Answer
Upon disease progression, individuals with HIV infection develop a moderate to severe hypoproliferative anemia. The most common form of anemia observed in patients infected with HIV has the characteristics of anemia of chronic disease. In addition, anemia may be a complication of opportunistic infections or may be due to marrow damage from the virus or from antiretroviral drug toxicity (eg, zidovudine).
Thrombocytopenia may be an early manifestation of HIV infection. Approximately 3% of patients infected with HIV with CD4 cell counts greater than 400/µL have platelet counts of less than 150,000/µL. Of patients who have CD4 cell counts less than 400 cells/µL, 10% also have platelet counts of less than 150,000 cells/µL.
HIV-associated thrombocytopenia is rarely a serious clinical problem. In most cases, platelet counts remain greater than 50,000 cells/µL and the condition can be treated conservatively.
Idiopathic thrombocytopenia in persons with HIV infection is very similar to the thrombocytopenia observed in individuals with idiopathic thrombocytopenic purpura (ITP). Antibodies against HIV (anti-GP160/120) have been shown to also bind to platelets (anti-GPIIb/IIIa). [3] Because these data point to an immunologic basis for thrombocytopenia in persons infected with HIV, most of the treatments used are immune-based.
Another mechanism for HIV-induced thrombocytopenia is a direct effect of HIV on megakaryocytes. This is evidenced by a defect and subsequent decrease in platelet production.
In addition, thrombocytopenia has been reported as a consequence of classic thrombotic thrombocytopenic purpura (TTP) in patients infected with HIV. This clinical syndrome, consisting of fever, thrombocytopenia, hemolytic anemia, and neurologic and renal dysfunction, is a rare complication of early HIV infection.
-
Electron microscopy of human immunodeficiency virus (HIV)–1 virions. Courtesy of CDC/Dr. Edwin P. Ewing, Jr.
