LAUSR

Background: Ankylosing spondylitis (AS) is a type of chronic inflammatory disease that compromises the axial skeleton and sacroiliac joints. Many studies have shown that neutrophils play an important roles in the inflammatory process of AS. However, the immunomodulatory roles and mechanisms of neutrophils in AS are poorly understood. T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) has been reported as an important regulatory molecule, expressed and regulated on different innate immune cells, plays a pivotal role in several autoimmunity diseases. Recent study indicates that Tim3 is also expressed on neutrophils. However, the frequency and roles of Tim3-expressing neutrophils in AS was not clear. Objectives: In this study, we investigated the expression of Tim3 on neutrophils in AS patients and analyzed the correlation between the level of Tim3-expressing neutrophils and the disease activity of AS. Methods: AS Patients were recruited from Guangdong Second Provincial General Hospital (n=49). Age/sex-matched volunteers as Healthy controls (HC) (n=39). The medical history, clinical manifestations, physical examination, laboratory measurements were recorded. The expression of costimulatory molecules including programmed death 1 (PD-1), Tim-3 on neutrophils were determined by flow cytometry. The frequencies of Tim3-expressing neutrophils in AS patients were further analyzed for their correlation with markers of inflammation ESR and CRP, disease activity and severity of AS. Results: The expression of Tim3 on neutrophils in patients with AS was increased compared to the HC (Figure 1A). The frequency of Tim3-expressing neutrophils in patients with AS showed an positive correlation with ESR, CRP and ASAS-endorsed disease activity score (ASDAS) (Figure 1B). Moreover, the frequency of Tim3-expressing neutrophils in active patients(ASDAS≥1.3) was increased as compare with the inactive patients (ASDAS Conclusion: Increased Tim-3 expression on neutrophils may be a novel indicator to assess disease activity and severity in AS, which may serves as a negative feedback mechanism preventing potential tissue damage caused by excessive inflammatory responses in AS patients. References: [1]Han, G., Chen, G., Shen, B. & Li, Y., Tim-3: an activation marker and activation limiter of innate immune cells. FRONT IMMUNOL4 449 (2013). [2]Vega-Carrascal, I. et al., Galectin-9 signaling through TIM-3 is involved in neutrophil-mediated Gram-negative bacterial killing: an effect abrogated within the cystic fibrosis lung. J IMMUNOL192 2418 (2014). Disclosure of Interests: None declared