Two Novel Monoallelic Calreticulin Mutations in a Patient With Essential Thrombocythemia.

Recently, mutations have been identified in the calreticulin (CALR) gene in JAK2 or myeloproliferative leukemia negative patients with myeloproliferative neoplasm. A 49-year-old male patient with incidental thrombocytosis was investigated for CALR mutation by direct sequencing method. The patient carried two novel monoallelic somatic mutations, the L367fs*52 and the p.R368W in the CALR gen, which resulted in a novel C-terminal sequence. The absent endoplasmatic reticulum retention signal in the mutant CALR results in an altered subcellular localization of the mutant protein. The new positively charged C-terminal domain has an importance for oncogenicity, effecting different signaling pathways, activating the cytokine-independent growth of the cells and down-regulating the apoptotic signaling. But the new, alternative C-terminal domain offers an opportunity for immunologic therapy as it represents a cancer-specific epitope.

Copy number variation of GSTT1 and GSTM1 and the risk of prostate cancer in a Caribbean population of African descent.

BACKGROUND: Deletions of the glutathione S-transferase genes M1 and T1 (GSTM1 and GSTT1) have been studied as potential risk factors for prostate cancer. Conflicting results have been obtained. Moreover, most such studies could not discriminate heterozygous from homozygous carriers of the non-deleted alleles. OBJECTIVE: We investigated whether copy number variation (CNV) of the GSTM1 and/or GSTT1 genes contribute to the risk of prostate cancer in the Caribbean population of African descent of Guadeloupe. METHODS: In a population-based case-control study, we compared 629 prostate cancer patients and 622 control subjects. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). Exact copy numbers of GSTM1 and GSTT1 were determined by real-time PCR. RESULTS: A higher copy number of GSTM1 was marginally associated with prostate cancer risk. Men with 2 and 3 or more GSTT1 genes were at higher risk of prostate cancer (OR: 1.55, 95% CI: 1.11-2.16 and OR: 4.89, 95% CI: 1.71-13.99, respectively; P(trend)<0.001). Men with 3, 4 and 5 or more copies of both GSTM1 and GSTT1 genes were at higher risk of prostate cancer (OR: 2.18, 95% CI: 1.21-3.91, OR: 3.24, 95% CI: 1.63-6.46, and OR: 5.77, 95% CI: 1.40-23.84, respectively; P(trend)<0.001). CONCLUSIONS: Copy number of GSTT1 and combined GSTM1/GSTT1 appear to be associated with prostate cancer risk in our population study with gene dose relationship. Our results support the hypothesis that variations in copy number of GSTT1 modulate the risk of prostate cancer.

Universal newborn screening for haemoglobinopathies in Guadeloupe (French West Indies): a 27-year experience.

OBJECTIVES: In Guadeloupe, an island in the French West Indies, a universal newborn screening programme for sickle cell disease and other abnormal haemoglobins was initiated in 1984. In 1990, a comprehensive sickle cell centre was established to carry on the management programme. We here report the main results from the newborn screening programme from 1984 to 2010, and consider how the establishment of the sickle cell centre affected the programme. METHODS: All blood samples were screened for the haemoglobinopathies using two reference methods in a single reference diagnosis laboratory. DNA analyses were also performed for confirmatory tests and analysis of the globin gene status. RESULTS: Between 1 January 1984 and 31 December 2010, 178,428 newborns were screened at birth, and 585 children were diagnosed with major sickle cell syndromes (ie. an overall incidence of 1 in 304 births). Sickle cell anaemia (haemoglobin SS disease) was the most frequently observed (1 in 575 births), followed by haemoglobin SC disease (1 in 771 births) and haemoglobin Sß-thalassemia disease (1 in 4,243 births). Some other rare haemoglobin variants were also detected, the most common being HbD(Punjab). The establishment of a comprehensive sickle cell centre resulted in a significant improvement in the screening coverage (p < 0.001) and a significant reduction of the delay between diagnosis and the first medical visit (p < 0.001). CONCLUSION: The universal screening programme has made it possible to establish the incidence of the major sickle cell syndromes in Guadeloupe, and the management centre has improved its efficiency.

Fetal hemoglobin and hydroxycarbamide moduate both plasma concentration and cellular origin of circulating microparticles in sickle cell anemia children.

Microparticles are cell membrane-derived microvesicles released during cell apoptosis and activation processes. They have been described as bio-markers in various vascular diseases, including sickle cell anemia, and associated with an increased risk of thrombosis. We investigated the effects of fetal hemoglobin level, a factor known to modulate the clinical expression of sickle cell anemia, and that of hydroxycarbamide treatment which reduces the frequency of vasoocclusive crises, the canonical clinical manifestation of the disease, on both the plasma concentration and the cellular origin of circulating microparticles. Flow cytometry was used to characterize microparticles in 62 sickle cell anemia children at steady state aged 2 months-16 years; 13 of them were treated with hydroxycarbamide. In untreated children, we observed negative correlations between fetal hemoglobin levels and the absolute plasma concentration of microparticles as well as that of microparticles specifically derived from platelets, erythrocytes, and monocytes. Compared to untreated children, those treated with hydroxyurea showed lower concentrations of total microparticles as a consequence of decreased microparticles shed by platelets and erythrocytes. In conclusion, in our sickle cell patients, neonatal decline of fetal hemoglobin coincided with an increase in circulating microparticles derived from erythrocytes, platelets, and monocytes. Hydroxyurea treatment was associated with a decrease in microparticles derived from erythrocytes and platelets.

