title: Life-threatening, antiglobulin test-negative, acute autoimmune hemolytic anemia due to a non-complement-activating IgG1 kappa cold antibody with Pra specificity.
abstract: A 21-year-old man with fulminant cold autoantibody hemolytic anemia (CAHA) was hospitalized with hemoglobinemia, hemoglobinuria, hemoglobin concentration of 3.3 gm per dL, a negative direct antiglobulin test (DAT) with polyspecific and anti-C3d reagents, a negative Donath-Landsteiner test, and a cold agglutinin titer of 80. He failed to respond to corticosteroids, multiple plasma exchanges, and cyclophosphamide; he required 54 transfusions in 10 days to maintain a hemoglobin concentration of 6.0 to 10.0 g per dL. He improved dramatically after a splenectomy was performed. The wide-thermal-amplitude cold agglutinin proved to be an IgG1 kappa antibody with Pra specificity. The patient's serum exhibited normal complement activation. When the DAT was carried out at 0 to 4 degrees C, the result was strongly positive for IgG; the indirect antiglobulin test at 0 to 4 degrees C was positive with the patient's serum diluted 1 in 640. Within 6 months, he was in complete remission and receiving no therapy. As compared with eight patients with CAHA that was exclusively IgG-mediated, this patient is remarkable for his requirement for many transfusions and for DATs that were consistently negative for C3d.
authors.affiliation: Department of Pathology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: B R
authors.initials: BR
authors.lastname: Curtis
authors.forename: J
authors.initials: J
authors.lastname: Lamon
authors.forename: D
authors.initials: D
authors.lastname: Roelcke
authors.forename: H
authors.initials: H
authors.lastname: Chaplin
mesh_terms: D000328:Adult; D000373:Agglutinins / Q000032:analysis*; D000744:Anemia, Hemolytic, Autoimmune / Q000276:immunology*; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000918:Antibody Specificity; D003167:Complement Activation; D015933:Complement C3d / Q000032:analysis; D003298:Coombs Test / Q000379:methods; D003450:Cryoglobulins; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D008875:Middle Aged
chemical_list: D000373:Agglutinins; D000888:Antibodies, Anti-Idiotypic; D003450:Cryoglobulins; D007074:Immunoglobulin G; C029443:cold agglutinins; D015933:Complement C3d