Lupus anticoagulant and anticardiolipin antibodies in polytransfused beta thalassemia major

Pathogenic Mechanisms in Thalassemia I: Ineffective Erythropoiesis and Hypercoagulability

Erythropoiesis is the physiological process that results in the production of red blood cells (RBCs). In conditions of pathologically altered erythropoiesis or ineffective erythropoiesis, as in the case of β-thalassemia, the reduced ability of erythrocytes to differentiate, survive and deliver oxygen stimulates a state of stress that leads to the ineffective production of RBCs. We herein describe the main features of erythropoiesis and its regulation in addition to the mechanisms behind ineffective erythropoiesis development in β-thalassemia. Finally, we review the pathophysiology of hypercoagulability and vascular disease development in β-thalassemia and the currently available prevention and treatment modalities.

Thalassemia and autoimmune diseases: Absence of evidence or evidence of absence?

The thalassemias are a group of inherited disorders of hemoglobin synthesis that continue to pause a global public health concern. The complex molecular and pathogenetic pathways involved in disease process lead to an array of comorbidities that require lifelong management. The disease and its treatment can also lead to alterations in immune function and a link to various autoimmune diseases has been frequently suggested. However, most data stem from single case reports and small studies that do not allow proper assessment of causal associations. Still, the high morbidity in thalassemia makes patients vulnerable to the added burden of coexisting autoimmune diseases, and special management considerations in this patient population are warranted. In this review, we explore insights and data from the literature on various autoimmune disease that have been observed in patients with thalassemia. The role of the thalassemia carrier state in modifying outcomes of patients with autoimmune diseases is also discussed.

High Prevalence of Antiphospholipid Antibodies in Children with Non-Transfusion Dependent Thalassemia and Possible Correlations with Microparticles

Antiphospholipid antibodies (APAs) are developed antibodies to the phospholipid surfaces or to the proteins binding to phospholipids. Increased PS-expressed red blood cells (RBC) may be a risk factor in APAs development. There were only a few studies reported on APAs in thalassemia, and their associations to PS-expressing microparticles (MPs), remain unknown. The presence of antiphospholipid antibodies (APAs) in pediatric thalassemia patients and their associations with phosphatidylserine (PS)- expressing microparticles (MPs), a previously unexplored relationship, were the aims of this report. We identified that positive APA rates were highest in non-transfusion-dependent thalassemia (NTDT) subjects, followed by transfusion-dependent thalassemia (TDT) subjects and controls (29.5%, 18.2% and 17.9%, respectively).  Subgroup analysis demonstrated that positive anti- ?2 glycoprotein I (a?2-GPI)- IgG rates in NTDT subjects were significantly greater than in controls and that the percentage of MPs was also significantly elevated in thalassemia subjects. More specifically, there were significant correlations found between a?2GPI-IgG and anticardiolipin (aCL)-IgM APAs, and MPs.

β-Thalassemia intermedia: a comprehensive overview and novel approaches

β-Thalassemia intermedia is a clinical condition of intermediate gravity between β-thalassemia minor, the asymptomatic carrier, and β-thalassemia major, the transfusion-dependent severe anemia. It is characterized by a significant clinical polymorphism, which is attributable to its genetic heterogeneity. Ineffective erythropoiesis, chronic anemia, and iron overload contribute to the clinical complications of thalassemia intermedia through stepwise pathophysiological mechanisms. These complications, including splenomegaly, extramedullary erythropoiesis, iron accumulation, leg ulcers, thrombophilia, and bone abnormalities can be managed via fetal hemoglobin induction, occasional transfusions, chelation, and in some cases, stem cell transplantation. Given its clinical diversity, thalassemia intermedia patients require tailored approaches to therapy. Here we present an overview and novel approaches to the genetic basis, pathophysiological mechanisms, clinical complications, and optimal management of thalassemia intermedia.

