Données récentes sur les Gammapathies monoclonales

Abstract

Monoclonal gammopathies (M.G.) are a group of disorders characterized by the proliferation of a single clone of plasma-cells that produce a Monoclonal Immunoglobulin (M-Ig). The presence of M-Ig can be demonstrated by electrophoresis in the patient' serum and identified by immunoelectrophoresis as a molecule containing two heavy chains of a single class and two light chains of a single type. In M.G. of malignant origin, free light chains (Bence Jones Proteins) can be evidenced in the concentrated urines. The fact that M.G. may be more frequent in certain families show the existence of a familial predisposition of this disease whereas its origin is still unknown. M.G. are often associated with malignant proliferation of B lymphocytes such as multiple myeloma, Waldenström's macroglobulinemia, heavy chain disease as well as some other lymphoproliferative disorders. However, in a certain number of cases, the malignant origin of the M.G. was not proved, because M-Ig can occur in the serum of people apparently in good health and without clinical or hematological features (asymptomatic "benign" M.G.). Asymptomatic benign M.G. have been detected in increasing numbers during the last decade due to use of cellulose acetate electrophoresis for the routine examination of patients or in the course of systemic screening in normal populations such as blood donors. At the present time, a malignant origin of M.G. cannot be proved in more than thirty per cent of case and these "asymptomatic M.G." must be follow-up by a yearly clinical, hematological and electrophoretical check-up in order to detect a possible malignant evolution. In other cases, M.G. can be associated with neoplasms of cells types not known to produce M-Ig, in cold chronic agglutinin disease, and during the course of some auto-immune disorders.