A 65-year-old Asian-American woman was diagnosed with chronic hepatitis C (HCV), genotype 2 and was referred for treatment of her HCV infection. Abdominal imaging showed a nodular appearance of the liver and hypersplenism with mild thrombocytopenia and leukopenia: baseline white blood cell count 3.2-3.5 × 109/L, neutrophil count 1.2-1.5 × 109/L, hemoglobin 13.5-14.0 g/dL and platelet count 90-100 × 109/L. She was treated with peg-interferon and ribavirin, but therapy was stopped after 3 weeks because of neutropenia and flu-like symptoms. Peg-interferon and ribavirin were re-initiated 8 months later with growth factor support: granulocyte-colony stimulating factor (G-CSF, Neupogen®) 300 μg subcutaneously once to twice weekly and epoetin-alfa (Procrit®) 40,000 units subcutaneously every 1 to 2 weeks. HCV viral load was undetectable by week 4 of therapy. At week 14, she developed severe pancytopenia, with a nadir absolute neutrophil count of 0.4 × 109/L, hemoglobin 6.5 g/dL and platelet count of 20 × 109/L despite continued use of growth factors. Packed red blood cell (PRBC) and platelet transfusions were initiated, and ribavirin was discontinued. Peg-interferon was continued at a reduced dose through week 27, at which time it was stopped. The patient continued to require intermittent transfusions between weeks 14 and 27 of treatment despite continued therapy with epoetin-alfa 40,000 units subcutaneously twice a week. HCV RNA was undetectable at the end of treatment.
Two months after discontinuation of anti-HCV therapy, the patient was referred to Hematology for persistent anemia. At that time, she denied any bleeding or jaundice, and her main symptoms were fatigue and dyspnea on exertion. On physical examination, she had normal vital signs, no jaundice, ecchymoses or petechiae, no lymphadenopathy and palpable hepatosplenomegaly. Laboratory examinations revealed: white blood cell count 4.0 × 109/L, neutrophil count 1.6 × 109/L, hemoglobin 8.9 g/dL, mean corpuscular volume 88 fL, platelet count 63 × 109/L, reticulocyte count 2.6 × 109/L (normal range, 26-110 × 109/L) and an erythropoietin level of 34 mIU/mL (normal range 4.1-19.5). A peripheral blood smear showed a reduction in all three hematopoietic cell lines but with normal cellular morphology. Her ferritin level was 2981 μg/L and thyroid stimulating hormone (TSH), vitamin B12 and folate levels were all normal. Lactate dehydrogenase (LDH) was mildly elevated at 189 IU/L (normal range 91-185) and the direct Coomb's test was negative.
Bone marrow biopsy showed 10% cellularity with profound erythroid hypoplasia, normal myeloid maturation and normal megakaryocytes (Figures and ). The hypocellularity was thought to be due to prior interferon therapy or possibly HCV infection (though the hepatitis C viral load was undetectable), and the thrombocytopenia was felt to be due to hepatic cirrhosis and hypersplenism. Given the clinical picture of severe anemia and near absent erythroid precursors in the bone marrow, the patient was initially thought to have ribavirin-induced PRCA, and she received two doses of intravenous gammaglobulin (IVIG) 1 g/kg monthly for 2 months, without any hematologic improvement. Analysis of the patient's serum showed IgG1 antibodies to epoetin alfa at a titer of 14.05 μg/mL, which neutralized the biologic activity of epoetin in vitro. This confirmed a diagnosis of PRCA due to anti-epoetin antibodies. Epoetin-alfa was discontinued.
Bone marrow aspirate. Bone marrow aspirate showing hypocellularity (overall 10%), near absence of erythroid precursors with full maturation of the myeloid series and normal megakaryocytes.
Bone marrow biopsy. Core biopsy showing hypocellularity (overall 10%), near absence of erythroid precursors with full maturation of the myeloid series and normal megakaryocytes.
The patient then received rituximab 375 mg/m2 intravenously weekly for four doses with monthly IVIG 0.5 g/kg for 4 months starting at the time of rituximab therapy. Within 5 months, the reticulocyte count began to increase, which corresponded to a decreasing trend in PRBC transfusions (Figure ). Eight months after treatment, she again had a drop in her reticulocyte count. The anti-epoetin alfa antibody titer was 7.52 μg/mL and was no longer neutralizing. She was retreated with rituximab at the same dose and schedule as before and there appeared to be another more transient reticulocyte count response, and though this did not translate to a significant change in PRBC transfusions initially, the anemia eventually resolved. Her last blood transfusion occurred 27 months after her initial rituximab course, and her hemoglobin remains stable and normal, 14 months after her last transfusion. The anti-epoetin alfa antibody titer at 37 months after her initial rituximab course was 3.19 μg/mL. The HCV viral load continues to be undetectable and her liver disease remains compensated.
Figure 3 Reticulocyte and red cell transfusions during rituximab therapy. Pattern of reticulocyte count and red cell transfusions over time since the diagnosis of pure red cell aplasia. Rituximab 375 mg/m2 was given weekly × 4 weeks during months 1 and (more ...)