Diagnostic value of serum high-mobility group box-1 in pediatric systemic lupus erythematosus

Background High-mobility group box-1 (HMGB1) acts as a damage-associated molecular pattern or as an alarmin and it stimulates inflammatory and immunological activities. Aim We sought to investigate serum HMGB1 protein expression in patients with pediatric systemic lupus erythematosus (pSLE) in relation to the disease characteristics and activity. Patients and methods This is a controlled cross-sectional study which comprised 50 children and adolescents with Systemic lupus erythematosus (SLE) and 50 age- and sex-matched healthy subjects who served as a control group. Study measurements included clinical assessment, laboratory workup for SLE (complete blood count, erythrocyte sedimentation rate, serum creatinine, creatinine clearance and 24-hour urinary protein, C3 and anti-double-stranded DNA, lupus anticoagulant and anticardiolipin antibodies) and measurement of serum HMGB1 by enzyme-linked immunosorbent assay in patients and controls. Results Serum HMGB1 expression was significantly higher in the pSLE patients than the control group (P < 0.001). Patients with lupus nephritis (LN) had significantly higher serum HMGB1 as compared to those with normal kidneys (P < 0.04). Serum HMGB1 in LN patients correlated positively to the SLE Disease Activity Index (P < 0.0001), and 24 hours urinary proteins and negatively to creatinine clearance (P < 0.001). At a cut-off point of >= 40 mu g/L, serum HMGB1 showed good diagnostic value for pSLE with sensitivity and specificity of 98% and 95%, respectively. Conclusion Serum HMGB1 seems to be a reliable biomarker for diagnosis of pSLE and monitoring disease status, especially in LN. HMBG1 might prove to be a potential therapeutic target in LN.