The transformation of T cells into ATLL cells induced by HTLV-1 is accompanied by an increase in immunosuppressive characteristics, such as the upregulation of CTLA4, LAG3, and MHCII.151 The HBZ protein can directly induce the expression of immunosuppressive receptors, such as Foxp3, CCR4, and TIGIT.664 Additionally, the Tax protein upregulates the secretion of the chemokine CCL22, which attracts and maintains a high-frequency circulation of CD4+ Foxp3+ CCR4+ Treg cells (Fig. 10g).665. This evidence concerns the gene CCR4 and adult T-cell leukemia/lymphoma.