CCR4 and Alzheimer disease: Flow cytometry results showed negative expression of CCR2, CCR3, and CCR5; moreover, CCR1 and CCR4 had low mRNA levels in UC-MSCs (Supplementary Figure S3A–E), although the expression levels of BM- and AD-MSCs are controversial (Ponte et al., 2007; Baek et al., 2011; She et al., 2022).