The key findings can be summarized as follows: (1) in the inflammatory network of adults with MDD, IL-1β is the most important and central inflammatory factor, and IL-1β and IL-4 are the most closely related inflammatory factors in the overall sample; (2) in Cluster 1 networks, characterized by more severe anxiety/somatization and sleep disruption, IL-1β is the most important inflammatory factor. Here, IL1B is linked to major depressive disorder.