Paolo Bucciarelli

Role of the JAK2 mutation in the diagnosis of chronic myeloproliferative disorders in splanchnic vein thrombosis

The diagnosis of an underlying chronic myeloproliferative disorder (CMPD) is often problematic in patients with primary extrahepatic portal vein obstruction (EHPVO) or Budd‐Chiari syndrome (BCS); indeed, conventional clinical and hematological parameters usually yield insufficient information. To assess the diagnostic contribution of the gain‐of‐function mutation V617F of the JAK2 gene, 93 patients with EHPVO or BCS were investigated. JAK2 V617F was identified in 35.6% of 73 patients with EHPVO and in 40% of 20 patients with BCS. Taking the JAK2 mutation as a test with the highest positive predictive value for the diagnosis of CMPD, conventional clinical‐hematological parameters had a sensitivity for CMPD lower than 48%. Bone marrow (BM) histology provided a diagnosis of CMPD in 41/74 (55.4%) patients, with a sensitivity of 93.5%. Clonality of hematopoiesis as assessed by granulocyte X‐chromosome inactivation was present in 65.1% of 43 informative female patients, with a sensitivity of 86.6%. By resolving the sensitivity bias of the JAK2 mutation with the results of BM histology and clonality assay, CMPD was diagnosed in 53% of patients with EHPVO or BCS. In conclusion, CMPD is the major cause of primary EHPVO or BCS. JAK2 V617F is a very reliable and noninvasive molecular marker for CMPD and should be used as a first test for diagnosis. (HEPATOLOGY 2006;44:1528–1534.)

Clinical and molecular predictors of thrombocytopenia and risk of bleeding in patients with von Willebrand disease type 2B: a cohort study of 67 patients

Type 2B von Willebrand disease (VWD2B) is caused by an abnormal von Willebrand factor (VWF) with increased affinity for the platelet receptor glycoprotein Ib-alpha (GPIb-alpha) that may result in moderate to severe thrombocytopenia. We evaluated the prevalence and clinical and molecular predictors of thrombocytopenia in a cohort of 67 VWD2B patients from 38 unrelated families characterized by VWF mutations. Platelet count, mean platelet volume, and morphologic evaluations of blood smear were obtained at baseline and during physiologic (pregnancy) or pathologic (infections, surgeries) stress conditions. Thrombocytopenia was found in 20 patients (30%) at baseline and in 38 (57%) after stress conditions, whereas platelet counts were always normal in 16 patients (24%) from 5 families carrying the P1266L/Q or R1308L mutations. VWF in its GPIb-alpha-binding conformation (VWF-GPIb-alpha/BC) was higher than normal in all except the 16 cases without thrombocytopenia (values up to 6-fold higher than controls). The risk of bleeding was higher in patients with thrombocytopenia (adjusted hazard ratio = 4.57; 95% confidence interval, 1.17-17.90) and in those with the highest tertile of bleeding severity score (5.66; 95% confidence interval, 1.03-31.07). Prediction of possible thrombocytopenia in VWD2B by measuring VWF-GPIb-alpha/BC is important because a low platelet count is an independent risk factor for bleeding.

