AHF related protein in clinical praxis

Elevated FVIII levels in hereditary hemorrhagic telangiectasia: Implications for clinical management

Objectives

The objective of this study was twofold: to determine the prevalence of arterial and venous thromboembolic events in the Norwegian Hereditary Hemorrhagic Telangiectasia (HHT) population, and to explore potential factors linked to such events, with particular emphasis on FVIII.

Methods

Patients with an HHT diagnosis attending the Otorhinolaryngology Department at Oslo University Hospital-Rikshospitalet were included consecutively between April 2021 and November 2022. We recorded the participants' medical history with an emphasis on thromboembolic events. Measurements of blood constituents, including FVIII, FIX, vWF, hemoglobin, iron, ferritin, and CRP were performed.

Results

One hundred and thirty-four patients were included in the study. The total prevalence of thromboembolic events among the participants was 23.1%. FVIII levels were high (>150 IU/dL) in the majority of HHT patients (n = 84) (68.3%) and were significantly associated with thromboembolic events (p < .001), as was age. Of the patients with high FVIII levels, 28 (33%) had experienced a thromboembolic event. Furthermore, FVIII levels were measured consecutively in 51 patients and were found to fluctuate above or below 150 IU/dL in 25% of these cases.

Conclusion

Thromboembolic events are highly prevalent in the Norwegian HHT population and are significantly associated with FVIII levels. FVIII levels can fluctuate, and measurements should be repeated in HHT patients to assess the risk of thromboembolic events.

Level of Evidence

4.

Overshoot of FVIII activity in patients with acquired hemophilia A who achieve complete remission

Acquired hemophilia A (AHA) is a rare, life-threatening bleeding disorder caused by autoantibodies against coagulation factor VIII (FVIII). Immunosuppressive therapy for AHA aims to arrest bleeding by eliminating FVIII inhibitors. Factor VIII activity overshoot after complete remission (CR) has been reported anecdotally, but details remain unclear. We retrospectively analyzed data from 17 patients with AHA who achieved CR under immunosuppressive therapy between 2009 and 2019 at Gunma University Hospital. FVIII activity overshoot was defined as ≥ 150%. All 17 patients had low FVIII activity (median 2.1%; range < 1.0-8.9%) due to FVIII inhibition (median 14.7 BU/mL; range 2.0-234.0) and all achieved CR within a median of 39 (range 19-173) days. Overshoot occurred in 11 (64.7%) patients and maximal FVIII activity reached > 200% in six of them. The median duration from CR to overshoot was 13 (range 0-154) days. The FVIII overshoot was transient (72.7%) or persistent (27.3%). Venous thromboembolism developed as a complication of overshoot in one patient due to iliac vein compression by a massive hematoma. Overshoot of FVIII activity after CR occurs more frequently than previously expected in patients with AHA.

Inheritable molecular variants of moderate and mild hemophilia A

Factor VIII clotting activity (VIII:C) and factor VIII clotting antigen (VIII:CAg) were investigated in 54 patients with hemophilia A of moderate or mild severity. The patients belonged to 28 kindreds. The study showed a genetically determined molecular variation within hemophilia A of both moderate and mild forms. Each form can be classified into 3 types according to the content of demonstrable VIII:CAg. Type I has no demonstrable VIII:CAg, type IIa has VIII:CAg in an amount smaller than, or approximately equal to, that of VIII:C and type IIb has a larger amount of VIII:CAg than VIII:C. Affected members of one and the same kindred always have the same type of the disease.

beta-Thromboglobulin in acute myocardial infarction

The plasma beta-thromboglobulin level was studied serially in 14 patients with acute myocardial infarction. In 7 patients the plasma beta-thromboglobulin was initially high. The most severely affected patients had the highest values. Three patients with a mild or moderate clinical course had a normal beta-thromboglobulin level at every stage. The remaining patients had a distinct pattern in the evolution of the plasma beta-thromboglobulin values. The initial phase was followed by a uniform fall during the first days and then by an increase. The highest values were in many cases measured at discharge. Platelet counts showed a similar pattern. Signs of activation of platelets were seen before changes in coagulation and fibrinolysis.

Pharmacokinetics of coagulation factors: clinical relevance for patients with haemophilia

