Synthesis of Macroglobulins in vitro

Abstract

THE increased concentration of macroglobulin (IgM) in the sera of patients with macroglobulmaemia is usually ascribed to excessive production of the protein by neoplastic cells of the lymphocytic series. This inference is based on, two observations: the association of increased concentrations of IgM and abnormal “lymphocytoid” or “plasmacytoid” cells, and the staining of these cells by fluorescein-labelled antibody to IgM (ref. 1). Recently, a patient (J. P.) with γ-macroglobulinaemia and circulating lymphosarcoma cells (leucolymphosarcoma) offered a rare opportunity to examine directly the capacity of these cells to synthesize IgM. For comparison, the synthesis of IgM by leucocytes of a normal subject and of patients with various haematological diseases was also investigated. In additional experiments, the synthesis of ribonucleic acid (RNA) by the lymphosarcoma cells and certain other leucocytes was investigated.