TNFSF4 and acute lymphoblastic leukemia: Additionally, leukemia blast cells of patients with B-ALL showed differentiated TNFSF4 expression, with only 34% of patients highly expressing TNFSF4. This suggests that the lack of TNFRSF4/TNFSF4-mediated co-stimulatory signaling may play a role in resistance to blinatumomab therapy.