What are the disadvantages of homologous blood?

Homologous blood has both practical and medical disadvantages. Bank blood is expensive, there is often a shortage of donated blood and there are sometimes dificulties finding a matching donor. Homologous blood transfusions are also accompanied by the risk of disease transmission, most importantly of HIV, HBV and HCV. Apart from known viruses no one knows what the next virus will be and when it will appear. Homologous blood transfusion also exposes the patient to the risk of transfusion reactions as well as negative immunological effects, such as higher rates of postoperative infections amongst patients who recieve homologous blood compared to those who recieve autologous blood.