Levels of STING in rheumatoid arthritis

Abstract

Aim: STING (stimulator of Type-I Interferon genes) is a transmembrane carrier protein that is responsible for the transduction of (deoxyribonucleic acid) DNA-triggered signals. In this study, we aimed to investigate the serum level of STING and its prognostic value related to the disease activity in patients with rheumatoid arthritis (RA). Material and Methods: We enrolled 80 patients with RA, and age-, gender-and body mass index (BMI)-matched 80 healthy individuals. Serum levels of STING were investigated using enzyme-linked immunosorbent assay kits. The SPSS (Statistical Package for the Social Sciences) program (IBM, Armonk, NY, USA) was used for statistical analysis of the data. Descriptive statistics were expressed as mean +/- standard deviation or median (minimum-maximum) for discrete and continuous numerical variables, and the number of cases and (%) for categorical variables. Cross-table statistics were used to compare categorical variables (Chi-square, Fisher). Comparisons between multiple groups were made with Post Hoc Tukey analysis. Results were defined as p<0.05 statistical significance. Results: Neutrophilia, higher values of erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP) and lower hemoglobin values were detected in the RA group (Neutrophil: 4.54 +/- 1.71x109/L, CRP: 1.03 +/- 1.30 mg/dL, ESR: 30.27 +/- 18.1 mm/h, and Hgb: 12.88 +/- 1.50 g/dL; p values: 0.013, 0.001, 0.001 and 0.029, respectively). The mean level of serum STING was 3422.75 +/- 398,92 pg/mL in the RA group, whereas 3548.70 +/- 126,03 pg/mL in the control group. Male patients and patients with higher ESR and CRP values had higher STING levels compared with female patients, and patients with lower ESR and CRP values (p-values: 0.044, 0.006 and 0.046, respectively). Discussion: Serum STING levels were similar in RA patients and healthy controls. Additional knowledge related to the STING pathway will be beneficial for the development of new immunotherapeutic strategies in many inflammatory diseases such as RA.