CD47 and B-cell chronic lymphocytic leukemia: Moreover, BNIP3 gene expression was found to be increased and regulated by hypoxia-inducible factor-1α (HIF-1α) following the ligation of CD47 by single-chain fragments of an anti-CD47 mAb which kills B-CLL cell lines both in vitro and in vivo, where the knockdown of HIF-1α represses CD47-induced cell death [82] (Figure 2).