Role of Thymus and Activation-Regulated Chemokine in Allergic Asthma.

Background: Asthma is a chronic inflammatory airway disease characterized by the predominant infiltration of inflammatory cells in the airways. Thymus and activation-regulated chemokine/C-C motif chemokine 17 (TARC/CCL17) is a chemokine responsible for trafficking T helper 2 cells into sites of allergic inflammation.

Objective: To validate the role of TARC in association with clinical and inflammatory parameters in adult asthmatics.

Methods: We enrolled 128 asthmatic patients and 70 healthy controls (HCs). Asthma-related clinical and laboratory parameters, including lung function and eosinophil counts, were measured. Serum levels of TARC, free immunoglobulin E (IgE), and eosinophil-derived neurotoxin (EDN) were determined by using enzyme-linked immunosorbent assay; serum total IgE level was measured using ImmunoCAP. The levels of inflammatory lipid mediators, such as leukotriene E4 (LTE4), 15-hydroxyeicosatetraenoic acid (15-HETE), thromboxane B2 (TXB2), and prostaglandin F2α (PGF2α), were measured by liquid chromatography-tandem mass spectrometry.

Results: Serum TARC levels are significantly higher in asthmatics than in HCs and in allergic asthmatics than in HCs ( < 0.010 for all), with significantly negative correlations between serum TARC levels and FEV%/MMEF% values ( = -0.314, = -0.268, < 0.050 for both). The patients with higher serum TARC levels had higher levels of serum total and free IgE levels ( < 0.050 for both) with positive correlations to serum levels of EDN, TXB2, and 15-HETE ( = 0.233, = 0.264, and = 0.223, respectively, < 0.050 for all).

Conclusion: We suggest the role of TARC in allergic asthma via contributing to mast cell and eosinophilic inflammation.