The PD7/26/16 and 2B11 antibody clones have been designated as CD45. CD45 belongs to a leukocyte common antigen (LCA antibody) family of glycoproteins with molecular weights of 180, 190, 205 and 220 kDa. CD45 recognizes an antigen found on lymphoid cells. Studies have shown that most neoplastic B-cells and T-cells stain positively with CD45 in leukemia and in non-Hodgkin’s lymphomas; whereas most neoplastic myeloid and erythroid cells are negative. CD45 has also been observed to be unreactive with epithelium and connective tissues in published studies.