Background/Purpose: Juvenile dermatomyositis (JDM) is a systemic vasculopathic disease of childhood affecting skeletal muscle, skin and other organs. Increased abundance of pro-inflammatory cytokines has been shown in JDM patients in the active phase of the disease. We now wanted to compare cytokine profiles in JDM patients 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 in JDM.

Methods: : Inclusion criteria were a probable or definitive diagnosis of Dermatomyositis (DM) according to the Bohan/Peter criteria for DM, disease onset before 18 years and minimum 24 months disease duration.  A retrospective inception cohort of JDM patients was established; 54 patients were clinically examined median 16.8 years (range 2-38 years) after disease onset and compared with 54 age- and sex-matched controls (randomly drawn from the Norwegian population register). Concentrations of 26 cytokines in plasma were quantified by Luminex technology or ELISA. In patients, disease activity score (DAS), myositis damage index (MDI) and other disease parameters were collected by clinical examination (at follow-up) or chart review (from one year post-diagnosis).

Results: Serum levels of eotaxin, monocyte chemoattractant protein 1 (MCP-1) and interferon inducible protein 10 (IP-10) were higher in JDM patients compared to controls (31.5%, 37.2% and 43.2%, respectively, all P < 0.05). Levels of eotaxin and MCP-1 correlated with disease duration (r_s = 0.47 and r_s = 0.64, both P < 0.001) and age in patients, but not with age in controls. MCP-1 levels were associated with MDI, DAS, physical health and cumulative prednisolone dose at follow-up (standardized β = 0.43, 0.29, 0.28 and 0.33 respectively, all P ≤ 0.020), after adjusting for disease duration and sex in a multivariate linear regression model. High MDI 1 year post-diagnosis predicted high levels of eotaxin and MCP-1 at follow-up (standardized β = 0.24 and β = 0.29, both P < 0.05) after adjusting for disease duration and sex.

Conclusion: Patients with JDM had higher eotaxin, MCP-1 and IP-10 levels than controls after median 17 years follow-up. High eotaxin and MCP-1 was predicted by early disease parameters and MCP-1 was associated with disease activity and damage at follow-up. It is not clear whether eotaxin and MCP-1 per se cause sustained inflammation; they might also be markers for disease damage as a result of disease activity caused by other unknown mechanisms. Either way, the novel knowledge on these substances can improve insight and treatment modalities of JDM.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/increased-levels-of-eotaxin-and-mcp-1-in-juvenile-dermatomyositis-median-17-years-after-diagnosis-associations-with-disease-activity-duration-and-organ-damage/