CCL27 and Alzheimer disease: Among the markers that could not be included in the meta-analysis, four studies reported significant differences between individuals with AD and controls, where CCL27 (Gongora-Rivera et al., 2020), CXCL12 (Gongora-Rivera et al., 2020), and CXCL10 (Mohd Hasni et al., 2017) were increased.