[Role of the TNF system in the pathomechanism of bronchial asthma].

Introduction: The activation of the TNF system during asthmatic attack has already been proved.

Aims: The aim of the study was to reveal the role of the tumor necrosis factor (TNF) system in the pathomechanism of bronchial asthma.

Patients/methods: Childhood asthmatic lately symptom-free adults (n:39) and their non-asthmatic offspring were examined (n:42). According to the methacholin airway challenge test, patients were divided into bronchial hyperreactive (n:44) and non-hyperreactive (n:37) groups. Tumor necrosis factor alpha (TNF-alpha) and its soluble receptors 55 (sTNF-R1) and 75 kDa (sTNF-R2) were measured by ELISA.

Results: Among the hyperreactive patients (n:44) significantly higher TNF-alpha (mean +/- SD: 5.13 +/- 1.37 vs. 3.91 +/- 0.61 pg/ml, p < 0.0001), sTNF-R1 (mean +/- SD: 1.37 +/- 0.28 vs. 1.16 +/- 0.13 ng/ml, p = 0.0002) and sTNF-R2 (mean +/- SD: 0.78 +/- 0.42 vs. 0.43 +/- 0.41 ng/ml, p < 0.0001) values were measured compared to the non-hyperreactives (n:37). In hyperreactive patients there was a significant correlation between the cytokine and cytokine receptor levels (TNF-alpha-sTNF-R1 p = 0.0184, r = 0.3541; TNF-alpha-sTNF-R2 p < 0.0001, r = 0.6468). Significant negative correlation was detected between the serum TNF-alpha and sTNF-R2 concentrations and PD20 FEV1 methacholin (dose of methacholin resulting in a 20% reduction of forced exspiratory volume in 1 second) in hyperreactive patients.

Conclusion: According to our results the activation of the TNF system may contribute to the bronchial hyperreactivity. It can be observed in asthmatic patients having been symptom-free for years and in their non-asthmatic offspring as well. These results refer to the presence of a minimal allergic inflammation.