Clinical Significance and Correlation of Plasma D-Dimer, Fibrinogen, and Cytokines in Idiopathic Inflammatory Myopathy.

PURPOSE

To investigate the clinical significance and correlation of plasma D-dimer, fibrinogen (FIB), and serum cytokines in patients with idiopathic inflammatory myopathy (IIM).

PATIENTS AND METHODS

Fifty patients with IIM and 50 healthy controls were included. Plasma D-dimer, FIB, and serum cytokine levels in IIM patients were analyzed and contrasted with the control group. The association between coagulation indicators and key clinical indices, as well as cytokines was also analyzed in IIM patients. Subgroup analyses were performed based on the presence of interstitial lung disease (ILD). Correlations among the variables were tested using Spearman correlation analysis.

RESULTS

The levels of D-dimer, FIB, interleukin (IL)-1β, IL-6, IL-8, IL-18, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ were significantly higher in the IIM group compared to healthy controls (all p ≤ 0.001). In IIM patients, plasma D-dimer was positively correlated with serum alanine aminotransferase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), erythrocyte sedimentation rate (ESR), and ferritin, while negatively correlated with manual muscle test (MMT8) score, peripheral blood lymphocyte count, and hemoglobin (p <0.05). Plasma FIB was positively associated with C-reactive protein, ESR, and ferritin (p <0.05). Additionally, plasma D-dimer showed significantly positive correlations with IL-1β (r = 0.325, p = 0.021), IL-6 (r =0.309, p = 0.029), IL-8 (r = 0.347, p = 0.014), and IL-18 (r = 0.333, p = 0.018). In subgroup analyses, serum IFN-γ levels were significantly higher in IIM patients with ILD compared to those without ILD (p = 0.021), while no significant differences were observed in D-dimer or FIB levels between these two groups.

CONCLUSION

Elevated plasma D-dimer in IIM patients may be associated with disease activity, with cytokines playing a potentially important role. Both D-dimer and cytokines hold clinical significance in evaluating the disease status of IIM patients.