IL27 and precursor B-cell acute lymphoblastic leukemia: <h4>Background</h4>Interleukin-27 (IL-27) is an immunoregulatory cytokine, but its role in B-cell haematopoiesis and B-cell acute lymphoblastic leukaemia (B-ALL) within the bone marrow (BM) niche remains unclear.<h4>Methods</h4>IL-27 was delivered in vivo using adeno-associated virus.