Interestingly, ATLL patients express high serum levels of the cytokine IL-10, likely induced by NF-κB signaling, which exhibits immunosuppressive functions partly via regulatory T cells (Tregs) in a positive feedback regulation resulting in impairment of Tax-specific CD8+ T cells [253,254,255]. Here, NFKB1 is linked to adult T-cell leukemia/lymphoma.