In our previous studies, we showed that the shift in one isoform of transferrin causes the reverse shift in the other, e.g., the increased level of tetrasialotransferrin was accompanied by the decreased level of pentasialotransferrin in the course of chronic hepatitis [25], and in pancreatic cancer [26], or mixed effect in the form of a significant decrease in tri- and pentasialotransferrin and a significant increase in tetrasialotransferrin in patients with rheumatoid arthritis [27]. Here, TF is linked to rheumatoid arthritis.