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Biomedical subjects

H J Neijens

Publications and source records attributed to H J Neijens.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Respiratory syncytial virus infections and preventive options].

Respiratory syncytial virus (RSV) is the most prominent pathogen found in respiratory tract infections in children and the most important cause of bronchiolitis in the first two years of life. In the Netherlands approximately 2000 children are admitted each winter season. A serious course is mostly seen in children younger than 3 months, (ex-)prematures, children with bronchopulmonary dysplasia or congenital cardiac anomalies, children with cystic fibrosis younger then 2 years and children with impaired T cell immunity; such cases not rarely require intensive care. Treatment (fluid, nutrition, bronchodilator agents, corticosteroids, oxygen and ventilation) is usually symptomatic. Antiviral therapy is only indicated in immunodeficient patients. For prevention by passive immunization palivizumab was recently registered in the Netherlands, a monoclonal antibody against RSV that has to be administered intramuscularly from the start of the RSV season (15 mg per kg bodyweight once a month during five months). In a number of large-scale American multicenter studies both the number of hospital admissions related to RSV infection and the mean duration of hospital stay showed a statistically significant reduction in high-risk children who had been treated with palivizumab. Palivizumab appears to be indicated in children from the categories with an increased risk for serious RSV disease.

Antibodies, Monoclonal↗
PubMed2000

Dose-responses over time to inhaled fluticasone propionate treatment of exercise- and methacholine-induced bronchoconstriction in children with asthma.

When treating bronchial hyperresponsiveness to so-called direct and indirect stimuli, distinct pathophysiological mechanisms might require differences in dose and duration of inhaled corticosteroid therapy. To test this hypothesis in children with asthma, we investigated the time- and dose-dependent effects of 2 doses of fluticasone propionate (FP, 100 or 250 microg bid.) in improving exercise- (EIB) and methacholine-induced bronchoconstriction during 6 months of treatment, using a placebo-controlled parallel group study design. Thirty-seven children with asthma (aged 6 to 14 years; forced expired volume in 1 sec (FEV(1)) >/=70% predicted; EIB >/=20% fall in FEV(1) from baseline; no inhaled steroids during the past 4 months) participated in a double-blind, placebo-controlled, 3-arm parallel study. Children receiving placebo were re-randomized to active treatment after 6 weeks. Standardized dry air treadmill exercise testing (EIB expressed as %fall in FEV(1) from baseline) and methacholine challenge using a dosimetric technique (expressed as PD(20)) were performed repeatedly during the study. During FP-treatment, the severity of EIB decreased significantly as compared to placebo within 3 weeks, the geometric mean % fall in FEV(1) being reduced from 34.1% to 9.9% for 100 microg FP bid, and from 35.9% to 7.6% for 250 microg FP bid (P < 0.05). These reductions in EIB did not differ between the 2 doses and were sustained throughout the treatment period. PD(20) methacholine improved significantly during the first 6 weeks as compared to placebo (P < 0.04) and steadily increased with time in both treatment limbs (P = 0.04), the difference in improvement between doses (100 microg FP bid, 1.6 dose steps; 250 microg FP bid, 3.3 dose steps) approaching significance after 24 weeks (P = 0.06). We conclude that in childhood asthma, the protection afforded by inhaled fluticasone propionate against methacholine-induced bronchoconstriction is time- and dose-dependent, whereas protection against EIB is not. This suggests different modes of action of inhaled steroids in protecting against these pharmacological and physiological stimuli. This has to be taken into account when monitoring asthma treatment.

Administration, Inhalation↗
PubMed2000

Markers for early sensitization and inflammation in relation to clinical manifestations of atopic disease up to 2 years of age in 133 high-risk children.

