Serum transferrin receptor levels in anaemic patients with rheumatoid arthritis.

The value of s-Transferrin Receptor (s-TfR) measurements in recognizing simultaneous iron deficiency in anaemia of chronic disease was examined in 35 anaemic patients with active rheumatoid arthritis. Based on a quantification of stainable bone marrow (marrow iron grade 0-4) and serum ferritin concentrations (levels < 60 micrograms l-1) compatible with iron deficiency) the anaemia was found to be aggravated by iron deficiency in 19/35 or 54% of the patients. There was no significant difference between the mean s-TfR concentrations in patients with adequate iron in comparison to patients with iron depletion [2.9 (1.6) mg l-1 v. 2.7 (1.4) mg l-1; t = 0.273; p = 0.786; Student's t-test]. Mean s-TfR levels in both patients with adequate iron and depleted iron stores were within the normal range, but tended to be higher than in normal individuals [mean (SD): 1.54 (0.43) mg l-1]. In patients with no stainable marrow iron (MIG 0; N = 15) a significant inverse correlation was found between s-TfR concentrations and s-ferritin levels (r = 0.57; p < 0.05). 5/15 patients with MIG = 0 exhibited significantly raised concentrations of s-TfR values > 3.05 mg l-1 (the highest normal value of the normal range). Increases of s-TfR levels were consistently moderate, and never exceeded a level of 7 mg l-1, which is markedly lower than concentrations measured in patients with iron deficiency anaemia.(ABSTRACT TRUNCATED AT 250 WORDS)