CCL17 and Alzheimer disease: Moreover, in AD patients, T2R38 expression levels were correlated with serum thymus and activation-regulated chemokine (TARC; r = 0.7840, P = 0.0043) and IgE levels (r = 0.9171, P < 0.0001), diagnostic markers for assessing the severity of AD (Fig. 1B,C).