Hemagglutination and hemolytic titrations of antisera using red cells to which antigens have been conjugated with bis(diazo)benzidine have been used as a measure of antibody activities (1--4) in this laboratory. Hemagglutination and immune hemolysis fitrations have comparable sensitivities. Immune hemolysis, however, can be modified to give a high degree of precision (5). Both methods have been...

1. The titer of an individual insulin antiserum measured by hemagglutination agrees favorably with the titer of the same antiserum as measured by immune hemolysis. 2. In contrast, a marked decrease is noted in the immune hemolysis titers relative to hemagglutination titers of antisera prepared against three different sialic acid-containing proteins (human chorionic gonadotropin, rabbit transfer...

Non-immune hemolytic anemia (NIHA) is characterized by positive routine hemolytic tests but negative anti-human immunoglobulin (Coombs) test. Hereditary non-immune hemolysis includes disorders of erythrocytic enzymes, membrane, hemoglobin (qualitative and quantitative disorders), as well as the rare hereditary forms of thrombotic microangiopathies. Acquired NIHA includes paroxysmal nocturnal he...

A quantitative method for the study of the kinetics of immune hemolysis is described. In the presence of excess C' and limited amounts of antibody the kinetics of hemolysis resemble those of enzymatic processes. Assays of hemolytic antibody should therefore be based on velocity measurements rather than end point titrations.

The Donath-Landsteiner reaction was studied using low and high titer antisera and purified antibody, normal and PNH erythrocytes, and human serum complement. The requirement for complement in both the cold and warm phases of the reaction depended upon the level of antibody used and the sensitivity of the cells to hemolytic antibodies. Complement was not necessary in the cold phase using PNH cel...