In recent years, several attempts have been made to elucidate the mechanisms leading to HIV-associated anemia. Direct infection of erythroid progenitors has been considered but remains unproven. Soluble factors like HIV proteins and cytokines have been suggested to inhibit growth of hematopoietic cells in the bone marrow of HIV-infected patients. However, it remains unproven whether these factors are directly involved in myelosuppression or mediate their effects by inhibiting growth factor synthesis. Opportunistic complications represent the underlying cause for anemia in a large number of HIV-infected persons.
Iatrogenic anemia induced by myelosuppressive drugs is also common.
Instead, other drugs that can induce anemia by themselves or by enhancing plasma concentrations of zidovudine must be considered important contributing factors. However, most HIV-infected persons maintain appropriate storage amounts of these micronutrients. Supplementation may be beneficial in some patients but often fails to correct HIV-related anemia. Reticulocytopenia is a consistent finding in HIV-related anemia. In addition, low endogenous erythropoietin concentrations have been repeatedly reported.