A new marker for evaluation of iron status in anaemic patients with rheumatoid arthritis

الملخص EN

Anemia associated with rheumatoid arthritis (RA), the prototype of anemia of chronic inflammation, is the most common extra-articular manifestation.

Iron deficiency anemia is also common and has been reported ri up to 70% of anemic patients with RA.

Distinguishing between the two types of anemia on clinical basis may be problematic.

Serum transferrin receptors (sTfR) is a new parameter that is particularly useful for evaluation of erythropoiesis and identifying mild iron deficiency.

In this study, we investigated the value of sTfR measurements for detecting iron deficiency in anemic patients 1 vith active rheumatoid arthritis (RAj.

A possible relationship between sTfR and the degree of anemia and/or the activity of the inflammatory process was also explored.

Using a sandwich ELISA technique sTfR was measured in 35 adult anemic patients wi*h active RA, 15 patients with iron deficiency anemia and no evidence of inflammation and 15 healthy control subjects.

RA patients were divided into 2 groups, the first (57%) considered to have iron deficiency (serum ferritin <60 ug/l), and the second without iron deficiency (serum ferritin >60 ug/l).

The mean sTfR levels were significantly higher in the whole group of patients with RA (5.1 +3.2 ug/ml) than the normal healthy controls (2.7±0.8ug/ml).

Meanwhile, sTfR concentrations were lower in RA patients with anemia of inflammation (2.6+1.4 ug/ml) than in patients with iron deficiency anemia with (6.5+4.

lug/ml) or without (7.9±3.7ug/ml) RA.

Among patients with RA correlations between sTfR and ferritin concentrations (r=-0.62, P<0.001), serum TfR and erythropoietin concentrations (r=0.69, P<0.001) sTfR and iron concentrations (r--0.41) (P<0.001) and sTfR and TIBC (r=0.37, P<0.05) were observed in iron deficiency subjects and not in subjects with anemia with inflammation alone.

A significantly negative correlation was observed between sTfR and hemoglobin levels both in RA patients with iron deficiency (r=-0.51, P<0.001) and those with anemia of inflammation (r=-0.32, p<0.05).

When RA patients were divided according to their hemoglobin level significantly higher values of sTfR (P<0.05) and ESR (P<0.01) were obtained in RA group with moderate anemia (Hb <9 gm) than the group of mild anemia (Hb >9 gm/dl).

In conclusion, sTfR can help to distinguish between anemia of inflammation and iron deficiency anemia and to identify iron deficiency in anemic patients with RA.

Serum TfR seems to be related to the degree of anemia and activity of the inflammatory process in these patients.