IRF1 and Crohn disease: Similarly, increased expression of IKZF3, a transcription factor that plays an important role in the regulation of B lymphocyte proliferation and differentiation, has been observed in patients with CD and UC [43, 44], and C5orf56 is known to influence the immune stimulus specific enhancer for IRF1, a gene established in the pathogenesis of Crohn’s disease [45–47].