Unreleased intracellular monoclonal macroglobulin in chronic lymphocytic leukaemia.

Abstract

In two patients presenting as chronic lymphocytic leukaemia, immunofluorescence studies have demonstrated the presence of an accumulated intracytoplasmic material reacting with antisera to μ chains and only to one type of light chains, whereas their serum contained neither monoclonal IgM nor free μ chains. In the first case, the IgM lambda inclusion bodies were crystals detected in the cytoplasm of small lymphocytes and were not clearly lined by rough endoplasmic reticulum. IgM λ molecules were present at the surface of the lymphocytes. In the other patient, who elaborated free κ light chains, the inclusions found in marrow plasma cells and in peripheral blood lymphocytes were Russell bodies. The practical and theoretical importance of non-secretory immunoproliferative disorders, characterized by an unreleased monoclonal immunoglobulin marker, is outlined.