title: Inflammation and intracranial aneurysms.
abstract: OBJECTIVE
  An intracranial aneurysm is an important acquired cerebrovascular disease that can cause a catastrophic subarachnoid hemorrhage. Despite modern therapy, most patients die or are left disabled as a direct result of a severe initial hemorrhage. The development of more effective treatment strategies depends on understanding the fundamental biology of cerebral aneurysms. The purpose of the present study is to determine whether inflammation or immunological reaction occurs in cerebral aneurysms.
  
  
  METHODS
  Aneurysm tissue was collected at the time of microsurgical repair from 23 unruptured and 2 ruptured aneurysms (25 patients) and compared with 11 control basilar arteries harvested at autopsy. Immunohistochemistry was used to localize complement (C3c, C9), immunoglobulins (IgG, IgM), vascular cell adhesion molecule-1, macrophages and monocytes (CD68), T lymphocytes (CD3), and B lymphocytes (CD20).
  
  
  RESULTS
  Complement (C3c, P < 0.0001; C9, P = 0.0017), immunoglobulin (IgG, P = 0.0013; IgM, P = 0.031), vascular cell adhesion molecule-1 (P = 0.0022), macrophages (CD68, P = 0.004), and T lymphocytes (CD3, P = 0.0004) were all frequently present in the wall of aneurysm tissue but were rarely identified in control basilar arteries. A few B lymphocytes (CD20, P = 0.41) were found in aneurysm tissue, but none were found in the basilar arteries.
  
  
  CONCLUSIONS
  Extensive inflammatory and immunological reactions are common in unruptured intracranial aneurysms and may be related to aneurysm formation and rupture.
authors.affiliation: Cerebrovascular Research Laboratory, Lerner Research Institute, The Cleveland Clinic Foundation 44195, Ohio, USA.
authors.forename: D
authors.initials: D
authors.lastname: Chyatte
authors.forename: G
authors.initials: G
authors.lastname: Bruno
authors.forename: S
authors.initials: S
authors.lastname: Desai
authors.forename: D R
authors.initials: DR
authors.lastname: Todor
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D001488:Basilar Artery / Q000276:immunology / Q000473:pathology / Q000601:surgery; D015932:Complement C3c / Q000378:metabolism; D003186:Complement C9 / Q000378:metabolism; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D002532:Intracranial Aneurysm / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D011379:Prognosis; D018746:Systemic Inflammatory Response Syndrome / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
chemical_list: D003186:Complement C9; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D019010:Vascular Cell Adhesion Molecule-1; D015932:Complement C3c