Autoimmune haemolytic anaemia induced in mice immunized with rat erythrocytes

Abstract

C₃H mice immunized with rat erythrocytes developed autoimmune haemolytic anaemia which was very similar to the `warm-type' autoimmune haemolytic anaemia of man. There was evidence of anaemia, reticulocytosis, shortened survival times of ⁵¹Cr-labelled erythrocytes in vivo, and a high incidence of positive direct Coombs' tests. There was no evidence of spherocytosis or of increased susceptibility to osmotically induced lysis. Bone marrow smears showed evidence of erythroid hyperplasia. Splenectomized mice were more severely affected than unsplenectomized mice. In these mice anaemia was more severe, individual positive direct Coombs' tests were stronger; ⁵¹Cr-labelled erythrocytes were cleared faster and the compensatory erythroid hyperplasia was less marked. After immunization was stopped both groups of mice quickly became haematologically normal. However, in mice in which immunization was continued, the blood pictures eventually reverted towards normal except for the persistent positive direct Coombs' tests. C57/B1 mice were also susceptible to the disease process but to a much lesser degree than C₃H mice.