The role of S100A12 and Toll-like receptor 4 in assessment of disease activity in familial Mediterranean fever and juvenile idiopathic arthritis

Objective Our aim was to investigate the possible relationship between the serum S100A12 and Toll-like receptor 4 (TLR4) levels, and the activity of familial Mediterranean fever (FMF) and juvenile idiopathic arthritis (JIA) in accordance with the routine biochemical parameters. Furthermore, the effectiveness of these 2 biomarkers in distinguishing FMF from JIA has been evaluated. Method Sixty-nine children with FMF, 68 children with JIA, and 35 healthy children were included in this study. S100A12 and TLR4 levels were measured by the sandwich enzyme-linked immunosorbent assay technique. Results In the FMF patient group, serum S100A12 level was found to be significantly higher than in both the JIA and control groups (P = .000 and P = .000, respectively). Although S100A12 levels were higher in the attack period compared to the attack-free period, this increase was not statistically significant (P > .05). TLR4 levels were statistically significantly higher in the attack period compared to the attack-free period in children with FMF (P < .05). Although there was no relationship between S100A12 levels and disease activity, there is a clear correlation between S100A12 and the Auto-Inflammatory Disease Activity Index in attack-free FMF patients (r = 0.612 P = .000). Conclusion Serum S100A12 levels were not found to be a potentially valuable biomarker for assessing disease activity in either FMF or JIA. However, TLR4 levels were found to be a valuable biomarker for assessing disease activity in children with FMF. Further research which includes serial monitoring of S100A12 and TLR4 levels in a large cohort will provide detailed information about accuracy of these 2 potential biomarkers in both patients group.