Risk factors for thrombophilia in extrahepatic portal vein obstruction

Scant information exists on the role of thrombophilia in extrahepatic portal vein obstruction (EHPVO). We studied 65 patients with EHPVO, 500 with deep vein thrombosis (DVT) of the lower limbs, and 700 healthy controls referred for thrombophilia screening, including the search for gain‐of‐function mutations in genes encoding coagulation factor V (factor V Leiden) and prothrombin (prothrombin G20210A); antithrombin, protein C, and protein S deficiency; and hyperhomocysteinemia. At least one abnormality in the thrombophilia screening was found in 40% of patients with either EHPVO or lower limb DVT and in 13% of controls, for odds ratios of 4.0 (95% CI, 2.3–7.0) and 4.4 (95% CI, 3.3–5.9), respectively. Statistically significant associations with EHPVO were observed for the prothrombin G20210A mutation (odds ratio, 8.1; 95% CI, 3.8–17.5) and the deficiencies of antithrombin, protein C, or protein S taken together (odds ratio, 4.5; 95% CI, 1.1–18.0). The odds ratio for the prothrombin G20210A was approximately twice that for lower limb DVT. Patients with factor V Leiden had an odds ratio for EHPVO of 0.8 (95% CI, 0.1–6.4) and for lower limb DVT of 7.5 (95% CI, 4.4–13.0). The odds ratio for EHPVO in patients with hyperhomocysteinemia was 2.0 (95% CI, 0.9–4.9). At variance with lower limb DVT, oral contraceptive use was not associated with an increased risk of EHPVO. Myeloproliferative disorders were diagnosed in 35% of patients with EHPVO. In conclusion, the risk for EHPVO is increased in the presence of thrombophilia resulting from the prothrombin G20210A mutation and from the deficiencies of the naturally occurring anticoagulant proteins, but not from factor V Leiden. (HEPATOLOGY 2005;41:603–608.)

A Common Mutation in the Methylenetetrahydrofolate Reductase Gene (C677T) Increases the Risk for Deep-Vein Thrombosis in Patients With Mutant Factor V (Factor V:Q506)

Hyperhomocysteinemia is a frequent risk factor for deep-vein thrombosis. A common mutation (C677T) in the gene encoding for methylenetetrahydrofolate reductase (MTHFR) is responsible, in the homozygous state, for decreased enzyme activity and mild hyperhomocysteinemia and is associated with increased risk for cardiovascular disease. We studied the prevalence of C677T MTHFR in 77 patients with deep-vein thrombosis and in 154 age- and sex-matched healthy control subjects. In the same individuals, we also evaluated the frequency of the coexistence of C677T MTHFR with mutant factor V:Q506, a common risk factor for deep-vein thrombosis. Sixteen patients (20.8%) and 35 control subjects (22.7%) were homozygous for the C677T MTHFR mutation (odds ratio [OR] = 0.8, 95% confidence interval [CI] = 0.4-2.0). Sixteen patients (20.8%) and 4 control subjects (2.6%) had factor V:Q506; of them, 10 patients and 3 control subjects had isolated factor V:Q506 (adjusted OR = 6.3, 95% CI = 1.6-25.3) and 6 patients and 1 control subject also had C677T MTHFR (adjusted OR = 17.3, 95% CI = 2.0-152.9). The OR for the coexistence of the two mutations was 65% to 75% higher than the expected joint effect calculated by either an additive (OR = 6.0) or multiplicative (OR = 4.4) model. The homozygous C677T mutation of MTHFR per se is not a risk factor for deep-vein thrombosis but increases the risk associated with factor V:Q506. Due to the high prevalence of C677T MTHFR, it is likely that previous studies, which did not look for this mutation, overestimated the relative risk of thrombosis associated with factor V:Q506 alone.

Interaction Between the G20210A Mutation of the Prothrombin Gene and Oral Contraceptive Use in Deep Vein Thrombosis

Single-point mutations in the gene coding for prothrombin (factor II:A20210) or factor V (factor V:A1691) are associated with an increased risk of venous thromboembolism. The use of oral contraceptives is also a strong and independent risk factor for the disease, and the interaction between factor V:A1691 and oral contraceptives greatly increases the risk. No information is available about the interaction between oral contraceptives and mutant prothrombin. We investigated 148 women with a first, objectively confirmed episode of deep vein thrombosis and 277 healthy women as controls. Fourteen patients (9.4%) were carriers of factor II:A20210, 24 (16.2%) of factor V:A1691, and 4 (2.7%) of both defects. Among controls, the prevalence was 2.5% for either factor II:A20210 or factor V:A1691, and there was no carrier of both the mutations. The relative risk of thrombosis was 6-fold for factor II:A20210 and 9-fold for factor V:A1691. The most prevalent circumstantial risk factor in patients and the only one observed in controls was oral contraceptive use, which per se conferred a 6-fold increased risk of thrombosis. The risk increased to 16.3 and 20.0 when women with factor II:A20210 or factor V:A1691 who used oral contraceptives were compared with noncarriers and nonusers. These figures indicate a multiplicative interaction between the genetic risk factors and oral contraceptives. No difference in the type of oral contraceptives was observed between patients and controls, those of third generation being the most frequently used (73% and 80%). We conclude that carriers of the prothrombin mutation who use oral contraceptives have a markedly increased risk of deep vein thrombosis, much higher than the risk conferred by either factor alone.

