P13 is a specific marker for human myeloid cells. Induction studies using HL-60 cells show that p13 is expressed during the early phases of myeloid differentiation. The mAb anti-p13 recognizes a nuclear antigen expressed in human granulocytes (98%) and monocytes (80%) residing in lymphoid and non-lymphoid tissues. BM3 is an early marker of myeloid differentiation. Immunoprecipitation experiments using S35 methionine labeled human myeloid leukemia cells show that BM3 identifies a 13,000 Dalton protein. Synonyms: P13 protein