Rheumatol Int. 2025 Jul 15;45(8):171. doi: 10.1007/s00296-025-05918-z.
ABSTRACT
BACKGROUND: Serum ferritin has been proposed as biomarker of interstitial lung disease (ILD) in anti-MDA5 dermatomyositis (DM). Nevertheless, no data exist for serum ferritin in other idiopathic inflammatory myopathies (IIM)-ILD nor in IIM without ILD. Aim of this case-control study was to assess whether serum ferritin may be considered a specific and sensitive biomarker for IIM-ILD, as well as to assess whether it correlates with clinical and immunological findings.
PATIENTS AND METHODS: All patients affected by IIM and followed at Siena (Italy), Palermo (Italy), Bari (Italy) and Lucknow, (India) IIM referral centers were retrospectively included. They had diagnosis of DM and ASS, with and without ILD. Myositis specific or myositis associated antibodies were tested through line immunoassay (Euroimmune, Lubeck, Germany). Serum ferritin concentrations at the first assessment (T0) were detected by ChemiLuminescent Enzyme Immunoassay technology.
RESULTS: A total of 139 IIM patients (study cohort n = 51 and validation cohort n = 88; mean age and standard deviation 44.3 ± 17.75) were included. The most common subtype was DM (n = 70, 50.3%), followed by ASS (n = 50, 35.9%). The three most common MSAs were MDA5 (n = 25, 18%), Jo1 (n = 25, 18%) and Mi2 (n = 10, 7%). ILD was assessed in 69 subjects. Ferritin values were higher in DM-MDA5 than DM-non-MDA5 (p = 0.0073) and ASS (p = 0.0006). All 69 patients affected by ILD were subsequently divided showing statistically significant difference for ferritin (p = 0.0013).
CONCLUSION: Our study included a huge number of patients from multicenter datasets, comprising patients of different ethnicities. Ferritin values lower than 303.5 ng/ml evaluated for the first time in a patient with suspected IIM and ILD, waiting for autoimmunity tests, allowed to exclude MDA5-DM. The strength of our findings was corroborated by binomial logistic regression, which proved the independence of ferritin from CPK and CRP to identify DM-MDA5-ILD. Such evidence allows to exclude that ferritin values are influenced by systemic inflammation.
PMID:40663209 | DOI:10.1007/s00296-025-05918-z
