Although different KIR and HLA variants may have been selected in different populations primarily due to differential risk of malaria, the role of other infectious pathogens that are prevalent in these malaria-endemic populations should not be overlooked, as they may also have exerted selective pressure on the evolution of KIR and HLA. Therefore, the role of other co-infections should be considered in future studies involving KIR and malaria, especially in populations affected by many infectious pathogens. The gene discussed is KIR3DL1; the disease is malaria.