Three control participants underwent SPTs and BATs and showed typical baseline levels in control BAT assays.6,7,8 In Figure 2, an example BAT assay histogram is shown in which the blood of a participant who had an allergic reaction to the vaccine was incubated with vaccine, anti-IgE, and normal saline, and proportion of CD63 cells was determined (Figure 2). Here, CD63 is linked to allergic disease.