Arterial and venous thrombosis by high platelet count and high hematocrit: 108 521 individuals from the Copenhagen General Population Study.

BACKGROUND: It is unclear whether high platelet count or high hematocrit predict risk of thrombosis in individuals from the general population. OBJECTIVES: We tested the hypothesis that individuals from the general population with high platelet count or high hematocrit have high risk of arterial and venous thrombosis. METHODS: We prospectively followed 108 521 individuals from The Copenhagen General Population Study for a median of 8 years. Platelet count and blood hematocrit were measured at study entry. RESULTS AND CONCLUSION: Multivariable adjusted hazard ratios for individuals with platelet counts in the top 5 percentiles (>398 × 109 /L) vs in the 25th-75th percentiles (231-316 × 109 /L) were 1.77 (95% confidence interval [CI], 1.38-2.24) for arterial thrombosis in the brain (38 and 26 events/10 000 person-years) and 0.82 (95%, 0.61-1.11) for arterial thrombosis in the heart (23 and 28 events/10 000 person-years). For individuals with hematocrit values in the top 5 percentiles (women/men: >45/>48%) vs the 25th-75th percentiles (women/men: 38.1-42/41.1-45%), hazard ratios were 1.27 (95% CI, 0.91-1.75) for arterial thrombosis in the brain (40 and 26 events/10 000 person-years) and 1.46 (95% CI, 1.06-2.00) for arterial thrombosis in the heart (43 and 25 events/10 000 person-years). Neither high platelet count nor high hematocrit was associated with risk of venous thromboembolism. When excluding individuals with myeloproliferative neoplasia from the main analyses, results on risk of thrombosis were similar. In this prospective study, high platelet counts were associated with 1.8-fold risk of arterial thrombosis in the brain, whereas high hematocrit was associated with 1.5-fold risk of arterial thrombosis in the heart.

JAK2V617F somatic mutation in the general population: myeloproliferative neoplasm development and progression rate.

Clinical significance of the JAK2V617F mutation in patients with a myeloproliferative neoplasm has been the target of intensive research in recent years. However, there is considerably uncertainty about prognosis in JAK2V617F positive individuals without overt signs of myeloproliferative disease. In this study, we tested the hypothesis that increased JAK2V617F somatic mutation burden is associated with myeloproliferative neoplasm progression rate in the general population. Among 49,488 individuals from the Copenhagen General Population Study, 63 (0.1%) tested positive for the JAK2V617F mutation in the time period 2003-2008. Of these, 48 were available for re-examination in 2012. Level of JAK2V617F mutation burden was associated with myeloproliferative neoplasm progression rate, consistent with a biological continuum of increasing JAK2V617F mutation burden across increasing severity of myeloproliferative neoplasm from no disease (n=8 at re-examination) through essential thrombocythemia (n=20) and polycythemia vera (n=13) to primary myelofibrosis (n=7). Among those diagnosed with a myeloproliferative neoplasm only at re-examination in 2012, in the preceding years JAK2V617F mutation burden increased by 0.55% per year, erythrocyte volume fraction increased by 1.19% per year, and erythrocyte mean corpuscular volume increased by 1.25% per year, while there was no change in platelet count or erythropoietin levels. Furthermore, we established a JAK2V617F mutation burden cut-off point of 2% indicative of disease versus no disease; however, individuals with a mutation burden below 2% may suffer from a latent form of myeloproliferative disease revealed by a slightly larger spleen and/or slightly higher lactic acid dehydrogenase concentration compared to controls. Of all 63 JAK2V617F positive individuals, 48 were eventually diagnosed with a myeloproliferative neoplasm.

Diagnostic value of JAK2 V617F somatic mutation for myeloproliferative cancer in 49 488 individuals from the general population.

