JAG1 and rheumatoid arthritis: Similarly, coordinated Notch signaling via engagement with Notch ligands such as Jagged1 and 2 and/or Delta1‐4 is required for normal Th1 biology 19, 32 – hence, dysregulations in Notch and/or CD46‐mediated T‐cell signals contribute to autoimmune diseases such as RA and MS 9, 16.