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The aim of this study was to investigate whether the immune system of patients with hemophilia A is skewed toward an aspecific activation and to identify the causative factors. It is well known that an immune derangement does exist in patients with hemophilia A. At least three factors potentially play a role: hepatitis C virus (HCV) infection, alpha-interferon therapy and the administration of factor VIII (FVIII). Sixty human immunodeficiency virus (HIV)-negative patients with severe or moderate hemophilia A were studied retrospectively. The serological markers of autoimmunity were evaluated and the results correlated with anti-HCV antibodies, FVIII treatment and alpha-interferon therapy. The role of these factors in the development of the anti-FVIII antibody was estimated concomitantly. The prevalence of autoantibodies and anti-FVIII antibodies was higher in HCV-positive than in HCV-negative patients before any treatment, although the difference was not statistically significant. The administration of FVIII further influenced the development of autoantibodies both in HCV-negative and HCV-positive patients, with no difference being observed between the two groups. As expected, fewer HCV-negative than HCV-positive patients developed anti-FVIII antibodies after administration of FVIII (31.8% versus 38%, respectively). Therapy with alpha-interferon did not seem to enhance significantly the risk of developing autoantibodies nor anti-FVIII antibodies. We observed a high prevalence of humoral signs of autoimmunity among patients with hemophilia A. Treatment with FVIII concentrate is probably the most important triggering factor. Monitoring these patients for autoimmune manifestations is recommended.

A new diagnostic test has recently become available which is highly specific for plasma soluble fibrin polymers, the thrombus precursor protein (TpP) enzyme immunoassay. In order to evaluate the diagnostic accuracy of this test and that of a new rapid and automated test for the determination of D-dimers, the BC D-dimer test, in patients with clinically suspected deep vein thrombosis (DVT), 70 consecutive symptomatic patients underwent laboratory analysis with both tests and with the classic enzyme-linked immunosorbent assay (ELISA) D-dimer test, followed by the execution of a compression ultrasound (CUS) test of the affected limb. Patients with a positive CUS test were considered to have DVT (20 of 70), whereas those with a serially negative test and an uneventful 3-month follow-up test were regarded as not having DVT (50 of 70). The sensitivity of the TpP test (45.0%) was significantly lower than that of both the BC D-dimer test (80.0%; P = 0.02) and the classic ELISA test (90.0%; P = 0.002). The specificity of the TpP test (66.0%) did not differ from that of either D-dimer test (60.0 and 64.0%, respectively). The negative predictive value of the TpP test (75.0%) was significantly lower than that of the classic ELISA D-dimer test (94.1%; P = 0.02), which in turn did not differ from that of the BC D-dimer test (88.2%). The positive predictive value was similarly low for each investigated test (34.6, 44.4, and 50.0%, respectively). In conclusion, the TpP test can neither be used to detect a DVT nor to exclude its development in patients with the clinical suspicion of this disease. By contrast, the BC D-dimer might safely replace the classic ELISA test for excluding DVT in symptomatic patients.

Prothrombin (factor II) deficiency was first described in 1947 by Quick et al., although the first prothrombin abnormality was reported in 1969 by Shapiro et al. The condition is still considered very rare. In spite of its rarity, the defect has allowed important improvements in our understanding of both congenital and acquired prothrombin deficiencies. The diagnosis of prothrombin deficiency or abnormality can be made using a combination of clotting, chromogenic and immunological assays. In cases of true deficiency, a parallel decrease in all these assays is observed, regardless of the activating agent. If discrepancies among the clotting assays are noted, particularly using viper venoms, a dysprothrombinemia should be suspected. Usually, activity levels less than 10% of normal are found in homozygotes, and between 40 and 60% in heterozygotes. Factor II levels in congenital dysprothrombinemias are more variable since one may encounter homozygotes, heterozygotes and compound heterozygotes between a heterozygous abnormality and heterozygous 'true' deficiency or between two distinct abnormalities. Usually the levels of factor II vary between 1 and 50% of normal. Antigen levels in congenital dysprothrombinemias will be normal, near normal or slightly decreased but always higher than the clotting counterpart. Cases with a parallel decrease in prothrombin activity and antigen should not be considered as examples of hypoprothrombinemia. The gene involved in the synthesis of prothrombin is located in chromosome 11. It is composed of 10 exons and 8 introns. Molecular biology studies have discovered several point mutations in some of the dysprothrombinemias. Bleeding manifestations may be severe in homozygous 'true' deficiency and may be more variable in dysprothrombinemias. Heterozygotes are usually asymptomatic. Prognosis is variable and generally in agreement with the prothrombin activity level. In homozygous true deficiency, hemarthroses and intracranial bleeding have been described. Substitution therapy is based on the administration of prothrombin complex concentrates or of plasma. The long half-life of prothrombin injected, about 70 h, allows the achievement of hemostatically effective levels (about 50% of normal) without difficulty.

The aim of our study was to determine the fibrinolytic potential in a large group of patients with Cushing's disease. These patients had a significant shortening of the activated partial thromboplastin time and increase in factor VIII/von Willebrand factor complex compared to normal controls. The mean levels of plasminogen, tissue plasminogen activator (t-PA) antigen and plasminogen activator inhibitor (PAI) activity were significantly higher than in normal subjects, whereas the basal fibrinolytic activity was similar to that seen in the control group. In 17 out of 30 Cushing patients and in 17 normal subjects the fibrinolytic potential was determined with the venous occlusion test. In the Cushing group, the release of t-PA antigen after 20 min of venous occlusion was comparable to that observed in the control group. However, Cushing patients showed a lower fibrinolytic activity than normal subjects, since a lesser shortening of the euglobulin lysis time and a non-significant rise of plasminogen activator activity levels were found. Moreover, in these patients the PAI activity values remained unchanged and significantly increased after venous occlusion test also. In conclusion, the impaired fibrinolytic activation seen in Cushing patients after venous occlusion can be explained by the inhibitory effect of the high PAI levels on plasminogen activators. The defective fibrinolytic potential could further contribute to the hypercoagulable state in Cushing's disease. High PAI levels before surgery may represent an additional risk factor for post-surgical thromboembolic complications in Cushing patients.