The plasma cell disorders are monoclonal neoplasms related to each other by virtue of their development from common progenitors in the B lymphocyte lineage. Multiple myeloma, Waldenström's macroglobulinemia, primary amyloidosis (Chap. 324), and the heavy chain diseases comprise this group and may be designated by a variety of synonyms such as monoclonal gammopathies, paraproteinemias, plasma cell dyscrasias, and dysproteinemias. Mature B lymphocytes destined to produce IgG bear surface immunoglobulin molecules of both M and G heavy chain isotypes with both isotypes having identical idiotypes (variable regions). Under normal circumstances, maturation to antibody-secreting plasma cells is stimulated by exposure to.
