Sickle cell disease (SCD) is characterized by a complex vasculopathy, consisting of endothelial dysfunction and increased arterial stiffness, with a global effect on cardiovascular function. The hypercoagulable state may result from chronic hemolysis and circulating cell-derived microparticles (MPs) originating mainly from activated platelets and erythrocytes. We measured the levels of platelet and erythrocyte-derived MPs (PMPs and ErMPs) in 50 young SCD patients compared with 40 age- and sex-matched healthy controls and assessed their relation to clinicopathological characteristics and aortic elastic properties. Patients were studied stressing on the occurrence of sickling crisis, transfusion history, hydroxyurea therapy, hematological, and coagulation profile as well as flow cytometric expression of PMPs (CD41b(+)) and ErMPs (glycophorin A(+)). Echocardiography was performed to assess aortic stiffness and distensibility, left ventricular function and pulmonary artery pressure. Both PMPs and ErMPs were significantly elevated in SCD patients compared with control group (p < 0.001). SCD patients had significantly elevated d-dimer and von Willebrand factor antigen (vWF Ag) levels with lower antithrombin III compared with controls (p < 0.001). Aortic stiffness index and pulmonary artery pressure were significantly higher in SCD (p < 0.001), whereas aortic strain and aortic distensibility were significantly lower (p < 0.001) compared with controls. MPs levels were significantly increased in SCD patients with pulmonary hypertension, acute chest syndrome, and stroke as well as those who had history of thrombosis or splenectomy (p < 0.001). Also, patients in sickling crisis during the study had higher PMPs and ErMPs levels than those in steady state (p < 0.001). Patients on hydroxyurea therapy had lower MPs levels than untreated patients (p < 0.001). PMPs and ErMPs were positively correlated with disease duration, transfusion index, white blood cell count, HbS, markers of hemolysis, serum ferritin, D-dimer, and vWF Ag, whereas negatively correlated with hemoglobin and HbF levels (p < 0.05). Both PMPs and ErMPs levels were positively correlated with aortic stiffness, pulmonary artery pressure, and tricuspid regurgitant velocity (p < 0.05) while negatively correlated with aortic distensibility. We suggest that PMPs and ErMPs overproduction may be considered a potential biological marker for vascular dysfunction and disease severity in SCD and may be implicated in the pathogenesis of coagulation abnormalities encountered in those patients. Their levels are closely related to sickling crisis, pulmonary hypertension, markers of hemolysis, fibrinolysis, and iron overload. Therefore, quantification of MPs in SCD may provide utility for identifying patients who are at increased risk of thrombotic events or cardiovascular abnormalities and would help to monitor response to hydroxyurea therapy.

Over diagnosis of acute rheumatic fever (ARF) based on a raised antistreptolysin O titer (ASOT) is not uncommon in endemic areas. In this study, 660 children (aged 9.2 ±1.7 years) were recruited consecutively and classified as: G1 (control group, n=200 healthy children), G2 (n=20 with ARF 1st attack), G3 (n=40 with recurrent ARF), G4 (n=100 with rheumatic heart disease (RHD) on long acting penicillin (LAP)), G5 (n=100 with acute follicular tonsillitis), and G6 (n=200 healthy children with history of repeated follicular tonsillitis more than three times a year). Serum ASOT was measured by latex agglutination. Upper limit of normal (ULN) ASOT (80th percentile) was 400 IU in G1, 200 IU in G4, and 1600 IU in G6. Significantly high levels were seen in ARF 1st attack when compared to groups 1 and 5 (P<0.001 and P<0.05, respectively). ASOT was significantly high in children over ten years of age, during winter and in those with acute rheumatic carditis. ASOT showed significant direct correlation with the number of attacks of tonsillitis (P<0.05). Egyptian children have high ULN ASOT reaching 400 IU. This has to be taken into consideration when interpreting its values in suspected ARF. A rise in ASOT is less prominent in recurrent ARF compared to 1st attack, and acute and recurrent tonsillitis. Basal levels of ASOT increase with age but the pattern of increase during infection is not age dependent.

Heart disease is the leading cause of mortality and morbidity in β-thalassemia major (β-TM). Aggregability of abnormal red cells and membrane-derived microparticles (MPs) stemming from activated platelets and erythrocytes are responsible for thrombotic risk. We measured platelet and erythrocyte MPs (PMPs and ErMPs) in 60 young β-TM patients compared with 40 age- and sex-matched healthy controls and assessed their relation to clinicopathological characteristics and aortic elastic properties. Patients were studied stressing on transfusion history, splenectomy, thrombotic events, chelation therapy, hematological and coagulation profiles, flow cytometric measurement of PMPs (CD41b(+) ) and ErMPs (glycophorin A(+) ) as well as echocardiographic assessment of aortic elastic properties. Aortic stiffness index and pulmonary artery pressure were significantly higher, whereas aortic strain and distensibility were lower in TM patients than controls (P < 0.001). Both PMPs and ErMPs were significantly elevated in TM patients compared with controls, particularly patients with risk of pulmonary hypertension, history of thrombosis, splenectomy or serum ferritin >2500 μg/L (P < 0.001). Compliant patients on chelation therapy had lower MPs levels than non-compliant patients (P < 0.001). PMPs and ErMPs were positively correlated to markers of hemolysis, serum ferritin, D-dimer, vWF Ag, and aortic stiffness, whereas negatively correlated to hemoglobin level and aortic distensibility (P < 0.05). We suggest that increased MPs may be implicated in vascular dysfunction, pulmonary hypertension risk, and aortic wall stiffness observed in thalassemia patients. Their quantification could provide utility for early detection of cardiovascular abnormalities and monitoring the biological efficacy of chelation therapy.

Our study of patients aged 12-13 months supported the theory of autonomic dysfunction in BHSs. The ECG findings, especially in patients with prolonged or frequent spells, need to be studied further to evaluate the risk of life-threatening events. Iron deficiency may play a role in autonomic dysfunction in patients with BHSs.

Elevated adiponectin level in children and adolescents with type I diabetes indicates poor glycemic control and development of complications, especially nephropathy.