IgE-induced blood coagulation alterations in the rabbit: consumption of coagulation factors XII, XI, and IX in vivo

Intravenous administration of BSA into 3-month-old rabbits producing detectable anti-BSA antibody only of the IgE class of immunoglobulin induced a variety of intravascular blood coagulation alterations observed in the plasma 15 min after antigen challenge included: a) the intravascular consumption of intrinsic blood coagulation factors XII, XI, and IX and possibly the reduction in clottable fibrinogen; b) a significant prolongation of the activated partial thromboplastin time but not the prothrombin time; and c) the production of an inhibitor affecting the last stage of blood coagulation. The observed blood coagulation alterations were not caused by the manipulative procedures utilized, the presence of anti-BSA, IgG or IgM antibody, histamine-induced alterations in the vascular endothelium or the development of hypotensive shock. It is proposed that specific IgE antibody can induce directly or indirectly the activation of intrinsic blood coagulation in vivo.

[Adsorption properties of Beidellite (author's transl)]

The beidellite is both an activator and an adsorbing agent for certain clotting factors: at low concentration (1 p. 1 000), factors XII and VII of human plasma are activated. At a concentration of 10 p. 1 000, the fibrinogen is totally adsorbed, leaving in the supernatant most of the VIII. At alpha 20 p. 1 000 concentrations, most of factor II remains unabsorbed, the remaining plasma being devoided of other clotting factors except minute amounts of factors XI and XII. Contrarely to bentonite, which has similar properties, beidellite does not absorb water and does not modify the pH. Beidellite is therefore a very useful agent for selective adsorption of clotting factors.

Current concepts of the mechanism of acute inflammation in gouty arthritis

The acute gouty attack develops after free crystalline monosodium urate crystals appear in the joint cavity (1). Recent developments in the investigation of urate crystal-induced inflammation have led to a better understanding of the pathogenesis of acute gouty arthritis. The purpose of this review is to summarize present concepts concerning the mechanism of the acute gouty attack.

A new family with congenital factor XII deficiency

The case of a patient with Hageman trait and his family study are reported. Commercial plasma thromboplastin time (PTT) reagents showed a good sensitivity for detecting the plasma defect. By prolonging the incubation time of the mixture containing PTT reagent and factor XII-deficient plasma the abnormal coagulation times were not corrected. Thus, a concomitant Fletcher factor deficiency could be excluded.

Substrates of Hageman factor. I. Isolation and characterization of human factor XI (PTA) and inhibition of the activated enzyme by alpha 1-antitrypsin

Unactivated partial thromboplastin antecedent (PTA) has been purified by sequential chromatography of plasma on quaternary aminoethyl Sephadex, sulphoprophyl Sephadex, Sephadex G-150, and passage over an anti-IgG immunoadsorbant. The preparation gave a single band after alkaline disc gel electrophoresis, sodium dodecyl sulfate (SDS) gel electrophoresis and isoelectric focusing in acrylamide gels and was found to have a mol wt of 175,000 by gel filtration, 163,000 by SDS gel electrophoresis, and an isoelectric point of 8.8-9.4 (peak 9.0-9.1). Pre-PTA was activated directly by activated Hageman factor or by Hageman factor prealbumin fragments. Its coagulant activity was inhibited by DFP, soybean trypsin inhibitor and trasylol but not by lima bean trypsin inhibitor or ovomucoid trypsin inhibitor indicating that activated PTA possesses the same inhibition profile utilizing these reagents as does plasma kallikrein. A major plasma inhibitor of activated PTA was found to be a 65,000 mol wt alpha-globulin which was isolated free of alpha(1)-chymotrypsin inhibitor, inter alpha-trypsin inhibitor, alpha(2)-macroglobulin, and the other known inhibitors of activated PTA, the activated first component of complement (C1 INH), and antithrombin III. Its physicochemical properties were identical to alpha(1)-antitrypsin, and it was absent in alpha(1)-antitrypsin-deficient plasma thereby identifying this PTA inhibitor as alpha(1)-antitrypsin.

Structural changes accompanying enzymatic activation of human Hageman factor

The structure of Hageman factor, isolated from human plasma, was analyzed before and after enzymatic activation. The purified molecule is a single polypeptide chain of 80,000 molecular weight (mol wt) sedimenting at 4.5S. An amino acid analysis has been performed. The concentration of Hageman factor in normal human plasma was found to be 29 mug/ml with variation between individuals ranging from 15 to 47 mug/ml. Treatment of the molecule with kallikrein, plasmin, or trypsin resulted in cleavage at two primary sites, yielding fragments of 52,000, 40,000, and 28,000 mol wt. No further changes occurred in the fragments with subsequent reduction. Prekallikrein-activating ability was associated exclusively with the 28,000 moiety.