BACKGROUND: The combination of genetic susceptibility and environmental factors induce allergic sensitization and subsequently local inflammation, resulting in atopic manifestations. OBJECTIVE: To examine whether immunological features reflecting sensitization (total and specific IgE levels, allergen-induced proliferative responses and skin tests) and markers of inflammation (plasma sE-selectin and blood eosinophils) are related to the clinical expression of atopy and whether they precede atopic disease in children up to 2 years of age. METHODS: The development of these markers during the first 2 years of life was studied prospectively in 133 newborns at high risk to develop atopic disease. RESULTS: The prevalence of atopic disease increased from 25% at 12 months to 32% at 24 months of age. The children with food allergy at 12 months, who all had atopic dermatitis (AD), turned out to have asthma-like disease in 40% and AD in 100% at the age of 24 months. Total IgE levels increased with time and from 12 months onward levels started to differ markedly between atopics and nonatopics. Food-specific IgE antibodies were significantly associated with AD (relative risk [RR] = 2.39), food (RR = 1.32) and upper-airway allergy (RR = 1.20), and house dust mite-specific IgE antibodies with upper-airway allergy (RR = 5.00). A positive skin test was significantly associated with AD (RR = 2.90) and food allergy (RR = 1.36). The inflammation markers investigated, were not related to the clinical expression or preceded atopic disease at 2 years of age in high-risk children. CONCLUSION: Positive skin tests and specific IgE to food or inhalant allergens were related to the clinical expression of different atopic diseases. The combination of AD and food allergy at 12 months reflected the strongest risk factor in this high risk cohort for the development of asthma-like disease at 24 months of age.

Allergens↗
PubMed2000

Influence of intranasal steroids during the grass pollen season on bronchial responsiveness in children and young adults with asthma and hay fever.

BACKGROUND: It has been reported that intranasal corticosteroids can influence bronchial hyperresponsiveness (BHR) in asthmatic subjects with seasonal rhinitis. The purpose of the present study was to evaluate the effect of intranasal fluticasone propionate and beclomethasone dipropionate on BHR and bronchial calibre (forced expiratory volume in one second, FEV(1)) in children and young adults with seasonal rhinitis and mild asthma during two consecutive grass pollen seasons. METHODS: In the first pollen season 25 patients aged 8-28 years were included in a double blind, placebo controlled study. The active treatment group used fluticasone aqueous spray 200 microgram once daily. In the second pollen season 72 patients aged 8-28 years participated in a double blind, placebo controlled study of a similar design to that of the previous year except that an additional treatment group of patients using beclomethasone 200 microg twice daily was included. FEV(1) was measured before and after three and six weeks of treatment; BHR to methacholine (PD(20)) was measured before and after six weeks of treatment. RESULTS: In the first season the mean (SD) logPD(20) of the patients decreased significantly both in the fluticasone group (from 2.43 (0.8) microgram to 1.86 (0.85) microgram) and in the placebo group (from 2.41 (0.42) microgram to 1.87 (0.78) microgram) without any intergroup difference in the change in logPD(20). In the second pollen season the mean logPD(20) in the fluticasone, beclomethasone, and placebo groups did not change significantly. CONCLUSIONS: Intranasal steroids did not influence BHR during two grass pollen seasons in children and young adults with seasonal rhinitis and mild asthma.

Administration, Intranasal↗
PubMed2000

Autoimmune lymphoproliferative syndrome (ALPS) in a child from consanguineous parents: a dominant or recessive disease?

Autoimmune lymphoproliferative syndrome (ALPS) is characterized by autoimmune features and lymphoproliferations and is generally caused by defective Fas-mediated apoptosis. This report describes a child with clinical features of ALPS without detectable Fas expression on freshly isolated blood leukocytes. Detection of FAS transcripts via real-time quantitative PCR made a severe transcriptional defect unlikely. Sequencing of the FAS gene revealed a 20-nucleotide duplication in the last exon affecting the cytoplasmic signaling domain. The patient was homozygous for this mutation, whereas the consanguineous parents and the siblings were heterozygous. The patient reported here is a human homologue of the Fas-null mouse, inasmuch as she carries an autosomal homozygous mutation in the FAS gene and she shows the severe and accelerated ALPS phenotype. The heterozygous family members did not have the ALPS phenotype, indicating that the disease-causing FAS mutation in this family is autosomal recessive.