Pulmonary hypertension associated with thalassemia syndromes

Chronic hemolytic anemia has increasingly been identified as an important risk factor for the development of pulmonary hypertension (PH). Within the thalassemia syndromes, there are multiple mechanisms, both distinct and overlapping, by which PH develops and that differ among β-thalassemia major or intermedia patients. PH in β-thalassemia major correlates with the severity of hemolysis, yet in patients whose disease is well treated with chronic transfusion therapy, the development of PH can be related to cardiac dysfunction and the subsequent toxic effects of iron overload rather than hemolysis. β-Thalassemia intermedia, on the other hand, has a higher incidence of PH owing to the low level of hemolysis that exists over years without the requirement for frequent transfusions, while splenectomy is shown to play an important role in both types. Standard therapies such as chronic transfusion have been shown to mitigate PH, and appropriate chelation therapy can avoid the toxic effects of iron overload, yet is not indicated in many patients. Limited evidence exists for the use of pulmonary vasodilators or other therapies, such as l-carnitine, to treat PH associated with thalassemia. Here, we review the most recent findings regarding the pathogenic mechanisms, epidemiology, presentation, diagnosis, and treatment of PH in thalassemia syndromes.

Thalassemia and the hypercoagulable state

Thalassemia, an inherited hemolytic disorder, is associated with a high incidence of thrombosis. The major mechanisms underlying thromboembolism (TE) are an abnormal red blood cell surface, platelet activation and endothelial cell activation. A higher risk of TE is found in splenectomized patients due to thrombocytosis and increased abnormal RBCs in the circulation. Regular RBC transfusions can reduce the proportion of abnormal RBCs and suppress erythropoiesis. Regular transfusion may also reduce levels of circulating coagulation markers and reduce elevated pulmonary artery pressure. To prevent thromboembolic events, aspirin is now recommended for splenectomized patients with thrombocytosis.

Stroke in a young boy with β-thalassemia intermedia secondary to moyamoya syndrome

Moyamoya disease is a rare cerebrovascular disorder, characterized by stenosis or occlusion of cerebral arteries. Well described with sickle cell anemia, its association with other hemoglobinopathies is a rarity. We report a 5-year-old boy with β-thalassemia intermedia, on hydroxyurea therapy, who presented with a stroke. Magnetic resonance angiography findings were consistent with bilateral moyamoya disease. The literature with regard to the pathogenesis and options of management is reviewed.

Thrombin activatable fibrinolysis inhibitor (TAFI): relationship to hemostatic alteration in patients with beta-thalassemia

Profound hemostatic changes have been observed among thalassemic patients. Thrombin activatable fibrinolysis inhibitor (TAFI) is a newly discovered protein that potentially attenuates fibrinolysis. The authors aimed to investigate plasma level of TAFI in beta-thalassemia patients in relation to clinical severity and hemostatic alteration. Fifty-one thalassemic patients (mean age 10.79 +/- 5.59 years) (21 splenectomized thalassemia major patients, 18 nonsplenectomized thalassemia major patients, 12 nonsplenectomized thalassemia intermedia) were recruited from Pediatric Hematology Clinic, Ain Shams University; in addition, 32 healthy age- and sex-matched controls (10.31 +/- 5.58 years) were also included. In addition to clinical assessment, laboratory investigations included complete blood count (CBC), hemoglobin electrophoresis, prothrombin time (PT), activated partial thromboplastin time (PTT), liver function tests, viral hepatitis markers, serum ferritin, and plasma TAFI levels. Nine out of 51 patients (17.5%) suffered from bleeding manifestations mainly in the form of epistaxis; none of the studied patients had thromboembolism. Significant reduction in TAFI levels was shown in thalassemic patients compared to controls (P < .0001), in splenectomized compared to nonsplenectomized thalassemia group (P < .0001), and in thalassemia major compared to thalassemia intermedia group (P < .0001). Negative correlation was present between TAFI levels and both liver enzymes and serum ferritin levels (P < .05). Thalassemic patients suffering from bleeding showed lower mean TAFI levels compared to those not suffering from bleeding (P < .001). Marked reduction in TAFI levels was observed in thalassemic patients with splenectomy, altered liver functions, and poor chelation who therefore might be at a higher risk for altered hemostasis.