Direct evidence for Hageman factor (factor XII) activation by bacterial lipopolysaccharides (endotoxins)

Purified precursor Hageman factor has been demonstrated to bind to soluble bacterial lipopolysaccharide (LPS, endotoxin) isolated from Escherichia coli 0111:B4, and this complex has been shown to have the capacity to convert prekallikrein to its active form. In addition, LPS-activated Hageman factor substantially reduces clotting times in XII-deficient plasma. The capacity to activate Hageman factor has been demonstrated to reside in the lipid A region of the LPS molecule. Activation of Hageman factor by LPS contrasts with fluid-phase activation (e.g., by kallikrein or trypsin) in that no cleavage to lower molecular weight fragments occurs. High concentrations of LPS inhibit the activity of Hageman factor, probably by a direct LPS-Hageman factor interaction.

Fletcher factor deficiency. A diminished rate of Hageman factor activation caused by absence of prekallikrein with abnormalities of coagulation, fibrinolysis, chemotactic activity, and kinin generation

Fletcher factor-deficient plasma is deficient in prekallikrein and therefore generates no bradykinin upon activation with kaolin. It also possesses a diminished rate of kaolin-activable coagulation and fibrinolysis and possesses a defect in kaolin-activable chemotactic activity. These abnormalities are also corrected by reconstitution with purified prekallikrein. Addition of intact activated Hageman factor corrected the coagulation, fibrinolytic, and chemotactic defects and addition of Hageman factor fragments corrected the fibrinolytic defect and partially corrected the chemotactic defect; neither of these corrected the kinin-generating defect. Although the Hageman factor-dependent pathways appear to be initiated by contact activation of Hageman factor, the kallikrein generated activates more Hageman factor; this feedback is necessary for the Hageman factor-dependent pathways to proceed at a normal rate. It is the absence of this feedback in Fletcher factor-deficient plasma that accounts for the diminished rate of activation of Hageman factor and therefore a diminished rate of activation of the coagulation and fibrinolytic pathways. The ability of prekallikrein to correct the coagulation, fibrinolytic, kinin-generating, and chemotactic defects of Fletcher factor-deficient plasma is consistent with the identity of the Fletcher factor and prekallikrein.

Activation of Hageman factor in solid and fluid phases. A critical role of kallikrein

The activation of Hageman factor in solid and fluid phase has been analyzed. Activation of highly purified Hageman factor occurred after it interacted with and became bound to a negatively charged surface. Activation was observed in the absence of enzymes that are inhibitable with diisopropylfluorophosphate, phenyl methyl sulfonyl fluoride and epsilon-amino-n-caproic acid. The binding of [(125)I]Hageman factor to the negatively charged surface was markedly inhibited by plasma or purified plasma proteins. Activation of Hageman factor in solution (fluid phase) was obtained with kallikrein, plasmin, and Factor XI (plasma thromboplastin antecedent). Kallikrein was greater than 10 times more active in its ability to activate Hageman factor than plasmin and Factor XI. The data offer a plausible explanation for the finding that highly purified kallikrein promotes clotting of normal plasma. In addition, the combined results of this and previously reported data from this laboratory indicate that the reciprocal activation of Hageman factor by kallikrein in fluid phase is essential for normal rate of activation of the intrinsic-clotting, kinin-forming, and fibrinolytic systems. Activation of Hageman factor was associated with three different structural changes in the molecule: (a) Purified Hageman factor, activated on negatively charged surfaces retained its native mol wt of 80-90,000. Presumably a conformational change accompanied activation. (b) In fluid phase, activation with kallikrein and plasmin did not result in cleavage of large fragments of rabbit Hageman factor, although the activation required hydrolytic capacity of the enzymes. (c) Activation of human Hageman factor with kallikrein or plasmin was associated with cleavage of the molecule to 52,000, 40,000, and 28,000 mol wt fragments. Activation of rabbit Hageman factor with trypsin resulted in cleavage of the molecule into three fragments, each of 30,000 mol wt as noted previously. This major cleavage occurred simultaneously with activation.