Variations of Factor XII Level During Pregnancy in a Woman with Hageman Factor Deficiency

Functional Determination of Factor XII in Plasma

Clinical assays for factor XII determination are based on measurements of coagulation time in a mul tifactorial assay requiring the availability of factor XII deficient plasma, and the determination is affected by the presence of heparin. Another way of determining the amount of functionally active factor XII in plasma is to measure the amidolytic activity of factor XIIa in a chro mogenic assay. We describe such an assay, which in con trast to previously described chromogenic assays, is in dependent of the presence of prekallikrein. To prevent kallikrein from interfering with the assay, soy bean trypsin inhibitor was added to the plasma. Factor XII was autoactivated by addition of ZnCl2 and sulfatide. Sul fatide could be exchanged with acidic phospholipids but not with dextran sulfate. Linear standard curves were obtained whether the plasma was diluted with factor XII deficient plasma or a physiological buffer. The presence of a pharmacologic concentration of heparin did not affect the assay. In 37 plasma samples from healthy donors, a linear correlation was found between factor XII activity and the amount of factor XII antigen. Key Words: Factor XII—Hageman factor—Determination—Plasma.

Myocardial Infarction and Arterial Thrombosis in Severe (Homozygous) FXII Deficiency: No Apparent Causative Relation

Twenty-one patients (12 female and 9 male) with severe (homozygous) factor XII (FXII) deficiency and 58 (32 female and 26 male) with heterozygous FXII deficiency were observed for an average 16.2 years. No patient with homozygous FXII deficiency experienced myocardial infarction or any other arterial thrombosis. The same was true for heterozygotes. The cases of FXII deficiency and arterial thrombosis reported in the literature were evaluated. In every instance, associated risk factors were present that could justify the arterial thrombosis. Dyslipidemia, hypertension, smoking, and diabetes mellitus were the most frequent findings. The examination of the few papers that dealt with the prevalence of arterial thrombosis in patients with severe FXII deficiency showed that only 1 patient of 61 experienced myocardial infarction. In conclusion, it seems that the role of FXII deficiency in the pathogenesis of arterial thrombosis is minor.

Thrombosis-free Surgical Procedures in Severe(Homozygote) Factor XII Deficiency: Report of Four Additional Cases and Literature Review

The outcome of various surgical procedures carried out in patients with severe (homozygote) factor XII deficiency were investigated for the appearance of blood coagulation-related complications with particular emphasis on thrombotic complications. The surgical procedures were total mastectomy, tonsillectomy and adenoidectomy, placement of a hip prosthesis, and double hernia repair. None of the patients slowed any complication. Several other reported cases of surgical procedures carried out in several patients ware found in the literature. Bleeding or thrombotic complications were noted in none of these cases. The surgical procedures in some cases were minor such as adenoidectomy, tonsillectomy, or nasal polyp removal. However several major surgical procedures were carried out in some patients (cholecystectomy, gastrectomy, repair of atrial septal defect, coronary bypass). All patients remained asymptomatic. In some cases whole blood and/or plasma were used as requested by the caring surgeons. In a few patients, the plasma was given prophylactically because of the long partial thromboplastin time. Finally, three patients (two for cardiac surgery and one after hip replacement) received heparin prophylaxis as foreseen by accepted procedures without the undue sequels. These data supply further evidence that factor XII deficiency does not only show any bleeding tendency but also can withstand even major surgical procedures without thrombotic complications.

Comparable Levels of Activity and Antigen in Factor XII Deficiency: A Study of 21 Homozygotes and 58 Heterozygotes

Results of coagulation studies on 21 homozygote patients with factor XII (FXII) deficiency revealed that all of them had no cross-reacting material (CRM) in their plasma. The 58 heterozygotes had in every instance an antigen level comparable to that of clotting activity namely, approximately 50% of normal. An analysis of all pertinent literature also showed that the presence of CRM is very rare in FXII deficiency. CRM is present in approximately 5% of homozygote patients. More precisely, seven of 145 patients. Only in one case, the antigen level was normal (FXII Washington). This prevalence appears lower than that observed for another contact phase factor (prekallikrein). The significance of blood abnormal forms of FXII has not been completely clarified yet. Their study appears useful in the attempt of clarifyng the structure-function relation of factor XII.

A novel 5'-upstream mutation in the factor XII gene is associated with a TaqI restriction site in an Alu repeat in factor XII-deficient patients

The factor XII gene from factor XII-deficient patients was screened for mutations at the genomic level. In patients negative for cross-reacting material, a T to C transition 224 bp upstream of exon 3 was identified (exon 3-224 (T --> C)) that creates an additional TaqI restriction site in intron B. This mutation is located within a putative hormone responsive element and within a B box promoter of an Alu repeat of the Sb0 family. The TaqI site is associated with a G to C transversion upstream of the transcription initiation site (exon 1-8 (G --> C)). We discuss the possible roles of these elements in factor XII gene regulation.

