Pure red cell aplasia is defined by the combination of anemia, reticulocytopenia, and the absence of erythroid precursors on the marrow examination, but the pathophysiologies are diverse. In children, a genetic defect in ribosome protein genes is responsible for Diamond-Blackfan anemia. In older adults, pure red cell aplasia is usually immune-mediated, sometimes associated with thymoma, and responsive to immunosuppressive therapies. The syndrome can overlap with other diseases, especially large granular lymphocytosis, or complicate them, as with chronic lymphocytic leukemia or myelodysplastic syndrome. Parvovirus B19 is an infectious etiology, acutely producing transient aplastic crisis of hemolytic anemia and, when persistent, identical to pure red cell aplasia. The exclusive loss of erythrocyte production is a rare complication of medical drug therapy, but pure red cell aplasia can be iatrogenic, as with anti-erythropoietin antibodies after administration of the hormone and in ABO-incompatible allogeneic transplantation caused by persistence of host isoagglutinins.
Acronyms and Abbreviations
B19, primate erythroparvovirus 1; BFU-E, burst-forming unit–erythroid; CD20, a cluster of differentiation molecule expressed on the surface of all mature B cells; CFU-E, colony-forming unit–erythroid; CLL, chronic lymphocytic leukemia; FA, Fanconi anemia; GATA1 gene, globin transcription factor 1; HLA, human leukocyte antigen; Ig, immunoglobulin; IL, interleukin; LGL, large granular lymphocytosis; NF-KappaB, nuclear factor kappa-light-chain-enhancer of activated B cells; RAS, ra(t) s(arcoma) a group of proteins that are found near cell membranes and regulate cell division and proliferation. Mutated RAS facilitate uncontrolled cell division, leading to the development of tumors; RPS ribosomal protein genes; STAT3 gene, signal transducer and activator of transcription 3 gene; T cell, thymus-derived lymphocyte; TP53, tumor protein p53
Pure red cell aplasia is the diagnosis applied to isolated anemia secondary to failure of erythropoiesis. Cardinal findings are a low hemoglobin level combined with reticulocytopenia and absent or extremely infrequent marrow erythroid precursors. Historical names for pure red cell aplasia include erythroblast hypoplasia, erythroblastopenia, red cell agenesis, hypoplastic anemia, and aregenerative anemia. Aplastic anemia confers the same meaning, of course, but denotes pancytopenia and an empty marrow (Chap. 36). Pure red cell aplasia as a diagnostic entity was separated from aplastic anemia by Kaznelson in 1922. The association of red cell aplasia and thymoma interested physicians in the 1930s and ultimately led to laboratory studies linking pure red cell aplasia to immune mechanisms, including the early identification of antierythroid precursor cell antibodies by Krantz and later characterization of T cells that inhibited erythropoiesis. Red cell aplasia as an acute and life-threatening complication of sickle cell disease and other hemolytic anemias was reported in the 1940s, presaging the role of a specific virus in the etiology of both acute and chronic erythropoietic failure. Despite its infrequency, pure red cell aplasia has been a subject of much laboratory research because of its link to an immune mechanism of erythropoietic failure and as a manifestation of parvovirus B19 infection and viral destruction of red cell progenitors. However, because of its ...