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AB0139 Interleukin-21 Is Overexpressed in Kidney Tissue from Lupus Nephritis Patients and Its Serum Levels Are Correlated with Systemic Lupus Erythematosus Disease Activity
  1. J.-M. Kim1,
  2. H.-J. Jeong1,
  3. S.-H. Kim1,
  4. S.-H. Park2
  1. 1Division of Rheumatology, Department of Internal Medicine, Dongsan Medical Center, Keimyung University School of Medicine, Daegu
  2. 2Division of Rheumatology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea, Republic Of

Abstract

Background Interleukin-21 (IL-21) has various effects on a number of immune cells including B cells, T cells, natural killer (NK) and NKT cells. One of the essential roles of IL-21 is to contribute to autoantibody production as a result of promoting hyperactivity of B cells. Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by pathogenic autoantibody production and systemic organ damage. A few studies have been conducted for investigating the contribution of IL-21 to the pathogenesis of murine SLE. However, only limited studies have been performed concerning the role of IL-21 in human SLE and the results are still controversial.

Objectives The aim of this study was to evaluate whether IL-21 participates in the pathogenesis of human SLE.

Methods Serum IL-21 levels were measured in SLE, osteoarthritis (OA) patients and healthy controls (HC). Serum IL-21 levels were analyzed for revealing the correlation with laboratory data or a disease activity index for SLE. Kidney tissues from patients with lupus nephritis and controls were used for evaluating the expression of IL-21 and IL-21R. Normal portions of human kidneys removed for renal carcinoma were used as normal controls.

Results Serum levels of IL-21 were increased in the patients with SLE as compared to the patients with OA or HC. Serum IL-21 levels of the patients with SLE were positively correlated with serum levels of IgG, the titers of anti–double-stranded DNA antibodies and the scores of SLE Disease Activity Index. SLE patients with low C4 concentrations had higher serum IL-21 levels than those with normal C4 concentrations. The expression of IL-21 was higher in renal tubular epithelial cells of the patients with lupus nephritis than in those of controls.

Conclusions This study reveals the association between IL-21 and disease activity in the patients with SLE. We also first demonstrate IL-21 expression in renal tissue of the patients with lupus nephritis. These findings suggest that IL-21 is critically implicated in the pathogenesis of SLE.

  1. Ettinger R, Kuchen S, Lipsky PE: Interleukin 21 as a target of intervention in autoimmune disease. Annals of the rheumatic diseases 2008, 67 Suppl 3:iii83–86.

  2. Herber D, Brown TP, Liang S, Young DA, Collins M, Dunussi-Joannopoulos K: IL-21 has a pathogenic role in a lupus-prone mouse model and its blockade with IL-21R.Fc reduces disease progression. Journal of immunology 2007, 178(6):3822–3830.

Disclosure of Interest None declared

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