NOTCH1 and rheumatoid arthritis: Elevated mRNA expression of NOTCH-2, -3, -4 and Hes-1 found in T helper cells from rheumatoid arthritis patients highlights active notch signaling in rheumatoid arthritis[11]. Increased production of NOTCH-1 intracellular protein in T cells has been shown in a mouse model of aAA[12]. It has also been implicated that Notch has a role in the pathogenesis of aAA[13,14].