CD22 and B-cell chronic lymphocytic leukemia: However, among the patients, only HCL patients responded with 19 (61%) CRs and six (19%) PRs (81% of overall response), likely because of the higher number of CD22 on the surface of HCL cells (5,000 to 70,000) compared with CLL (350–1,000) and NHL cells (unknown) (68).