OJPathology> Vol.5 No.1, January 2015

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Huimin Liu, Jing Geng, Zhimin Liu, Baoguo Liu^*

Department of Dermatology and Venereology, Affiliated Hospital of Hebei Engeering University, Handan, China.

Objective: To evaluate the clinical significance of high mobility group box 1 (HMGB1) expression in nephridial tissues of lupus nephritis (LN). Methods: Sixty-three patients with active LN and 15 systemic lupus erythematosus (SLE) (combined without LN) were included. Renal biopsies were performed in the two groups. The biopsies were evaluated according to the World Health Organization (WHO) classification and renal disease activity was estimated using the British Isles lupus assessment group (BILAG) index. Serum levels of HMGB1 were analyzed by western blot. HMGB1 expression in renal tissue was assessed by immunohistochemistry in the two groups. The correlation between HMGB1 and renal active index (AI), chronicity index (CI), pathological type of LN was analyzed. Results: LN biopsies showed WHO class III, IV or V and all patients had high renal disease activity (BILAG A/B). The HMGB1 expression was higher in the LN groups than the control groups (t = 9.263, P < 0.05). It showed positive correlation between HMGB1 expression and SLE DAI classification (r = 0.579, P < 0.05), AI (r = 0.708, P < 0.05) and renal tubule interstitial (TIL) classification (r = 0.815, P < 0.05), and negative correlation between HMGB1 expression and CI classification (r = 0.582, P < 0.05). In all patients, serum levels of HMGB1 increased only slightly in the patients only with SLE; however, in patients with LN WHO class IV a significant decrease was observed (P = 0.02). Immunostaining revealed a pronounced extranuclear HMGB1 expression predominantly outlining the glomerular endothelium and in the mesangium. There were significant differences in HMGB1 expression between LN and control biopsies and it existed with apparent association to histopathological classification and clinical outcome. Conclusions: Renal tissue expression and serum levels of HMGB1 were elevated in LN. The unusual elevation of HMGB1 in serum and tissue in LN may reflect persistent inflammatory activity, which clearly indicates a role for HMGB1 in pathogenesis of LN.

Lupus Erythematosus, Systemic, Lupus Nephritis, High Mobility Group Protein 1 (HMGB1)

Liu, H. , Geng, J. , Liu, Z. and Liu, B. (2015) Renal Expression and Clinical Significance of High Mobility Group Box 1 in Lupus Nephritis. Open Journal of Pathology, 5, 12-19. doi: 10.4236/ojpathology.2015.51003.