[Hemolytic anemia secondary to taking cyanidanol: demonstration of the mechanism of the erythrocyte damage].

A 36-year-old patient with chronic active hepatitis developed Coombs direct positive acute hemolytic anemia 2 weeks after a second course of cyanidanol (Cy). The patient's serum agglutinated control 0 Rh- erythrocytes only in the presence of Cy. Human anti-globulin test showed that the red cells were covered with IgG as well as C3 and C4. Control erythrocytes previously treated with Cy were also agglutinated by the patient's serum (dilution 1:64). Upon addition to the serum of Cy (concentration up to 10 micrograms/ml), the agglutination was enhanced up to a serum dilution of 1:256. Further increase of the Cy concentration (greater than 10 micrograms/ml) was followed by a decreased reaction. These results indicate that red cell damage in this patient was mediated by both mechanisms, i.e. with immune complexes acting on "normal" red cells and also with antibodies acting on cyanidanol-coated red cells.