title: Immunohistologic analysis of zygapophyseal joints in patients with ankylosing spondylitis.
abstract: OBJECTIVE
  Zygapophyseal joints of the spine are often affected in ankylosing spondylitis (AS). In this study, we undertook a systematic immunohistologic evaluation of the immunopathology of the zygapophyseal joints in patients with advanced AS.
  
  
  METHODS
  We obtained zygapophyseal joints from 16 AS patients undergoing polysegmental correction of kyphosis and from 10 non-AS controls (at autopsy). Immunohistologic analysis of the bone marrow was performed by analyzing the number of infiltrating T cells (CD3, CD4, CD8), B cells (CD20), osteoclasts (CD68), bone marrow macrophages (CD68), and microvessel density (CD34) per high-power field.
  
  
  RESULTS
  Zygapophyseal joints from 6 of 16 AS patients, but from none of the controls, exhibited 2 or more CD3+ T cell aggregates, signifying persistent inflammation. Interstitial CD4+ and CD8+ T cells were significantly more frequent in AS patients compared with non-AS controls (P = 0.002 and P = 0.049, respectively). While there was no clear difference between the number of CD20+ B cells in AS patients overall compared with controls, there was a significant difference when persistently inflamed joints from patients with AS were compared with joints without active inflammation from patients with AS or joints from controls (both P = 0.03). Microvessel density in bone marrow from AS patients with active inflammation was significantly higher than that in bone marrow from controls.
  
  
  CONCLUSIONS
  This immunohistologic study of bone marrow from zygapophyseal joints demonstrates persistent inflammation in the spine of patients with AS, including those with longstanding disease. The findings of increased numbers of T cells and B cells and neoangiogenesis suggest that these features play a role in the pathogenesis of AS.
authors.affiliation: Charité Berlin, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: Heiner
authors.initials: H
authors.lastname: Appel
authors.forename: Maren
authors.initials: M
authors.lastname: Kuhne
authors.forename: Simone
authors.initials: S
authors.lastname: Spiekermann
authors.forename: Harald
authors.initials: H
authors.lastname: Ebhardt
authors.forename: Zarko
authors.initials: Z
authors.lastname: Grozdanovic
authors.forename: Dorothee
authors.initials: D
authors.lastname: Köhler
authors.forename: Marc
authors.initials: M
authors.lastname: Dreimann
authors.forename: Axel
authors.initials: A
authors.lastname: Hempfing
authors.forename: Martin
authors.initials: M
authors.lastname: Rudwaleit
authors.forename: Harald
authors.initials: H
authors.lastname: Stein
authors.forename: Peter
authors.initials: P
authors.lastname: Metz-Stavenhagen
authors.forename: Joachim
authors.initials: J
authors.lastname: Sieper
authors.forename: Christoph
authors.initials: C
authors.lastname: Loddenkemper
mesh_terms: D015703:Antigens, CD / Q000032:analysis*; D001175:Arthrography; D001344:Autopsy; D017252:CD3 Complex / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D012016:Reference Values; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging / Q000276:immunology* / Q000473:pathology* / Q000601:surgery; D013601:T-Lymphocytes / Q000276:immunology*; D021801:Zygapophyseal Joint / Q000276:immunology* / Q000473:pathology*
chemical_list: D015703:Antigens, CD; D017252:CD3 Complex