The value of erythropoietin in the pathogenesis of anemia of chronic diseases in the rheumatic patients

The features of erythropoietin secretion in patients with a rheumatic pathology and anemia of the chronic diseases in comparison with patients having iron deficiency anemia, as well as the relationship between erythropoietin, hepcidin, proinflammatory, and antiinflammatory cytokines, have been investigated. 126 patients suffering from the rheumatic pathology were examined, including 34 men aged 36–55 years and 92 women aged 38–60 years. At the same time, 104 (82.5%) patients suffered from anemia, 22 (17.5%) patients did not have it. Patients suffering from anemia, depending on the leading pathogenetic factor, were divided into three groups such as: the 1^st group — patients suffering from anemia of chronic diseases; 2nd group—patients suffering from a combination of anemia of chronic diseases and iron deficiency anemia; 3^rd group—patients suffering from iron deficiency anemia. In patients suffering from anemia of chronic diseases, the maximum concentration of interleukin-6, hepcidin, and the minimum concentration of erythropoietin were detected in comparison with the patients suffering from iron deficiency anemia and patients suffering from anemia of chronic diseases, and iron deficiency anemia (p < 0.05). The maximum concentration of the erythropoietin has been established in patients suffering from iron deficiency anemia. About the concentrations of interleukin-10 and interleukin-1β, tumor necrosis factor-α, interferon-γ, no differences were found in the study groups. A direct correlation was found between the erythropoietin and erythrocytes (r = 0.57), hemoglobin (r = 0.41), hepcidin (r = 0.65). There was a strong negative correlation between the erythropoietin and interleukin-6 (r = –0.75), and a weak relationship with interferon gamma, tumor necrosis factor alpha, interleukin-10, and interleukin-1β (r < 0.3). Thus, for patients with a rheumatic profile, a specific molecular profile should be identified, leading to the development of anemia of the chronic diseases, which consists in increased concentrations of hepcidin and interleukin-6 in combination with the insufficient secretion of erythropoietin. The found changes fit into the structure of the previously proposed working version of the classification of anemia of chronic diseases (with a predominant iron deficiency, with disturbances in the regulatory mechanisms of the erythropoiesis, with an insufficient production of erythropoietin). Isolation of the leading factor in the development of anemia of chronic diseases in the future will allow for a more optimal approach to its correction, including with the targeted therapy drugs.