Plasma concentration of thymus and activation-regulated chemokine is elevated in childhood asthma

Background: Thymus and activation-regulated chemokine (TARC) is responsible for the trafficking of T(H)2 lymphocytes into sites of allergic inflammation. Serum TARC levels correlate with the severity of atopic dermatitis. The relationship between this marker and the occurrence and severity of asthma has not been evaluated. Objective: We tested whether plasma TARC level is a useful marker for asthma and atopy in children. Methods: Plasma total IgE levels were measured by means of microparticle immunoassay, and specific IgE levels to common aeroallergens were measured by, using a fluorescent enzyme immunoassay. We used a sandwich enzyme immunoassay to measure plasma TARC concentrations. Results: Sixty asthmatic children and 28 age- and sex-matched control subjects were recruited, with mean logarithmic plasma total IgE levels of 2.66 +/- 0.60 kIU/L and 1.74 +/- 0.58 kIU/L, respectively (P<.0001). The median plasma TARC concentration was higher in asthmatic patients without inhaled corticosteroid treatment (131.0 pg/mL) compared with those seen in steroid-treated patients (97.5 pg/ml.) and control subjects (76.0 pg/ml,; P=.01 and P<.0001, respectively,). Plasma TARC concentration was found to correlate with total IgE level in plasma (r=0.219, P=.04). This marker was also increased in subjects who were sensitized to cat allergen (P=.001) but not in subjects sensitized to other aeroallergens. Disease severity, score, FEV1 value, and atopy were not associated with increased plasma TARC levels. Conclusion: Our results suggest that plasma TARC concentrations are elevated in childhood asthma. This marker is also linked to plasma total IgE levels and cat allergen sensitization.