In other cases of severe malaria, such as cerebral and placental malaria, high levels of pro-inflammatory cytokines and growth factors, such as TNF, interferon (IFN)-γ and granulocyte/macrophage colony stimulating factor (GM-CSF) could potentially polarize tissue macrophages to M1 phenotype; this remains to be proven in future studies. This evidence concerns the gene CSF2 and malaria.