Katia Paciaroni

The Risk of Recurrent Deep Venous Thrombosis among Heterozygous Carriers of Both Factor V Leiden and the G20210A Prothrombin Mutation

BACKGROUND Point mutations in the factor V gene (factor V Leiden) and the prothrombin gene (the substitution of A for G at position 20210) are the most common causes of inherited thrombophilia. Whether or not factor V Leiden increases the risk of recurrent deep venous thrombosis is controversial, and there is no information on the risk of recurrence among carriers of both mutations. METHODS We studied a retrospective cohort of 624 patients who were referred for a first episode of deep venous thrombosis. After excluding 212 patients with other inherited or acquired causes of thrombophilia, we compared 112 patients who were heterozygous carriers of factor V Leiden with 17 patients who were heterozygous for both factor V Leiden and the prothrombin mutation and 283 patients who had neither mutation. The relative risk of recurrent deep venous thrombosis was calculated with use of a proportional-hazards model. RESULTS Patients who were heterozygous for factor V Leiden alone had a risk of recurrent deep venous thrombosis that was similar to that among patients who had neither mutation (relative risk, 1.1; 95 percent confidence interval, 0.7 to 1.6; P=0.76). In contrast, patients who were heterozygous for both factor V Leiden and the prothrombin mutation had a higher risk of recurrent thrombosis than did carriers of factor V Leiden alone (relative risk, 2.6; 95 percent confidence interval, 1.3 to 5.1; P=0.002). When the analysis was restricted to patients with spontaneous recurrences (i.e., ones that occurred in the absence of transient risk factors for venous thrombosis), the risk among carriers of both mutations, as compared with carriers of factor V Leiden alone, remained high (relative risk, 3.7; 95 percent confidence interval, 1.7 to 7.7; P<0.001), particularly if the first event had also been spontaneous (relative risk, 5.4; 95 percent confidence interval, 2.0 to 14.1; P<0.001). In contrast, the risk of recurrence in the presence of transient risk factors was similar among carriers of both mutations and carriers of factor V Leiden alone. CONCLUSIONS The risk of recurrent deep venous thrombosis is similar among carriers of factor V Leiden and patients without this mutation. Carriers of both factor V Leiden and the G20210A prothrombin mutation have an increased risk of recurrent deep venous thrombosis after a first episode and are candidates for lifelong anticoagulation.

Purified T-depleted, CD34+ peripheral blood and bone marrow cell transplantation from haploidentical mother to child with thalassemia.

Fetomaternal microchimerism suggests immunological tolerance between mother and fetus. Thus, we performed primary hematopoietic stem cell transplantation from a mismatched mother to thalassemic patient without an human leukocyte antigen-identical donor. Twenty-two patients with thalassemia major were conditioned with 60 mg/kg hydroxyurea and 3 mg/kg azathioprine from day -59 to -11; 30 mg/m(2) fludarabine from day -17 to -11; 14 mg/kg busulfan starting on day -10; and 200 mg/kg cyclophosphamide, 10 mg/kg thiotepa, and 12.5 mg/kg antithymocyte globulin daily from day -5 to -2. Fourteen patients received CD34(+)-mobilized peripheral blood and bone marrow progenitor cells; 8 patients received marrow graft-selected peripheral blood stem cells CD34(+) and bone marrow CD3/CD19-depleted cells. T-cell dose was adjusted to 2 x 10(5)/kg by fresh marrow cell addback at the time of transplantation. Both groups received cyclosporine for graft-versus-host disease prophylaxis for 2 months after transplantation. Two patients died (cerebral Epstein-Barr virus lymphoma or cytomegalovirus pneumonia), 6 patients reject their grafts, and 14 showed full chimerism with functioning grafts at a median follow-up of 40 months. None of the 14 patients who showed full chimerism developed acute or chronic graft-versus-host disease. These results suggest that maternal haploidentical hematopoietic stem cell transplantation is feasible in patients with thalassemia who lack a matched related donor.

The risk of recurrent venous thromboembolism among heterozygous carriers of the G20210A prothrombin gene mutation

The G20210A mutation in the prothrombin gene is associated with an increased risk of a first venous thromboembolic episode; few data are available about the long‐term risk for recurrent venous thromboembolism and it is not known whether or not carriers of the mutation should be recommended lifelong anticoagulant treatment after the first thrombosis. We investigated 624 patients, referred for previous objectively documented deep venous thrombosis of the legs or pulmonary embolism, to determine the risk of recurrent thromboembolism in heterozygous carriers of the G20210A mutation in the prothrombin gene after the first episode of venous thromboembolism. After exclusion of other inherited (anti‐thrombin, protein C, protein S deficiency and factor V Leiden) or acquired (anti‐phospholipid antibody syndrome) causes of thrombophilia, 52 heterozygous carriers of the prothrombin mutation were compared with 283 patients with normal genotype. The relative risk for recurrent venous thromboembolism was calculated between groups using a Coxs proportional hazard model. The patients with the prothrombin mutation had a risk for spontaneous recurrent venous thromboembolism similar to that of patients with normal genotype (hazard ratio 1·3; 95% CI, 0·7–2·3). The circumstances of the first event (spontaneous or secondary) did not produce any substantial variation in the risk for recurrence. In conclusion, the carriers of the prothrombin mutation should be treated with oral anticoagulants after a first deep venous thrombosis for a similar length of time as patients with a normal genotype.