Hemorheological risk factors of acute chest syndrome and painful vaso-occlusive crisis in children with sickle cell disease.

BACKGROUND: Little is known about the effects of blood rheology on the occurrence of acute chest syndrome and painful vaso-occlusive crises in children with sickle cell anemia and hemoglobin SC disease. DESIGN AND METHODS: To address this issue, steady-state hemorheological profiles (blood viscosity, red blood cell deformability, aggregation properties) and hematologic parameters were assessed in 44 children with sickle cell anemia and 49 children with hemoglobin SC disease (8-16 years old) followed since birth. Clinical charts were retrospectively reviewed to determine prior acute chest syndrome or vaso-occlusive episodes, and rates of these complications were calculated. RESULTS: Multivariate analysis revealed that: 1) a higher steady-state blood viscosity was associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, but not in children with hemoglobin SC disease; 2) a higher steady-state red blood cell disaggregation threshold was associated with previous history of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. CONCLUSIONS: Our results indicate for the first time that the red blood cell aggregation properties may play a role in the pathophysiology of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. In addition, whereas greater blood viscosity is associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, no association was found in children with hemoglobin SC disease, underscoring differences in the etiology of vaso-occlusive crises between sickle cell anemia and hemoglobin SC disease.

Endurance running trial in tropical environment: a blood rheological study.

PURPOSE: The aim of this study was to clarify whether exercising in a tropical climate induces blood rheology alterations despite ad libitum hydration. METHODS: Hematological, biochemical and hemorheological changes were investigated in young healthy adults (N = 9 men, 20.7 ± 0.8 yrs) after a 10-km race in hot and humid conditions. Subjects' maximal aerobic abilities were tested using a maximal ramp exercise. Blood was sampled at rest (TR), at the end of the race (TEx), and after 24 hours of recovery (T24). Ad libitum hydration was allowed during the race. Blood viscosity (ηb), red blood cell deformability (EI), aggregation (AI) and disaggregation shear rate (γ) were measured. RESULTS: Hematocrit, hemoglobin and plasma concentration of chlorine, sodium and potassium did not change in response to exercise. No functional consequence was observed on RBC deformability since EI remained unchanged. Percentages of echinocytes, schizocytes and stomatocytes remained in the subclinical range at all times. AI, γ and ηb did not present change. CONCLUSION: Running exercise in tropical climate with ad libitum hydration does not alter the main rheological properties of blood.

Effect of strenuous physical exercise on circulating cell-derived microparticles.

Strenuous exercise is associated with an inflammatory response involving the activation of several types of blood cells. In order to document the specific activation of these cell types, we studied the effect of three maximal exercise tests conducted to exhaustion on the quantitative and qualitative pattern of circulating cell-derived microparticles and inflammatory molecules in healthy subjects. This study mainly indicated that the plasma concentration of microparticles from platelets and polymorphonuclear neutrophils (PMN) was increased immediately after the strenuous exercise. In addition, the increase in plasma concentration of microparticles from PMN and platelets was still observed after 2 hours of recovery. A similar pattern was observed for the IL-6 plasma level. In contrast, no change was observed for either soluble selectins or plasma concentration of microparticles from red blood cells, monocytes and endothelial cells. In agreement, sVCAM-1 and sICAM-1 levels were not changed by the exercise. We conclude that a strenuous exercise is accompanied by platelet- and PMN-derived microparticle production that probably reflects the activation of these two cell types.

Alpha-thalassemia is associated with a decreased occurrence and a delayed age-at-onset of albuminuria in sickle cell anemia patients.

The aim of this study was to identify possible risk factors for albuminuria, an early marker of sickle cell anemia (SCA) glomerulopathy, in a cohort of 189 SCA adult patients followed at the Sickle Cell Center of Guadeloupe, a French Caribbean island. Biological parameters obtained at baseline, alpha-globin gene status, and beta(S) haplotypes were compared in patients stratified accordingly to graded albuminuria. Abnormal albumin excretion rate was detected in half of the studied adult patients and macroalbuminuria occurred in 21.6%. Graded albuminuria was associated with advanced age (p=0.006), systolic blood pressure (p=0.031), and worsened anemia, i.e. low hemoglobin rate (p<0.0001) and red blood cell count (p<0.0001). Alpha-thalassemia frequency was lower in microalbuminuric and macroalbuminuric patients than in normoalbuminuric patients, 12.5%, 13.75% and 26%, respectively (p=0.0057). Comparison of albuminuria-free survival curves in SCA patients without and with alpha-thalassemia showed that the median time of albuminuria onset was delayed in the later ones (p=0.021). In contrast, no association of albuminuria was detected with the Bantou beta(S) haplotype. Our results strongly suggest a protective effect of alpha-thalassemia against glomerulopathy in SCA adult patients which could be related to a decreased hemolytic rate.