The JAK2 V617F somatic mutation is present in the majority of patients with myeloproliferative cancer (polycythaemia vera, essential thrombocytosis, and primary myelofibrosis). However, the diagnostic value of the JAK2 V617F somatic mutation for myeloproliferative cancer in the general population is unknown. We examined this question in 49 488 individuals from the Copenhagen General Population Study. We also examined the association between JAK2 V617F somatic mutation, rs10974944 germline genotype, haematological phenotype, any cancer, haematological cancer, myeloproliferative cancer, ischaemic heart disease, and venous thromboembolism. The JAK2 V617F somatic mutation was present in 0·1% (n = 68), increasing across rs10974944 germline genotypes (P-trend = 0·001). JAK2 V617F somatic mutation positives versus negatives had higher erythrocyte (P = 2 × 10(-5) ), thrombocyte (P = 2 × 10(-16) ), and leucocyte (P = 4 × 10(-9) ) counts, and had 2·7-/2·5-fold risk of cancer (prevalent/incident), 44-/28-fold risk of haematological cancer, 221-/97-fold risk of myeloproliferative cancer, 2·2-/1·2-fold risk of ischaemic heart disease, and 3·1-/1·0-fold risk of venous thromboembolism. By combining conventional haematological parameters with a test for the JAK2 V617F somatic mutation, myelo;?>proliferative cancer could be identified or ruled out with a sensitivity of 47-100% and a specificity of 98-100%. In conclusion, in the general population the JAK2 V617F somatic mutation has a high diagnostic value for myeloproliferative cancer when combined with conventional haematological parameters.

Risk of thyroid cancer, brain cancer, and non-Hodgkin lymphoma after adult leukemia: a nationwide study.

Patients with childhood leukemia surviving into adulthood have elevated risk of developing thyroid cancer, brain cancer, and non-Hodgkin lymphoma (NHL); these risks cannot automatically be extrapolated to patients surviving adult leukemia. We tested whether survivors of adult leukemia are at increased risk of developing thyroid cancer, brain cancer, and NHL. We included the entire adult Danish population (14 years of age or older), in a 28-year follow-up period from 1980 through 2007, composed of 6 542 639 persons; during this period, 18 834 developed adult leukemia, 4561 developed thyroid cancer, 13 362 developed brain cancer, and 15 967 developed NHL. In nested studies using Cox regression models on individual participant data, we found that, after adult leukemia, the multivariate adjusted hazard ratios were 4.9 (95% confidence interval [CI], 2.8-8.5) for thyroid cancer, 1.9 (95% CI, 1.2-3.1) for brain cancer, and 3.3 (95% CI, 2.5-4.4) for NHL. Corresponding hazard ratios after childhood leukemia were 10.4 (95% CI, 0.4-223) for thyroid cancer, 7.2 (95% CI, 2.0-26) for brain cancer, and 6.5 (95% CI, 0.4-110) for NHL. Patients with adult leukemia have excess risk of thyroid cancer, brain cancer, and NHL, similar to patients with childhood leukemia.

The JAK2 V617F somatic mutation, mortality and cancer risk in the general population.

JAK2 V617F is present in the majority of patients with myeloproliferative cancer; however, its prevalence and clinical significance in the general population is unknown. We screened for presence of the mutation in 10,507 participants from the Copenhagen City Heart Study with up to 17.6 years of follow up. Prevalence of the mutation was 0.2% (n=18). All 18 mutation positives died during follow up corresponding to a multifactorially adjusted hazard ratio for early death of 3.0 (95%CI:1.9-4.9). Corresponding hazard ratios for men versus women and 1-year age increases were 1.4 (1.1-1.9) and 1.1 (1.1-1.1). Multifactorially adjusted hazard ratios for any cancer, hematologic cancer and myeloproliferative cancer were 3.7 (1.7-8.0), 58 (13-261) and 161 (12-2,197), respectively. Corresponding hazard ratios were 1.2 (0.8-2.0), 2.3 (0.2-25), 1.3 (0.3-5.4) for men versus women, and 1.0 (1.0-1.1), 1.1 (0.9-1.2), 0.9 (0.8-1.1) for 1-year age increases. In the general population, JAK2 V617F is associated with increased morbidity and mortality, although only present in 18 of 10,507 (0.2%).

Rituximab chimeric anti-CD20 monoclonal antibody treatment for adult refractory idiopathic thrombocytopenic purpura.