Autoimmune Diseases↗
PubMed2000

Type 1-like immune response is found in children with respiratory syncytial virus infection regardless of clinical severity.

The immunological response of infants younger than six months to infection with respiratory syncytial virus (RSV) was studied in relation to clinical severity. IL-6 and IL-8 were found more frequently and at higher levels in the plasma samples of more severely ill patients and no significant differences were found in the levels of cytokines differentiating between Type 1 and Type 2 responses. Cellular infiltrates in nasopharyngeal washings consisted mainly of polymorphonuclear granulocytes and monocytes. Eosinophils, IgE positive cells and tryptase positive cells were found sporadically. Analyses of RSV stimulated T cell cultures established from peripheral blood mononuclear cells, for intracellular and secreted cytokines showed that, irrespective of clinical severity, the responses were dominated by the production of IFN-gamma, and that only low levels of IL-4 and IL-10 were detectable. Collectively these data do not indicate an association between clinical severity and a Type 2-like T cell response.

Cytokines↗
PubMed1998

Ciprofloxacin in preterm neonates: case report and review of the literature.

UNLABELLED: We report the use of ciprofloxacin in a preterm boy suffering from an invasive multiple resistant Enterobacter cloacae infection. The treatment was effective, after other antibiotics failed, and no adverse effects were observed during 3 years of follow up. The literature on compassionate ciprofloxacin use in 28 preterm or low birth weight infants is reviewed. Ciprofloxacin has been used to treat neonatal pneumonia, meningitis and septicaemia and was effective in all cases. Side-effects were limited to dental dyschromia and one observation on the emergence of resistance. Pharmacokinetics of ciprofloxacin were studied in seven preterm infants; iv doses ranging from 4 to 40 mg/kg per day revealed adequate serum peak concentrations (0.98-5.7 mg/l) but trough-peak ratios were high (median ratio: 32%), suggesting slower elimination in preterm infants as compared to older children. CSF concentrations were 0.10-1.45 mg/l. CONCLUSION: Ciprofloxacin treatment of preterm or low birth weight infants may be effective and without severe side effects in infections with bacteria resistant to other antibiotics

Anti-Infective Agents↗
PubMed1998

Soluble E-selectin, other markers of inflammation and disease severity in children with atopic dermatitis.

E-selectin, P-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are membrane-bound adhesion molecules which mediate the attachment of leucocytes to endothelial cells. These molecules are preferentially expressed on activated endothelium. The soluble forms of these molecules (sE-selectin, sP-selectin, sICAM-1 and sVCAM-1) are present in the circulation as a result of shedding. Some of the soluble adhesion molecules have been thought to reflect disease activity in atopic dermatitis (AD). To evaluate their potential to reflect disease activity in AD, we correlated their plasma concentration with clinical severity measured by objective SCORAD (SCORing Atopic Dermatitis). Furthermore, levels of total IgE, specific IgE, and eosinophil cationic protein (ECP) were determined. SCORAD and sE-selectin levels were significantly increased in children with specific IgE for both food and inhalation allergens (P < 0.05). ECP consistently showed an increase with the scores of SCORAD, but no statistical significance was reached. Disease activity was significantly correlated with the plasma levels of sE-selectin (rs = 0.6, P < 0.0005) but not with sP-selectin, sICAM-1 and sVCAM-1. This agrees with recent studies performed in adults with AD, and supports the potential of sE-selection as a parameter for monitoring disease activity in young children with AD.

Allergens↗
PubMed1998

CD4+ cells proliferate after peanut-extract-specific and CD8+ cells proliferate after polyclonal stimulation of PBMC of children with atopic dermatitis.

