IGHE and Arthritis: Blockade of PI3Kδ attenuates inflammation in arthritis in K/BxN serum-transferred mice [49], IgE- or ovalbumin-related allergic models [50,51,52,53], a multiple sclerosis model [54], imiquimod-induced dermatitis [55], and experimental systemic lupus erythematosus in BXSB mice [56].