These results suggest that this nomogram model, using machine learning identified four immune-related genes <i>CXCL1</i>, <i>ITGA5</i>, <i>PTX3</i>, and <i>TIMP1</i>, displays superior diagnostic ability in distinguishing AD and healthy individuals, and immune cells commonly associated with these hub genes may be therapeutic targets for AD. Here, PTX3 is linked to Alzheimer disease.