Recognizes a protein of 30-33kDa which is identified as CD20. The epitope of L26 Mab is located in the cytoplasmic domain of CD20 and was, therefore, ascribed as CD20cy in the 5th Workshop. L26 Mab reacts with the majority of B-cells present in peripheral blood and lymphoid tissues and their derived lymphomas. In lymphoid tissue, germinal center blasts and B immunoblasts are particularly reactive with L26. L26 is a reliable antibody for ascribing a B-cell phenotype in known lymphoid tissues. Rarely, L26-positive T-cell lymphomas have been reported. Reactivity has also been noted with Reed-Sternberg cells in cases of Hodgkin’s disease, particularly of lymphocyte predominant type.