Subsets of hairy cell leukemia defined by unique membrane proteins

Leukemic cell membrane proteins of 27 patients with hairy cell leukemia were evaluated by SDS gel electrophoresis in order to identify subsets of these patients and to define molecules for isolation and the development of diagnostic reagents. [³⁵S]methionine metabolic labeling, gel electrophoresis of isolated membranes and fluorography demonstrated about 100 membrane proteins. Variations in the amount of synthesis of two principal proteins, p35 and p15 (35,000 and 15,000 dalton proteins respectively), defined, in relative terms, three subtypes of hairy cell leukemias: (a) p35⁺, p15^? cells, (b) p35^?, p15⁺ cells, and (c) p35^?, p15^? cells. At this time, it is not known whether these subsets represent various related disease entities or stages in the progression of one disorder. Although p35 migrated in the gels with one component of the HLA-DR (p23,30) protein complex, immunoprecipitation studies with anti-p23, 30 serum indicated that it probably was not derived from HLA-DR antigen, which was, in fact, synthesized in addition to p35 on all hairy cells which were tested. Cultured lymphoblastoid cell lines established from the peripheral blood of hairy cell leukemia patients were substantially different in membrane protein patterns from the fresh leukemic cells. In particular, p35 and p15 were minimally expressed by cultured cells.