Serum levels of adipokines in patients with idiopathic inflammatory myopathies: a pilot study

Adipokines are cytokines not only regulating metabolic and endocrine activities, but also modulating inflammatory and immune responses in several clinical settings, including autoimmunity. This study was aimed to evaluate whether serum adipokine levels may be useful as markers of disease activity in patients with idiopathic inflammatory myopathies (IIM). Adiponectin, leptin, chemokine C-C motif ligand-2 (CCL2), interleukin (IL)-6, and tumor necrosis factor (TNF) were measured in the serum of all participants. For each adipokine, we evaluate the area under the ROC curve (AUC) and its correlation with creatine kinase (CK) levels. Thirteen patients with IIM and 13 age- and gender-matched healthy individuals were studied. In patients, the levels of CK (273 ± 321 versus 54 ± 29 U/L; P < 0.0001), leptin (1994 ± 1355 versus 818 ± 738 pg/mL; P = 0.024), and IL-6 (32.4 ± 24.1 versus 13.9 ± 3.5 pg/mL; P = 0.003) were significantly higher than in controls. As a result, CK (AUC = 0.929, 0.833-1.00; P = 0.0002), leptin (AUC = 0.783, 0.588-0.977; P = 0.025), and IL-6 (AUC = 0.846, 0.680-1.00; P = 0.005) significantly discriminated between patients and controls. Neither CCL2 (3256 ± 4585 versus 1118 ± 399 pg/mL; P = 0.319) nor TNF (85.1 ± 83.3 versus 58.2 ± 16.8 pg/mL; P = 0.809) levels were different. Additionally, only serum levels of CCL2 were significantly correlated with CK titers (Spearman´s rho coefficient 0.620, 0.087-0.877; P = 0.023). The levels of CCL2 are in parallel with CK activity in the serum of patients with IIM, suggesting a potential utility as markers of disease activity. Elevated levels of leptin and IL-6 also support a role for adipokines in IIM.