendt, Cm, and Mertens, Av
3. Evolution of lymphocyte transformation to wasp venom antigen during immunotherapy for wasp venom anaphylaxis.
- Author
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Stevens WJ, Ebo DG, De Clerck LS, Bridts CH, De Gendt CM, and Mertens AV
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- Adolescent, Adult, Aged, Antigens immunology, Antigens pharmacology, Female, Humans, Immunoglobulin E blood, Male, Middle Aged, Time Factors, Anaphylaxis therapy, Immunotherapy, Lymphocyte Activation immunology, Wasp Venoms immunology, Wasp Venoms therapeutic use
- Abstract
Background: Venom immunotherapy (VIT) has proven to be safe and effective in wasp venom anaphylaxis. However, there are no good parameters to indicate when to stop venom immunotherapy., Objective: To evaluate the relationship of the lymphocyte transformation test (LTT) to history and specific IgE determination, and to address the time course of lymphocyte transformation responses to wasp (Vespula) venom during VIT and the possible utility of LTT to determine the duration of therapy., Methods: Peripheral blood mononuclear cells (PBMCs) of 18 individuals with a history of wasp sting anaphylaxis and a positive serum-venom-specific IgE, were stimulated with wasp venom before immunotherapy, at the end of a 5-day semi-rush immunotherapy and at 24 months during venom immunotherapy. Results, expressed as stimulation index (SI), were compared with the SI in seven asymptomatic stung controls., Results: In controls the median (minimum-maximum) of the SI were 2.39 (0.52-3.39) before therapy and 2.39 (1.12-6.02) when repeated after 24 months. For patients the median (minimum-maximum) of the SI were 10.13 (1.19-44.88) before immunotherapy (d0), 2.73 (0.67-12.03) at the end of the build-up immunotherapy (d5) and 4.21 (0.88-14.66) at the end of 24 months of maintenance therapy (m24). The proliferation responses in vespid-allergic patients were significantly higher than in stung controls (P = 0.006) but only 13/18 patients showed a positive LTT result before the start of immunotherapy (sensitivity of the LTT 72%). When the LTT was repeated after a 5 day build-up hyposensitization course the SI significantly dropped as compared to the pre-treatment levels (P = 0.002). The SI of the LTT was negative in eight out of 18 patients at 24 months and the median values were significantly lower than before therapy (P = 0.03)., Conclusions: Although, in the absence of sting challenge data it is not possible to draw conclusions about the predictive value of the LTT, our data may suggest that abolition of the LTT during VIT might indicate clinical insensitivity. Further studies, comparing the results of sting challenges, with the results of lymphocyte transformation will be necessary in order to evaluate the role of LTT in stopping immunotherapy.
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- 1998
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4. Relapse of Wegener's granulomatosis presenting as a destructive urethritis and penile ulceration.
- Author
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Ebo DG, Mertens AV, De Clerck LS, Gentens P, and Daelemans R
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- Fatal Outcome, Granulomatosis with Polyangiitis complications, Humans, Male, Middle Aged, Recurrence, Granulomatosis with Polyangiitis diagnosis, Penile Diseases etiology, Ulcer etiology, Urethritis etiology
- Abstract
Non-renal urogenital Wegener's granulomatosis is considered to be rare. Generally it occurs in a setting of concurrent multisystem disease or in patients already diagnosed as having Wegener's granulomatosis. We present a patient with a penile ulceration related to a destructive urethritis, as presentation of a relapse of Wegener's granulomatosis.
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- 1998
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5. Actin polymerisation in neutrophils of rheumatoid arthritis patients in relation to treatment with non-steroidal anti-inflammatory drugs.
- Author
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De Clerck LS, Mertens AV, De Gendt CM, Bridts CH, and Stevens WJ
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- Actins blood, Arthritis, Rheumatoid drug therapy, Arthritis, Rheumatoid metabolism, Biopolymers blood, Drug Synergism, Humans, N-Formylmethionine Leucyl-Phenylalanine pharmacology, Neutrophils drug effects, Sulfasalazine pharmacology, Actins drug effects, Actins metabolism, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Arthritis, Rheumatoid blood, Neutrophils chemistry
- Abstract
There is evidence that neutrophil functions such as chemotaxis and oxygen radical formation are disturbed in rheumatoid arthritis (RA). Medication might also influence these functions. Cyclic formation and depolymerisation of actin microfilaments is crucial in cell motility, but this phenomenon has not been studied in RA. The aim of this study was to investigate basal and dynamic (formyl-methionyl-leucyl-phenylalanine (fMLP)-induced) neutrophil actin polymerisation in ten RA patients (a) during therapy with non-steroidal anti-inflammatory drugs (NSAIDS) and (b) after stopping NSAIDS> The results were compared with those of ten age-matched controls. Basal F-actin content in RA patients with NSAIDS was significantly lower than in RA patients without NSAIDS and controls: 35.5 (25.0-49.0), 50.5 (27.0-75.0) and 52.5 (32.0-85.0), respectively. Conversely, upon stimulation with fMLP, the actin polymerisation curve of RA patients with NSAIDS was higher than for RA patients without NSAIDS and controls. These results suggest that, in RA, the effects orf NSAIDS on neutrophil functions might be related to changes in the actin polymerisation-depolymerisation cycle.
