Autoimmune haemolytic anaemias. 3. Preparation and examination of specific antisera against complement components and products, and their use in serological studies.

The preparation and examination of agglutinating antisera, specific for β1E, β1A, α2D and the /β1C/ determinant of the β1C molecule are described. With these reagents it could be established that anticomplement serum does not contain antibodies against the B determinant of the β1C molecule, while antiserum prepared with β1C globulin does. Further, the complement factors present on red cells, the complement coating of which was effected in various ways, were studied. Whereas red cells incubated with haemolytic iso- or auto-antibodies are agglutinated by anti-β1E, anti-β1A and anti-α2D sera, the cells of patients with autoimmune haemolytic anaemia of any of the serologically defined groups of this disease, only reacted with anti-α2D. The possible significance of these findings is discussed.