Cyclosporin A therapy in a cat with pure red cell aplasia

The case of a one year and 7 months old castrated male cat suffering from severe, non regenerative anaemia (packed cell volume: 8,6%; reticulocyt count: 1 parts per thousand) is presented. A combined ELISA-test for feline leukaemia virus antigen and antibodies against feline immunodeficiency virus was negative. Using indirect Coomb's test IgM as well as the complement component C3b could be demonstrated on the erythrocytes. Cytological investigation of the bone marrow revealed a selective, nearly complete aplasia of the erythropoiesis. Immunosuppressive therapy with cyclosporin A (6,25 mg/kg BW orally, twice daily) and prednisolone (initially 5 mg/kg BW intravenously, twice daily) from the 9th day on led to a distinct regeneration of erythropoiesis with reticulocyte counts up to 126 parts per thousand (341.000/mu l)and normalisation of the red blood picture as well as the general state of health. The therapy with cyclosporin A was continued for five months, reducing the dosis after 30 days to 6,25 mg/kg EW orally once daily corresponding to an extremly high blood level of cyclosporine A. At control examinations 24 and 63 days after depositing therapy all parameters of the red blood picture were within the reference range. This case report indicates that pure red cell aplasia can be due to an autoimmune process in cats also as well.