B-Lymphoproliferative disorders: A Proposed unified pathogenetic pathway

The clinical features of lymphoproliferative diseases associated with paraproteinemia are briefly reviewed and correlated with current immunologic concepts in an effort to clarify the pathophysiology of B‐lymphocyte disorders. B‐lymphocyte maturation proceeds in a predictable manner from the Pre‐B cell to the formation of idiotype specific plasma cells and memory B‐lymphocytes. The immunoglobulin isotype produced by the mature plasma cell is determined by a site specific process of gene switching which proceeds from μ to a production. Lymphoproliferative diseases are the result of disordered B cell maturation and their clinical features can be explained by identifying the locus of the maturational defect.