T activation haemolysis and death after blood transfusion

A 30 week gestation infant developed necrotising enterocolitis associated with Clostridium perfringens septicaemia at 3 weeks of age. He responded to treatment with intravenous fluids, antibiotics, and blood, but his blood haemolysed. Because of anaemia further blood was given, but, within minutes he died. Examination of his red cells showed an increase in T activation.