Abstract
T helper 2 (Th2) lymphocytes, the key effector cells in pathogenesis of atopic dermatitis (AD), express CCR4 receptors. CCR4 ligands (macrophage-derived chemokine 'MDC' and thymus and activation-regulated chemokine 'TARC') direct trafficking and recruitment of Th2 cells into lesional skin in AD. These chemokines appear to be useful inflammatory markers for assessing severity of AD in adults. However, the same results have not been replicated in children. Therefore, we were stimulated to elucidate the expression of CCR4 ligands in children with AD and their relation to clinical disease severity. To investigate this, serum concentrations of CCR4 ligands were determined in 60 children, of whom 30 had AD and 30 were healthy matched subjects. Patients were classified into mild (n = 8), moderate (n = 12) and severe (n = 10) according to the objective scoring AD (obj-SCORAD) index. Serum concentrations of MDC and TARC were significantly increased in children with AD (2697 +/- 982.6 pg/ml and 945.5 +/- 494.7 pg/ml, respectively) compared with controls (357.2 +/- 233.2 pg/ml and 214.2 +/- 116.6 pg/ml, respectively, p < 0.0001). Serum levels of both chemokines went hand in hand with disease severity as they were significantly higher in severe than moderate and in moderate than mild AD. In addition, they correlated positively with obj-SCORAD (r = 0.99 for both, p < 0.0001). Furthermore, both chemokines had significant positive correlations to blood eosinophil counts and serum immunoglobulin E. In conclusion, serum CCR4 ligands may be useful inflammatory markers for assessing AD severity in children. Further studies may pave way for CCR4 ligands antagonism among the adjuvant therapeutic strategies of AD.