Positive irregular antibody screen due to leukocyte antibody

A case is described of a multi-transfused, multiparous woman whose serum gave positive results in routine screening for irregular antibodies. No red cell antibodies could be identified, however, and apparently compatible units were crossmatched for this patient. Upon administration of a unit of whole blood, the patient exhibited severe chills and fever. Her serum was found to contain a strong anti-HLA 17, and possibly other white cell antibodies, as well. It is suggested that the positive irregular antibody screen detected the leukocyte antibody, because of expression of HLA antigens on the screening cells.