Measuring serum levels of high-mobility group box 1 by enzyme-linked immunosorbent assay does not identify bacterial infections in patients with systemic lupus erythematosus.
BACKGROUND
studies have shown that high-mobility group box 1 (HMGB1) may play a role in the propagation of inflammatory response in infectious and autoimmune diseases. However, its utility in the differentiation between infections and disease flares in systemic lupus erythematosus (SLE) patients has not been investigated.


METHODS
we prospectively recruited 38 hospitalized patients from Taiwan with SLE. Among them, 13 patients suffered from superimposed bacterial infections while the other 25 patients experienced disease flares. SLE disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Serum levels of HMGB1 were measured by an enzyme-linked immunosorbent assay (ELISA). Additionally, serum levels of high-sensitivity C-reactive protein (hsCRP) were determined among 34 of the SLE patients.


RESULTS
there was no significant difference between the serum HMGB1 levels in SLE patients with disease flares and patients with bacterial infections. Among SLE patients with disease flares, serum HMGB1 levels were significantly higher in patients with mild to moderate flares (3.53 ng/ml) compared to those with severe flares (1.72 ng/ml, p < 0.05). For identifying bacterial infections in patients with SLE, the area under the receiver operating characteristic (ROC) curve was 0.705 (95% CI: 0.524-0.848) for hsCRP and 0.497 (95% CI: 0.331-0.663) for HMGB1. The best cutoff value for hsCRP was 1.07 mg/dl for detection of bacterial infections in SLE patients, with a sensitivity of 75% and a specificity of 68%.


CONCLUSIONS
the determination of serum HMGB1 level is not useful in the differentiation between disease flares and bacterial infections in SLE patients.
Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taiwan.
Kuo-Tung
KT
Tang
Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taiwan.
Tsu-Yi
TY
Hsieh
Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taiwan Faculty of Medicine, National Yang-Ming University, Taiwan.
Yi-Ming
YM
Chen
Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taiwan Faculty of Medicine, National Yang-Ming University, Taiwan.
Chia-Wei
CW
Hsieh
Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taiwan Faculty of Medicine, National Yang-Ming University, Taiwan.
Yi-Hsing
YH
Chen
Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taiwan Faculty of Medicine, National Yang-Ming University, Taiwan Institute of Microbiology and Immunology, Chung Shan Medical University, Taiwan Institute of Biomedical Science, National Chung Hsing University, Taiwan dychen@vghtc.gov.tw.
Der-Yuan
DY
Chen
D000328:Adult; D001424:Bacterial Infections / Q000097:blood* / Q000150:complications*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D024243:HMGB1 Protein / Q000097:blood*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
D024243:HMGB1 Protein
High-mobility group box 1; high-sensitivity C-reactive protein; infection; systemic lupus erythematosus