On the other side, DOCK8 is a Cdc42-specific GEF that regulates interstitial migration of dendritic cells and DOCK8 deficiency causes the AR Hyper-IgE syndrome (HIES), a combined immunodeficiency characterized by recurrent viral infections, early-onset malignancy and atopic dermatitis (no. 15 in Table 1 and Figure 1). Here, CDC42 is linked to hyper-IgE syndrome.