In addition, the most prominent candidate AD biomarkers include Th2-related chemokines namely MDC/CCL22, PARC/CCL18, CTACK/CCL27, eotaxin-3/CCL26, the key Th2 cytokine IL-13 and the key Th22 cytokine IL-22 [18], although further investigation is needed. Here, CCL22 is linked to Alzheimer disease.