Increased Cytokine Levels in Seronegative Myositis: Potential Th17 Immune Response Implications

Abstract

Th17 cells are known for producing IL-17 and their role in the pathogenesis of various autoimmune diseases, including myositis. Likewise, the participation of the IL-23/IL-17 pathway in autoimmunity has been confirmed. In this study, we aimed to evaluate the behavior of cytokines in myositis, focusing on the autoantibodies profile and the myositis core set measures. Twenty-five myositis patients were enrolled in this cross-sectional study. An expert rheumatologist evaluated the myositis core set measures. Serum levels of cytokines and chemokines were quantified using the LEGENDplex Multi-Analyte Flow Assay Kit from BioLegend. The autoantibodies detection was carried out using the line-blot assay kit Euroline: Autoimmune Inflammatory Myopathies from EUROIMMUN. We found higher serum levels of IL-33, CXCL8, IL-6, IL-23, and IL-12p70 in seronegative patients. A multiple linear regression analysis revealed that MYOACT scores could be predicted by the increment of IL-23 and the decrement of CCL2, IL-10, and CXCL8 serum levels. These findings suggest that the immune response in seronegative myositis patients exhibits an IL-23-driven Th17 immune response. The relevance of this discovery lies in its potential therapeutic implications. Insights into the IL-23-driven Th17 immune response in seronegative patients highlight the potential for targeted therapies aimed at modulating Th17 activity.

Keywords: IL-23; MYOACT; cytokines; myositis.

Figure 1

Cytokine and chemokine levels in myositis patients contrasted to healthy subjects; higher serum levels of IL-10, IL-6, CXCL8, IL-1β, IL-33, IFN-γ, TNF-α, IL-23, and IL-17A in myositis patients were observed. (a) Heatmap of cytokine serum levels according to z-score in each patient; (b) IL-10 (p < 0.001, r = 0.7); (c) IL-6 (p < 0.001, r = 0.5); (d) CXCL8 (p < 0.001, r = 0.5); (e) IL-1β (p < 0.001, r = 0.4); (f) IL-33 (p < 0.001, r = 0.4); (g) IFN-γ (p < 0.001, r = 0.4); (h) TNF-α (p = 0.013, r = 0.4); (i) IL-23 (p = 0.030, r = 0.3); and (j) IL-17A (p = 0.041, r = 0.3). * Mann–Whitney U test with Fisher’s Exact test. The size effect was calculated by the rank–biserial correlation.

Figure 2

Cytokine and chemokine levels according to autoantibodies presence. Higher serum levels of the following autoantibodies were detected in the seronegative myositis subset: (a) IL-33 (p = 0.003, r = 0.6); (b) IL-12p70 (p = 0.009, r = 0.5); (c) CXCL8 (p = 0.013, r = 0.5); (d) IL-23, (p = 0.033, r = 0.4); and (e) IL-6 (p = 0.040, r = 0.4). * Mann–Whitney U test with Fisher’s Exact test. The size effect was calculated by the rank–biserial correlation.

Figure 3

Cytokine and chemokine serum levels according to core set measures in myositis patients: (a) higher serum levels of IL-1β in MYOACT > 0 (p = 0.007, r = 0.5); (b) higher serum levels of CCL2 in MYOACT > 0 (p = 0.031, r = 0.4); (c) negative correlation between IL-1β serum levels and MYOACT score (p = 0.023, r_s = −0.452); (d) negative correlation between CCL2 serum levels and MYOACT score (p = 0.042, r_s = −0.410); and (e) negative correlation between IL-1β serum levels and MDI score (p = 0.005, r_s = −0.540). * Mann–Whitney U test with Fisher’s Exact test. The size effect was calculated by the rank–biserial correlation.