Plasma requirement for expression of lupus-like anticoagulant

Described here are five patients with lupus-like anticoagulants, four of whom required coincubation of normal plasma in order to inhibit the pro-coagulant activity of crude brain phospholipid. It is suggested that this plasma requirement for expression of anticoagulant activity is similar or identical to the "lupus-cofactor" effect described by earlier observers.