Idiopathic thrombocytopenic purpura is an autoimmune disease which involves opsonization of platelets by autoantibodies directed against different surface glycoproteins, leading to their premature destruction by the reticuloendothelial system. Management of patients with refractory ITP is difficult. Recent studies have shown that rituximab, a chimeric anti-CD20 monoclonal antibody, is useful in the treatment of these patients, with overall response rates of about 50%. Most published reports have included a small number patients including case reports. The present study reports the results of a retrospective Danish multicenter study of rituximab in the treatment of adult patients with refractory ITP. Thirty-five patients (median age 52 years, range 17-82 years, 17 males) were included. One patient had immune thrombocytopenia and neutropenia. All patients had received prednisolone (Pred). Next to Pred, 25 patients had been treated with high-dose IgG, and in 16 patients a splenectomy had been performed. Sixteen patients had been treated with azathioprine. Other treatments included, e.g., cyclosporine, danazol, cyclophosphamide, vincristine, interferon, and dexamethasone. The patients were treated with a dose regimen of 375 mg/m2 i.v. approximately once weekly for 4 consecutive weeks. Six patients received a fixed dose of 500 mg disregarding their weight supplemented by 100 mg of methylprednisone i.v. or 50-100 mg of Pred given as premedication together with an antihistamine just before infusion of rituximab. The large majority of patients also received Pred and, in some cases, other concomitant immunosuppressive treatment during part of their rituximab treatment. A complete response (CR) was defined as a rise in the platelet count > 100 x 10(9)/L, a partial response (PR) as a rise in the platelet count > 50 x 10(9)/L, and a minor response (MR) as a rise in the platelet count < 50 x 10(9)/L. No response (NR) was defined as no increase in the platelet count. Because 4 patients were treated twice, a total of 39 outcomes of rituximab treatment were evaluated. Rituximab proved to be effective in 17 of 39 treatments [overall response 44% with 7 CR (18%) (1 patient showed a CR twice), 6 PR (15%), and 4 MR (10%)]. In 9/13 cases of CR or PR, the response (platelet level > 50 x 10(9)/L) was prompt, 1-2 weeks after the first infusion. The remaining patients responded 3-8 weeks later. Patients with CR and PR have been in remission for a median of 47 weeks. In general the side effects were few. In 2 cases, the treatment was stopped because of side effects either during or after the first infusion. Two fatal outcomes were recorded. A 71-year-old female with severe lung disease died 6 days after the first infusion of respiratory failure. The other patient, a 73-year-old man also with severe chronic obstructive lung disease, died of pneumonia approximately 13 weeks following the last rituximab treatment. It is concluded that rituximab may be a useful alternative therapy in patients with severe and symptomatic ITP refractory to conventional treatment.

[alpha-thalassemia among Danish immigrants]. / alpha-thalassaemia hos den danske indvandrerbefolkning.

INTRODUCTION: alpha-thalassaemia is the most common hereditary anaemia in the world. The majority of Danish immigrants come from countries, where the prevalence of alpha-thalassaemia is high. The aim of this study was to evaluate its frequency in Danish immigrants. MATERIAL AND METHODS: Over a year, all samples sent for haemoglobin analysis to our institution from patients with an MCV value < or = 80 fl were examined for an alpha-thalassaemia haplotype by a PCR-based method. All samples were measured, irrespective of the MCV value, over a period of 3 months. RESULTS: We received 239 samples with an MCV m80 fl. Fifty-seven individuals (23.8%) had one or two alpha-thalassaemia haplotypes. In comparison, a beta-thalassaemia trait was found in 44 individuals (18.4%). The -alpha 3.7 haplotype was the most common (91%). Most were heterozygous, but homozygous cases and combinations with an alpha 0-deletion or a haemoglobin variant were also found. The more serious alpha 0-haplotype was found in nine cases (15.8%), among whom four cases had haemoglobin H disease. In 141 patients with MCV values above 80 fl, 11 patients had an alpha(+)-deletion. From these findings and with the knowledge of the prevalence of beta-thalassaemia in immigrants in Denmark, we assessed the prevalence of alpha-thalassaemia to be between 3 and 8%. CONCLUSIONS: alpha-thalassemia is no longer a rare, differential diagnosis in Denmark. A national strategy is indicated for prophylactic measures, including screening for the serious alpha 0-deletion and prenatal diagnosis in accordance with international recommendations.