Haemophilia is a recessively inherited coagulation disorder, in which an X-chromosome mutation causes a deficiency of either coagulation factor VIII (FVIII) in haemophilia A, or factor IX (FIX) in haemophilia B. Intravenous administration of FVIII or FIX can be used to control a bleeding episode, to provide haemostasis during surgery or for long term prophylaxis of bleeding. In special cases, activated factor VII (FVIIa) may be used instead of FVIII or FIX. The aim of this work is to review the pharmacokinetics of FVIII, FIX and FVIIa and to give an outline of the use of pharmacokinetics to optimise the treatment of patients with haemophilia. The pharmacokinetics of FVIII are well characterised. The systemic clearance (CL) of FVIII is largely determined by the plasma level of von Willebrand factor (vWF), which protects FVIII from degradation. Typical average CL in patients with normal vWF levels is 3 ml/h/kg, with an apparent volume of distribution at steady state (Vss) that slightly exceeds the plasma volume of the patient, and the average elimination half-life (t1/2) is around 14 hours. There are still some discrepancies in the literature on the pharmacokinetics of FIX. The average CL of plasma-derived FIX seems to be 4 ml/h/kg, the Vss is 3 to 4 times the plasma volume and the elimination t1/2 often exceeds 30 hours. FVIIa has a much higher CL (average of 33 ml/h/kg), and a short terminal t1/2 (at 2 to 3 hours). The Vss is 2 to 3 times the plasma volume. Since the therapeutic levels of coagulation factors are well defined in most clinical situations, applied pharmacokinetics is an excellent tool to optimise therapy. Individual tailoring of administration in prophylaxis has been shown to considerably increase the cost effectiveness of the treatment. Dosage regimens for the treatment of bleeding episodes or for haemostasis during surgery are also designed using pharmacokinetic data, and the advantages of using a constant infusion instead of repeated bolus doses have been explored. The influence of antibodies (inhibitors) on the pharmacokinetics of FVIII and FIX is in part understood, and the doses of coagulation factor needed to treat a patient can tentatively be calculated from the antibody titre. In conclusion, therapeutic monitoring of coagulation factor levels and the use of clinical pharmacokinetics to aid therapy are well established in the treatment of patients with haemophilia.

Bleeding complications and coagulopathy in acute leukaemia

Factors and inhibitors of coagulation and fibrinolysis were investigated on admission in 57 patients with acute leukaemia and they were correlated to the occurrence of haemorrhage. Coagulation disturbances were found in 98%. Seventeen of the patients with haemorrhagic symptoms had major bleeding. Severe thrombocytopenia (< 20 x 10(9)/l) was found in 16%. Patients with major bleedings had significantly lower concentrations of prothrombin complex, fibrinogen, protein C and platelets. Low levels of antiplasmin and fibrinogen were characteristic of 'bleeders' with promyelocytic and lymphoblastic leukaemia. We found a positive correlation between vWF:Ag and leukaemic cell count especially in lymphoblastic leukaemia (ks = 0.72). Reduced levels of antithrombin indicated a poorer prognosis.

Type IIB von Willebrand's disease: gene mutations and clinical presentation in nine families from Denmark, Germany and Sweden

Type IIB of von Willebrand's disease (vWD) is a variant in which the structurally abnormal von Willebrand factor (vWF) shows an increased affinity for the platelet vWF receptor, glycoprotein Ib (GPIb). This may sometimes give rise to platelet aggregation and thrombocytopenia in vivo. In 20 patients from nine unrelated families with type IIB vWD from Denmark, Germany and Sweden we studied the molecular defect by amplification and direct sequencing of parts of exon 28 which encode for the vWF domain that interacts with platelet GPIb. Three different point mutations were identified one of which has not previously been reported. Fifteen patients from five families were heterozygous for the Arg543-->Trp substitution. The mutation had occurred independently in all five families and in two of them represented a de novo mutation. In one of these families the father, though asymptomatic and with normal laboratory test results, carried the mutation in heterozygous form. In three families, four affected members were found to be heterozygous for the Arg543-->Cys substitution. The mutations were of different origin at least in two of the families. The third substitution, Val551-->Leu, which has not previously been described, was found in one patient and was due to a de novo mutation. In most of the patients spontaneous thrombocytopenia had been recorded on at least one occasion. Five of the patients with the Arg543-->Trp substitution and the one with the Val555-->Leu substitution had all had bleeding associated with thrombocytopenia in the neonatal period of early infancy.

Immunoquantitation of von Willebrand factor (factor VIII-related antigen) in vinyl chloride exposed workers

Angiosarcoma of the liver is a rare malignant tumor which has been associated with occupational exposure to vinyl chloride (VC). We have determined by ELISA the level of von Willebrand factor (vWf) in the serums of 107 VC-exposed workers, active or retired, and of 133 blood donors used as controls. The vWf level was slightly but significantly higher in the VC-exposed group than in the control group (P = 0.035). Seventeen VC-exposed workers exhibited a raised level of vWf, with no biochemical sign of hepatic disturbance, nor any evidence of illness; only one of them exhibited elevated alkaline phosphatase and gamma-glutamyl transpeptidase values. The vWf serum level of 3 patients with hepatic angiosarcoma associated to VC-exposure was markedly elevated. These increased levels of vWf in VC-exposed workers most likely reflect an increased activity of liver endothelial cells; whether an elevated level of vWf could be associated with increased risk of developing liver angiosarcoma remains to be determined.

Effects of desmopressin acetate on platelet aggregation, von Willebrand factor, and blood loss after cardiac surgery with extracorporeal circulation

The effects of desmopressin acetate (DDAVP) on platelet aggregation and the von Willebrand factor antigen (vWF:Ag) were studied in 19 patients undergoing cardiac surgery with extracorporeal circulation. The patients represented one of five blocks in a randomized double-blind placebo-controlled parallel group trial on the effects of DDAVP on postoperative bleeding after uncomplicated coronary artery bypass operations. After termination of extra-corporeal circulation, DDAVP (0.3 microgram/kg body wt) or its vehicle was infused into a peripheral vein throughout 15 minutes. The increase in factor VIII coagulant activity after infusion did not differ between the groups but there was a significantly larger increase in vWF:Ag levels in DDAVP-treated patients. The aggregatory response to adenosine-diphosphate (ADP) and ristocetin showed a normal pattern and was not significantly different between the two groups. As compared with placebo, DDAVP did not decrease the bleeding time or the postoperative blood loss. We conclude that DDAVP causes an increase in vWF:Ag levels but does not alter platelet aggregation, bleeding time, or blood loss in uncomplicated coronary artery bypass patients.

