[Cold agglutinin disease and paroxysmal cold hemoglobinuria].
Recent progress on the studies of cold agglutinin disease and paroxysmal cold hemoglobinuria is reviewed. In both types of autoimmune hemolytic anemia, auto-antibodies are directed specifically to the antigenic epitopes which have physiological significance as differentiation antigens. They are the metabolic precursors for the synthesis of strong allo-antigens such as ABO(H). Although both antigen epitopes, i.e., differentiation and allo-antigen epitopes, are present on the red blood cells, the autoimmune reaction is directed specifically to the differentiation antigen epitopes, and not directed to the strong allo-antigenic epitopes. Most of auto-antigens also serve as receptors for some viruses, bacteria and drugs. Recent analysis on the sequence of auto-antibodies indicated that most of the auto-antibodies in cold agglutinin disease are encoded by the VH-4-21 gene of VH4 family, indicating the auto-antibodies are produced by dysregulation of very limited B cell clones. This implies that immune system is prone to be disturbed with self differentiation antigens rather than strong self allo-antigens, and that the dysfunction of auto-reactive B cell clones could be triggered by infection of some viruses and bacteria, or by certain medication.
Kannagi
R
R
Laboratory of Experimental Pathology, Aichi Cancer Center.
Mitsuoka
C
C
D000373:Agglutinins / Q000276:immunology*; D000744:Anemia, Hemolytic, Autoimmune / Q000175:diagnosis / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology; D003080:Cold Temperature; D003450:Cryoglobulins; D006388:Hemagglutinins / Q000276:immunology*; D006457:Hemoglobinuria, Paroxysmal / Q000175:diagnosis / Q000276:immunology*; D006801:Humans
D000373:Agglutinins; D001324:Autoantigens; D003450:Cryoglobulins; D006388:Hemagglutinins; C029443:cold agglutinins