Decreased serum IL-16 and increased serum TSG-14 levels in myasthenia gravis

Background: Myasthenia gravis (MG) is an autoimmune disease characterized by an imbalance between inflammatory mediators and immune cells. The diagnosis and assessment of disease severity require the aid of more specific biomarkers. Methods: Utilizing the Luminex assay, we quantified the serum levels of CD137, galectin-9, MMP12, TSG14, IL-16, IL-31, and IL-34 in a cohort of 157 participants, which comprised 98 patients with MG and 59 healthy controls (HCs). Correlation analyses were performed to examine the relationship between serum IL-16 and TSG-14 levels and clinical outcomes. Results: Serum levels of IL-16 were significantly lower in MG patients compared to the HC group (median [inter-quartile range (IQR)], 102.1 [73.58-126.7] pg/mL versus 162.4 [95.72-312.7] pg/ mL, P < 0.0001). Conversely, the serum concentration of TSG-14 was significantly higher in MG patients than in HCs (1249 [809.3-2134] pg/mL versus 883.0 [512.5-1264] pg/mL, P = 0.0035). No significant differences were observed in the serum levels of CD137, galectin-9, IL-31, IL-34, and MMP12 between MG patients and HCs. Correlation analysis revealed a negative correlation between serum IL-16 levels and Quantitative Myasthenia Gravis (QMG) scores, as well as Activities of Daily Living (ADL) scores; TSG-14 displayed a positive correlation with QMG scores. Conclusion: Serum IL-16 concentrations were reduced, whereas TSG-14 concentrations were elevated in MG patients. These findings suggest that these serum proteins can potentially serve as biomarkers for assessing disease severity in MG patients.