Effects of combinations of stem cell factor and hemin on erythropoiesis after azidothymidine treatment of immunosuppressed mice.

Recombinant cytokines such as stem cell factor (SCF) are currently being tested for the ability to ameliorate 3'azido-3'deoxythymidine (AZT) induced anemia in AIDS patients. Recently, we demonstrated that SCF and hemin in vitro greatly increased the resistance of burst-forming units erythroid (BFU-E) to AZT. We therefore attempted to ameliorate AZT-induced anemia in vivo using SCF and hemin in immunodeficient LP-BM5 infected (MAIDS) mice. SCF and hemin were administered with oral AZT for 3 wk and the effects on erythropoiesis examined. Hemin significantly increased hematocrits of AZT-treated mice and control mice. However, SCF and SCF-hemin combinations failed to raise hematocrits. Reticulocyte numbers were significantly consistently increased only in hemin-treated mice receiving AZT. The numbers of CFU-E were increased in bone marrow of AZT-treated mice receiving hemin. Therefore, SCF did not enhance the erythropoietic effect of hemin in AZT-treated immunodeficient mice.