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- 1997
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6. Influence of hyposensitization on soluble interleukin-2 receptor, eosinophil cationic protein, in vitro lymphocyte proliferation, in vitro lymphocyte adhesion, and lymphocyte membrane markers in childhood asthma.
- Author
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Moens MM, Van Bever HP, Stevens WJ, Mertens AV, Bridts CH, and De Clerck LS
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- Adolescent, Asthma physiopathology, Asthma therapy, Cell Adhesion, Child, Child, Preschool, Endothelium, Vascular cytology, Eosinophil Granule Proteins, Flow Cytometry, Humans, Integrin beta1, Integrins analysis, Lymphocyte Activation, Lymphocyte Function-Associated Antigen-1 analysis, Lymphocytes physiology, Antigens, CD analysis, Asthma immunology, Blood Proteins analysis, Desensitization, Immunologic, Lymphocytes immunology, Receptors, Interleukin-2 analysis, Ribonucleases
- Abstract
Soluble interleukin-2 receptor (sIL-2R), eosinophil cationic protein (ECP), the lymphoproliferative response to house-dust mite (HDM), adhesion to human umbilical vein endothelial cells (HUVEC), and lymphocyte membrane markers were studied in three groups of children: healthy children, asthmatic children without hyposensitization (HS), and asthmatic children with HS. HS was associated with significantly lower numbers of peripheral blood eosinophils (PBE) and lower sIL-2R serum levels and with a tendency to lower ECP serum levels and lymphoproliferative response to HDM. There were no changes in the T-lymphocyte phenotypic markers CD4 and CD8 among the three groups. The interleukin-2 receptor (IL-2R, CD25) on HDM-stimulated T lymphocytes increased over unstimulated T lymphocytes in the three groups. The CD25 expression was higher on HDM-stimulated lymphocytes in both asthmatic groups than in healthy children. Adhesion of lymphocytes on HUVEC increased significantly after HDM stimulation in asthmatic children without HS, whereas no change was observed in the two other groups. However, there was no change in the expression of adhesion molecules CD29 and CD11a on lymphocytes in either of the groups. This study provides further evidence that HS can modify lymphocyte and eosinophil functions.
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- 1994
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7. Lymphocyte activation status, expression of adhesion molecules and adhesion to human endothelium in rheumatoid arthritis--relationship to disease activity.
- Author
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Mertens AV, de Clerck LS, Moens MM, Bridts CH, and Stevens WJ
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- Adult, Aged, Aged, 80 and over, CD4-CD8 Ratio, Cell Adhesion, Cells, Cultured, Flow Cytometry, Humans, Immunophenotyping, Middle Aged, Receptors, Interleukin-2 analysis, Arthritis, Rheumatoid immunology, CD4-Positive T-Lymphocytes immunology, Cell Adhesion Molecules biosynthesis, Endothelium, Vascular immunology, Lymphocyte Activation immunology, T-Lymphocytes, Regulatory immunology
- Abstract
The synovial tissue of patients with rheumatoid arthritis (RA) is characterized by infiltration with inflammatory cells, mainly memory helper cells (CD4+CD29+). An important initiating step in tissue infiltration is the adhesion of peripheral blood lymphocytes to the vascular endothelium. Therefore, we studied lymphocyte-endothelium adhesion in 40 RA patients and in 19 controls by a sensitive fluorimetric assay, using human umbilical vascular endothelial cells. Furthermore, expression of adhesion molecules VLA (CD29) and LFA-1 (CD11a) on CD4+ and CD8+ T cells was determined. In order to evaluate the activation state of lymphocytes, the soluble interleukin-2 receptor (sIL2R) was measured. The relationship to disease activity was evaluated using the Ritchie articular index. RA patients had a higher percentage of CD4+ cells (p < 0.005) and a lower percentage of CD8+ cells (p < 0.001) than controls did. The CD4+CD29+/CD4+CD29- ratio and the CD8+CD29+/CD8+CD29- ratio were increased in patients with active RA (p < 0.01 and p < 0.05, respectively) and in patients with inactive disease (p = 0.09 and p < 0.005, respectively) compared with controls. LFA-1 (CD11a) was present on almost all T lymphocytes and its density did not differ between patients and controls. Serum levels of sIL2R were significantly higher in both patient groups compared with controls (p < 0.0005); patients with active disease showed significantly higher levels than patients with inactive disease (p < 0.05). Lymphocyte-endothelium adhesion was not increased in patients, although the expression of the adhesion molecule CD29 on T lymphocytes of RA patients was higher.(ABSTRACT TRUNCATED AT 250 WORDS)
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- 1994
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8. Study of eosinophil-endothelial adhesion, production of oxygen radicals and release of eosinophil cationic protein by peripheral blood eosinophils of patients with rheumatoid arthritis.
