Author Information

An event is serious (based on the ICH definition) when the patient outcome is:

  • * death

  • * life-threatening

  • * hospitalisation

  • * disability

  • * congenital anomaly

  • * other medically important event

A 10-year-old boy developed thrombocytopenia and haemolytic anaemia following treatment with tacrolimus for immunosuppression and allograft preservation [route, dosage and time to reaction onset not stated].

The boy, who had undergone liver transplant, had been receiving immunosuppressant therapy with tacrolimus. Three and a half year after the transplantation, he developed severe thrombocytopenia. Three months after the diagnosis of thrombocytopenia, he was admitted with scleral icterus, pallor and splenomegaly. Laboratory findings revealed haemoglobin 5.4 g/dL, reticulocyte count 27.3%, WBC 9600/mm3, platelet count 233000/mm3, total bilirubin 2.8 mg/dL and lactate dehydrogenase 763 U/L. A peripheral blood smear showed marked spherocytosis, and a direct Coombs test was positive for warm antibodies.

The boy was diagnosed with autoimmune haemolytic anaemia and he was treated with prednisone. At the time of admission, his tacrolimus dose was also reduced to target a serum level of 2.8 ng/mL. His haemoglobin was maintained at 10−11 g/dL and reticulocyte count was maintained at 7−10%. His steroid dose was reduced, and treatment with immune-globulin was initiated, but no improvement was observed. After two weeks of initial presentation, he again developed fatigue, shortness of breath and palpitations. Laboratory tests revealed reticulocytes 17.2% and haemoglobin 6.4 g/dL. His haemoglobin continued to decrease, so he started receiving methylprednisolone and immune-globulin, after which no improvement was observed. After another month with no response to corticosteroids and IVIG, tacrolimus was suspected to be the causative agent and was discontinued. Hence, he started receiving sirolimus as immunosuppression therapy. Two weeks after switching to sirolimus, his haemoglobin normalised to 12.8 g/dL and reticulocyte count was 2%.

Author comment: "On the basis of what is known and the events that we observed in our case, we believe that tacrolimus use was responsible for our patient developing thrombocytopenia and immune hemolytic anemia."