That is most likely to have been the case.

Transfusion-Related Acute Lung Injury (TRALI) In A Multipara Patient

"TRALI is a severe transfusion reaction resulting in acute lung collapse damage due to blood transfusion. It is considered to be initiated by leucoaglutinins or HLA specific antibodies transfer which already existed in the donor serum."

—The Internet Journal of Anesthesiology