Surface markers in non-phagocytic hairy cell leukemia

By phase contrast and scanning electron microscopy hairy cells were demonstrated in the peripheral blood, bone marrow and spleen of a patient with hairy cell leukemia. Immunofluorescent tests revealed IgD on the surface of 92 per cent, IgG, on 76 per cent, IgM on 12 per cent and albumin on 95 per cent of the cells from the spleen. After overnight culture, IgG and albumin were detected on 4 and 6 per cent of the cells respectively, while the number of IgD and IgM positive cells persisted. Fifty-two per cent of the hairy cells formed rosettes with erythrocytes sensitized with IgG antibodies (EA), whereas 70 per cent formed rosettes after trypsin and protease treatment. The hairy cells did not form rosettes with erythrocytes sensitized with IgM antibodies and complement (EAC), or with sheep and mouse erythrocytes. Cryostat sections of spleen strongly adsorbed EA, whereas no adsorption occurred with EAC or sheep erythrocytes. The hairy cells did not phagocytize latex particles or ingest a strain on yellow staphylococci. The results suggest that hairy cells from this patient probably were of B-lymphocyte origin.