From the Guidelines
Elevated IL-1 beta levels can reflect low ferritin in the context of inflammation, as ferritin is an acute-phase reactant that can be elevated in response to inflammation, independent of iron status 1.
Key Points
- In the presence of inflammation, ferritin levels up to 100 µg/L may still reflect iron deficiency 1.
- Elevated IL-1 beta levels, indicative of inflammation, can lead to increased ferritin levels, making it challenging to diagnose iron deficiency based on ferritin levels alone 1.
- Other markers of inflammation, such as C-reactive protein, and measures of iron status, such as total iron binding capacity, should be considered to aid in the diagnosis of iron deficiency in patients with chronic inflammation 1.
- A ferritin threshold value of <45 ng/mL has a sensitivity for iron deficiency of 85% and specificity of 92%, but in patients with chronic inflammatory conditions, ferritin levels may not accurately reflect body iron stores 1.
- In such cases, other clinical tests, such as serum iron, transferrin saturation, soluble transferrin receptor, or C-reactive protein, may be useful adjunctive tests to assist in the diagnosis of iron deficiency 1.
From the Research
Relationship Between IL-1 Beta and Ferritin Levels
- Elevated IL-1 beta levels can influence ferritin synthesis and iron metabolism, as demonstrated in studies 2, 3, 4, 5.
- IL-1 beta increases the binding of iron regulatory proteins to iron responsive elements, leading to increased ferritin synthesis 3.
- The cytokine-induced increase in the labile iron pool stimulates ferritin synthesis, resulting in a subsequent decrease in the labile iron pool 3.
- IL-1 beta regulates ferritin expression by translational mechanisms, with no changes in mRNA levels, but increased association of ferritin mRNA with polyribosomes 4, 5.
Impact of IL-1 Beta on Iron Metabolism
- IL-1 beta, along with other pro-inflammatory cytokines, can decrease transferrin-iron uptake into cells and affect the proportion of iron associated with ferritin 2.
- The effects of IL-1 beta on iron metabolism may contribute to the observed perturbations of iron metabolism in inflammatory diseases 2.
- In cystic fibrosis patients, sputum iron, ferritin, and IL-1 beta levels are elevated, and changes in IL-1 beta are related to changes in sputum ferritin content 6.