CD22 and acute lymphoblastic leukemia: Similarly, a hydrazone linker is also used to connect anti-CD22 mAbs to cytotoxins such as calicheamicin (inotuzumab ozogamicin) and pasudotox-tdfk (moxetumomab pasudotox-tdfk) for treatment of CD22-positive ALL and relapsed hairy cell leukemia in clinics, respectively [49,66,99,100].