A prospective survey of risk factors in young adults with arterial occlusive disease

Few studies have presented a thorough analysis of young adults with symptoms of arterial occlusive disease. To learn more about the possible risk factors of vascular disease playing a role in these young patients, we have reviewed all patients of 45 years of age and younger with symptoms of arterial occlusive disease who had been referred to our department between 1978 and 1987. Thirty-seven patients (28 males and 9 females) were included in the study. The mean age at which the first symptoms occurred was 34 years. Most patients presented with chronic arterial obliterations of the lower extremities (31/37, 84%). In addition, 4 patients showed signs of ischaemic heart disease. A strongly positive family history of arteriosclerosis was obtained from 13 patients (35%). Hypertension was present in 7 patients (19%), diabetes in three (8%) and nicotine abuse was found in 27 patients (73%). Fifty-four percent of the patients (20/37) had undergone vascular reconstructive surgery, 19% (7/37) underwent transluminal dilatation, and 3 had had subsequent treatment of newly developed lesions. For this study, all patients were recalled to the outpatient clinic. A complete case history was taken followed by a physical examination and ECG. Laboratory examinations were performed to analyse parameters of: (a) coagulation; (b) fibrinolysis; (c) fat- and (d) methionine metabolism. Clear-cut laboratory abnormalities were found in 33 patients (33/37, 89%). Coagulation parameters were abnormal in 11 patients (30%) (protein S deficiency: 3 pts). Fibrinolysis was impaired in 15 patients (40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Promotion and subsequent inhibition of plasminogen activation after administration of intravenous endotoxin to normal subjects

To evaluate the effect of endotoxin on the fibrinolytic response, we administered Escherichia coli endotoxin (4 ng per kilogram of body weight) intravenously to 19 healthy volunteers and measured fibrinolytic proteins, protease inhibitors, neutrophil elastase, and von Willebrand factor in serial blood samples obtained over 24 hours. One hour after endotoxin administration, the level of tissue plasminogen activator (t-PA) antigen rose from 10 to 23 ng per milliliter, peaking at 52 ng per milliliter at three hours. The level of alpha 2-plasmin inhibitor-plasmin complexes increased sevenfold, peaking at three hours. Plasminogen-activator inhibitor-1 activity rose more slowly, from 7 U per milliliter to a maximum of 49 U per milliliter at five hours. The concentrations of neutrophil elastase and von Willebrand antigen were unchanged at one hour, increased approximately threefold by 3 hours, and remained elevated at 24 hours. None of these measures changed in a control group (n = 5) given intravenous saline instead of endotoxin. We studied t-PA functional activity in four subjects. The level of activity rose rapidly, from 1.2 ng per milliliter at base line to 8.3 ng per milliliter at one hour and 13.9 ng per milliliter at two hours; it was undetectable at three hours. This increase in plasminogen activator activity was abolished in vitro by incubation of t-PA with an antiserum specific for human t-PA, suggesting that t-PA may be directly responsible for plasmin generation in the response to endotoxin. We conclude from this study of healthy subjects that endotoxin activates the fibrinolytic system, beginning with release of t-PA in the blood within one hour. The early activation of plasmin by endotoxin may prevent thrombosis, and the increase in fibrinolysis is then offset by the release of plasminogen activator inhibitor.

von Willebrand factor is an acute phase reactant in man

Plasma von Willebrand factor antigen (vWfAg) concentrations in 19 patients with acute infectious illnesses of bacterial, viral or parasitic origin were significantly elevated with a mean greater than 3-fold above normal. In individual patients the elevation of vWf correlated strongly with the elevation of serum C-reactive protein (CRP). When patients were studied longitudinally, vWfAg and CRP concentrations both returned to normal values over 3-4 weeks. Similarly, in 14 volunteers infected with cold virus, vWfAg and CRP levels rose significantly and fell together during the course of infection. VWf is thus an acute phase reactant in man.

Immediate effects of heparin and LMW heparin on some platelet and endothelial derived factors

Heparin and a low molecular heparin fragment, injected intravenously in volunteers, increased the plasma concentrations of platelet factor 4, but did not induce platelet activation as judged from excretion of 2,3-dinor-TxB2 (a major thromboxane A2 metabolite) and beta-thromboglobulin (btg) in urine and from btg levels in plasma. Heparin prolonged, within the normal range, the bleeding time in all six subjects. Platelet aggregation in platelet rich plasma was potentiated by both heparins, but platelet number, mean platelet volume and platelet distribution width were not affected. No evidence for endothelial release of prostacyclin was obtained as judged from urinary excretion of 2,3-dinor-6-keto-PGF1 alpha (a major prostacyclin metabolite), and plasma concentrations of tissue plasminogen activator, its inhibitor (PAI-1) and the von Willebrand-factor were unchanged.

