Figure 1. Study Design: After enrollment (Visit 0), a matching drug placebo was administered subcutaneously at visit 1. Benralizumab 30mg was then administrated subcutaneously at three consecutive monthly intervals (visits 2, 3, and 4). Clinical outcomes (UAS7, CU-QoL) were recorded at each visit. Blood samples were collected at each visit for total and differential blood cell counts. Blood was also collected at Visits 2 and 5 for RNA-sequencing. Skin biopsies (from lesional and non-lesional skin) were obtained at visit2 (post-placebo/pre-benralizumab treatment) and again at visit 5 (4 weeks after last benralizumab treatment) from all CSU patients for histology and RNA-sequencing. Similar skin and blood samples were obtained from 5 non-CSU healthy controls at visit 0 only. Vital sign parameters were
measured at every visit. RNA-extracted from blood and skin biopsies were stored at -80° C for later use.