CD244 and acute myeloid leukemia: Interestingly, Tim-3 + CD4+ and Tim-3 + CD244 + CD4+ T cells primarily accumulated in the BM group, which may suggest that the AML BM microenvironment also has effects on CD4+ T cells, leading to higher expression of Tim-3 with the exhausted phenotype, as it is known that upregulating Tim-3 reduces the activation of T cells [34, 35].