Phenotype of the Hairy Cells of Leukemic Reticuloendotheliosis Defined by Monoclonal Antibodies

Abstract
Hairy cell populations of greater than 90% purity were prepared from six samples obtained from four patients with leukemic reticuloendotheliosis (LRE). These then were analyzed for surface immunoglobulin (SIg) and antigens specified by a panel of monoclonal antibodies. The hairy cells from all patients displayed SIg and antigens reactive with OKIa-1 and OKM-1 antibodies; these markers often were expressed simultaneously. T-cell-specific antigens were not displayed on the surface of hairy cells. The simultaneous expression of SIg and OKM-1, which ordinarily are unique for B cells or myeloid cells, respectively, suggests that hairy cells may represent an aberrant form of either cell type with defective regulation of antigen expression. It alternatively suggests the possibility that B cells and myeloid elements develop along a common pathway and that the hairy cell is a component of such a pathway.