CD28 and hereditary angioedema: In addition, IFN-γ protein accumulation in the medium upon CD3/CD28 stimulation was lower after T-cell coculture with neutrophils from both HAE patients (p < 0.0001) and healthy controls (p < 0.006; Wilcoxon test); however, the decrease in IFN-γ concentration was significantly more pronounced in HAE patients (p < 0.002; Mann-Whitney test) (Figure 7).