Peanut agglutinin shows specificity for bone marrow plasma cells.

A panel of lectins was used to study surface carbohydrate expression on myeloma cells with the aim of finding a possible agent for in vitro bone marrow purging. Peanut agglutinin (PNA, galactose beta 1,3 N-acetylgalactosamine-binding) bound to all plasma cells in 33/34 bone marrow samples from myeloma patients and to all plasma cells in 11 bone marrow from patients with monoclonal gammopathy of undetermined significance and 10 normal bone marrow samples. Bone marrow and peripheral blood monocytes reacted weakly with PNA except in one case of acute monoblastic leukaemia and two of chronic myelomonocytic leukaemia in which monocytes were strongly positive. The only case of plasma cell leukaemia studied was PNA negative. All other bone marrow mononuclear cells were negative for PNA but became positive after sialidase treatment. Peanut agglutinin may have potential as an agent to be used in myeloma for in vitro marrow purging prior to autologous transplantation in combination with high dose chemotherapy.