Pure red-cell aplasia (PRCA) is defined as the absence of mature erythroid precursors in a bone marrow that otherwise exhibit normal cellularity. Acquired PRCA may occur in association with neoplasms (such as lymphoproliferative disorders), thymoma, autoimmune disorders, pregnancy, or as a consequence of chronic human parvovirus B19 (B19) infection in an immunologically incompetent host. PRCA may also develop after exposure to drugs (erythropoietin or tacrolimus). PRCA of autoimmune origin was first treated successfully with intravenous immunoglobulins (IVIg) more than 20 years ago. Since then, B19-associated PRCA in solid-organ transplant recipients and in human immunodeficiency virus (HIV)-infected patients has also been successfully treated with IVIg. Routine maintenance therapy is probably not indicated in HIV-infected patients with CD4+ counts above 300/microL, whereas repeated infusions might be necessary if CD4+ count is below 80.