Soluble transferrin receptors levels in pediatric connective tissue diseases

Abstract EN

The aim of this study was to verify the relationship between the levels of soluble transferrin receptors (sTfR) and the degree of anemia, as well as the activity of juvenile connective tissue diseases.

Forty patients comprising 22 with rheumatoid arthritis, 14 with systemic lupus erythematosus and 4 with mixed connective tissue disease together with 20 healthy children as controls were enrolled in this study.

In addition to measurement of hemoglobin (Hb) concentration and red blood cell indices, serum iron, serum ferritin and total iron binding capacity (TIBC), soluble transferrin receptor (sTfR) were determined with enzyme immunoassay (EIA).

Significant higher levels of sTfR were detected in patients with connective tissue diseases (1017.6 ± 538.38 ug / dl) than in the controls (422.1 ± 93.16 ug / dl).

Meanwhile, no significant difference in sTfR levels was found between patients with rheumatoid arthritis and those with other connective tissue diseases.

Among patients with rheumatoid arthritis, a significant increase in sTfR values was detected during relapse (1433.06 ± 584.28 μg / dl) than in remission (705.71 ± 130.16 μg / dl).

According to the degree of anemia, a significant increases of sTfR levels were observed from mild (935.22 ± 398.18 μg / dl) to moderate (1176.6 ± 6.01 μg / dl) and severe anemia (2185.9 ± 320.18 μg / dl).

Moreover, there was a significant higher value of sTfR among patients who had iron deficiency anemia (1699.85 ± 510.46 μg / dl) as compared with those who did not have iron deficiency (625.22 ± 96.63 μg / dl).

Meanwhile, no significant difference in the mean level of sTfR was found among patients receiving combined treatment of methotrexate and prednisone (1214.25 ± 523.23 ug / dl) versus those on NSAIDs (765 ± 303.87 μg / dl) or others who received oral prednisone whether alone or combined with NSAIDs (1025.4 ± 579.44 μg / dl).

Among patients with connective tissue diseases, sTfR levels showed a significant negative correlation with Hb concentrations (r = -0.31 ; p < 0.05), while, no significant correlation was fond between sTfR levels and serum iron (r = 0.01 ; p > 0.05), serum ferritin (r = 0.22 ; p > 0.05) or TIBC (r = -0.18 ; p > 0.05).

Therefore, the increase in sTfR levels in patients with connective tissue diseases appears to be related to the degree of anemia and the activity of the disease.

The observed significant increase in sTfR levels among patients with concomitant iron deficiency anemia than those with anemia of chronic diseases calls for its utilization as a single test that can be performed for patients with chronic inflammatory disease when iron deficiency anemia is suspected.