Increased Levels of Eotaxin and MCP-1 in Juvenile Dermatomyositis Median 16.8 Years after Disease Onset; Associations with Disease Activity, Duration and Organ Damage

Objective: To compare cytokine profiles in patients with juvenile dermatomyositis (JDM) after medium to long-term follow-up with matched controls, and to examine associations between cytokine levels and disease activity, disease duration and organ damage. Methods: Fifty-four JDM patients were examined median 16.8 years (2-38) after disease onset (follow-up) and compared with 54 sex- and age-matched controls. Cytokine concentrations in serum were quantified by Luminex technology. In patients, disease activity score (DAS), myositis damage index (MDI) and other disease parameters were collected by chart review (early parameters) and clinical examination (follow-up). Results: Serum levels of eotaxin, monocyte chemoattractant protein-1 (MCP-1) and interferon-inducible protein 10 (IP-10) were elevated in JDM patients compared to controls (31.5%, 37.2% and 43.2% respectively, all p<0.05). Patients with active (n = 28), but not inactive disease (n = 26) had a higher level of MCP-1 than their respective controls. Levels of eotaxin and MCP-1 correlated with disease duration (r = 0.47 and r = 0.64, both p<0.001) and age in patients, but not with age in controls. At follow-up, MDI was associated with MCP-1(standardized beta = 0.43, p = 0.002) after adjusting for disease duration and gender. High MDI 1 year post-diagnosis predicted high levels of eotaxin and MCP-1 at follow-up (standardized beta = 0.24 and 0.29, both p<0.05) after adjusting for disease duration and gender. Conclusion: Patients with JDM had higher eotaxin, MCP-1 and IP-10 than controls. High eotaxin and MCP-1 at follow-up was predicted by early disease parameters, and MCP-1 was associated with organ damage at follow-up, highlighting a role of these chemokines in JDM.