Effect of Tumor Necrosis Factor-Alpha on Erythropoietin- and Erythropoietin Receptor-Induced Erythroid Progenitor Cell Proliferation in β-Thalassemia/Hemoglobin E Patients

OBJECTIVE: Thalassemia is one of the genetic diseases that cause anemia and ineffective erythropoiesis. Increased levels of several inflammatory cytokines have been reported in β-thalassemia and might contribute to ineffective erythropoiesis. However, the mechanism by which tumor necrosis factor-alpha (TNF-α) is involved in ineffective erythropoiesis in thalassemic patients remains unclear. The objective of this study is to investigate the effect of TNF-α on the erythropoietin (EPO) and erythropoietin receptor (EPOR) expression involved in proliferation of β-thalassemia/hemoglobin (Hb) E erythroid progenitor cells compared with cells from healthy subjects. MATERIALS AND METHODS: CD34-positive cells were isolated from heparinized blood by using the EasySep® CD34 selection kit. Cells were then cultured with suitable culture medium in various concentrations of EPO for 14 days. The effect of TNF-α on percent cell viability was analyzed by trypan blue staining. In addition, the percentage of apoptosis and levels of EPOR protein were measured by flow cytometry. RESULTS: Upon EPO treatment, a higher cell number was observed for erythroid progenitor cells from both healthy participants and β-thalassemia/Hb E patients. However, a reduction of apoptosis was found in EPO-treated cells especially for β-thalassemia/Hb E patients. Interestingly, TNF-α caused higher levels of cell apoptosis and lower levels of EPOR protein in thalassemic erythroid progenitor cells. CONCLUSION: TNF-α caused a reduction in the level of EPOR protein and EPO-induced erythroid progenitor cell proliferation. It is possible that TNF-α could be involved in the mechanism of ineffective erythropoiesis in β-thalassemia/Hb E patients.