Serum S100A12 levels in children with childhood-onset systemic lupus erythematosus, systemic juvenile arthritis, and systemic undefined recurrent fevers.

ABSTRACT

BACKGROUND: We compared serum levels of S100A12, a proinflammatory protein predominantly secreted by neutrophils, in children with newly diagnosed childhood-onset systemic lupus erythematosus (cSLE), systemic juvenile arthritis (sJIA), and systemic undefined recurrent fevers (SURFS) to examine its role as a diagnostic and discriminative marker of inflammation and to indirectly point out the importance of neutrophils and innate immunity in the pathogenesis of these diseases. MATERIALS AND METHODS: In a cross-sectional study, the serum levels of S100A12 protein of 68 children (19 with cSLE, 18 with sJIA, 7 with SURFS, and 24 controls) were determined by enzyme-linked immunosorbent assay and compared between groups and with clinical and laboratory findings. RESULTS: The median serum S100A12 levels were 469 ng/mL in the cSLE group, 6103 ng/mL in the sJIA group, 480 ng/mL in the SURFS group, and 44 ng/mL in the control group. Children with cSLE, sJIA, and SURFS had significantly higher serum S100A12 levels compared to the control group (p < 0.0001). sJIA patients had the highest levels of S100A12 in comparison to other patients (p < 0.0001), while there was no significant difference between children with cSLE and SURFS. CONCLUSION: Elevated serum SA100A12 levels in children with cSLE, sJIA, and SURFS may indicate intense neutrophil activation, which may play an important role in innate immunity in chronic inflammation in these diseases. Serum S100A12 levels could be used as a diagnostic marker of inflammation and be suitable for distinguishing sJIA and other disorders.