Serology of Acquired Hemolytic Anemias.

I F A SERUM contains a gamma globulin which will react with ( agglutinate, hemolyze or sens tize ) certain enetically well-defined red blood cells but not others, it is said to possess an antibody and the antibody is said to be specific for a certain property of the red cells. Thus the specificity of an antibody depends on this selective reactivity. This is often difficult to demonstrate if the range of activity is widespread and if there are only a very few cells available which will lack the property against which the antibody reacts. A good many blood grouping laboratories have in their freezers, sera containing antibodies against “Public Antigens” which up to now remained unclassified because they react with all available red cells except those of the patient or donor. Nobody, however, will dispute the antibody nature of these reagents or call them “unspecific.” It is remarkable that this point of view is not applied to the antibodies found in acquired hemolytic anemia (AHA ) . Some of these antibodies have been demonstrated to have narrow blood group specificity, but nevertheless some workers designate the majority of them as “unspecific” and even doubt that they are antibodies. If these “unspecific” agents could be shown to be “specific,” that is, not to react with certain genetically welldefined red cells, more workers might be persuaded to regard them as true antibodies. We, therefore, thought that a useful purpose might be served by investigating hemolytic anemias with the use of a large cell panel which included some rare and very rare cells.