Patients with Still's disease show a prominent acute phase reaction. Our hypothesis is that under these circumstances the iron uptake of ferritin will not keep pace with its synthesis, and is therefore not a valid reflection of the iron status in these patients.
Previously we developed a method to measure the iron content of ferritin; we investigated the usefulness of this method to establish the iron status of patients with anemia of inflammation.
In 9 patients with adult onset Still's disease (AOSD) we observed high ferritin concentrations and measured the iron saturation of ferritin. The mean value of saturation was 9.1%, while saturation in the healthy control group was 17.8%, a statistically significant difference (p < 0.005). Soluble transferrin receptor concentrations indicated a functional iron deficiency.
We conclude that the acute phase ferritin in patients with AOSD contains less iron in comparison to ferritin in healthy controls. We suggest that soluble transferrin receptor is the method of choice in estimating the iron status of patients with an acute phase reaction.