BACKGROUND: Few studies describe in vitro food-allergen induced proliferative responses and cytokine production of PBMC of children with atopic dermatitis. This is especially true for peanut-allergen. OBJECTIVES: To analyse the specificity of the T cell in proliferative responses, in children with atopic dermatitis with or without peanut allergy and healthy age-matched children. METHODS: Proliferative responses were measured by [3H]-thymidine incorporation and by expression of the intracellular Ki67-antigen using flow cytometry after antigen-specific stimulation of PBMC with peanut-extract (day 7) or polyclonal stimulation with Phorbol-12myristate-13acetate and Ca-ionophore (day 3). Cytokine mRNA (Interferon-gamma (IFNgamma), IL-4) was detected by semiquantitative RT-PCR. Cytokine production (IL-4, IFNgamma) was measured by ELISA. RESULTS: Peanut-extract induced proliferative responses of PBMC from children with atopic dermatitis and peanut allergy (AD+PA+) were significantly higher as compared with the other groups studied. Ki67-antigen double staining revealed that 80-100% of the proliferating cells were CD4+. These proliferative responses correlated significantly with the increase in IL-4 mRNA expression after peanut-extract specific stimulation. After polyclonal stimulation, however, CD8+ cells preferentially proliferated. The degree of proliferation after polyclonal stimulation correlated inversely with the ratio of IL-4/IFNgamma production. CONCLUSIONS: The principal responding population of T cells in proliferative responses is different after peanut-extract specific and polyclonal stimulation of PBMC from AD+PA+ patients. Furthermore, we found indirect evidence that the PBMC fraction of AD+PA+ children contains increased frequencies of peanut-specific T helper-2 cells.

Antibodies, Monoclonal↗
PubMed1998

Levels of soluble intercellular adhesion molecule-1, soluble E-selectin, tumor necrosis factor-alpha, and soluble tumor necrosis factor receptor p55 and p75 in atopic children.

During inflammation, membrane expression of adhesion molecules and tumor necrosis factor (TNF)-receptors (TNF-R) are increased, and soluble forms of these molecules are released. This study analyzed plasma levels of sICAM-1 and sE-selectin as well as TNF-alpha, sTNF-R55, and sTNF-R75 in nonallergic (NAA) and allergic asthma patients (AA), atopic dermatitis patients (AD), and healthy children (HC) by ELISA. Plasma levels of sICAM-1, sE-selectin, and sTNF-R, but not TNF-alpha, were detectable, but were not significantly different between the patient groups and healthy children. In the AA group, a significant correlation (rs = 0.78, P = 0.008) was found between sICAM-1 and sE-selectin levels. Furthermore, a significant correlation was found between sTNF-R55 and sTNF-R75 levels in the AA group (rs = 0.70, P = 0.025) and in the AD group (rs = 0.69, P = 0.027). In AD patients, a significant correlation was observed between sE-selectin and the disease severity, as measured by the SCORAD index (rs = 0.73, P = 0.038). Our data demonstrate that plasma levels of sICAM-1, sE-selectin, TNF-alpha, sTNF-R55, and sTNF-R75 were not different between atopic and nonatopic children during a stable phase of the disease. In AD patients, levels of sE-selectin seemed to be related to clinical severity of the disease.

Age Factors↗
PubMed1997

[Indications for influenza vaccination in children with lung disorders. Dutch Association for Pediatric Medicine].

The Dutch Association for Paediatric Medicine has formulated guidelines regarding influenza vaccination of children with pulmonary disease. Influenza virus is the most frequent cause of airway infections in humans over two years of age. It may lead to serious morbidity in children with pulmonary disease: exacerbations, (transient) disturbances in pulmonary function, and symptoms lasting weeks, but mortality is probably very low. The effects of influenza vaccination of children with pulmonary disease are similar to those in normal healthy children. A positive long-term effect on the asthma has never been demonstrated. It is advised that children with moderate to severe asthma who require treatment to be vaccinated against influenza every year. If the first vaccination ever occurs before the age of six years, it should be followed by a booster vaccination after four weeks. In both instances, a full vaccination dose should be administered.