IIB von Willebrand's disease: pathogenetic and therapeutic studies

Infusion of 1-deamino-(8-D-arginine)-vasopressin (DDAVP) into patients with IIB von Willebrand's disease (vWD) has been reported to induce thrombocytopenia. In some families with this disorder thrombocytopenia is present even in the resting state. We have investigated the basis of this chronic thrombocytopenia in one such patient by performing platelet recovery and survival studies. Increased platelet consumption was suggested by a decrease in platelet recovery (40.5%, normal 45%) and mean platelet survival (112 h, normal range 144-224 h). In addition, we have administered test infusions of DDAVP and observed the effect on bleeding time and platelet count. DDAVP caused a decrease in the median platelet count from 86 x 10(9)/l (range 30-221) to 60 x 10(9)/l (range 5-144), the individual decline in the nine subjects ranging from 12% to 84% compared to the pretreatment values. Formation of platelet aggregates was observed in all patients following DDAVP. The bleeding time was prolonged before DDAVP in all patients and lengthened further in two after the infusion. However, partial correction of the bleeding time was seen in three and normalization in one patient following DDAVP infusion. Two IIB vWD patients were treated with virus-inactivated cryoprecipitate (Ristofact). Infusion of cryoprecipitate was followed by rapid appearance of all but the largest vWF multimers in plasma and did not affect the platelet count. The bleeding time was normalized in one patient but remained prolonged in the other. In conclusion, in IIB vWD patients virus-inactivated cryoprecipitate is the treatment of choice in the case of bleeding. Infusion of DDAVP might be effective in a subset of IIB vWD patients that has yet to be characterized.

Interleukin 1 or endotoxin increases the release of von Willebrand factor from human endothelial cells

von Willebrand factor (vWF), a large adhesive glycoprotein, is synthesized by vascular endothelial cells (EC). Plasma levels of vWF manifest a broad normal range, and are elevated during sepsis and in inflammatory states. Since the inflammatory mediator, interleukin 1 (IL1) and bacterial endotoxin (LPS) both initiate procoagulant changes in vascular endothelium, we investigated the effect of these substances on endothelial cell release and residual endothelial cell content of vWF-antigen (vWFAg). Cultured human EC exposed to either IL1 or LPS released greater amounts of vWFAg compared to control EC. The augmented release could be detected within 1-2 h after exposure to IL1 or LPS and was not inhibited by cycloheximide, suggesting that de novo protein synthesis was not required for release to occur. Residual cellular vWFAg was reciprocally lower in IL1- or LPS-treated EC at 24 and 48 h, indicating that compensatory increase in synthesis of vWFAg did not occur during this time interval. Released vWF contained the higher molecular weight multimers observed in normal endothelial cells, and it possessed ristocetin cofactor activity. We propose that release of functional vWF from EC exposed to inflammatory mediators may be at a mechanism for localization of platelets and enhanced thrombogenicity at inflammatory foci.

Interleukin 1 or endotoxin increases the release of von Willebrand factor from human endothelial cells

von Willebrand factor (vWF), a large adhesive glycoprotein, is synthesized by vascular endothelial cells (EC). Plasma levels of vWF manifest a broad normal range, and are elevated during sepsis and in inflammatory states. Since the inflammatory mediator, interleukin 1 (IL1) and bacterial endotoxin (LPS) both initiate procoagulant changes in vascular endothelium, we investigated the effect of these substances on endothelial cell release and residual endothelial cell content of vWF-antigen (vWFAg). Cultured human EC exposed to either IL1 or LPS released greater amounts of vWFAg compared to control EC. The augmented release could be detected within 1-2 h after exposure to IL1 or LPS and was not inhibited by cycloheximide, suggesting that de novo protein synthesis was not required for release to occur. Residual cellular vWFAg was reciprocally lower in IL1- or LPS-treated EC at 24 and 48 h, indicating that compensatory increase in synthesis of vWFAg did not occur during this time interval. Released vWF contained the higher molecular weight multimers observed in normal endothelial cells, and it possessed ristocetin cofactor activity. We propose that release of functional vWF from EC exposed to inflammatory mediators may be at a mechanism for localization of platelets and enhanced thrombogenicity at inflammatory foci.

Factor VIII related antigen in the assessment of vasculitis

Factor VIII related antigen, an endothelial cell product, was markedly raised in systemic necrotising arteritis, reflecting disease activity, but was not raised in active cutaneous vasculitis. In rheumatoid arthritis high levels were only found in systemic vasculitis or Felty's syndrome, but in other connective tissue diseases increased levels were more frequently detected and usually related to disease activity. It did not correlate with C reactive protein. It was also raised in non-inflammatory peripheral vascular disease and after surgery and was not specific for vasculitic endothelial damage. Factor VIII related antigen may be useful in identifying and monitoring systemic necrotising and large vessel arteritis.