Factor XII (Hageman) deficiency in women with habitual abortion: new subpopulation of recurrent aborters?

OBJECTIVE

To examine the possible association between factor XII (FXII) deficiency and an elevated number of abortions.

DESIGN

Factor XII activity, FXII antigen concentration, other blood clotting parameters, and phospholipid antibodies were examined in venous blood from 43 women with repeated (3 to 7) abortions before the 28th week of gestation but without gynecological and chromosomal abnormalities. The data were compared with those obtained from 49 age-matched women without fetal loss.

RESULTS

Eight cases with moderately reduced FXII activity (35% to 68% of normal) could be identified in the abortion group, whereas among controls no abnormalities in FXII activity and antigen concentration were found. The relative occurrence of reduced FXII level was higher among patients with more than three abortions as compared with those with three abortions.

CONCLUSION

Repeated abortions may be associated with reduced level of FXII activity of unknown origin.

Hageman factor and risk of myocardial infarction in middle-aged men

In order to evaluate whether Hageman factor (XII) is increased in survivors of myocardial infarction and whether this in turn influences factor VII coagulant activity (VIIc), we examined the coagulation and lipoprotein profiles in 82 subjects, 51 of whom had a definite history of myocardial infarction and 31 healthy volunteers invited from a local general practice register for a cardiovascular screen. Both serum cholesterol (P = 0.03) and plasma fibrinogen levels (P = 0.02) were significantly elevated in cases compared with controls. There were no significant differences in coagulant activities, and in particular factor XII concentration was not significantly different between groups. Furthermore, in 47 of the subjects, 28 of whom had a history of myocardial infarction, a more detailed analysis, including measurement of VIIc after overnight incubation of plasma at 4 degrees C, was undertaken. Approximately half the subjects in either group showed some evidence of activation, though history of myocardial infarction was not in itself a significant predictor of this. All measures of XII concentration related positively to VIIc after cold activation, the strongest being the measure of amidolytic activity following activation of factor XII (XIIAm) (r = 0.5, P < 0.01). In addition, XIIa, a measure of activity due to enzymes derived from factor XII, related strongly to many of the measured lipoprotein variables, particularly VLDL cholesterol and triglycerides, supporting the hypothesis that negatively charged molecules such as free fatty acids on larger lipoprotein particles provide the contact surface necessary to activate factor XII. The findings confirm the importance of this alternative pathway in leading to activation of factor VII.

Contact activation factors in plasma from pregnant women--increased level of an association between factor XII and kallikrein

The plasma levels of FXII, prekallikrein (PK), and high- and low molecular weight kininogens (HK and LK) were studied in pregnant women in the last trimester and in non-pregnant controls. FXIIa and plasma kallikrein were assayed in acetone-treated citrated plasma (CPLa) with the tetrapeptide S-2222 as substrate, using soybean trypsin inhibitor and corn inhibitor to exclude kallikrein and FXIIa respectively. No difference in PK-level could be registered for the two kinds of plasma, but the level of FXII had increased to about 150% in the pregnancy plasma. No difference in HK-level was observed, whereas the LK-level was significantly higher in pregnancy plasma, about 250% and 160% in rocket immunoassay and bioassay respectively. In fractions from gel filtration of plasma acetone-activated in the presence of benzamidine (BPLa), kallikrein was assayed as S-2302 amidase, HK and LK were measured in rocket immunoassay, and HK and FXII were studied in PAGE immunoblot experiments. In contrast to previous results obtained upon gel filtration of CPLa, not only kallikrein and HK, but in addition also FXII now appeared together in the same fractions and as two separate peaks. One peak eluting in early fractions (gel mol. wt. 300-400 KD), and one late eluting peak of proteins adsorbed to the gel material. The first peak was notably marked in pregnancy plasma. The results provide support for the assumption of an association in plasma between the three contact activation factors studied.

Superficial thrombophlebitis. II. Secondary hypercoagulable states

Secondary hypercoagulable states are complex clinical conditions associated with an increased risk of thrombosis in which the exact pathophysiology is poorly understood. Secondary causes of superficial thrombophlebitis include malignancy, pregnancy, use of oral contraceptives, infusion of prothrombin complex concentrates, Behçet's disease, Buerger's disease, Mondor's disease, infectious agents, conditions that promote venous stasis, intravenous catheters and intravenous drug use. Conditions that may stimulate superficial thrombophlebitis include dermatophyte cellulitis at saphenous phlebectomy sites, sarcoidal granulomas, cutaneous polyarteritis nodosa, and hyperalgesic pseudothrombophlebitis in patients who test positive for human immunodeficiency virus. The distinguishing features, clinical evaluation, treatment, and histologic characteristics of the various disorders are reviewed.