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THU0380 Increased Expression of Bruton Tyrosine Kinase in Patients with Lupus Nephritis and its Clinic Significance
  1. W. Kong,
  2. W. Deng,
  3. X. Feng,
  4. G. Yao,
  5. W. Chen,
  6. X. Tang,
  7. Y. Sun,
  8. S. Huang,
  9. Z. Zhang,
  10. B. Shi,
  11. L. Sun
  1. Department of Rheumatology and Immunology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China

Abstract

Background Systemic lupus erythematosus (SLE) is an autoimmune disease manifested by multiorgan impairment including glomerulonephritis, cutaneous lesions and arthritis. B cells participate in the onset of SLE. As a downstream signaling molecule of B-cell receptor (BCR) signaling pathway, Bruton tyrosine kinase (Btk) is involved in the development, activation and survival of B cells. It is reported that transgenic mice overexpressing Btk specifically in B cells could produce antinuclear antibody and develop a lupus-like symptoms.

Objectives The aim of our study was to identify the specific role of Btk in lupus nephritis.

Methods The percentages of Btk positive CD19+ B cells from 28 SLE patients and 28 healthy donors were examined by flow cytometry. The correlation between the percentages of Btk positive CD19+ B cells and some lupus related clinical indicators were analyzed. Immunohistochemistry was used to detect the Btk expression in kidney biopsies from 8 lupus nephritis (LN) patients and 8 controls. The levels of Btk expression in glomerulus were detected by image-pro plus analysis, and represented by mean optical density (MOD).

Results The frequency of Btk+CD19+ B cells from SLE patients is up-regulated compared with the healthy controls (3.89±0.31 vs 2.61±0.21, p<0.01), significantly correlating with the SLE activity (SLEDAI) (r=0.53), levels of serum anti-dsDNA antibody (r=0.41), levels of serum C3 (r=-0.41), and the amount of 24 hours urine protein (r=0.59). We also found that the frequency of Btk+CD19+ B cells in the patients with lupus nephritis was significantly higher compared with the patients without lupus nephritis (4.71±0.481 vs 3.19±0.30, p<0.05). The levels of Btk expression in glomerulus were markedly increased in LN patients compared with controls (0.04±0.01 vs 0.01±0.00, p<0.001).

Conclusions Btk expression is significantly increased in LN, which may be a promising therapeutic target for the molecular therapy of SLE.

Disclosure of Interest None declared

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