CD4+ CCR9+ T helper cells express high amounts of interleukin 21 and induce T cell costimulatory factor, transcription factor B cell CLL/lymphoma 6 (Bcl-6), and Maf, which are local features of autoimmune diseases that affect the accessory organs of the digestive system (McGuire et al., 2011). The gene discussed is BCL6; the disease is autoimmune disease.