A pilot study; desmopressin (DDAVP) in the treatment of deep venous thrombosis

In a pilot study on 9 patients with acute deep venous thrombosis of the leg the fibrinolytic response and the possible thrombolytic effect of desmopressin (DDAVP), when given supplementary to standard heparin treatment, was examined. Six injections of 0.3-0.4 microgram DDAVP/kg b.w. at 12 hours intervals were given. No serious side effects were observed. The fibrinolytic variables that followed showed that plasma levels of t-PA increased significantly and most pronounced after the first injection. Rephlebography 4-7 days after hospitalization showed partial thrombolysis in 7 out of 9 patients. The phlebographic score according to Marder was reduced from 22.7 +/- 12.1 to 18.4 +/- 10.1 (p = 0.018), corresponding to a thrombus size reduction of 19%. No correlation between the level of the fibrinolytic variables measured and the degree of thrombolysis in the individual patients, could be demonstrated in this small number of patients.

Epidemiology and pathogenesis of venous thrombosis

Venous thrombi are intravascular deposits composed predominantly of fibrin and red blood cells with a variable platelet and leukocyte component. They frequently arise in large venous sinuses in the calf, in valve cusp pockets either in the deep veins of the calf or thigh or in venous segments that have been exposed to direct trauma. Venous thrombosis can be produced experimentally by a combination of stasis and systemic hypercoagulability or by stasis and endothelial damage. Thrombosis is augmented if the fibrinolytic mechanism is inhibited or defective. A number of clinical conditions and laboratory abnormalities are associated with and predispose to venous thrombosis and, in many of these, it is possible to identify one or more of the thrombogenic factors discussed. Venous thromboembolism (venous thrombosis and pulmonary embolism) is a serious and potentially fatal disorder that usually complicates the course of sick hospitalized patients, but occasionally affects ambulant and otherwise healthy individuals. Screening studies with iodine-125 fibrinogen leg scanning, impedance plethysmography and perfusion lung scanning have shown that the majority of venous thrombi and pulmonary emboli that occur in hospitalized patients are small and asymptomatic, and it is likely that most are clinically insignificant. In bedridden patients, most thrombi commence in the calf and are asymptomatic. When a calf vein thrombus extends into the proximal venous segment, the risk of clinically significant pulmonary embolism increases. Less is known about the incidence and clinical significance in a nonhospital population; although asymptomatic disease occurs, its frequency is unknown. In contrast to the patients with asymptomatic venous thrombosis, symptomatic patients with venous thrombosis usually have large occulsive thrombi localized in their proximal veins.

Hemostasis and fibrinolysis in severe liver failure and their relation to hemorrhage

In a study of severe, decompensated liver failure, we tried to find a correlation between hemorrhage and parameters of hemostasis and fibrinolysis. Three groups of patients were studied: alcoholic cirrhosis; nonalcoholic cirrhosis, and acute liver failure without known prior liver disease. The two cirrhotic groups did not differ significantly from each other in coagulation or in fibrinolytic parameters, although liver function was more impaired in nonalcoholic cirrhosis. The levels of clotting factors, antithrombin III, prekallikrein, plasminogen and alpha 2-antiplasmin were significantly lower in the third group. Mean values of fibrinolytic activity (fibrin plate method) were slightly reduced as compared to normal in all three groups. Tissue plasminogen activator-related antigen tended to be elevated especially in alcoholic cirrhosis. The free fast-acting plasminogen activator inhibitor showed extremely high and extremely low levels in some patients among all three groups. Nonvariceal, capillary-type bleeding, including mucosal bleeding, hematomas and bleeding from puncture sites correlated with low thrombotest and normotest levels (p less than 0.01), low fibrinogen concentration (p less than 0.05) and with a high quotient of fibrinolytic activity (square root of lysis area) and normotest (p less than 0.001). The ratio between fibrin formation and dissolution appears to be an important parameter of hemorrhagic tendency in liver disease. Variceal bleeding appeared not to be related to impairment of hemostasis or fibrinolysis.

Factor VIII related antigen in gestational trophoblastic disease

Serum factor VIII related antigen (factor VIII R:Ag) levels were determined in 34 patients with hydatidiform mole at diagnosis and at 2, 4 and 6 weeks after evacuation of uterus and in 272 normal pregnant women. Serum factor VIII R:Ag levels in molar pregnancies before evacuation of the uterus were significantly higher than those in normal pregnancies of the same gestation age. Serum factor VIII R:Ag levels in the group of patients with residual trophoblastic disease were significantly higher than those in the group without residual trophoblastic disease before evacuation and at 6 weeks after evacuation of uterus, but there is considerable overlap in the levels of factor VIII R:Ag between the two groups of patients especially before evacuation of uterus. Factor VIII R:Ag level does not appear to be an useful marker in predicting the outcome of hydatidiform mole.

Factors and inhibitors of blood coagulation and fibrinolysis in acute nonlymphoblastic leukaemia

Factors of coagulation and fibrinolysis have been evaluated in 15 patients with untreated acute nonlymphoblastic leukaemia (ANLL). 10 patients had major bleeding (MB) and 6 had laboratory signs of DIC. 5 patients went into complete remission (CR). Antithrombin III (AT III) was decreased in 7 patients, antiplasmin (AP) in 9, fibronectin (FN) in 6 and factor XIII in 4/12. The ratio between factor VIIIR:Ag and factor VIII:C was over 2.0 in 11 patients, and high values were especially seen in patients with MB and patients with DIC. Spontaneous proteolytic activity, measured with S-2288 was increased in 3 patients who all had MB, and none of whom achieved CR. 2 patients with promyelocytic leukaemia (M3) had low fibrinogen and AP, high FDP and normal AT III, speaking for primary fibrinolysis, which in addition to proteolytic enzymes in the blast cells are important contributing factors regarding MB in ANLL.

