Immunoglobulin synthesis in hairy cell leukaemia

In vitro studies were performed with leukaemic cells from two patients with hairy cell leukaemia in order to define the nature and kinetics of immunoglobulin synthesis by the neoplastic cells. Both patients had clinically and morphologically well-defined disease and their cells contained abundant tartrate-resistant acid phosphatase. One patient had associated macroglobulinaemia. The hairy cells had B-lymphocyte characteristics as determined by fluorescent immunoglobulin staining and surface receptor properties. They synthesized monoclonal IgM and IgG respectively in vitro. The kinetics of immunoglobulin synthesis were different in cells from the two patients as measured by equilibration time, intracellular degradation, and secretion. Permanent cell lines were established with cells from these patients. The lines grow as typical B-lymphoblastoid cultures and continue to produce tartrate-resistant acid phosphatase and immunoglobulin. These studies unequivocally demonstrate the B-lymphocyte nature of the hairy cells in these patients and provide evidence for their clonal origin both in terms of immunoglobulin and enzyme synthesis.