Adolescent↗
PubMed1997

Respiratory syncytial virus specific serum antibodies in infants under six months of age: limited serological response upon infection.

The decline of maternal respiratory syncytial virus (RSV) specific serum antibodies was studied in 45 children during the first 6 months of life, using a virus neutralization assay and competition ELISAs measuring fusion protein and glycoprotein specific antibodies. In all children RSV neutralizing antibodies were demonstrated at birth, with titers ranging from 33 to 1382. The calculated mean half life of these antibodies was 26 days. Furthermore, in a group of 38 children with suspected RSV infection, all younger than 6 months of age on admission, the diagnostic value of serological assays was evaluated. In 32 children RSV infection was confirmed by virus isolation, direct immune fluorescence and RT-PCR. In 7 patients of this group a significant titer rise in virus neutralization assay was demonstrated. Six additional RSV infected children could be identified by showing the presence of RSV-specific IgM or IgA serum antibodies or by showing an increase in fusion protein or glycoprotein specific antibodies. All serological tests together identified 13 (41%) of the 32 RSV infected patients. It is concluded that in children of this age group, which represent the majority of patients hospitalized with RSV infections, serological assays not only have a limited diagnostic value but are of limited value for sero-epidemiological studies.

Antibodies, Viral↗
PubMed1997

T cell subsets and cytokines in allergic and non-allergic children. I. Analysis of IL-4, IFN-gamma and IL-13 mRNA expression and protein production.

Interleukin 4 (IL-4) and IL-13 are key cytokines inducing switching to immunoglobulin E (IgE), whereas interferon gamma (IFN-gamma) acts inhibitory on this process. We analysed whether differences existed in IL-4, IFN-gamma and IL-13 mRNA expression and protein production between T cells of children with allergic and non-allergic asthma, atopic dermatitis and health control children. IL-4 mRNA expression was increased in stimulated T cells of children with allergic asthma and atopic dermatitis, but not in those with non-allergic asthma as compared with healthy controls. Thus the increase in IL-4 expression can be considered as an underlying mechanism of the allergic disease process and not so much of the asthmatic state of the children. In unstimulated T cells of children with atopic dermatitis increased IFN-gamma mRNA expression with a reduced IFN-gamma protein production was found, indicating a post-translational defect in IFN-gamma. Differences in IL-13 expression between the groups were not significant, but IL-13 was significantly correlated with the height of the radio-allergo-sorbent test (RAST) class and with the severity scoring of atopic dermatitis (SCORAD) index. This indicates the clinical relevance of IL-13 for the degree of allergen-specific sensitization and severity of atopic dermatitis. In conclusion, the imbalance in IL-4 and IFN-gamma secretion in patients with atopic dermatitis may reflect general T cell activation in the presence of an intrinsic defect of IFN-gamma secretion.

Asthma↗
PubMed1997

T cells subsets and cytokines in allergic and non-allergic children. II. Analysis and IL-5 and IL-10 mRNA expression and protein production.

Interleukin 5 (IL-5) has an enhancing effect on IL-4 induced immunoglobulin E (IgE) synthesis. Furthermore, IL-5 plays an important role in the differentiation, recruitment, activation and survival of eosinophils. IL-10 has a downmodulating effect on interferon gamma (IFN-gamma) production and can exert strong anti-inflammatory activities. Therefore, we analysed whether differences were present in IL-5 and IL-10 mRNA expression and protein production between T cells of children with allergic and non-allergic asthma, atopic dermatitis and healthy control children. We demonstrated significant increases in IL-5 mRNA expression and protein production in different T cell fractions of children with allergic and non-allergic asthma and children with atopic dermatitis as compared to healthy controls. This indicates that IL-5 is not only involved in allergy, but also plays a role in the inflammatory process of non-allergic asthma. Interestingly, IL-10 mRNA expression by purified T cells of children with allergic and non-allergic asthma and children with atopic dermatitis was strongly decreased as compared with that of healthy controls. In the peripheral blood mononuclear cell (PBMC) fraction, IL-10 mRNA expression was comparable between the four groups. We hypothesize that this decreased T cell derived IL-10 expression results in a lack of immunosuppression of the inflammatory process in these diseases. However, a role of monocyte derived IL-10 cannot be ruled out.

