Individuals with ATL develop pneumopathies caused by opportunistic infections due to ATL cell proliferation, which leads to a low expression of naive T cells, increased expression of FoxP3+ and interleukin-10 (IL-10), and an increased number of Treg cells (CD4+ and CD25+), which suggests the development of immunodeficiency (9). Here, IL10 is linked to immunodeficiency disease.