- Author
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Mertens AV, De Clerck LS, Moens MM, Bridts CH, and Stevens WJ
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- Adult, Aged, Aged, 80 and over, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Arthritis, Rheumatoid drug therapy, Autoimmune Diseases drug therapy, Cell Adhesion, Cells, Cultured, Endothelium, Vascular metabolism, Eosinophil Granule Proteins, Eosinophils drug effects, Eosinophils metabolism, Female, Humans, Inflammation, Interleukin-1 pharmacology, Macrophage-1 Antigen biosynthesis, Male, Middle Aged, N-Formylmethionine Leucyl-Phenylalanine pharmacology, Tetradecanoylphorbol Acetate pharmacology, Umbilical Cord, Arthritis, Rheumatoid blood, Autoimmune Diseases blood, Blood Proteins metabolism, Endothelium, Vascular pathology, Eosinophils pathology, Reactive Oxygen Species metabolism, Ribonucleases
- Abstract
Beside lymphocytes and neutrophils, eosinophils are also involved in the inflammatory reaction in rheumatoid arthritis (RA). In this study, adhesion characteristics of peripheral blood eosinophils were studied in 43 RA patients and 19 controls, together with the expression of the beta2-integrin Mac-1 (CD11b/CD18). In addition, the production of oxygen radicals of isolated peripheral blood eosinophils and serum levels of eosinophil cationic protein (ECP) were measured in order to evaluate eosinophil activation. Adhesion of eosinophils to unstimulated human vascular endothelium was significantly higher in RA patients with active disease (n = 4) compared with controls (n = 14) (P < 0.005) and compared with patients with less active RA (n = 16) (P < 0.05). Nevertheless, the expression of the adhesion molecule Mac-1 (CD11b/CD18) was not increased in RA patients. ECP levels were higher in RA patients with active disease (P < 0.01). Release of oxygen radicals in response to phorbol stimulation was significantly elevated in active RA compared with controls (P < 0.05) and to less active RA (P < 0.05). We conclude that eosinophils of RA patients, especially those with active disease, are activated or at least primed and are involved in the inflammatory process in RA, analogous to the inflammation in asthma. The higher adhesion to inflamed endothelium is indicative of a higher infiltration in the joints, where tissue damage can be caused by toxic oxygen radicals and by granular proteins, such as ECP.
- Published
- 1993
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9. Lymphocyte transformation test with house dust mite (Dermatophagoides pteronyssinus) in normal children, asthmatic children and asthmatic children receiving hyposensitization.
- Author
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van Bever HP, Bridts CH, Moens MM, De Rijck TE, Mertens AV, De Clerck LS, and Stevens WJ
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- Allergens immunology, Animals, Antigens, Dermatophagoides, Asthma therapy, Cells, Cultured, Child, Humans, Immunoglobulin E immunology, Immunoglobulin G immunology, Interleukin-2 immunology, Phytohemagglutinins immunology, Asthma diagnosis, Desensitization, Immunologic, Glycoproteins immunology, Lymphocyte Activation, Mites immunology
- Abstract
In the first part of this study the proliferative response of lymphocytes (lymphocyte transformation test) to house dust mite (HDM) stimulation in cultures was studied in normal children (n = 16), asthmatic children who never received hyposensitization (HS) (n = 50) and asthmatic children receiving HS with HDM for at least 6 months (n = 20). The results are expressed as disintegrations per minute (d.p.m.) and as stimulation index (SI = d.p.m. in the presence of the allergen/d.p.m. in the control culture). A positive SI (> 2) was found in 54% of the asthmatic children who never received HS, in 30% of the asthmatics receiving HS and in none of the normal children. Furthermore, between asthmatics with and without HS, the SI was not statistically different, although asthmatics without HS tended to have a higher SI (median value: 2.13 vs 1.38) (P = 0.10). In a second series of experiments the effect of adding interleukin-2 (IL-2) to the lymphocyte cell culture was studied in asthmatic children with and without HS. Interleukin-2 induced an additional stimulatory effect on the lymphoproliferative response to HDM and to phytohaemagglutinin in patients who never received HS, but had no effect in patients receiving HS. We conclude that HS treatment seems to have an inhibiting effect upon this proliferative response, not only inhibiting the degree of the allergen-induced lymphocyte proliferation, but also inhibiting the sensitivity of proliferating lymphocytes for IL-2. These inhibiting effects upon lymphocytic activation could be responsible for the anti-inflammatory effects (i.e. suppression of the late asthmatic reaction) of HS.
