Henk F. Kauffman

No effects of probiotics on atopic dermatitis in infancy: a randomized placebo‐controlled trial

Background Studies have been performed suggesting that administration of probiotics may have therapeutic and/or preventive benefits in the development of sensitization and atopic disease, particularly in infants with atopic dermatitis (AD).

Antileukoprotease: An Endogenous Protein in the Innate Mucosal Defense against Fungi

Previous studies have suggested that endogenous protease inhibitors may participate in the mucosal host defense. Antileukoprotease (ALP) is an important protease inhibitor found on various mucosal surfaces, including those of the respiratory and genital tracts. This study reports on the antimicrobial activity of recombinant (r) ALP toward the human fungal pathogens Aspergillus fumigatus and Candida albicans. rALP expressed pronounced fungicidal activity toward metabolically active A. fumigatus conidia and C. albicans yeast cells; however, metabolically quiescent A. fumigatus conidia were totally resistant. In contrast with the protease inhibitory activity of rALP, the fungicidal activity was localized primarily in the NH2-terminal domain. On a molar base, the fungicidal activity of rALP was comparable with that of human defensins and lysozyme. In addition, rALP caused inhibition of C. albicans yeast cell growth. By exhibiting antifungal activity, ALP may play an important role in the innate mucosal defense against human pathogenic fungi.

Proteases from Aspergillus fumigatus Induce Release of Proinflammatory Cytokines and Cell Detachment in Airway Epithelial Cell Lines

Aspergillus fumigatus is a pathogen causing diverse respiratory disorders. Several studies have suggested that fungal proteases may play a role in the pathogenicity of fungi. Since the airways are the most common route for entry of A. fumigatus, this study focused on the ability of fungal proteases to induce the release of proinflammatory cytokines and to cause cell detachment in human pulmonary epithelial cell lines. It was shown that fungal serine protease activity induced the production of interleukin (IL)-8 and IL-6 and monocyte chemotactic protein-1 and caused cell detachment in a dose-dependent fashion. Chymostatin, antipain, phenylmethylsulfonyl fluoride, and heat treatment completely inhibited fungal protease activity, cytokine production and cell detachment; antileukoprotease partially inhibited these activities. By causing cell detachment, fungal proteases may decrease the physical barrier function of the epithelium; however, by eliciting a cytokine response, the epithelium may signal the mucosal inflammatory response against A. fumigatus.

Clinical effects of air cleaners in homes of asthmatic children sensitized to pet allergens.

BACKGROUND Exposure to cat and dog allergens is very common in the Western World and is a serious cause of asthma in sensitized subjects. OBJECTIVE We sought to study the clinical effects of air cleaners in living rooms and bedrooms of asthmatic children sensitized to cat or dog allergens. METHODS Twenty asthmatic children sensitized to pet allergens (cat/dog) and with an animal at home participated in a double-blind, placebo-controlled, cross-over study in which the effects of air cleaners placed in the living room and bedroom for 3 months were compared with the effects of sham air cleaners. Before and after each study period, lung function, airway hyperresponsiveness (adenosine monophosphate), and peak flow variation were recorded. Cat and dog allergen levels were assessed in the filters of the air cleaners. RESULTS After a 3-month intervention with active air cleaners, airway hyperresponsiveness decreased significantly, showing a 1.2 doubling dose increase of PC(20 )adenosine (P =.003). Peak flow amplitude also decreased (P =. 045). Substantial amounts of airborne cat and dog allergen were captured by the air cleaners in living rooms and bedrooms as well. Allergen levels in floor dust were not changed. CONCLUSION In young asthmatic patients sensitized and exposed to pets in the home, application of air cleaners in living rooms and bedrooms was accompanied by a significant improvement in airway hyperresponsiveness and a decrease in peak flow amplitude.

