Surface immunoglobulins and lymphocyte-specific surface antigens on leukaemic reticuloendotheliosis cells.

Hairy cells from two cases of `leukaemic reticuloendotheliosis' were studied for their enzyme content, adherence to nylon wool columns, phagocytosis, and the presence of surface immunoglobulins and lymphocyte-specific surface antigens. The cells reacted negatively for peroxidase, chloroacetate-esterase, alpha-naphthyl-acetate-esterase and naphthol-AS-acetate-esterase. They did not adhere to nylon wool columns nor did they show significant phagocytosis. Most of the hairy cells were found to be positively labelled for surface immunoglobulins of different classes; μ chain-positive hairy cells were predominant in number. In a homo-genate of isolated, washed hairy cells from the spleen of one case only IgM could be detected in significant amounts. With peroxidase-coupled anti-thymocyte IgG most of the hairy cells of both cases showed a ring-like labelling very similar to lymphocytes, whereas monocytes and granulocytes showed no labelling. The data suggest that hairy cells are closely related to lymphatic cells of the B-cell type. They exclude with some certainty the possibility that hairy cells are directly derived from cells of the myeloid system, particularly monocytes, or from classical reticulum cells of the lymphatic tissue.