Associations between TARC/TSLP with asthma characteristics in adults: the EGEA study

Thymus and Activation Regulated Chemokine (TARC) and Thymic Stromal Lymphopoeitin (TSLP) are involved in the pro-Th2 inflammatory response. To date, there is no epidemiological studies that have simultaneously investigated TARC and TSLP with various asthma characteristics and allergy in adults. We investigated the associations between TARC/TSLP and various asthma and allergic characteristics in the Epidemiological study on the Genetics and Environment of Asthma (EGEA). Cross-sectional analyses were performed at EGEA2 (second survey, 2003-2007). Asthma characteristics were defined by standardized questionnaires and lung function tests. Allergy was defined by positive skin prick test. Plasma TARC and TSLP levels were measured by enzyme-linked immunosorbent assay. Generalized logistic models adjusted (a) for age, sex, smoking habits, body mass index and taking into account familial dependence were used. The correlation between TARC and TSLP in the 958 adults (43 years old, 48% men, 43% current asthmatics, 56% with allergy) was 0.11 (p=0.0009). High TSLP level was associated with an increased risk of current asthma (aOR [CI95%]=1.37 [1.11-1.68]). Among current asthmatics (n=380), TSLP level was negatively correlated with FEV1 (r=-0.23, p<0.0001), and high TARC level was associated with increased risks of breathlessness and wheezing, chronic cough and chronic bronchitis (aOR ranging from 1.40 to 2.27), and eosinophilic asthma ≥250/mm³, aOR=1.48[1.07-2.04]). No associations were found with allergy. Results suggest that TARC and TSLP are associated with different asthma characteristics but not with allergy. Longitudinal analyses between TARC/TSLP levels and changes in asthma characteristics are on-going.