ULBP2 and acute lymphoblastic leukemia: Therefore, MICB and ULBP2 upmodulation by HMBA on T-ALL cells (Fig. 1B,C) does not enhance their susceptibility to NK-cell killing and, moreover, HMBA impairs the overall cytotoxicity of IL-15-stimulated NK cells against T-ALL targets, possibly affecting other activating pathways in addition to the one mediated by NKG2D.