Serum Levels of Interleukins (IL)-4, IL-5, IL-13, and Interferon-gamma in Acute Asthma

T-cell activation and alteration of cytokine levels are involved in the pathogenesis of bronchial asthma. However, the profile of circulating T-lymphocyte subsets and related cytokines during acute asthmatic attacks is still unclear. We hypothesized that serum levels of interleukin (IL)-4, IL-5, and IL-13 would be increased, whereas IFN-y would be decreased in acute asthma. The subjects enrolled in this study included 58 acute asthmatics, 22 asymptomatic asthmatics, and 10 healthy controls. Serum levels of IL-4, IL-5, IL-13, and IFN-gamma were measured using a sandwich enzyme-linked immunosorbent assay. We correlated serum levels of IL-4, IL-5, IL-13, and IFN-gamma with initial forced expiratory volume in 1 sec (FEV1). Compared with control subjects, acute asthmatics had significantly increased levels of circulating IL-4 (p < 0.001), IL-5 (p < 0.001), and IL-13 (p < 0.001), although the differences were of borderline significance in serum IFN-gamma (p = 0.069). There were also significant differences in the circulating levels of IL-4, IL-5, and IL-13 between acute asthmatics and asymptomatic asthmatics. There was no significant association between initial FEV1 and serum levels of IL-4 or IL-13, however, among acute asthmatics, a lower initial FEV1 was associated with higher IL-5 and/or lower IFN-gamma levels. Our results suggest that serum levels of IL-4, IL-5, and IL-13 may be elevated in acute asthma, and that higher levels of IL-5 and/or lower levels of IFN-gamma are associated with severe airway obstruction.