Risk Factors and Recurrence Rate of Primary Deep Vein Thrombosis of the Upper Extremities

Background—One third of cases of upper-extremity deep vein thrombosis (DVT) are primary, ie, they occur in the absence of central venous catheters or cancer. Risk factors for primary upper-extremity DVT are not well established, and the recurrence rate is unknown. Methods and Results—We studied 115 primary upper-extremity DVT patients and 797 healthy controls for the presence of thrombophilia due to factor V Leiden, prothrombin G20210A, antithrombin, protein C, protein S deficiency, and hyperhomocysteinemia. Transient risk factors for venous thromboembolism were recorded. Recurrent upper-extremity DVT was evaluated prospectively over a median of 5.1 years of follow-up. The adjusted odds ratio for upper-extremity DVT was 6.2 (95% CI 2.5 to 15.7) for factor V Leiden, 5.0 (95% CI 2.0 to 12.2) for prothrombin G20210A, and 4.9 (95% CI 1.1 to 22.0) for the anticoagulant protein deficiencies. Hyperhomocysteinemia and oral contraceptives were not associated with upper-extremity DVT. However, in women with factor V Leiden or prothrombin G20210A who were taking oral contraceptives, the odds ratio for upper-extremity DVT was increased up to 13.6 (95% CI 2.7 to 67.3). The recurrence rate was 4.4% patient-years in patients with thrombophilia and 1.6% patient-years in those without thrombophilia. The hazard ratio for recurrent upper-extremity DVT in patients with thrombophilia compared with those without was 2.7 (95% CI 0.7 to 9.8). Conclusions—Inherited thrombophilia is associated with an increased risk of upper-extremity DVT. Oral contraceptives increase the risk only when combined with inherited thrombophilia. The recurrence rate of primary upper-extremity DVT is low but tends to be higher in patients with thrombophilia than in those without.

Risk of Venous Thromboembolism and Clinical Manifestations in Carriers of Antithrombin, Protein C, Protein S Deficiency, or Activated Protein C Resistance A Multicenter Collaborative Family Study

Deficiencies of antithrombin (AT), protein C (PC) or protein S (PS), and activated protein C resistance (APCR) are very well-established coagulation defects predisposing to venous thromboembolism (VTE). We performed a retrospective cohort family study to assess the risk for VTE in individuals with AT, PC, or PS deficiency, or APCR. Five hundred thirteen relatives from 9 Italian centers were selected from 233 families in which the proband had had at least 1 episode of VTE. We calculated the incidence of VTE in the whole cohort and in the subgroups after stratification by age, sex, and defect. The overall incidence of VTE (per 100 patient-years) in the group of relatives was 0.52. It was 1.07 for AT, 0.54 for PC, 0.50 for PS, 0.30 for APCR, and 0.67 in the group with a double defect. The incidence was associated with age, but not with sex. The mean age at onset was between 30 and 40 years for all the coagulation defects. Women had the peak of incidence in the age range of 21 to 40 years, earlier than men. The lifetime risk for VTE was 4.4 for AT versus APCR, 2.6 for AT versus PS, 2.2 for AT versus PC, 1.9 for PC versus APCR, and 1.6 for PS versus APCR. AT deficiency seems to have a higher risk for VTE than the other genetic defects. There is a relation between age and occurrence of thrombosis for both men and women. The latter had the peak of incidence earlier than the former.

