BTK and autoimmune disease: BTK has become an important pharmacological target (Bond et al., 2019; Feng et al., 2019; Kim, 2019) due to its essential role downstream of immune receptors; for example, increased receptor signaling increases BTK activity driving multiple B-cell malignancies, autoimmune diseases, and allergies (Pal Singh et al., 2018; Smith, 2017; Mohamed et al., 2009).