title: Characterization of autoantibodies in mixed-type autoimmune hemolytic anemia.
abstract: Three of 46 patients with autoimmune hemolytic anemia (AIHA) satisfied the diagnostic criteria for mixed-type AIHA in which both warm-type and cold-type autoantibodies against red blood cells (RBCs) are present. The specificities of these autoantibodies were analyzed. All of the warm-type autoantibodies were IgG-chi, and the specificities were not serologically classified. The autoantibody of patient 1 reacted to the 41- and 80-kD peptides on immunoblotting, and the epitope corresponding to it was papain sensitive. Two warm-type autoantibodies from patients 2 and 3 resembled each other in serological analyses and reacted with a protease- and neuraminidase-resistant antigen. However, the antigen corresponding to the autoantibody of patient 3 was located on the 37-kD peptide by immunoprecipitation. All of the cold-type autoantibodies were IgM-cha and showed high titer and high thermal amplitude. According to the reaction pattern with untreated and enzyme-treated RBCs, the cold-type autoantibodies of patients 2 and 3 were revealed to be anti-Om and anti-I, respectively. In patient 1, the cold-type autoantibody was characterized as having high affinity for autologous RBCs, but its specificity was unclassified. The antigens corresponding to the cold-type autoantibodies were not located by immunoblotting and immunoprecipitation. These serological and immunochemical approaches to autoantibodies in mixed-type AIHA revealed that the warm and cold components recognized the different antigens.
authors.affiliation: Department of Forensic Medicine and Human Genetics, Tochigi, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Kajii
authors.forename: Y
authors.initials: Y
authors.lastname: Miura
authors.forename: S
authors.initials: S
authors.lastname: Ikemoto
mesh_terms: D000368:Aged; D000744:Anemia, Hemolytic, Autoimmune / Q000209:etiology / Q000276:immunology*; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology* / Q000302:isolation & purification; D001323:Autoantibodies / Q000276:immunology* / Q000302:isolation & purification; D003298:Coombs Test; D003450:Cryoglobulins / Q000276:immunology* / Q000302:isolation & purification; D004910:Erythrocyte Membrane / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology*; D007145:Immunoglobulin kappa-Chains / Q000276:immunology; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000150:complications; D013696:Temperature
chemical_list: D000888:Antibodies, Anti-Idiotypic; D001323:Autoantibodies; D003450:Cryoglobulins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007145:Immunoglobulin kappa-Chains