T cells and eosinophils in bronchial smooth muscle cell death in asthma.

BACKGROUND: Bronchial smooth muscle cells (SMC) proliferate, express adhesion molecules, secrete cytokines and thus efficiently contribute to the pathogenesis of asthma. OBJECTIVE: The aim of the study was to investigate whether, and by which mechanism, T cells and eosinophils can cause death of airway SMC. METHODS: The T cell- and eosinophil-induced cell death was analysed in primary human bronchial SMC cultures as well as in bronchial biopsy specimens from non-asthmatic and asthmatic individuals. RESULTS: Bronchial SMC death showed characteristic morphological features of apoptosis in 3-6 days cultures with inflammatory cytokines (IFN-gamma, TNF-alpha), soluble death ligands [sFasL, TNF-related apoptosis-inducing ligand (TRAIL)] and activated T-helper type 1 (Th1) and Th2 cell supernatants. The recombinant eosinophil cationic protein induced SMC necrosis within 1 h. Resting SMC expressed the death receptors TNFR1, TNFR2, Fas, TRAILR1, TRAILR2 and membrane FasL as a death-inducing ligand. IFN-gamma and TNF-alpha up-regulated TNFR1, TNFR2, Fas and membrane FasL on SMC. TNF-alpha up-regulated TRAILR1 and TRAILR2; sFasL up-regulated TNFR2. The intracellular caspase-3 activation in SMC was significantly increased by IFN-gamma, sFasL, TRAIL, Th1 and Th2 cell supernatants. Increased expression of TRAIL in asthmatics, but not in non-asthmatic individuals was demonstrated in situ. The apoptosis receptors TRAILR1 and TRAILR2 were expressed in SMC and epithelial cells both in healthy and asthmatic biopsies. Prominent apoptosis of SMC was observed in fatal asthma, but not intermittent asthma biopsies. CONCLUSION: The demonstration of bronchial SMC death both by apoptosis and necrosis indicates the essential role of T cells and eosinophils in the bronchial tissue injury particularly in the severe asthma.

Highlights in cellular and molecular mechanisms of allergic diseases. XXVth Congress of the European Academy of Allergology and Clinical Immunology in Vienna.

This year, the annual congress of the European Academy of Allergology and Clinical Immunology was held on 10-14 June in Vienna. More than 6,000 delegates, practicing bench or bedside work or both, gathered from over 50 countries throughout the world. Health professionals, basic scientists and fellows in training could choose between a variety of activities in plenary, main, educational and workshop sessions, highlights of the past year, pros and cons, and oral abstract and poster sessions, and met with experts. A total of 1,713 abstracts, 31 symposia, and 54 workshops were presented, ranging from basic science to clinical trials and modern treatment of allergic diseases. Here, we summarize the highlights of cellular and molecular mechanisms of allergic disease.

Natural occurrence of scirpentriol in cereals infected by Fusarium species.

Wheat, barley and oat grain samples naturally contaminated with Fusarium spp. were analysed for the presence of scirpentriol (STO). This toxin was detected in 1, 37 and 8% of 248 wheat, 32 barley and 99 oat grain samples, respectively, and the maximum concentration was 83 microg x kg(-1). Samples of wheat and oat grain with visible scab symptoms were also analysed, and STO (mean level 255 microg x kg(-1)) was detected only in oat samples infected with F. sporotrichioides and F. poae as the dominant species. We analysed 15 barley samples that were subdivided based on seed size into fractions of <2.5 and > 2.5 mm in diameter. The smaller kernels contained an average 94% of the STO in the samples (in kernel fraction > 2.5 mm 28 microg x kg(-1), <2.5 mm 297 microg x kg(-1)). In oats, STO levels were highest in the chaff, lower in the stalk's apical internode and lowest in the grain.

Natural contamination of oat with group A trichothecene mycotoxins in Poland.

Ninety-nine naturally contaminated oat grain samples were collected in 12 plant breeding stations in different parts of Poland. T-2 toxin, HT-2 toxin and diacetoxyscirpenol (DAS) levels were determined by gas chromatography with mass selective detection (GC-MS). HT-2 was the major toxin with an incidence of 24% and its average level in positive samples was 21 microg kg(-1). The incidence of T-2 and DAS was 15 and 12%, and their average levels were 60 and 23 microg kg(-1), respectively. The highest concentrations of HT-2, T-2 and DAS were 47, 703 and 111 microg kg(-1), respectively. Sixty-five samples were free of detectable amounts of the toxic metabolites analysed.