CXCL13 as a possible immunological surrogate marker of dermatomyositis: higher levels of CXCL13 in dermatomyositis than polymyositis

Abstract

CXCL13 is a chemokine involved in the pathophysiology of connective tissue diseases by contributing to ectopic lymphoid follicle formation. 59 patients with new-onset dermatomyositis (DM) (n = 42) / polymyositis (PM) (n = 17) were evaluated from October 2018 to March 2023 for clinical and pathophysiological significance of CXCL13 in DM and PM at our university hospital. Plasma CXCL13 levels were measured by ELISA, and their correlation with clinical characteristics and treatment was analyzed. Plasma CXCL13 levels were higher in patients with DM than in those with PM (P = 0.016), and these subsets could be differentiated using a cut-off value of 81.1 U/L (area under curve = 0.8). In patients positive for anti-aminoacyl-tRNA synthetase antibodies, those with DM had significantly higher plasma CXCL13 levels than those with PM (P = 0.001). Plasma CXCL13 levels correlated with serum levels of creatine kinase (P = 0.007), but not with KL-6 (P = 0.288) in patients with DM. Following treatment, plasma CXCL13 levels significantly decreased in patients with DM (P = 0.008). In conclusion, plasma CXCL13 levels were high, especially in patients with DM. CXCL13 can be an important chemokine implicated in the pathophysiology of DM, which serves as a novel immunological marker of disease activity in patients with DM.