Factor VIII-related antigen levels in normal pregnancy and puerperium

The changes in serum Factor VIII-related antigen (Factor VIII RAg) levels in normal pregnancy and puerperium in Chinese women were studied by the Laurell 'rocket' immunoelectrophoresis. At 6 wk of gestation, the serum Factor VIII RAg levels were already higher than those of non-pregnant women and gradually increased through term pregnancy. Parturition did not have immediate effects on the circulating levels of Factor VIII RAg. The levels of Factor VIII RAg observed during labour and days 1-5 postpartum were similar to those of term pregnancy. By the 6th wk postpartum, the serum Factor VIII RAg declined to basal levels, similar to those of non-pregnant control samples.

Platelet aggregation induced by 1-desamino-8-D-arginine vasopressin (DDAVP) in Type IIB von Willebrand's disease

Type IIB von Willebrand's disease is a distinct form of this disorder, in which there are abnormal factor VIII/von Willebrand factor multimers in plasma (but normal multimers in platelets) and heightened interaction between the von Willebrand factor and platelets in the presence of ristocetin. We have found that infusion of desmopressin acetate (1-desamino-8-D-arginine vasopressin [DDAVP]), an agent used in the treatment of von Willebrand's disease, causes platelet aggregation and thrombocytopenia in patients with Type IIB disease. In vitro, platelets in normal plasma and those obtained from patients with Type IIB disease before DDAVP infusion aggregated upon the addition of platelet-poor plasma from Type IIB patients treated with DDAVP. Platelet aggregation was associated with adsorption of multimers of factor VIII/von Willebrand factor onto the platelets and was inhibited by EDTA. We conclude that in Type IIB von Willebrand's disease, DDAVP releases an abnormal factor with platelet-aggregating properties. DDAVP should not be used to treat patients with Type IIB disease, since the presence of platelet aggregates in the circulation may be harmful.

Factor VIII complex in chronic renal failure: influence of protein C, fibrinolysis and diabetes mellitus

Chronic renal failure causes elevations of factor VIII coagulant activity and Factor VIII-related antigen even before the patients enter chronic hemodialysis. The change from control of Factor VIII ristocetin cofactor does not reach significance. The elevations are not effected by entering onto hemodialysis. These parameters are the same for non-diabetic and diabetic patients. Protein C, plasminogen and total fibrinolytic capacity are normal in diabetic and non-diabetic patients, with or without hemodialysis for chronic renal failure. However, before entering onto hemodialysis some of these parameters had negative correlation coefficients with parts of the factor VIII complex among the diabetic and non-diabetic patients. These negative correlates turned positive after hemodialysis. Thus, there are differences in these catabolic mechanisms for factor VIII when hemodialysis is used for diabetic and non-diabetic patients with chronic renal failure.

Fast migrating protein, immunochemically related to human factor VIII, studied by crossed immunoelectrophoresis in agarose

A fast migrating protein (FMP) was detected by agarose radio-crossed immunoelectrophoresis, in addition to factor VIII antigen (VIII:RAg), using antiserum to human factor VIII (FVIII). FMP had partial immunochemical identity with FVIII, migrated as an alpha-protein, and was distinct from alpha-2 macroglobulin, fibronectin or IgM. FMP was precipitated by concanavalin A and was separable from the bulk of VIII:RAg by ammonium sulphate fractionation. A significant amount of FMP was seen in normal serum (n = 12), plasma from patients with: (a) disseminated intravascular coagulation (n = 12) and (b) severe haemophilia A (n = 6). Trace amounts of FMP were observed in plasma from normal donors (n = 12), but neither VIII:ARg nor FMP was detectable in the plasma or serum from patients with severe von Willebrand's disease (n = 3). Freshly prepared cryoprecipitate contained trace amounts of FMP, similar to normal plasma, but increased levels were observed in antihaemophilic factor concentrates prepared for patient use. Significant levels of FMP were also seen in cryoprecipitate after storage at 4 degrees C for 7 d and this generation of FMP was diminished by the addition of protease inhibitors. The presence of significant levels of FMP in situations where proteolytic enzymes may be activated and inhibition of its generation by protease inhibitors, suggest that this protein is produced by proteolytic action of enzyme(s) on the FVIII molecule.

Comparative behaviour of the components of the factor VIII complex in acute myocardial infarction

The three components of the factor VIII complex: VIII coagulant (VIII:C), VIII related antigen (VIII R:Ag) and the VIII related von Willebrand factor (VIII R:WF) were studied in patients with acute myocardial infarction (AMI). Using a carefully standardized technique for the determination of VIII R:WF, a significantly higher R:WF level was found in 32 patients compared to 19 control subjects, confirming our previous results. However VIII R:AG was increased to an even greater extent, resulting in a VIII R:Ag/VIII R:WF ratio of 1.58 +/- 0.084 in patients, compared to 1.21 +/- 0.045 in controls. A similar increase of the VIII R:AG/VIII:C ratio was noted in the 13 patients in whom VIII:C was investigated. In 7 patients with severe AMI who could be investigated twice the plasma levels of both VIII R:Ag and VIII R:WF were found to be lower a week after the acute event than during the first 48 hours. However the VIII R:Ag/VIII R:WF ratio was not significantly reduced after 7 days. Acute phase reaction and endothelial injury resulting in release of multimers which are less polymerised are probably involved in the above changes.