Asthma↗
PubMed1997

Immunophenotyping of blood lymphocytes in childhood. Reference values for lymphocyte subpopulations.

OBJECTIVE: Immunophenotyping of blood lymphocytes is an important tool in the diagnosis of hematologic and immunologic disorders. Because of maturation and expansion of the immune system in the first years of life, the relative and the absolute size of lymphocyte subpopulations vary during childhood. Therefore we wished to obtain reference values for the relative and the absolute size of all relevant blood lymphocyte subpopulations in childhood. STUDY DESIGN: We used the lysed whole blood method for analysis of lymphocyte subpopulations in 429 blood samples from neonates (n = 20), healthy children (n = 358), and adults (n = 51). The following age groups were used: 1 week to 2 months (n = 13), 2 to 5 months (n = 46), 5 to 9 months (n = 105), 9 to 15 months (n = 70), 15 to 24 months (n = 33), 2 to 5 years (n = 33), 5 to 10 years (n = 35), and 10 to 16 years (n = 23). RESULTS: Our results show that the absolute number of CD19+ B lymphocytes increases twofold immediately after birth, remains stable until 2 years of age, and subsequently gradually decreases 6.5-fold from 2 years to adult age. The CD3+ T lymphocytes increase 1.5-fold immediately after birth and decrease threefold from 2 years to adult age. The absolute size of the CD3+/CD4+ T-lymphocyte subpopulation follows the same pattern as the total CD3+ population, but the CD3+/CD8+ T lymphocytes remain stable from birth up to 2 years of age, followed by a gradual threefold decrease toward adult levels. In contrast to B and T lymphocytes, the absolute number of natural killer cells decreases almost threefold in the first 2 months of life and remains stable thereafter. Our study also showed that changes in the absolute size of lymphocyte subpopulations are not always consistent with changes in their relative size. This demonstrates that the relative counts of lymphocyte subsets do not reflect their actual size and are therefore of limited value. CONCLUSION: On the basis of this study we strongly recommend that immunophenotyping of blood lymphocytes for the diagnosis of hematologic and immunologic disorders be based on the absolute rather than on the relative size of lymphocyte subpopulations. Our data can be used as age-matched reference values for blood lymphocyte immunophenotyping.

Adolescent↗
PubMed1997

Mutations in the granulocyte colony-stimulating factor receptor gene in patients with severe congenital neutropenia.

Previously, nonsense mutations in the gene encoding the granulocyte colony-stimulating factor receptor (G-CSF-R) have been described in three patients with severe congenital neutropenia (SCN) (Proc Natl Acad Sci USA 1994; 91: 4480; New Engl J Med 1995; 333: 487). The mutations resulted in the truncation of the carboxy-terminal region of G-CSF-R essential for transduction of maturation signals. Two of these patients developed acute myeloblastic leukemia (AML). We present the results of a search among 20 additional cases of congenital neutropenia (CN) and SCN for the presence of mutations in the cytoplasmic domain of G-CSF-R. This series includes patients with familial and nonfamilial forms of CN and SCN. Mutations in the G-CSF-R gene were found in two new SCN cases. These mutations were nonsense mutations, located in the same cytoplasmic region of G-CSF-R as those found earlier, resulting in the truncation of the C-terminus. Both of these patients developed AML. None of the other patients showed clinical symptoms or cytogenetic features indicative of AML or progression to leukemia. The analysis in this extended series of patients thus has revealed five SCN cases with G-CSF-R mutations, four of whom developed AML. These results add support to the notion that mutations in the G-CSF-R gene, affecting the maturation signaling function of the receptor, define a distinct subgroup of SCN with increased susceptibilty to AML.

Adolescent↗