AHR and acute lymphoblastic leukemia: It is also suggested that a low level of Th22 cells could be a risk factor for ALL.20,103 However, in controversy with the above-mentioned data, Tian et al. in 2014 suggested that Th22 and Th17 frequencies, serum IL-22 level and AHR expression were significantly increased in newly diagnosed or ALL patients with complete remission compared with healthy donors.