Factor VIII complex in myelomatosis and related disorders

The behaviour of the factor VIII/von Willebrand factor complex (VIII:C, VIIIR:Ag and VIIIR:RCof) was investigated in 23 patients with secretory myeloma, in 2 patients with non-secretory myeloma and in 5 patients with macroglobulinemia. In most patients (21 of 25 patients with plasma cell myeloma and 2 of 5 patients with macroglobulinemia) VIIIR:Ag was increased usually without corresponding increases in VIII:C and VIIIR:RCof. There was no correlation between the VIIIR:Ag levels and paraprotein Ig type or level nor with the presence or the absence of Bence Jones proteins in serum and urine. Furthermore, increased levels of VIIIR:Ag were found in patients with non-secretory myeloma. In general, VIIIR:Ag was higher in patients with extensive bone lesions and there was a significant correlation between cell mass and the VIIIR:Ag level. The crossed-immunoelectrophoresis of plasmas with discrepant VIIIR:Ag and VIIIR:RCof showed variation from the normal pattern.

Oral contraceptives and venous thromboembolism

In 58 patients with phlebographically diagnosed deep vein thrombosis during oral contraception the extension and localization of the thrombotic process was analysed in relation to the coagulation and fibrinolytic system 6 months after thrombosis. Left-sided thrombi dominated and the thrombi were more extensive and proximal on the left side. This left-sided dominance was more apparent with higher oestrogen content in the pills. The right-sided thrombi more often were the source of pulmonary embolism. In 31% of the patients a defective fibrinolytic system was found; this defect was seen more often in patients with right-sided thrombi. Only very few defects were found in the coagulation system. No patients had an antithrombin III deficiency.

A study of hemostasis in ischemic cerebrovascular disease. I. Abnormalities in factor VIII and antithrombin

A sample of in all 119 young adults below the age of 55, with ischemic cerebrovascular disease (TIA and minor stroke), was investigated later than three months after acute disease. Factor VIII biological activity and antithrombin antigen were significantly (p less than 0.001) increased as compared to 80 healthy controls. In combination, these two variables correctly classified 85 percent of patients and controls at a stepwise discriminant analysis. Factor VIII related antigen was increased (p less than 0.02) in patients with atherosclerotic signs at cerebral angiography and in postmenopausal female patients (p less than 0.001). It is suggested that high levels of factor VIII might predispose for thrombosis/atherosclerosis. Antithrombin biological activity was normal in spite of high antithrombin antigen levels, possibly indicating a relative insufficiency in the antithrombin defense line. It is concluded that young stroke patients provide good opportunities to look for early operating factors and predictors in human atherosclerosis and arterial thromboembolism.

Plasma beta-thromboglobulin in acute myocardial infarction

Serial measurements of plasma beta-thromboglobulin concentration were made in 25 patients with acute myocardial infarction. The beta-thromboglobulin level was elevated in 18 patients on the day of presentation and the mean beta-thromboglobulin of the patients (83 ng/ml) differed significantly from the normal mean (26 ng/ml; p less than 0.001). When grouped according to the clinical severity, the most severely affected patients had the highest values (mean 128 ng/ml; n = 11). Two patients with a mild or moderate clinical course had a normal beta-thromboglobulin level throughout the study. The patients showed a distinct pattern in the evolution of the plasma beta-thromboglobulin values. The initial elevation was followed by a decrease in beta-thromboglobulin levels (mean 37 ng/ml on day 3), when only the severely affected patients differed from the normals. The beta-thromboglobulin level started to increase thereafter, reaching in many cases the highest and in some cases the only abnormally high values at the end of the second week (mean 75 ng/ml) in the survivors. The levels were mostly normal again 4-6 months after the infarction.

Alterations of factor VIII von Willebrand factor in clinical conditions associated with an increase in its plasma concentration

Factor VIII-related antigen (VIIIR:Ag) was consistently higher than factor-VIII procoagulant activity (VIII:C) in 57 patients with clinical conditions characterized by acute-phase reactions. Two different methods for measuring VIII:C (one- and two-stage assays) and VIIIR:Ag (electroimmunodiffusion and immunoradiometric assay) gave concordant results in the majority of cases. In 43% of plasma samples, crossed immunoelectrophoresis in agarose gel was characterized by the appearance of an additional, fast-moving precipitin peak which was immunologically identical with the major, slower-moving VIIIR:Ag peak. The fast-moving peak was detected in all the patients with clinical conditions typically associated with increased plasma proteolysis (DIC, acute pancreatitis, during thrombolytic therapy). It was present in a smaller proportion of cases with liver and renal failure and malignancies and in the post-operative period. The additional VIIIR:Ag peak is thought to be the result of in vivo factor VIII/von Willebrand factor fragmentation by proteolytic enzymes.