Interleukin-10 and interleukin-6 gene polymorphisms as risk factors for Alzheimer’s disease

In the pathogenesis of Alzheimer disease (AD), it has been proposed that the anti-inflammatory interleukins such as IL-10 regulate beta-amyloid-induced microglial inflammatory responses inhibiting the proinflammatory cytokine IL-6. Since the promoters of the IL-10 and IL-6 genes show single nucleotide polymorphisms (SNPs) (IL-10: -1082 G --> A; IL-6: -174 G --> C), we investigated these SNPs and cytokine production by peripheral blood mononuclear cells in 65 AD patients and 65 controls (HC). In AD there was a significant increase of the -1082A IL-10 allele (P=0.009) and a decrease of -1082GG genotype (P=0.019). The frequency of the GG IL-6 genotype in AD was lower and the C allele significantly higher (P <0.005). The co-occurrence of IL-10 A and IL-6 C alleles significantly raised the odds ratio (OR 11.2, confidence interval: CI 1.3-97.3; P <0.05) independently of apolipoprotein E4 (adjusted OR 10.3, CI 1-108; P <0.05). Only amyloid-stimulated IL-10 production differed between the groups (P=0.023). These results raise questions regarding the inflammatory theory in AD, pointing to a pivotal role of IL-10 and IL-6 and a selective alteration in this network.

Thrombotic risk factors: basic pathophysiology.

Although venous thrombosis has been traditionally associated with stasis and hypercoagulability, arterial thrombosis is mainly associated with heightened platelet reactivity and damage to the vessel wall. Accordingly, classic risk factors for venous and arterial thrombosis are usually considered distinct. Those for the former include cancer, surgery, pregnancy, and estrogens use, whereas risk factors of arterial thrombosis include smoking, hypertension, diabetes, the metabolic syndrome, and hyperlipidemia. However, a number of studies have recently challenged this dichotomy, and it is now recognized that venous and arterial thromboses share several risk factors, suggesting a closer link between the two clinical conditions. Typical examples of shared risk factors are age and the metabolic syndrome. This review addresses the mechanism whereby established risk factors increase the risk of venous or arterial thrombosis, or both.

Long-Term Evaluation of the Risk of Recurrence After Cerebral Sinus-Venous Thrombosis

Background— The clinical course of cerebral sinus-venous thrombosis (CSVT) is largely unknown because prospective studies with a long follow-up and with the goal to assess thrombosis recurrence rate and predisposing factors for recurrence are lacking. Methods and Results— One hundred forty-five patients with a first CSVT were followed up for a median of 6 years after discontinuation of anticoagulant treatment. End points were recurrent CSVT or other clinical manifestations of venous thromboembolism. CSVT recurred in 5 patients (3%) and other manifestations of venous thromboembolism (deep vein thrombosis of the lower limbs or pulmonary embolism) were seen in 10 additional patients (7%), for a recurrence rate of 2.03 per 100 person-years (95% confidence interval, 1.16 to 3.14) for all manifestations of venous thromboembolism and 0.53 per 100 person-years (95% confidence interval, 0.16 to 1.10) for CSVT. Nearly half of the recurrences occurred within the first year after discontinuation of anticoagulant therapy. Risk factors for recurrent venous thrombosis were male sex (adjusted hazard ratio, 9.66; 95% confidence interval, 2.86 to 32.7) and, for thromboses other than CSVT, severe thrombophilia resulting from antithrombin, protein C, protein S deficiency, anti-phospholipid antibodies, or combined abnormalities (adjusted hazard ratio, 4.71; 95% confidence interval, 1.34 to 16.5). Conclusions— The risk of recurrent CSVT is low and is higher in the first year after discontinuation of anticoagulant treatment and among men. Mild thrombophilia abnormalities are not associated with recurrent CSVT, but severe thrombophilia entails an increased risk of deep vein thrombosis of the lower limbs or pulmonary embolism.