High serum levels of tumour necrosis factor-α and interleukin-8 in severe asthma: markers of systemic inflammation?
Article first published online: 31 MAY 2006
Clinical & Experimental Allergy
Volume 36, Issue 11, pages 1373–1381, November 2006
How to Cite
Silvestri, M., Bontempelli, M., Giacomelli, M., Malerba, M., Rossi, G. A., Di Stefano, A. , Rossi, A. and Ricciardolo, F. L. M. (2006), High serum levels of tumour necrosis factor-α and interleukin-8 in severe asthma: markers of systemic inflammation?. Clinical & Experimental Allergy, 36: 1373–1381. doi: 10.1111/j.1365-2222.2006.02502.x
- Issue published online: 31 MAY 2006
- Article first published online: 31 MAY 2006
- Submitted 14 July 2005; revised 6 December 2005; accepted 14 March 2006
- asthma severity;
- nitric oxide;
Background Severe asthma is characterized by elevated levels of pro-inflammatory cytokines and neutrophilic inflammation in the airways. Blood cytokines, markers of ‘systemic’ inflammation, may be a feature of amplified inflammation in severe asthma.
Objective To detect differences in IL-8, TNF-α, IL-16 and IL-13 levels in the serum(s) of stable severe and mild–moderate asthmatics related to blood leucocytes proportion, airway calibre and exhaled nitric oxide (NO) levels.
Methods We assessed cytokine serum levels by ELISA and blood leucocyte counts by an alkaline peroxidase method in 20 healthy controls, 22 mild–moderate [forced expiratory volume in 1 s (FEV1)(%pred): 89±3] and 14 severe asthmatics [FEV1(%pred): 49±2].
Results IL-8 and TNF-α levels were higher in severe asthmatics than in mild–moderate asthmatics or in controls (P<0.05). No differences in IL-16 and IL-13 levels were detected. Severe asthmatics showed higher circulating neutrophil and eosinophil number than controls (P<0.05). In severe asthmatics, exhaled NO levels were superior than in controls (P<0.05), but inferior than in mild–moderate asthmatics (P<0.05). We found positive correlation between TNF-α levels and exhaled NO (r=0.67; P=0.01) or circulating neutrophil counts (r=0.57; P=0.03) in severe asthmatics.
Conclusion sTNF-α and sIL-8 are markers of ‘systemic’ inflammation in severe asthmatics, in conjunction with augmented circulating neutrophils, suggesting the involvement of neutrophil-derived cytokine pattern in severe asthma.