Characterization of peripheral blood, spleen and bone marrow cells from a patient with hairy cell leukaemia.

The peripheral blood cells, spleen cells and bone marrow cells from a patient with hairy cell leukaemia were studied by means of several immunological methods and by phase contrast and electron microscopy. Both by light and electron microscopy the cells had the morphology of hairy cells. 60 % of all the peripheral blood cells, and 80 % of the spleen cells had membrane-bound IgGk immunoglobulin. 60 % of the peripheral blood lymphocytes and 90 % of the spleen cells were positive for Ia-antigens, and 80 % of the peripheral blood, and 70 % of the spleen cells had receptors for complement factor C3. The percentages of cells with receptor for the Fc part of IgC and receptors for sheep red blood cells (SRBC) were low both in peripheral blood and in spleen. Reduced numbers of peroxidase positive cells and cytotoxic plaque-forming cells were also observed as well as reduced lymphocyte responses after stimulation of peripheral blood lymphocytes with PHA, PWM, ConA, PPD and allogeneic cells. A normal antibody-dependent cell cytotoxicity (ADCC) and PHA-induced cytotoxicity was observed for the peripheral blood lymphocytes of the patients. Our results suggest that the hairy cells in our patient are derived from B lymphocytes and have a monoclonal origin.