TITLE:
Renal Expression and Clinical Significance of High Mobility Group Box 1 in Lupus Nephritis
AUTHORS:
Huimin Liu, Jing Geng, Zhimin Liu, Baoguo Liu
KEYWORDS:
Lupus Erythematosus, Systemic, Lupus Nephritis, High Mobility Group Protein 1 (HMGB1)
JOURNAL NAME:
Open Journal of Pathology,
Vol.5 No.1,
January
13,
2015
ABSTRACT: 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 P P P P 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.