Pure Red Cell Aplasia

Key Features

• Acquired disease is rare; in adults, it is usually idiopathic

• Cases have been seen in association with systemic lupus erythematosus, chronic lymphocytic leukemia (CLL), lymphomas, or thymoma

• Some medications (phenytoin, chloramphenicol) may cause red cell aplasia

• Rarely, anti-erythropoietin antibodies cause pure red cell aplasia in patients who are treated with recombinant erythropoietin

Clinical Findings

• The only signs are those of anemia unless the patient has an associated autoimmune or lymphoproliferative disorder

• Transient episodes of red cell aplasia are probably common in response to viral infections, especially parvovirus infections

• Acute episodes go unrecognized unless the patient has a chronic hemolytic disorder or a chronic immunocompromised state, in which case the hematocrit may fall precipitously

Diagnosis

• Anemia is often severe and normochromic, with low or absent reticulocytes

• Red blood cell morphology is normal, and the myeloid and platelet lines are unaffected

• Bone marrow

  • Normocellular with markedly reduced or absent erythroid progenitors

  • All non-erythroid elements are present and normal

• The bone marrow karyotype is normal on standard banding cytogenetics

• Chest imaging may reveal a thymoma

Treatment

• Possible offending drugs should be stopped

• Most patients will require red blood cell transfusion support

• Resection of thymoma may result in amelioration of anemia

• High-dose intravenous immune globulin has produced responses in a small number of cases, mainly during parvovirus infections

• Treatment of choice for idiopathic cases is immunosuppressive therapy with a calcineurin inhibitor (ie, cyclosporine)

• Monotherapy with corticosteroids produce responses in 30–60% of cases, but relapses are common once corticosteroids are discontinued

• Anti-CD20 monoclonal antibody (rituximab) is the treatment of choice in the setting of anti-erythropoietin antibodies

• In patients with an associated lymphoproliferative disorder, treating the neoplasm should also treat the anemia