Prevalence of mild hyperhomocysteinaemia and association with thrombophilic genotypes (factor V Leiden and prothrombin G20210A) in Italian patients with venous thromboembolic disease

Mild hyperhomocysteinaemia is an established risk factor for deep vein thrombosis (DVT); few data concerning its potential interaction with thrombophilic genotypes are available at the present time. We investigated 121 thrombosis‐free individuals and 111 patients with at least one objectively confirmed episode of DVT. A thrombophilic condition (deficiency in antithrombin, protein C and S, factor V Leiden, prothrombin G20210A) was detected in 25.2% of the patients; mutant factor V or prothrombin genotypes were present in 6.6% of the controls. Hyperhomocysteinaemia was found in 14.4% of patients and 3.3% of the controls, with a 3.7‐fold increase in risk for DVT (95% CI 1.1–12.3). Adoption of different cut‐off levels for definition of hyperhomocysteinaemia did not substantially change the magnitude of the risk. Carriership of both hyperhomocysteinaemia and factor V Leiden or prothrombin G20210A was detected in 2.7% of patients for each combination and in none of the controls. An approximate estimate of 30‐fold increased risk in carriers of both hyperhomocysteinaemia and factor V Leiden and 50‐fold increased risk in carriers of both hyperhomocysteinaemia and prothrombin G20210A was calculated, suggesting a synergistic interaction between hyperhomocysteinaemia and such thrombophilic genotypes. Yet statistical analysis is highly unstable due to the small number of individuals with combined defects. Further investigations on large series of patients are needed.

G20210A Prothrombin gene polymorphism and coronary ischaemic syndromes: a phenotype-specific meta-analysis of 12 034 subjects

Objective: To investigate the possible link between the G20210A prothrombin gene variant and different forms of ischaemic heart disease. Design: Phenotype-specific meta-analysis of 19 studies published within March 2002, globally including 4944 patients and 7090 controls. Sample size, inclusion criteria, geographical location, clinical presentation, age, cardiovascular risk factors, and angiographic extent of disease were extracted from each study. Analyses were done according to Mantel-Haenszel. Results: Overall, the odds ratio (OR) for unspecified ischaemic heart disease associated with the 20210A allele was 1.21 (95% confidence interval (CI) 0.99 to 1.59, n  =  12 034). Similar findings were seen for acute coronary syndromes (unstable angina and myocardial infarction) and for myocardial infarction without age limits (OR 1.24, 95% CI 0.98 to 1.63, n  =  10 240; and OR 1.19, 95% CI 0.93 to 1.58, n  =  9765). The effects were similar in male and female subjects. In the 1931 subjects < 55 years of age, the OR for myocardial infarction increased to 1.77 (95% CI 1.16 to 3.42) and in the 1359 subjects < 45 years to 2.30 (95% CI 1.27 to 4.59). No significant association was found between the 20210A allele and the presence of angiographically documented coronary disease (OR 1.08, 95% CI 0.70 to 1.64, n  =  3444). However, patients with 0/1 vessel disease at angiography showed a greater prevalence of the A allele than those with multivessel disease (relative risk 2.0, 95% CI 1.2 to 3.1, n  =  2376). Conclusions: G20210A prothrombin gene polymorphism may represent a modest but significant risk factor for myocardial infarction at young ages and favour the expression of ischaemic heart disease among individuals who have a limited extent of coronary atherosclerosis at angiography.

Prevalence of factor V Leiden and the G20210A prothrombin-gene mutation in inflammatory bowel disease

A hypercoagulable state has been hypothesized as a contributing factor in the pathogenesis of inflammatory bowel disease (IBD); moreover, such patients have an increased risk of thrombotic complications. The aim of the present paper was to study the prevalence of the two most important causes of inherited thrombophilia: factor V Leiden and the G20210A prothrombin-gene mutation in patients with Crohns disease (CD) and ulcerative colitis (UC). Fifty-two patients affected by IBD (33 UC and 19 CD, 16 female and 36 male; mean age, 42 years) and 156 healthy controls (48 female and 108 male; mean age, 37 years) were studied. Seven out of 52 patients (13%) had previous thrombotic events. High molecular weight DNA was analysed for the presence of factor V Leiden and the G20210A prothrombin-gene mutation. One out of 52 IBD patients (1.9%) and three out of 156 control subjects (1.9%) were heterozygous for factor V Leiden. One IBD patient (1.9%) and four healthy controls (2.6%) were heterozygous for the prothrombin-gene mutation. The prevalence of the two mutations was similar in patients and controls. In the subgroup of IBD patients with previous thrombotic events, only one patient was heterozygous for the prothrombin-gene mutation. Factor V Leiden and the G20210A prothrombin-gene mutation do not seem to play a major role in the pathogenesis of IBD or be associated with an increased incidence of thrombotic complications, but with limited data.

