CD8+ T Cells in Acute Lymphoblastic Leukemia Show a Progenitor-exhausted Phenotype.

Exhausted T cells are phenotypically and functionally heterogeneous, from progenitor- to terminally-exhausted T cells. We evaluated gene expression profile of CD8+ T cells in acute leukemia to characterize the phenotype of exhausted T cells. Blood samples were collected from acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) patients prior to treatment and from control subjects. Additionally, samples were obtained from ALL patients after induction therapy. TCF7, NFATc1, IRF4, and BATF gene expression was then evaluated in isolated CD8+ T cells. CD8+ T cells from ALL patients showed higher expression of TCF7 and NFATc1 compared to the control group. The two study groups did not have a significant difference in the expression of BATF and IRF4. When compared to the control group, CD8+ T cells of AML patients showed an elevated expression level of NAFTc1 and IRF4. Significant differences were not found between the two study groups in AML when it came to the expression of BATF and TCF7. To our findings, the majority of CD8+ T cells found in ALL patients consist of progenitor-exhausted T cells.