[Current pathophysiologic aspects of allergic rhinitis. I].
Allergic rhinitis is a classic example of a type I immunological reaction. After allergic provocation tests a biphasic reaction is seen in the respiratory tract that is more pronounced in the lower than in the upper respiratory tract due to the physiological changes during the nasal cycle. The early phase of the immediate reaction starts some minutes after allergen provocation. After 5-10 h the nasal symptoms (discharge, blockage, sneezing and itching of the nose) reappear, a phenomenon which is called the "late-phase response" (LPR). The LPR is of great clinical importance in the pathophysiology of perennial allergic rhinitis and phenomena such as nasal priming and nasal hyper-reactivity. The most important effector cell of the early phase of the immediate reaction is the mast cell, whereas basophils, eosinophils and neutrophil granulocytes seem to be more important for the LPR. There is also evidence for morphological and functional heterogeneity of mast cells in man. The role of the chemotactically immigrated eosinophils in allergic reactions has not been clear until now: the eosinophil-derived mediators may enhance or inhibit the allergic reaction. Also the eosinophils show different morphological and functional states (so-called hypo- and hyperdense eosinophils). The symptoms of allergic rhinitis (sneezing, discharge, blockage, itching of the nose) are caused by different mediators, of which the most important is histamine. Other mediators or modulators of the allergic reactions are leucotrienes, prostaglandins, PAF, serotonin, and the kallikrein-kinine and complement systems. In recent years many regulatory peptides have been detected in the human nasal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)
Albegger
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HNO-Abteilung, St. Johann's Spitals Salzburg.
D000485:Allergens / Q000276:immunology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology; D007073:Immunoglobulin E / Q000096:biosynthesis; D009297:Nasal Mucosa / Q000276:immunology; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*
D000485:Allergens; D007073:Immunoglobulin E
Aktuelle pathophysiologische Aspekte der allergischen Rhinitis. Teil I.