[Studies of IgG subclasses of anti-erythrocyte antibodies contained in human plasma preparation products].

Anti-A and anti-B antibodies (1: 1-1: 1, 024) of IgM or IgG type of the titers 1: 1-1: 1, 024 were detected in all of the lots of heat-treated human plasma protein (38 Lots), albumin (15 Lots), factor VIII or IX products (9 Lots) and immune globulin preparations for intravenous use (IVIG) (20 Lots) examined. Twelve out of 20 lots of IVIG contained unexpected anti-erythrocyte antibodies of IgG type. Though IgG1 antibody was detected in all of these 12 lots, antibodies composed of all subclasses including IgG3 could be detected in only 8 lots of them, all showing the anti-erythrocyte antibody titer of IgG type over 1:64. Conversely, none of the lots, in which the titer was less than 1:32, contained IgG3 antibodies. A patient of chronic ITP, 28-year-old female of blood type A and Rh-positive, showed contradictive results between the main (A type) and the accessory test (O type) of red blood cell grouping, accompanied with hemolytic anemia, following intravenous high-dose immune globulin therapy (400 mg/kg x successive 5 days), which was attributable to the anti-A antibody of IgG type composed of IgG1,2,3,4 in the IVIG administered. For high dosage administration of human plasma preparation products, those containing only low titer of unexpected anti-erythrocyte antibody should be selected.