Tumor necrosis factor alpha (TNF-alpha) plays a central role in pathogenesis of many inflammatory diseases including asthma and allergic rhinitis. Its capability for cell activation, chemotaxis and upregulation of adhesion molecule expression on surface of inflammatory cells suggests that TNF-alpha may be responsible for bronchial hyperresponsiveness (BHR) and clinical symptoms of atopic diseases.
The aim: Relationships between serum concentration of TNF-alpha and clinical course as well as nonspecific BHR in patients with isolated seasonal rhinitis (SR) and seasonal bronchial asthma (SA) were assessed.
Material and methods: The study was performed in 19 subjects with SR and 26 subjects with asthma sensitized to pollens, with measurable BHR during symptomatic phase of disease. Control group consists of 16 healthy volunteers. Serum concentration of TNF-alpha, ventilatory parameters, BHR to methacholine, asthma and seasonal rhinitis score were assessed two times--during and outside pollen season.
Results: Nonspecific BHR was find in 10 (21%) patients with SR and 18 (69%) patients with asthma symptoms out of season. In both groups postseasonal mean geometric values of PC20M were significant higher than during season. There were no marked changes in ventilatory parameters accompanied the increase in BHR. TNF-alpha concentration in serum in both groups of patients was significant higher than in healthy subjects. Further increase of its activity about 50-70% compared to baseline values was observed during pollen season. There was no correlation between serum concentration of TNF-alpha, BHR and symptom score. There is increased serum concentration of TNF-alpha in patients with seasonal airway allergy even in asymptomatic period of disease.
Conclusions: Natural exposure to allergens causes significant increase of TNF-alpha concentration in patients with rhinitis and asthma. Although level of BHR and intensification of clinical symptoms coexist with changes in TNF-alpha concentration there is no correlation between them.