Acute effects of cigarette smoking on inflammation in healthy intermittent smokers

BackgroundChronic smoking is the main risk factor for chronic obstructive pulmonary disease. Knowledge on the response to the initial smoke exposures might enhance the understanding of changes due to chronic smoking, since repetitive acute smoke effects may cumulate and lead to irreversible lung damage.MethodsWe investigated acute effects of smoking on inflammation in 16 healthy intermittent smokers in an open randomised cross-over study. We compared effects of smoking of two cigarettes on inflammatory markers in exhaled air, induced sputum, blood and urine at 0, 1, 3, 6, 12, 24, 48, 96 and 192 hours and outcomes without smoking. All sputum and blood parameters were log transformed and analysed using a linear mixed effect model.ResultsSignificant findings were: Smoking increased exhaled carbon monoxide between 0 and 1 hour, and induced a greater decrease in blood eosinophils and sputum lymphocytes between 0 and 3 hours compared to non-smoking. Compared to non-smoking, smoking induced a greater interleukin-8 release from stimulated blood cells between 0 and 3 hours, and a greater increase in sputum lymphocytes and neutrophils between 3 and 12 hours.ConclusionWe conclude that besides an increase in inflammation, as known from chronic smoking, there is also a suppressive effect of smoking two cigarettes on particular inflammatory parameters.

Proteases from Aspergillus fumigatus induce interleukin (IL)-6 and IL-8 production in airway epithelial cell lines by transcriptional mechanisms.

Proteases secreted by Aspergillus fumigatus induce the production of cytokines by epithelial cells, including interleukin (IL)-6 and IL-8. In the present study, we focused on the mechanism(s) by which A. fumigatus-derived proteases elicit cytokine production in epithelial cells. In the epithelial cell line A549, IL-6 and IL-8 mRNA levels were enhanced by proteases as a result of transcriptional induction of the respective genes. Transcriptional induction of both genes coincided with enhanced DNA binding of nuclear factor (NF)-kappaB and NF-IL6, whereas activator protein-1 was unlikely to be involved. The enhanced transcriptional activity could be inhibited by the addition of chymostatin, showing serine protease dependency. Posttranscriptional mechanisms affecting the stability of IL-6 and IL-8 mRNAs were not involved in protease-induced IL-6 and IL-8 production. These data show that after exposure to A. fumigatus-derived proteases, IL-6 and IL-8 gene expressions are up-regulated as a result of transcriptional mechanisms.

Down-Regulation of E-Cadherin in Human Bronchial Epithelial Cells Leads to Epidermal Growth Factor Receptor-Dependent Th2 Cell-Promoting Activity

Airway epithelial cells are well-known producers of thymus- and activation-regulated chemokine (TARC), a Th2 cell-attracting chemokine that may play an important role in the development of allergic airway inflammation. However, the mechanism responsible for up-regulation of TARC in allergy is still unknown. In the asthmatic airways, loss of expression of the cell-cell contact molecule E-cadherin and reduced epithelial barrier function has been observed, which may be the result of an inadequate repair response. Because E-cadherin also suppressed multiple signaling pathways, we studied whether disruption of E-cadherin-mediated cell contact may contribute to increased proallergic activity of epithelial cells, e.g., production of the chemokine TARC. We down-regulated E-cadherin in bronchial epithelial cells by small interference RNA and studied effects on electrical resistance, signaling pathways, and TARC expression (by electric cell-substrate impedance sensing, immunodetection, immunofluorescent staining, and real-time PCR). Small interference RNA silencing of E-cadherin resulted in loss of E-cadherin-mediated junctions, enhanced phosphorylation of epidermal growth factor receptor (EGFR), and the downstream targets MEK/ERK-1/2 and p38 MAPK, finally resulting in up-regulation of TARC as well as thymic stromal lymphopoietin expression. The use of specific inhibitors revealed that the effect on TARC is mediated by EGFR-dependent activation of the MAPK pathways. In contrast to TARC, expression of the Th1/Treg cell-attracting chemokine RANTES was unaffected by E-cadherin down-regulation. In summary, we show that loss of E-cadherin-mediated epithelial cell-cell contact by damaging stimuli, e.g., allergens, may result in reduced suppression of EGFR-dependent signaling pathways and subsequent induction of Th2 cell-attracting molecule TARC. Thus, disruption of intercellular epithelial contacts may specifically promote Th2 cell recruitment in allergic asthma.

