Abstract
A case of chronic lymphocytic leukemia associated with the excessive production of a monoclonal γG-globulin has been investigated by immunofluorescent technics. Gamma globulin was demonstrated within the cytoplasm of young and mature lymphocytes and these cells were interpreted as the cells of origin of the monoclonal protein. The finding of gamma globulin within the cytoplasm of mature small lymphocytes in the absence of any apparent morphologic relationship with the occasional plasma cells present was interpreted as indicating a population of gamma globulin forming cells distinct from plasma cells, and suggested that a small number of lymphocytes may also contribute to the formation of immunoglobulins under normal conditions. The distribution of the fluorescent lymphocytes in sharply defined small and large cells groups within a lymph node supports the concept of the clonal origin of single molecular species of gamma globulin.
