Since MPN represents stem cell disorders, the presence of elevated expression of PD-1 and PD-L1 in these cells suggests that the exploration of PD-1 and PD-L1 pathway inhibitor therapy may be worthwhile in Ph(-) MPN.
JAK2<sup>V617F</sup> mutational burden, pSTAT3, and PD-L1 expression were highest in primary MPN patient-derived monocytes, megakaryocytes, and platelets.
This could imply that the tumor specific immune response in MPN could be enhanced by vaccination with PD-L1 derived epitopes by boosting the anti-regulatory immune response hereby allowing tumor specific T cell to exert anti-tumor immunity.
The current understanding of immune dysfunction in MPNs and analogous MyMs offers a compelling rationale to study PD-1/PD-L1 inhibition in patients as a novel treatment option.