STIM1 and Splenomegaly: In accordance with the immune cell dysregulation in patients, cytokine expression is impaired in mice with T CD4+ cell-specific deletion of Stim1 or Orai1, and chimeric Orai1R93W/R93W animals (corresponding to R91W in humans) and Stim1 and Stim2 double knockout mice additionally show a reduced suppressive function of Treg and NKT cells and an associated autoimmunity and splenomegaly (Gwack et al., 2008; Oh-Hora et al., 2008, 2013; McCarl et al., 2010).