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Hemoglobin E/β-thalassemia (HbE/β-thalassemia) is the most important type of thalassemia in northeastern Thailand. Serious complications of the disease are associated with iron overload and the consequences of oxidative damage to various organs, especially the cardiovascular system. Endothelial dysfunction is an important predictor for the long-term outcome of the disease. In this study, 19 patients with HbE/β-thalassemia (aged 12.9 ± 2.8 years) and 18 healthy controls (aged 11.8 ± 1.6 years) were enrolled and their oxidant and antioxidant status was determined. Their vascular endothelial function was assessed by ultrasonographic measurement of flow-mediated dilation (FMD) of the brachial artery. The thalassemia patients were found to have higher levels of oxidative stress (based on plasma levels of malondialdehyde and protein carbonyls) and significantly reduced antioxidant levels [based on levels of glutathione (GSH) in whole blood (p < 0.001)]. Thalassemia patients showed endothelial dysfunction as shown by their FMD response during reactive hyperemia (p < 0.001). The degree of impaired FMD response was correlated with the age, hemoglobin levels and serum free iron levels of subjects (p < 0.05). In conclusion, the FMD response was reduced in children with HbE/β-thalassemia and the degree of this reduction was correlated with the severity of anemia. FMD can be used for clinical evaluation of endothelial dysfunction, which could be an independent predictor of the cardiovascular events of thalassemia patients.

In order to study the role of the cytokine interleukin-3 (IL-3) and its signaling pathways in erythropoiesis of beta-thalassemia/HbE erythroid progenitor cells, CD34 positive cells were isolated from peripheral blood of patients and healthy subjects. After culturing the cells in the presence or absence of IL-3, cell viability was measured by trypan blue staining and apoptotic cells were analyzed by flow cytometry. After 7 days of culture the highest percent erythroid progenitor cell viability was obtained with cells from healthy subjects, while the lowest percentage was found in those from splenectomized beta-thalassemia/HbE. Viability of beta-thalassemia/HbE erythroid progenitor cells in the presence of IL-3 was higher than that of nonsupplemented cells. In addition, specific inhibitors of protein kinase C (Ro-318220), phospholipase C (U-73122) and Janus kinase 2 (AG-490) were used to investigate the involvement of signaling pathways in erythropoiesis. Percent apoptosis of erythroid progenitor cells from splenectomized beta-thalassemia/HbE subjects treated with RO-318220 was higher than those of nonsplenectomized beta-thalassemia/HbE and healthy subjects. Treatment with U-73122 resulted in enhanced percent apoptotic cells from normal and beta-thalassemia/HbE subjects. All these effects were independent of IL-3 treatment.

The antioxidant status of hemoglobin-E carriers was studied pre- and post-treatment with vitamin E for 3 months. Fourteen hemoglobin-E carriers (age = 21.36 +/- 1.08 years, BMI = 18.32 +/- 1.22 kg/m2) were treated with vitamin E 200 I.U. daily for 3 months. Fasting blood samples were collected and analyzed for erythrocyte superoxide dismutase activity, total antioxidant activity, hemoglobin concentration, hematocrit, MCV, Heinz body formation and osmotic fragility test. The blood parameters before and after vitamin E treatment were compared. The results showed that superoxide dismutase activity in the erythrocytes was significantly decreased, while total antioxidant activity in plasma, and the osmotic fragility of the erythrocytes, was significantly increased after vitamin E supplementation. However, hematocrit, MCV, and Heinz body formation did not change significantly. This demonstrated that vitamin E 200 IU could be used as a lipophilic antioxidant in red blood cells and could help increase the level of antioxidant in hemoglobin-E carriers.

Accurate and precise hemoglobin separation and the quantitation of Hb A2 and Hb F are essential for the diagnosis of the thalassemias and hemoglobinopathies. Presented in this study is the validation of the the Hb A2 assay of the HbGold analyzer, a fully automated liquid chromatography system for hemoglobin separation and quantitation. Variability of Hb A2 quantitation was quite low; the CV's of within-run, between-run and interlaboratory studies were 1.8-3.1%, 3.4-6.0% and 6.8-8.8% respectively. The results of the %Hb A2 quantitated by HbGold analyzer correlated well with those given by the Bio-Rad Variant Hb testing system (r=0.98). The application of the HbGold analyzer for the diagnosis of the thalassemia phenotypes frequently observed in Thailand is considered. In conclusion, the Hb A2 assay of the HbGold analyzer could be used for the quantitation of Hb A2 and Hb F and the presumptive identification of abnormal hemoglobins.

Prevalence of thalassemias and/or hemoglobinopathies, particularly hemoglobin E, and cholangiocarcinoma were found more prominently in the lower part of the Northeast of Thailand as compared with the upper part of this region or any other area of the country. The aim of this study was to evaluate if there was coincident distribution or some relationship. Hemoglobin typing by the cellulose acetate method was performed in 111 cases of cholangiocarcinoma, mainly diagnosed by ultrasonography, compared with 146 normal controls. It was found that hemoglobin E trait and beta-thalassemia trait were significantly higher in the former group.