Exogenous immunoglobulin and the macrophage origin of Reed-Sternberg cells in Hodgkin's disease.

We studied Reed-Sternberg cells from 14 patients with Hodgkin's disease to learn whether they had monoclonal immunoglobulin synthesized by the cell or polyclonal immunoglobulin of external origin. Double-label immunofluorescence with F(ab')2 anti-serums to human light chains showed that cytoplasmic immunoglobulin of individual Reed-Sternberg cells is always polyclonal and usually associated with membrane-bound immunoglobulin of the same type. The predominant immunoglobulin was IgG; in one case IgM was also present. In vitro studies confirmed the internalization of exogenous IgG and phagocytosis of immune complexes by viable Reed-Sternberg cells. Their exclusion of trypan blue dye and lack of albumin and fibrinogen suggests relatively specific uptake of immunoglobulin, mediated by the Fc receptor or antigen (or antigens) associated with Hodgkin's disease at the cell membrane. Our studies support other recent evidence that the Reed-Sternberg cell is derived from a macrophage.