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Pure Red Blood Cell Aplasia

By

Gloria F. Gerber

, MD, Johns Hopkins School of Medicine, Division of Hematology

Reviewed/Revised Jun 2023
View PATIENT EDUCATION

Acquired pure red blood cell aplasia is a disorder of erythroid precursors that results in an isolated normocytic anemia. White blood cells and platelets are not affected. Symptoms result from anemia and include fatigue, lethargy, decreased exercise tolerance, and pallor. Diagnosis requires demonstration of peripheral normocytic anemia and a normocellular bone marrow biopsy with absence of erythroid precursors. Treatment usually involves treatment of underlying cause and in some cases thymectomy or immunosuppression.

Etiology of Pure Red Blood Cell Aplasia

Pure red blood cell (RBC) aplasia is most often due to an inappropriate immune response causing suppression of erythropoiesis. Well-known causes include

Symptoms of Pure Red Blood Cell Aplasia

Symptoms of pure RBC aplasia are generally mild and relate to the degree of the anemia or to the underlying disorder. The onset of pure red blood cell anemia usually is insidious, often occurring over weeks or months. Symptoms related to anemia include fatigue, lethargy, decreased exercise tolerance, and pallor.

Diagnosis of Pure Red Blood Cell Aplasia

  • Complete blood count (CBC), reticulocyte count

  • Bone marrow examination

  • Peripheral blood smear looking for large granular lymphocytes

  • Sometimes peripheral blood flow cytometry and T cell gene rearrangement testing

Pure RBC aplasia manifests with a normocytic anemia but normal white blood cell and platelet counts. Reticulocytes are decreased (absolute reticulocyte count < 10,000/microliter, reticulocyte percentage < 1%).

The bone marrow reveals normal cellularity with a maturation arrest at the proerythroblast stage. In parvovirus B19 infection, giant pronormoblasts may be present. Although not widely available, if possible, a marrow burst forming units-erythroid (BFU-E) assay should be obtained to differentiate autoimmune causes of pure red cell aplasia from primary bone marrow disorders such as myelodysplastic syndrome Myelodysplastic Syndrome (MDS) The myelodysplastic syndrome (MDS) is group of clonal hematopoietic stem cell disorders typified by peripheral cytopenia, dysplastic hematopoietic progenitors, a hypercellular or hypocellular... read more (1 Diagnosis reference Acquired pure red blood cell aplasia is a disorder of erythroid precursors that results in an isolated normocytic anemia. White blood cells and platelets are not affected. Symptoms result from... read more ).

Chest CT is indicated to evaluate for thymoma in the absence of another identified cause.

Diagnosis reference

Treatment of Pure Red Blood Cell Aplasia

  • Immunosuppression

  • Sometimes intravenous immunoglobulin (IVIG) or thymectomy

Some patients undergo spontaneous remission after an ABO-incompatible stem cell transplant, if the causative medication is stopped, or following delivery if pregnancy is the cause.

Pure RBC aplasia has been successfully managed with immunosuppressants (eg, prednisone, cyclosporine, cyclophosphamide), especially when an autoimmune mechanism is suspected.

Pure RBC aplasia secondary to parvovirus infection is treated with intravenous immune globulin.

Thymectomy is done in patients with thymoma-associated pure RBC aplasia; most patients improve but are not always cured and require immunosuppressive agents.

Key Points

  • Pure red cell aplasia involves isolated erythroid hypoplasia.

  • Immune-mediated suppression of the erythroid cell line is the most likely cause.

  • Bone marrow cellularity is normal with an arrest of erythroid maturation causing a normocytic anemia.

  • Direct treatment of underlying cause with thymectomy, IV immune globulin (IVIG), or immunosuppression.

Drugs Mentioned In This Article

Drug Name Select Trade
No brand name available
Deltasone, Predone, RAYOS, Sterapred, Sterapred DS
Cequa, Gengraf , Neoral, Restasis, Sandimmune, SangCya, Verkazia, Vevye
Cyclophosphamide, Cytoxan, Neosar
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NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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