title: Increased serum levels of macrophage migration inhibitory factor (MIF) in patients with microscopic polyangiitis.
abstract: OBJECTIVE
  To test the hypothesis that macrophage migration inhibitory factor (MIF) is involved in the disease activity of systemic vasculitis.
  
  
  METHODS
  Patients with systemic vasculitis were divided into three groups based on the size of the affected vessels. Microscopic polyangiitis (MPA) was considered as small vessel vasculitis (SVV), polyarteritis nodosa as medium-sized vessel vasculitis (MVV), and giant cell arteritis and Takayasu arteritis as large vessel vasculitis (LVV). Sera from patients with systemic vasculitis and healthy individuals were collected, and MIF levels were measured using an enzyme-linked immunosorbent assay. Disease activity of vasculitis was assessed using the Birmingham Vasculitis Activity Score (BVAS).
  
  
  RESULTS
  Serum MIF levels were significantly higher in the vasculitis patients than in healthy individuals. Among the vasculitis patients, MIF levels were significantly higher in patients in the SVV group (median; 4161.7 pg/ml) than in the other groups (MVV; 1443.2 pg/ml and LVV; 1576.7 pg/ml). In patients with MPA, a positive correlation was observed between serum MIF levels and CRP levels and disease activity (BVAS). Notably, serum MIF levels were significantly diminished after clinical improvement.
  
  
  CONCLUSIONS
  Our findings suggest that MIF may have an important role in small vessel vasculopathy and serve as a useful serologic marker of MPA disease activity.
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Hirohito
authors: H
authors: Kanemitsu
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Mizuho
authors: M
authors: Matsunawa
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Kuninobu
authors: K
authors: Wakabayashi
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Michihito
authors: M
authors: Sato
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Ryo
authors: R
authors: Takahashi
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Tsuyoshi
authors: T
authors: Odai
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Takeo
authors: T
authors: Isozaki
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Nobuyuki
authors: N
authors: Yajima
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Yusuke
authors: Y
authors: Miwa
authors: Division of Rheumatology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan.
authors: Tsuyoshi
authors: T
authors: Kasama
keywords: cytokine; macrophage migration inhibitory factor; microscopic polyangiitis; systemic vasculitis