The Profile of Serum Transferrin Isoforms in Rheumatoid Arthritis

Transferrin, a microheterogeneous iron-transporting N-glycoprotein, is an optimal model for the analysis of the glycosylation profile in rheumatoid arthritis (RA). The aim of this study was to assess the transferrin isoforms profile in RA patients at the time of diagnosis and then look into their associations with disease activity.

Serum samples were collected from 48 patients with RA. The patients were males (6) and females (42) (age range: 33-85 years). Control group consisted of 30 healthy volunteers. Transferrin isoforms were analysed by capillary electrophoresis on MINICAP electrophoretic system.

There was a significant decrease in the relative concentrations of trisialo- (mean ± SD; 2.130 ± 1.112) and pentasialotransferrin (13.562 ± 3.088), and significant increase in tetrasialotransferrin (83.640 ± 3.165) in RA patients when compared to the control group (3.615 ± 1.156; 76.840 ± 5.621; 18.610 ± 6.027, respectively) (U Mann-Whitney test: p < 0.001 for all comparisons). There were no significant changes in the disialotransferrin concentrations in RA patients. Trisialotransferrin concentration correlated with RA activity expressed as DAS 28 in RA patients (p < 0.001). The low trisialotransferrin concentration was also associated with high platelet count and high ESR (p < 0.001 for both). Disialo-, tetrasialo- and pentasialotransferrin concentrations did not correlate with DAS 28.

In patients with RA the serum profile of transferrin isoforms is altered. We predict that the levels of trisialylated isoforms of transferrin will serve as a useful biochemical marker of the RA activity.