mRNA expression of 10 genes related to PMN activation (CD274, IL1β, IL1RN, CXCL8, MMP9, and TLR4) was increased in HAE patients in symptom-free periods compared with healthy donors in addition to increased CD11b, decreased CD16 plasma membrane deposition, and increased relative CD274+ and CD87+ neutrophil counts, but not by increased NE or MPO plasma levels (Table 1). Here, CD274 is linked to hereditary angioedema.