Pathology of the mononuclear cell leukemia of Fischer rats. II. Hematology.

Complete hemograms were evaluated for 57 rats with mononuclear cell leukemia and compared to hemograms obtained from 52 age- and sex-matched nonleukemic rats. All leukemic rats had marked hemolytic anemia and associated spherocytosis, reticulocytosis, anisocytosis, and polychromasia. The anemia varied with the stage of illness and was more severe in rts with advanced leukemia. Death appeared to be related to anemia. There was a marked neutrophilia with left shift, mild lymphopenia, and moderate to severe thrombocytopenia. Atypical mononuclear cells were detected in circulation in all but three rats. Total white blood cell counts ranged from 5.0-370 x 10(3) cells/ml. There was an increase in erythrocyte osmotic fragility with separation into two distinct populations of erythrocytes. Eight of nine rats were Coombs' positive indicating an immune-mediated pathogenesis for the anemia. Hemostasis tests revealed a markedly prolonged prothrombin time, hypofibrinogenemia, slightly increased to normal partial thromboplastin time, and undetected fibrin degradation products. These findings suggest significant liver disease associated with the leukemia.