CCL13 and Cognitive impairment: Two studies reported significantly different concentrations of markers in individuals with MCI: CXCL11, CCL13, and CCL15 (Nie et al., 2022) were increased, and CXCL16 (Nie et al., 2022) and IL-16 (Abe et al., 2020) were decreased in individuals with mild cognitive impairment compared to controls.