PTGER2 and familial isolated congenital asplenia: Furthermore, macrophage specific deletion of the prostaglandin E (PGE) receptor subtype 2 (EP2) (Ptger2), an upstream signaling receptor for NF-κB activation, significantly suppresses the development of ICAs in mice, indicating that prostaglandin E2-EP2-NF-κB signaling in macrophages plays a crucial role in ICA development (12).