Annexin A1 is antibody to the ANXA1 gene product (cell membrane), and is normally expressed in T-cells, macrophages, and myeloid cells. It is a useful marker for Hairy Cell Leukemia. This marker is better than the TRAcP antibody, and helps to distinguish HCL from other mimics (splenic lymphoma with villous lymphocytes and marginal zone lymphoma).
It should be noted that with the identification of BRAF mutations in hairy cell leukemia and other markers (and flow cytometry) this antibody is not utilized widely.
Clone: 29
Titer: 1:4,000