The C807T/G873A polymorphism in the platelet glycoprotein Ia gene and the risk of acute coronary syndrome in the Italian population

Membrane glycoprotein (GP) Ia/IIa mediates platelet adhesion to collagen. The linked C807T/G873A polymorphisms in the GP Ia gene are correlated with a variable expression of the platelet surface receptor, the 807 TT/873 AA genotype being associated with a higher receptor density. Our study aimed to evaluate the possible role of the GP Ia C807T/G873A polymorphism as a risk factor for acute coronary syndrome in the Italian population. We investigated 157 patients with acute coronary syndrome (117 with myocardial infarction and 40 with severe unstable angina) as the first manifestation of coronary disease occurring before 65 years of age, compared with 312 healthy controls. All individuals were of Italian ancestry and were genotyped for the GP Ia C807T/G873A polymorphism. Complete linkage between the 807 and 873 sites was found in all samples. The 807 TT genotype was present in 12·7% of cases and in 4·8% of controls; the odds ratio for acute coronary syndrome was 2·9 (95% CI 1·4–5·8) for the 807 TT genotype compared with C‐allele carriers and 0·6 (95% CI 0·4–0·9) for the 807 CC genotype compared with T‐allele carriers. For the TT genotype, compared with CC homozygotes, the increase in risk was 3·4‐fold in patients with at least one risk factor (smoking, hypercholesterolaemia, diabetes, systemic hypertension) and 4·1‐fold in patients with angiographically diagnosed two‐ or three‐vessel disease. We conclude that the GP Ia 807 TT (873 AA) genotype is associated with an increased risk of acute coronary syndrome in the Italian population; conversely, the GP Ia 807 CC (873 GG) genotype seems to represent a protective factor.

T cell-depleted hla-haploidentical stem cell transplantation in thalassemia young patients

The cure for thalassemia involves correcting the genetic defect in a hematopoietic stem cell that results in reduced or absent β-globin synthesis and an excess of α-globin dimers. Intracellular precipitation and accumulation of α- dimers results in ineffective erythropoiesis and hemolytic anemia. Replacing the abnormal thalassemic marrow with allogeneic normal or heterozygous stem cells carrying the functional gene restores appropriate β-globin chain synthesis.

Bone marrow transplantation for thalassemia from alternative related donors: improved outcomes with a new approach

Bone marrow transplantation (BMT) performance can be limited by a lack of ideal donors, and the role of alternative donor hematopoietic cell transplantation in thalassemia is not well established. Here we used a new treatment protocol (Pc 26.1) in 16 thalassemia patients to perform BMT using phenotypically HLA-identical or 1-antigen-mismatched relatives (related donors [RDs]). We compared these results with HLA-matched sibling (matched sibling donors [MSDs]) BMT in 66 patients. The entire RD group and 88% of MSD group had sustained engraftment. Rejection incidence was 0% in the RD and 12% (95% confidence interval [95% CI], 6%-21%) in MSD groups (P = .15), with respective thalassemia-free survival probabilities of 94% (95% CI, 63%-99%) and 82% (95% CI, 70%-89%) (P = .24). Transplant-related mortality was 6% (95% CI, 1%-26%) in the RD group and 8% (95% CI, 3%-16%) in the MSD group (P = .83). The intensified new protocol was not associated with increased nonhematologic toxicity. The present data show that the Pc 26.1 preparative regimen allows thalassemia patients to safely undergo BMT from RDs who are not HLA-matched siblings, with transplant outcomes similar to patients with MSD grafts.

Sustained and full fetal hemoglobin production after failure of bone marrow transplant in a patient homozygous for beta 0‐thalassemia: A clinical remission despite genetic disease and transplant rejection

An adult patient affected by β0‐thalassemia major underwent allogeneic bone marrow transplant (BMT) from a matched related donor. Forty days after transplant, allogeneic engraftment failure and autologous β0‐thalassemic bone marrow recovery were documented. Red blood cell transfusions were required until 118 days post‐transplant. Thereafter, the haemoglobin (Hb) levels stabilized over 11.8 gr/dl throughout the ongoing 34‐month follow‐up, abolishing the need for transfusion support. The Hb electrophoresis showed 100% Hb Fetal (HbF). This unexplained case suggests full HbF production may occur in an adult patient with β0‐thalassemia major. Am. J. Hematol. 2009.