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- 1993
- Full Text
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10. Effect of a bronchial provocation test with house-dust mite on blood eosinophilia, eosinophil cationic protein, soluble interleukin-2 receptor, and interleukin-6 in asthmatic children.
- Author
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Van Bever HP, Moens MM, Bridts CH, De Clerck LS, Mertens AV, Bosmans E, and Stevens WJ
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- Adolescent, Allergens, Animals, Asthma diagnosis, Asthma immunology, Asthma physiopathology, Child, Eosinophil Granule Proteins, Forced Expiratory Volume, Histamine, Humans, Hypersensitivity, Delayed blood, Hypersensitivity, Delayed diagnosis, Hypersensitivity, Delayed immunology, Hypersensitivity, Delayed physiopathology, Hypersensitivity, Immediate blood, Hypersensitivity, Immediate diagnosis, Hypersensitivity, Immediate immunology, Hypersensitivity, Immediate physiopathology, Asthma blood, Blood Proteins analysis, Bronchial Provocation Tests, Dust, Eosinophils, Interleukin-6 analysis, Mites, Receptors, Interleukin-2 analysis, Ribonucleases
- Abstract
Eighteen children with perennial asthma and allergy to house-dust mite (HDM) underwent a bronchial challenge with HDM. Before and 24 h after the test, a venous blood sample was taken to determine levels of eosinophils, eosinophil cationic protein (ECP), soluble interleukin-2 receptor (IL-2R), and interleukin-6 (IL-6). A histamine challenge was performed before and 24 h after the HDM challenge. All subjects showed an immediate asthmatic reaction (IAR). A definite late asthmatic reaction (LAR) was observed in 15 children, a probable LAR in two, and no LAR in one. Because of persistent bronchial obstruction (FEV1 < 70%), eight children were unable to perform a histamine challenge 24 h after the allergen challenge. These were the children with the lowest prechallenge provocation dose (PD20) of histamine. In the other 10 children, the mean PD20 histamine decreased after the HDM challenge (mean PD20 before was 0.56 mg/ml; after challenge it was 0.14 mg/ml; P = 0.007). After the HDM challenge, an increase was detected in the mean values of blood eosinophils (mean before was 446/mm3; mean after was 733/mm3; P = 0.002), ECP (mean before was 26.3 micrograms/l; mean after was 34.3 micrograms/l; P < 0.040), and IL-2R (mean before was 116.35 U/ml; mean after was 128.52 U/ml; P < 0.040). On the other hand, IL-6 remained unchanged after the HDM challenge (mean before was 9.47 pg/l; mean after was 9.70 pg/l; P = 0.360).(ABSTRACT TRUNCATED AT 250 WORDS)
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- 1993
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11. Are hypodense eosinophils in children activated or immature?
- Author
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Moens MM, Mertens AV, De Clerck LS, Van Bever HP, Bridts CH, and Stevens WJ
- Subjects
- Adult, Age Factors, Asthma blood, Biomarkers, Blood Proteins analysis, Cell Differentiation, Child, Eosinophil Granule Proteins, Eosinophils metabolism, Humans, Interleukin-6 blood, Lymphocyte Activation, Receptors, Interleukin-2 analysis, Asthma immunology, Eosinophils cytology, Ribonucleases
- Abstract
In patients with allergic asthma and rhinitis high numbers of hypodense eosinophils (HE) have been demonstrated. In a previous study we reported that asthmatic and healthy children had more HE than their adult counterparts. We assumed that this might, in part, be due to the presence of immature eosinophils in children. To distinguish between immature and activated eosinophils, determination of eosinophil cationic protein (ECP) might be interesting as it is known that high serum levels of ECP are associated with increased activation of eosinophils. In this study we determined the levels of ECP in serum in asthmatic and healthy children and adults trying to distinguish activated from immature eosinophils. We found that ECP levels were not increased in children (healthy and asthmatic) compared to adults (healthy and asthmatic). This supports the hypothesis that increased numbers of HE in childhood are, at least in part, immature eosinophils. Nevertheless, we could confirm that inflammation was present in children because soluble interleukin-2-receptor (sIL-2R), a marker of lymphocyte activation, was higher in asthmatic children as compared to healthy children. IL-6, a marker of macrophage/monocyte activation, was not different in the different patient groups. We conclude that although signs of inflammation are present in childhood asthma, the increased numbers of HE in children are in part due to the presence of immature eosinophils.
- Published
- 1993
- Full Text
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