Lastly, in the analysis of CD33's expression on immune cell subtypes, the MR results showed that increased expression on all CD33 + cell subtypes, including CD14+ monocytes, CD66b++ myeloid cells, CD33dim cells and CD33+ cells were all leading to a higher risk of AD (p < 0.05) with IVW and other sensitivity analyses (Fig. 2A and Supplementary Table 4). This evidence concerns the gene CEACAM8 and Alzheimer disease.