Methods: We analyzed peripheral eosinophil counts, serum ECP, and 27 cytokines/chemokines in 71 virus-induced acute wheezing/asthma cases with or without aeroallergen sensitization. Wheezing/asthma due to sensitization was defined by a positive reaction to at least one aeroallergen in serum specific IgE antibody tests. Virus detection was performed using antigen detection kits and/or RT-PCR, followed by direct DNA sequencing analysis. Serum cytokines/chemokines were measured using a multi-cytokine detection system.
Results: The two major viruses detected, rhinovirus and respiratory syncytial (RS) virus, did not differ significantly between sensitized and nonsensitized cases of acute exacerbations of wheezing/asthma. Peripheral eosinophil counts and serum ECP and IL-5 levels were significantly elevated in sensitized cases compared with nonsensitized cases. Conversely, among the 27 cytokines/chemokines, serum IP-10 values were significantly higher in nonsensitized cases. An inverse correlation between serum IP-10 and IL-5 production was identified in virus-induced acute exacerbations of childhood wheezing/asthma but not in controls.
Conclusions: Cytokine profiles and eosinophil activation status might be different between sensitized and nonsensitized cases of virus-induced acute exacerbations of wheezing/asthma. IP-10 is a biomarker for these virus-induced acute exacerbations, specifically in nonsensitized cases.