Other factors that may contribute to anemia during HIV infection include the direct effect of HIV-1 on bone marrow cells, adverse reactions to antiretroviral drugs, opportunistic infections and neoplasms infiltrating the bone marrow, vitamin B12 or iron deficiency, autoimmune hemolytic anemia, circulating anti-EPO autoantibodies, and other coexisting medical conditions [5]. Here, EPO is linked to anemia (phenotype).