Coagulation studies in children and young adults with cerebral ischemic episodes

One hundred and one patients below 45 years and showing objective signs of cerebral ischemia were studied retrospectively for pathogenic factors. Twelve were below 15 years; the male to female ratio was 1:1. Factors known as predisposing (heart disease, hypertension, hyperlipemia, diabetes mellitus or infectious diseases) and other possible factors (e.g. trauma, abuse) were found in 41 patients. Among women using contraceptive pills there might be an increased risk of development of cerebral thrombosis, but the material was not large enough to warrant statistical analysis. In 64 patients one or more abnormal coagulation values were found, the most frequent being a deficient vessel wall fibrinolysis, which was noted in 38%. We therefore consider it worthwhile to investigate the fibrinolytic defence mechanism of the vessel wall in patients with cerebral thrombosis, since it is possible to treat this condition with specific fibrinolytic stimulating agents.

Blood coagulation and fibrinolytic systems in patients with erysipelas and necrotizing fasciitis

Necrotizing fasciitis (NF) is a skin infection caused by a group A streptococci, resulting in an erythematous lesion with cyanosis and vesicles or bullae leading to gangrene. The condition is prostrating and often accompanied with cerebral confusion. A table of diagnostic scores is given to differentiate initial symptoms and signs of NF from erysipelas (E). Assays of blood coagulation and fibrinolysis together with routine laboratory examinations were made in 12 patients with NF on admission to the hospital and they were compared with similar analyses of 5 patients with E. The NF and E patients showed increased levels of fibrinogen, factor V and factor VIII as well as positive ethanol gelation test, which hypercoagulability as did also decrease antithrombin III and increased levels of fibrinopeptide A. Slightly increased levels of fibrinogen degradation products were also noted. The Hageman factor was low in E compared to NF. In both conditions fibrin formation seems to be enhanced, most probably more extensively in NF. General signs of secondary fibrinolysis were less conspicuous. It is possible that the Hageman factor is activated to modulate the inflammatory response differently in E than in NE.

Fanconi's anaemia associated with haemophilia A

Fanconi's anaemia and haemophilia A are born inherited diseases creating haemostatic defects. The association of these two rare diseases in one patient is described. The patient's haemophilia was studied with a newly developed immunological technique determining the plasma antigen associated with Factor VIII activity, and was found to be a genetic variant of moderately severe haemophilia A. It was not possible to demonstrate a common bone marrow defect or a common immunological or genetical background of the two diseases. The double haemostatic defect created, i.e. Factor VIII deficiency and thrombocytopenia, resulted in only a slight increase in bleeding tendency. A favourable result was obtained with corticosteroid and androgenic treatment.

Measurement of antihaemophilic factor A antigen (VII:CAg) with a solid phase immunoradiometric method based on homologous non-haemophilic antibodies

Antihaemophilic-factor-A-antibodies, which had spontaneously arisen in 2 patients, were used to develop an immunoradiometric method for measurement of antihaemophilic factor A antigen (VIII:CAg). 13 patients with severe haemophilia A had VII:CAg below the limit of detection (0.01 U/ml). Patients with moderate and mild haemophilia A either had VII:CAg roughly equal to factor VIII clotting activity (VIII:C) or a not detectable VII:CAg, suggesting 2 different molecular mechanisms in moderate and mild haemophilia A. VIII:CAg could be detected in serum but in lower amounts than in plasma. In 2 patients with von Willebrand's disease VIII:CAg equalled VII:C. The post-transfusional retarded increase of VII:C in 1 patient with von Willebrand's disease was accompanied by a slight increase in VIII:CAg. Fetal plasma contained measurable amounts of VII:CAg.

Coagulation activation and hyperviscosity in infection

A serial study of coagulation activation and whole-blood viscosity was performed on 37 patients with local or systemic bacterial infection, malaria, or a viral infection. Thrombocytopenia, without consumption of coagulation factors, was the main feature of benign tertian malaria and viral infection, whereas in septicaemia and malignant tertian malaria it was associated with activation of coagulation and fibrinolysis. Patients with evidence of intravascular coagulation showed the highest levels of factor VIII related antigen which did not correlate with fibrinogen and probably reflected vascular endothelial cell damage rather than an acute-phase protein reaction. Hyperviscosity, which has been implicated in the pathogenesis of endotoxic shock and cerebral malaria, occurred in parallel with the acute-phase rise in plasma fibrinogen. There was, however, no evidence to implicate hyperviscosity as a major causative factor in the pathogenesis of septic shock or severe infective illness.

Abnormal factor VIII in chronic renal failure

Factor VIII procoagulant activity (VIII-C), related antigen (VIII-AG), and von Willebrand factor (VIII-vWf) were measured in 38 patients with chronic renal failure (CRF), in 19 patients with normal renal function from a general medical ward, and in 17 normal subjects. Wide variation in the levels of factor VIII (FVIII) functions were found in the group of CRF patients. There was no correlation between the levels of the three individual activities of FVIII in renal disease. The levels of the three functions were elevated in the patient controls and no significant differences were found between the two groups of patients, although both groups were significantly different from the normal subjects. Increased electrophoretic mobility (EM) was detected in 22 of the 38 patients with CRF (58%) compared to seven of the 19 patients controls (37%). These studies suggest caution in interpretation of changes in FVIII status in patients with other clinical disorders, such as liver disease.