IgD and IgM on the membrane of lymphoid cells in macroglobulinemia. Evidence for identity of membrane IgD and IgM antibody activity in a case with anti‐IgG receptors

Abstract

AbstractMonoclonal B lymphocyte populations from the bone marrow of seven cases of Waldenström's macroglobulinemia were studied for membrane IgD and IgM. In all cases lymphocytes with both classes on the membrane were found as well as cells with IgD or IgM only; the relative percentages of these three groups of lymphocytes were different in different cases. The IgM‐containing plasma cells always had membrane IgM and some of these also had IgD. Of particular interest was one patient whose macroglobulin had an anti‐IgG reactivity. The peripheral blood B lymphocytes of this patient had both membrane IgM and membrane IgD: it was possible to show, by capping with anti‐IgG or with aggregated IgG, that both classes of immunoglobulin receptors shared reactivity with human IgG.