Cytokine production from peripheral whole blood in atopic and nonatopic asthmatics: relationship with blood and sputum eosinophilia and serum IgE levels

Background: The cytokine network is thought to be essential in orchestratin g airway inflammation in asthma. Although evidence has accumulated to sugge st that atopic asthma is a Th2 disease, much less is known about nonatopic asthma. Methods: We have compared the production of IL-4, IL-6, IFN-gamma, and TNF- alpha from peripheral blood leukocytes between atopic (n = 21) and nonatopi c (n = 22) asthmatics and healthy nonatopic subjects (n = 20). Peripheral b lood was incubated for 24 h either without stimulus or with LPS or PHA. Cyt okines were measured by the immunotrapping technique (Dynamic Immunoassay). Results: When compared to healthy nonatopic subjects, both atopic and nonat opic asthmatics showed increased blood and sputum eosinophilia associated w ith raised total serum IgE levels. Similarly, both asthma groups displayed spontaneous, endotoxin-induced overproduction of IL-6. Enhanced spontaneous , endotoxin-induced release of IL-4 combined with reduced spontaneous IFN-g amma production was seen only in atopic asthma. In this group of patients, the production of IL-4 was related to the extent of blood and sputum eosino philia. In nonatopic asthmatics, serum levels of IgE were inversely related to the production of IFN-gamma. Conclusions: Both atopic and intrinsic asthma display raised blood and airw ay eosinophilia, raised total serum IgE, and overproduction of IL-6 from pe ripheral blood. Atopic asthma is also characterized by impaired spontaneous release of IFN-gamma and increased production of IL-4 that correlates with the magnitude of eosinophilic inflammation.