MS4A4A and Alzheimer disease: Moreover, we validated the significantly high expression of Ms4a4a in microglia from WT mouse brains (Figure 1E), aligning with the high expression of MS4A4A in microglia observed in AD patients.[40] In addition to microglia, we also compared the expression of Ms4a4a in peritoneal macrophages, alveolar macrophages and bone marrow‐derived macrophages (BMDMs) from WT mice.