Allergic reaction to transfused cephalothin antibody.

Antibodies to cephalothin sodium (Keflin) can be transferred passively via whole blood transfusion. In one case a mild allergic-type reaction was initiated in a patient who was receiving cephalothin therapy. This case is differentiated from a penicillin-caused allergic reaction. All patients that demonstrate allergic-type transfusion reactions should give drug histories. Investigation of passive transfer of antibodies to these drugs might be of benefit in any evaluation made.