To investigate whether EP2 and/or EP4 receptors transduced the effects of PGE2, whole blood from patients with AD/ACLF was pre-incubated with either PF-04418948, an EP2 selective antagonist (IC50 = 16 nM with >2,000-fold selectivity over EP1, EP3, and EP 4) or MF498, a selective EP4 receptor antagonist (Ki = 0.7 nM vs. a Ki >1 μM for other EP receptors). The gene discussed is PTGER2; the disease is Alzheimer disease.