Soluble PD-L1 as prognostic biomarker in acute myeloid leukemia.

Soluble immune mediators, such as checkpoint and cytokine receptors and their ligands, are emerging as biomarkers and potential therapeutic targets in hematologic malignancies. We assessed pretreatment levels of soluble PD-L1 (sPD-L1) as a prognostic biomarker in a retrospective single-center cohort of 54 newly diagnosed acute myeloid leukemia (AML) patients. Higher sPD-L1 levels were significantly associated with a greater disease burden and with patients undergoing allogeneic transplantation. Interpretation of longitudinal sPD-L1 data suggests that marked declines may reflect treatment response, whereas persistently high levels may indicate ongoing disease activity. In non-transplanted patients, high sPD-L1 levels were independently associated with inferior overall survival. These results indicate that sPD-L1 may inherently reflect high-risk characteristics that could potentially help guide treatment decisions.