P1000: JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) INHIBITS T CELL PROLIFERATION VIA THE ECTONUCLEOTIDASE CD39 AND THE PURINERGIC NETWORK - Jovana Rajak; Naile Koleci; Andreea Mesesan; Christian Flotho; Charlotte Niemeyer; Bertram Bengsch; Miriam Erlacher (HemaSphere, 2023)