Increased plasma levels of interleukin-6 and interleukin-8 in beta-thalassaemia major

Abstract

Several immunological defects can be found in patients with beta-thalassaemia, among which the impairment of neurophil and macrophage phagocytic and killing functions and the production of some cytokines are the most important. It is known that interleukin-6 (IL-6) and interleukin-8 (IL-8) are important components of the pro-inflammatory response. The plasma levels of these cytokines may be relevant in the pathophysiology of beta-thalassaemia. To assess this hypothesis, the plasma IL-6 and IL-8 concentrations in patients with beta-thalassaemia, were investigated. Fourteen patients with thalassaemia major were studied by evaluating body iron status, iron supply for erythropoiesis, and plasma IL-6 and IL-8 levels, together with 12 age-matched healthy controls. The plasma levels of IL-6 and IL-8 were determined by enzyme-linked immunosorbent assay (ELISA). Patients with beta-thalassaemia were found to have higher IL-8 concentrations than normal controls (p < 0.001) and plasma IL-6 concentrations increased significantly in the beta-thalassaemic patients compared with control subjects (p = 0.01). Serum ferritin levels of beta-thalassaemic patients were significantly higher than those of control groups (p < 0.05). IL-8 levels correlated with ferritin levels (r = 0.694; p < 0.05) and the total number of transfusions (r = 0.64; p < 0.05). Plasma IL-6 levels in beta-thalassaemic patients did not correlate with any clinical, haematological or biochemical parameters. It was also found that plasma IL-8 levels in the patients who had blood transfusions over 100 times were significantly higher than those of under 100 times (p < 0.05), whereas there was no statistical difference for IL-6. Markedly increased plasma IL-6 and IL-8 levels were documented in patients with beta-thalassaemia. Increased production of IL-6 and IL-8 might have contributed to abnormalities in iron metabolism and it is probably due to overstimulation of macrophages. Before a clinical value can be ascribed to these changes in plasma cytokine levels in beta-thalassaemia, the follow-up samples of larger series of patients with beta-thalassaemia should be evaluated.