VSIR and acute myeloid leukemia: Consistent with database analyses of PD-1H mRNA transcript, M4 and M5 AML were the subtypes with higher expression of PD-1H surface protein (Figure 1, E and G, and Supplemental Table 2), and t(8;21) AML blasts had very low expression of PD-1H (Figure 1, E and F, and Supplemental Table 2).