Dextran-induced anaphylactoid reaction in man: altered reactivity of high molecular weight kininogen.

Normal levels of factor XII and of high and low molecular weight kininogens (HMWK and LMWK) were registered in plasma specimens from 5 individuals who had developed anaphylactoid reactions upon injection of dextran during surgery (dextran reactors, DR). Factor XII was assayed as prekallikrein activator (PKA) activated with kaolin at 0 degrees, and kininogen fractions were estimated through the release of kinin caused by plasma kallikrein or hog pancreas kallikrein (HPK). Subnormal levels of factor XII apparently present in plasma from one DR, and after affinity chromatography on a lysine-Sepharose column also in plasma from another DR, were normalized by addition of plasma deficient in factor XII or by addition of purified HMWK. Treatment of plasma from DR with acetone (25% v/v) induced a conversion of HMWK into a state which was non-functional as a cofactor in the surface-dependent activation of factor XII, and the passage of plasma from DR through a lysine-Sepharose column altered the HMWK present to a substance that released kinin only very slowly by incubation with HPK. It is concluded that the treatments mentioned will favour the activation in plasma from DR of a factor that will cause the conversion of HMWK. Previous experiments with rat plasma demonstrated that plasmin and also a plasmin-like factor without affinity for lysine-Sepharose were able to destroy the capacity of HMWK to function as a cofactor in the surface-dependent activation of factor XII, without a corresponding release of kinin.