Seasonal variation in airway hyperresponsiveness and natural exposure to house dust mite allergens in patients with asthma

Nonspecific airway hyperresponsiveness is a fundamental characteristic of patients with asthma and can be influenced by several stimuli. In nine patients with asthma and an isolated allergy to house dust mite, the variation of natural exposure to the house dust mite allergen Der p I and the corresponding changes in nonspecific airway hyperresponsiveness were followed up for 1 year. The concentration of Der p I in floor dust from living rooms and bedrooms (as a measure of exposure) reached maximum levels in late summer and the beginning of autumn (August to October), whereas the lowest levels were found during the months of March to May (delta Der p I = +2.31 micrograms/gm and -1.33 micrograms/gm respectively, both compared with the year average). Airway hyperresponsiveness (as measured by the provocative concentration of histamine causing a 20% fall in forced expiratory volume in 1 second [PC20] threshold) also showed a seasonal variation, with most severe hyperresponsiveness during the months of August to November, almost the same period in which the exposure to house dust mite allergens reached maximal levels (delta PC20 histamine = -1.47 mg/ml in November vs +1.79 mg/ml in March, both compared with the year average). Our results support the view that seasonal changes of exposure to environmental allergens such as house dust mite allergens will have an effect on the level of airway hyperresponsiveness in patients with allergic asthma.

Interactions between inhalant allergen extracts and airway epithelial cells: Effect on cytokine production and cell detachment

BACKGROUND The factors responsible for inducing or maintaining airway inflammation are poorly understood. Various studies have focussed on the mechanisms leading to allergic airway inflammation in patients with asthma and rhinitis. The observation of local airway inflammation in nonallergic patients with asthma or rhinitis, including those with nasal polyposis, suggest that non-IgE-related mechanisms exist that may lead to airway inflammation. Various lines of evidence suggest that epithelial cells may participate in local inflammation of the airways. OBJECTIVE This study focused on the interaction of airway epithelial cells with clinically relevant inhalant allergen extracts in vitro. METHODS Cultures of airway epithelial cells were exposed to mite, Timothy grass pollen, and birch pollen extracts. Production of IL-8, IL-6, monocyte-chemotactic protein-1 (MCP-1), and granulocyte-macrophage colony-stimulating factor and cell detachment were monitored while protease inhibitors and chromatography techniques were applied to identify the factors responsible for these effects. RESULTS With the mite extracts, cytokine production and cell detachment was largely dependent on protease activity. With the pollen extracts, cytokine production without cell detachment seemed to be independent of protease activity. CONCLUSION These findings support the view that epithelial cells may contribute to the pathogenesis of airway disease by their interaction with inhalant allergen extracts. Furthermore, allergen extracts may enhance airway inflammation by means other than their IgE-binding activity through both protease-dependent and protease-independent mechanisms.

Secretory leukoprotease inhibitor: a native antimicrobial protein presenting a new therapeutic option?

Secretory leukoprotease inhibitor (SLPI) is a low molecular weight serine protease inhibitor found on various mucosal surfaces and has been ascribed an important role in maintaining the protease-anti-protease balance of the airways. Recent scientific evidence has suggested that SLPI may also have a broad spectrum antibiotic activity that includes antiretroviral, bactericidal, and antifungal activity. Given the unpropitious development of drug resistance to infectious micro-organisms in the human population, the need for therapeutic alternatives in the treatment of infectious diseases has become clear. SLPI may prove valuable in the prophylaxis and future treatment of infectious diseases, yet the clinical efficacy of SLPI remains largely to be elucidated.